Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe © 2023 The International Bank for Reconstruction and Development/The World Bank 1818 H Street, NW, Washington, DC 20433 Telephone: 202-473-1000; Internet: www.worldbank.org All rights reserved This volume is a product of the staff of the World Bank Group. The findings, interpretations, and conclusions expressed in this volume do not necessarily reflect the views of the Executive Directors of World Bank Group or the governments they represent. The World Bank Group does not guarantee the accuracy of the data included in this work. The boundaries, colors, denominations, and other information shown on any map in this work do not imply any judgment on the part of World Bank Group concerning the legal status of any territory or the endorsement or acceptance of such boundaries. Rights and Permissions The material in this publication is copyrighted. 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Other photos are property of the World Bank Group Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe Table of Contents Acronyms and Abbreviations X Glossary of Key Terms XII Acknowledgments XIII Key Messages and Recommendations XIV 1. Introduction 1 1.1 Background 1 1.2 Study Objectives 1 1.3 Structure of the Report 2 2. Selection of the Focal Landscape 5 2.1 Overview 5 2.2 High-Service Provision Areas 5 2.3 High Degradation Areas 6 2.4 Selection of Focal Landscape 7 3. The Mazowe Catchment Area 11 3.1 Topography, Drainage and Climate 11 3.2 Geology, Vegetation and Land Cover 12 3.3 Administrative Areas, Land Tenure, and Protected Areas 14 3.4 Population 16 3.5 Livelihoods and Socioeconomic Status 17 3.6 Water Supply 19 4. Ecological Trends, Drivers, and Impacts 21 4.1 Overview 21 4.2 Ecological Status and Trends 22 4.3 Key Drivers 27 4.4 Implications for a Future Under Climate Change 32 5. Ecosystem Services, Beneficiaries and Value 37 5.1 Overview of Concept, Key Services, and Beneficiaries 37 5.2 Provisioning Services 38 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe V 5.3 Cultural Services 45 5.4 Regulating Services 48 5.5 Summary of Ecosystem Values and Their Beneficiaries 56 6. Enhancing the Asset Value of the Mazowe Landscape: A Scenario Analysis 61 6.1 Overview 61 6.2 Potential Management Actions 61 6.3 Potential Measures to Bring About Sustainable Practices 67 6.4 Scenario Analysis 70 Conclusions and Recommendations 81 References 84 Appendix 1: Selection of the Focal Landscape: Detailed Methods and Results 96 Methodology 96 Detailed Results 98 Appendix 2: Rural Livelihood Zones in Mazowe Catchment 102 Appendix 3: Land Cover Accounts 104 Appendix 4: Assessment of Land Degradation 107 Appendix 5: Methods for Quantifying and Valuing Ecosystem Services 108 Harvested Wild Resources 108 Ecosystem Inputs to Crop Production 108 Ecosystem Inputs to Livestock Production 109 Tourism Value 109 Carbon Storage 109 Flow Regulation 110 Sediment Retention 111 Appendix 6: Relative Future Potential for Maize and Sorghum 114  enefits and Costs of Sustainable Landscape Investments in the Appendix 7: B Subcatchments 115 VI Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe List of Tables 1 Candidate Priority Landscapes for Consideration for Deep-Dive Assessment of Ecosystem Services Benefits and Tradeoffs Relating to Landscape Management Investments 8 2 Estimated Production of 10 Major Food and Cash Crops in the Mazowe Catchment 39 3 Estimated Value of Crop Production Based on Gross Revenue and Gross Margin, Assuming a 15 Percent Profit Margin 41 4 Estimated Populations of Cattle, Goats, and Sheep in the Mazowe Catchment and the Aggregated Number of TLUs 42 5 Estimated Value of Livestock Production, Expressed in Terms of Sales Revenue and Gross Margin (US$ Million Per Year, Latter Includes the Value of Ploughing, Manure, and Milk Production for Communal Areas) 43 6 Estimated Quantities and Values of Subsistence Harvesting of Selected Natural Resources in the Mazowe Catchment. Per Hectare Harvesting Values are Based on the Total Area of Natural Habitats in the Catchment, as Stocks of Harvested Resources Were Restricted to Natural Habitats Only 44 7 Estimated Quantities and Values of Subsistence Harvesting of Selected Natural Resources in the Mazowe Catchment Across Different Natural Habitats 45 8 Total Aboveground and Belowground Carbon Storage Across the Mazowe Catchment 49 9 Average Quickflow and Net Infiltration Across Different Land Cover Types in the Mazowe Catchment 51 10 Estimated Sediment Export and Sediment Retention Across Different Land Cover Types Within Dam Catchment Areas of the Study Region, and the Estimated Value of the Service 57 11 Summary of the Current Values of Selected Ecosystem Services Assessed in This Study, in US$ Millions per Year 57 12 Summary of Baseline Ecosystem Services Value (US$ per ha) 58 13 Summary of Proposed Landscape Management Interventions and Their Relative Extents and Costs 70 14 Crop Production With Full Restoration of the Study Area and Changes Relative to the Baseline Situation 72 15 Present Value (PV) Costs and Benefits and ROI of the Landscape Interventions for Each Sub-Catchment and for Mazowe Catchment as a Whole (US$, millions, 25 years, 4.56 percent) 78 16 Present Value of Costs and Benefits of Landscape Interventions in Mazowe 79 17 Indicators Utilized for Provision of Ecosystem Services and the Beneficiaries of Services 97 18 Metrics Utilized as Land and Water Degradation Indicators 97 19 Description of the Four Main Rural Livelihood Zones That Occur Within the Study Area 102 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe VII 20 Changes in Extent in Land Cover Classes Between 1992 and 2018 in Mazowe Catchment 105 21 Land Cover Change Matrix for Mazowe Catchment Showing Land Cover Change Pathways Between 1992 and 2018 106 List of Figures 1 Results of the National Screening Analysis of Five Key Ecosystem Services: Food, Erosion Control, Water, Carbon, and Ecotourism, and Their Potential Beneficiaries 6 2 Results of the National Screening Analysis of Five Key Ecosystem Services: Food, Erosion Control, Water, Carbon, and Ecotourism, and Their Potential Beneficiaries 6 3: Comparison of Areas in Top 50 Percent of Land and Water Degradation Indexes (Left) With Land Productivity Dynamics Results from the UNCCD LDN Study (Right) 7 4 Selected LDN Hotspots, Identified by the Ministry of Environment, Water and Climate 9 5 The Location and General Topography of the Mazowe Catchment 12 6 Habitats, Including Land Cover and Vegetation Types in the Mazowe Catchment 13 7 Provinces and Districts Intersecting the Mazowe Catchment. Districts are Labelled 14 8 Land Tenure in the Mazowe Catchment 15 9 Population Density of Mazowe Catchment 16 10 Livelihood Zones in the Mazowe Catchment 17 11 Areas of Tall Tree Canopy Cover (Trees > 5m Height) Loss Between 2001 and 2020, Shown by Year in Yellow-Red Scale, Superimposed on a Map of Tree Canopy Cover as 2010 23 12: Loss of Tall Tree Cover and Associated Gross Greenhouse Gas Emissions in Mazowe Catchment Between 2001 and 2020 (for Vegetated Areas With 30 Percent Canopy Cover or More) 23 13 Mazowe Sub-Catchments and the Percentage of the Total Area That Has Been Classified as Having Lost Tall Tree Cover Between 2001 and 2020 24 14 Primary Productivity Trajectory in the Period 2001–2017 on a Scale From Significant Increase to Significant Decline in Productivity as Well as Areas of Relative Stability 25 15 Lantana (L. Camara) and Prickly Pear (Opuntia spp.) Distribution and Extent Across Zimbabwe 27 16 Satellite Image Showing the Subsistence Farming Area Adjacent to the Nyadire River in the Mazowe Catchment 28 17 Changes in Population Between 2000 and 2020, Expressed in Terms of Change in the Number of People per km2 31 18 Estimated Aggregate Production of the Ten Major Crops Across the Mazowe Catchment (Grey Represents Non-Farmland Pixels) 40 19 Map of Livestock Densities (Expressed in TLU Terms) Across the Mazowe Catchment 42 20 Total Value of Selected Harvested Wild Resources (Wood, Thatching Grass, Wild Plant Foods, Mushrooms and Honey Across the Mazowe Catchment) 46 21 Estimated Tourism Value of the Mazowe Catchment in 2019 47 VIII Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 22 Carbon Biomass (Above and Below Ground) Across the Mazowe Catchment 50 23 Difference in Net Infiltration Between Current Land Cover and Bare Ground 53 24 Relationship Between Vegetation Density (as Indicated by NDVI) and the Concentration of Suspended Solids in Rivers in the Mazowe Catchment 55 25 Sediment Retention Across the Mazowe Catchment Relative to a Landscape Where All Cover Has Been Converted to Bare Ground 56 26 The Three Broad Interventions to Achieve Sustainable Use of the Mazowe Catchment Area That Derives Maximal Benefit From Its Ecological Capital and the Various Measures that Can Be Used to Achieve Them 62 27 An Example of a Heavily Cultivated Riparian Area Along the Mazowe River Near Glendale, With Minimal Riparian Vegetation Remaining 66 28 Changes in the Gross Margin of Crop Production at the Sub-Catchment Level With Full Restoration of the Study Area (Sub-Catchments Numbered on Map) 73 29 Changes in the Annual Value of Wild Resource Harvesting at the Sub-Catchment Level With Full Restoration of the Study Area, Relative to BAU (Sub-Catchments Numbered on Map) 74 30 Increase in Total Carbon Storage at the Sub-Catchment Level With Full Restoration of the Study Area, Relative to BAU (Sub-Catchments Numbered on Map) 75 31 Changes in Groundwater Recharge at Sub-Catchment Scale With Full Restoration of the Study Area, Relative to BAU (Sub-Catchments Numbered on Map) 76 32 Avoided Sediment Export to Dams at the Sub-Catchment Level With Full Restoration of the Study Area, Relative to the Baseline Landscape 77 33 ROI per Sub-Catchment With Implementation of the Proposed Landscape Interventions (Numbers Correspond With Sub-Catchment Numbers Used in Table 14) 80 34 Soil Retention by Vegetation (Left) and the Top Watersheds for Providing Sediment Retention Service in the Current Landscape (Right) 99 35 Water Yield (Left) and the Top Watersheds for Providing Water Flow Ecosystem Service in the Current Landscape (Right) 99 36 Total Aboveground and Belowground Carbon Storage in the Current Landscape (Left), and the Top Watersheds in Terms of Storing Carbon (Right) 100 37 NPP (Biomass), Used as a Proxy for Crop and Livestock Productivity 100 38 Protected Areas, Used as a Proxy for Ecosystem Services Relating to Ecotourism 100 39 Dams and Their Catchment Areas, Considered as Beneficiaries for Sediment Retention and Water Flow Ecosystem Services 101 40 Population, Considered as Direct Beneficiaries of Crop Production and Water Regulation Services 101 41 Number of Grazing Animals per Watershed, Considered as Beneficiaries of Biomass Production in Livestock Grazing Areas 101 42 FSR Values for Maize (Left) and Sorghum (Right) 114 43 Projected Future Yields of Maize (Left) and Sorghum (Right) Based on Adjustment of Current Yield by the Estimated Change in Future Suitability 114 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe IX Acronyms and Abbreviations AET Actual Evapotranspiration AGB Aboveground Biomass AMD Acid Mine Drainage ANR Assisted Natural Regeneration ASA Advisory Services and Analytics ASCC Annualized Social Cost of Carbon BAU Business-as-Usual BGB Belowground Biomass CA Conservation Agriculture CAMPFIRE Community Areas Management Programme for Indigenous Resources CBD Convention of Biodiversity CSA Climate-Smart Agriculture CSAIP Climate-Smart Agriculture Investment Plan CBNRM Community-Based Natural Resources Management CN Curve Number DEM Digital Elevation Model EMA Environmental Management Agency ESA European Space Agency FAO Food and Agriculture Organization FSR Future Suitability Ratio FTLRP Fast-Track Land Reform Programme GCF Green Climate Fund GDP Gross Domestic Product GEF Global Environment Facility GLW3 Gridded Livestock of the World GoZ Government of Zimbabwe GRanD Global Reservoir and Dam Database IAP Invasive Alien Plant InVEST Integrated Valuation of Ecosystem Service Tradeoffs LAI Leaf Area Index LDN Land Degradation Neutrality MAP Mean Annual Precipitation MAT Mean Annual Temperature MECTHI Ministry of Environment, Climate, Tourism and Hospitality Industry MLAFWRR Ministry of Lands, Agriculture, Fisheries, Water and Rural Resettlement NDVI Normalized Difference Vegetation Index NPP Net Primary Productivity NPV Net Present Value PES Payments for Ecosystem Services PUD Photo User Day PV Present Value ROI Return on Investment RUSLE Revised Universal Soil Loss Equation SADC Southern African Development Community SCC Social Cost of Carbon SDGs Sustainable Development Goals X Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe SDR Sediment Delivery Ratio SWY Seasonal Water Yield TLU Tropical Livestock Unit UN United Nations UNICEF United Nations Children’s Fund UNCCD United Nations Convention to Combat Desertification UNFCCC United Nations Framework Convention on Climate Change WDPA World Database on Protected Areas WFP World Food Programme WWF World Wide Fund for Nature ZINWA Zimbabwe National Water Authority ZPWMA Zimbabwe Parks and Wildlife Management Authority ZTA Zimbabwe Tourism Authority Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe XI Glossary of Key Terms Biodiversity The variability among living organisms and the ecological complexes of which they are part. This includes variation within species, the diversity of species within ecosystems, and the diversity of ecosystem types in nature. Carbon Sequestration The process of capturing and storing atmospheric carbon dioxide. Catchment An area where water is collected by the natural landscape. Precipitation that falls in a catchment runs downhill into creeks, rivers, lakes, oceans, or into built infrastructure, such as reservoirs. In this document, the terms catchment and watershed are used interchangeably. Climate-Smart Agriculture A broad term for reforming agricultural practices to achieve a more productive, resilient, and low-emission agricultural sector. Conservation Agriculture A farming system that promotes minimum soil disturbance, maintenance of permanent soil cover, and diversification of plant species. Cost-Benefit Analysis A conceptual framework and tool used to evaluate the viability and desirability of projects or policies based on their costs and benefits over time. Discount Rate The interest rate used in discounted cash flow analysis to determine the present value of future cash flows. Ecosystem Services The benefits people obtain from the earth’s many life-support systems. The Millennium Ecosystem Assessment defines four categories of ecosystem services: provisioning, regulating, cultural, and supporting services. Groundwater Recharge Water added to an aquifer through the unsaturated zone after infiltration and percolation following any storm rainfall event. Land Degradation The reduction or loss in biological or economic productive capacity of the land resource base. Land Degradation Neutrality A state whereby the amount and quality of land resources necessary to support ecosystem functions and services remain stable or increase within specified temporal and spatial scales and ecosystems. Net Present Value (NPV) A calculation used to estimate the net benefit over the lifetime of a particular project. Net present value allows decision-makers to compare various alternatives on a similar time scale by converting all options to current dollar figures. A project is deemed acceptable if the net present value is positive over the expected lifetime of the project. Payments for Ecosystem A scheme where beneficiaries of ecosystem services compensate ecosystem managers Services (PES) (landowners or resource stewards) to change their practices, to secure those ecosystem services. This may involve desisting from damaging activities or adopting more expensive practices that are less damaging to the environment. Return on Investment A simple ratio of the gain from an investment relative to the amount invested. ROI is calculated by dividing net profit (current value of investment − cost of investment) by the cost of investment. Riparian Buffer Land occurring along watercourses and water bodies. For this study, it can be defined as the area within 30 m of the river channel. Sustainable Resource Managing the use and protection of natural resources in a way (or at a rate) which Management enables social, economic, and cultural well-being while ensuring these resources are sustained for future generations and any adverse effects on the environment are minimized. XII Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe Acknowledgments T his Technical Assistance report was funded by the Global Partnership for Sustainable and Resilient Landscapes (ProGreen), a World Bank Multi-Donor Trust Fund that supports efforts to improve livelihoods while addressing land and ecosystem degradation and biodiversity loss in a cost-effective manner to meet national and sustainable development goals. The analytical work embraces an integrated landscape approach in recognition that such approach fosters healthy ecosystems that provide essential ecosystem services and sustain livelihoods. Strategic direction for the study was provided by Holger Kray, (Practice Manager for Agriculture and Food Security, World Bank) Iain Shuker (Practice Manager for Environment and Blue Economy, World Bank) and Marjorie Mpundu (World Bank Country Manager for Zimbabwe). The effort was led jointly by Ademola Braimoh (Senior Natural Resources Management Specialist) and Enos Esikuri (Senior Environmental Specialist) working closely with Easther Chigumira (Senior Agriculture Specialist), Gibson Guvheya (Senior Climate Change Expert), Shylock Muyengwa (Digital Climate and Advisory Services Consultant), and Dipti Thapa (Agriculture Economist). The assessment of national focal ecosystem services was led by Adrian Vogl (Lead Scientist, Natural Capital Project, Stanford University and World Bank Consultant), while detailed assessment of ecosystem services in Mazowe catchment, including the identification, modelling, and economic analysis of potential landscape interventions was led by Jane Turpie, and supported by Luke Wilson, Gwyn Letley, and Joshua Weiss (Anchor Environmental Consultants, South Africa). Thanks to Stella Ilieva, Francisco Obreque, Urvashi Narain, Stephen D’Alessandro, Maurice Rawlins, and Fadzai Mukonoweshuro, (World Bank) for their review and comments on an earlier draft of the report. The team wishes to acknowledge the following stakeholders for supporting the preparation of this analytical work: Edward Samuriwo (Director, Ministry of Environment, Climate. Tourism and Hospitality Industry, MECTHI), Takudza Makwangudze (Director, Engineering & Hydrology, ZINWA); Edson Gandiwa Director, ZIMPARKS; J. Gombe Manager, Research & Training Zimbabwe Forestry Commission; Arthur Musakwa Chief of Operations ZIMPARKS; Maxwell Maturure Manager, Environmental Planning & Monitoring, EMA; Freeman Gutsa Deputy Director, Strategic Policy Planning & Business Development, MLAWFRR. Rutendo Nhongonhema Chief Agronomist AGRITEX; Abednego Marufu General Manager Zimbabwe Forestry Commission; Veronica Jakarasi, (Manager, Climate, Finance & Sustainability Infrastructure Development Bank of Zimbabwe, IDBZ), Paul Zakariya (Secretary General Zimbabwe Farmers Union, ZFU), and Prince Kuipa (Executive Director, ZFU). We also acknowledge the support provided by Zondiwe Chiripamberi (Executive Assistant), Cheryl Khuphe (Communications Specialist), Priscilla Mutikani (Program Assistant), and Hope Murombwi (Program Assistant) for the entire duration of the study. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe XIII Key Messages and Recommendations Understanding the value of ecosystems is key to Zimbabwe’s future 1. Valuing ecosystem services is an important step in devising interventions to achieve sustainable livelihoods and climate resilience. The services provided by healthy ecosystems are essential for supporting life. Their loss would have a disproportionately large impact on developing countries. Zimbabwe is highly dependent on natural resources and related sectors for livelihoods and economic growth. However, the country is experiencing high levels of land degradation, which threatens the very resource base on which most of the nation’s population depends. Already, land degradation costs up to 6.3 percent of the country’s gross domestic product (GDP) annually, and this will worsen with climatic change. It is also heavily dependent on its groundwater, which is highly vulnerable relative to other African countries. 2. Zimbabwe has committed to addressing land degradation and has recognized the need to better understand and invest in its biodiversity economy. Zimbabwe is a signatory to several multilateral agreements concerning land degradation, biodiversity conservation, and climate change. It is also embarking on natural capital accounting as a means to more accurately assess and monitor the impact and dependence of economic activity on natural resources. Understanding the drivers and value of ecosystems is key to Zimbabwe’s future 3. Zimbabwe is one of the climate change hotspots in Southern Africa, whereby large adverse impacts of climate change are predicted to coincide with a preponderance of poor people who are least able to cope. The country ranks 174 out of 182 countries in the 2019 ND-GAIN Index, which indicates a greater vulnerability and reduced capacity to adapt to climate change. Observed climate change over the last three decades attests to a heightened frequency of extreme-weather events particularly droughts, flooding, late-onset and early-cessation rainfall, severe winds and tropical cyclones, and increased crop and livestock diseases. A recently revised agro-ecological map for Zimbabwe shows that the drought prone regions (IV and V) have become drier and increased in area at the expense of the major food producing regions (II and III). Global climate-change models (CGMs) predict with reasonable confidence that Zimbabwe is trending towards more arid (hotter) climatic conditions in the future. There is however a wide variation across climate projections on rainfall, with some GCMs projecting a wetter climate especially in the north-eastern regions. These predictions will likely increase evapotranspiration, and crop and livestock stress as well as pests and diseases of concern for both human and animal health expanding to previously non-endemic regions. These factors will conspire to reduce agricultural and ecosystem productivity. The World Bank is supporting Zimbabwe to sustainably manage the ecosystem services provided by critical landscapes 4. This study forms part of the technical assistance that the World Bank is providing on ecosystem services and landscape interventions in Zimbabwe. The work is being carried out with financing from the Global Partnership for Sustainable and Resilient Landscapes (ProGreen). The objective of the study is to generate the evidence base for the development of a scaled-up, integrated biodiversity and sustainable production landscapes investment XIV Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe project in the area. Targeted funding sources include ProGreen, the Global Environment Facility (GEF), and the Green Climate Fund (GCF). 5. The Mazowe Catchment was selected as a key area for intervention in Zimbabwe. A national screening assessment was undertaken to rapidly identify areas in Zimbabwe providing a high level of key ecosystem services as well as areas experiencing or at risk of significant land degradation. This assessment expanded on and added granularity to previous mapping of ecosystem services under the Land Degradation Neutrality Framework of the United Nations Convention to Combat Desertification (UNCCD). The national screening identified several candidate focal landscapes for more detailed assessment, including the 40,000 km2 Mazowe Catchment north of Harare, which was estimated to provide a high level of ecosystem services and thus good opportunities for conserving and enhancing service provision. Drawing on the findings of the national-level screening assessment, the selection of the Mazowe Catchment as a focal landscape was undertaken by the government, considering its local knowledge of the candidate areas. 6. The main outputs of the study are 1) An analysis of the ecological status and trends of the Mazowe Catchment and a high-level assessment of the drivers of environmental degradation; 2) Methods for quantifying and valuing ecosystem services in the Mazowe Catchment that can be used in ecosystem services accounting going forward and that can be scaled up to the other catchment areas of Zimbabwe; 3) Estimation and spatial mapping of the benefits of a range of provisioning, regulating, and cultural ecosystem services; and 4) Quantification of the benefits and return on investment (ROI) of implementing sustainable land management and conservation-focused interventions. KEY MESSAGE 1. Productive natural ecosystems in the Mazowe Catchment are being lost and degraded by poorly planned and managed commercial and small-scale livelihood activities, and threats will be further exacerbated by climate change. 7. The study area lost over 1,100 km2 of its dense woodland and over 400 km2 (90 percent) of its wooded grassland, mostly to dryland cultivation, in the last 25 years (1992–2018). About 594 km2 of forest and woodland (above 10 percent tree cover) experienced a loss of tree cover between 2001 and 2020. Some 9 percent of remaining natural areas have experienced significant losses in productivity between 2001 and 2017. 8. Cultivation, fuelwood harvesting, mining, and invasive alien plants (IAPs) are the main causes of degradation. Expanding cultivation is driven by the growth of the rural population and the reliance on extensification as the main strategy for increasing food production. Land scarcity and poor land management practices mean erosion rates from farmlands are often high, particularly in communal areas, contributing to water quality and sedimentation issues. Population pressure has also increased the harvesting of firewood and other natural resources and worsened grazing pressure on the increasingly small areas of remaining grazing land. The study area has high incidences of veld fires, often started to stimulate grass growth for livestock at the end of the dry season or to clear land for cultivation. Fires cause further degradation of natural habitats, which significantly increases erosion rates at the start of the rainy season. In addition, commercial and artisanal mining have a serious impact on surface and groundwater quality and add to the sedimentation issues arising from farming practices. In addition, catchment productivity is seriously affected by the invasion of lantana, alien grasses, and water weeds. 9. The underlying drivers include poverty, population growth, and lack of secure property rights. High poverty levels and limited economic opportunities mean most inhabitants have limited options, making their living off the Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe XV FIGURE E1: PRIMARY PRODUCTIVITY TRAJECTORY IN THE PERIOD 2001–2017 ON A SCALE FROM SIGNIFICANT INCREASE TO SIGNIFICANT DECLINE IN PRODUCTIVITY AS WELL AS AREAS OF RELATIVE STABILITY Data source: Conservation International 2018. Note: This excludes agricultural and other modified land cover (shown in grey). land through any opportunities that arise, legal or illegal. Poverty leaves households in a position of having a very short time horizon, in which the need for immediate survival obscures any need to plan for a sustainable income. Poverty is also a driver of high fertility rates and population growth. This becomes a problem in situations where land and resources are finite. Problems associated with mining are also linked to poverty and the country’s economic collapse. Informal artisanal mining (both alluvial panning and reef mining) is not regulated by any legislation, and has become a critical, if not the largest, source of income for many households. In addition to population pressure, tenure insecurity is another underlying driver of poor land management, particularly in areas resettled during the Fast-Track Land Reform Programme (FTLRP), where perceived tenure security is lower, discouraging investments in sustainable land management. 10. Climate change will directly affect ecosystem condition and services and will indirectly increase existing pressures. Climate change could contribute to significant reductions in crop yield due to greater heat stress and more erratic rainfall patterns. Climate change is expected to reduce groundwater recharge and surface runoff in the Mazowe Catchment. Although this is expected to be moderate relative to other areas in Zimbabwe, water availability for agriculture and domestic use will be negatively affected by increased evaporation losses and unreliable rainfall patterns. Degradation of ecosystems in the study area is already compromising water security, food security, human health, and livelihoods. Climate change puts pressure on ecosystems in the same direction. If the drivers of degradation are not addressed through climate-resilient landscape management interventions, the population of the Mazowe Catchment could face catastrophic consequences under future climate conditions. XVI Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe KEY MESSAGE 2. The services supplied by natural ecosystems are broader and more valuable than the agricultural production value of cultivated areas. 11. Cultivated areas contribute a gross margin value of US$68 million per year, mostly from maize and tobacco. The Mazowe Catchment is a key region for agriculture in Zimbabwe, particularly the southwest, which contains some of the best areas for crop production in the country. The catchment accounts for over 20 percent of national production of most crops, despite covering just 10 percent of Zimbabwe’s area. Maize and tobacco account for the bulk of this value, reflecting the areal dominance of maize and the high value per ton of tobacco relative to other crops. About 127 km2 of timber plantation are also supported in the study area. 12. The remaining natural areas support a range of provisioning, regulating, and cultural ecosystem services that provide current and potential benefits to local farmers and villagers, to the tourism sector, water utilities, and to Zimbabwean society as a whole. The provisioning services include ecosystem inputs to livestock production and harvested wild resources. Regulating services are the functions that ecosystems and their biota perform that benefit people in surrounding or downstream areas or even in distant areas. In this assessment, quantified and valued regulating services include avoided climate change costs attributable to land-based carbon storage, regulation of flows and groundwater recharge, and soil erosion and sedimentation control. The value of tourism (a cultural service) was also assessed. Together, these services alone provide benefits of over US$429 million to Zimbabweans annually, over three times the combined value of crop and livestock production in the catchment. 13. Ecosystem inputs to livestock are estimated to be US$65 million per year. The catchment has relatively high populations of cattle, due to its large rural population and the socioeconomic importance of cattle for rural households. 14. Wild resource harvesting is estimated to be worth at least US$106 million per year. Modelling of harvested wild resource use was based on (a) the capacity of the landscape to supply different types of resources and (b) the spatial distribution of the human demand for a given resource. A further factor considered is accessibility, with resources in protected areas assumed to be less available for harvesting. Five key harvested wild resources were modelled: wood, thatching grass, wild plant foods, mushrooms, and honey. Due to data limitations, our estimate excludes medicinal plants. Miombo woodland was estimated to have particularly high values for resource harvesting. 15. Rural tourism attractions in the Mazowe Catchment were estimated to generate about US$43 million in 2019 or 4.6  percent of national attraction-based tourism (that is, excluding expenditure on business tourism, visiting friends and family, and so on). Most of this value (US$36 million) is derived from natural ecosystem areas (as opposed to cultivated/planted areas or human settlements). The area includes Umfurudzi Safari Area and part of Nyanga National Park, as well as popular hiking spots such as Domboshawa. 16. Maintaining natural ecosystem cover in the study area saves about US$250 million per year in water supply costs. Vegetation cover mediates the infiltration of rainfall into the ground, which later emerges at springs to join streams and rivers (‘baseflow’) or replenishes groundwater or aquifers (‘groundwater recharge’). Of these flow regulating functions, groundwater recharge is estimated to be particularly important in the study area, estimated to be worth US$84 million per year. Vegetative cover also supports water supply by reducing erosion and trapping sediments. Erosion rates in the Mazowe Catchment are relatively high, particularly from degraded natural habitats and communal farmland, causing serious reservoir sedimentation issues in parts of the study area. Sediment retention by the landscape was estimated to be worth US$166 million per year in terms of dredging cost savings. 17. Maintaining the remaining forest cover avoids billions of dollars of global climate change damages and offers a potential source of income for Zimbabwe. Degradation and loss of natural habitats releases CO2 into the atmosphere. While much of the Mazowe Catchment has low biomass due to historical conversion of natural habitat to agriculture, settlement, mining, and other uses, there are some notable areas of woody natural habitats remaining. This includes Umfurudzi Safari Area and densely wooded hilly terrain in the extreme northeast of the catchment. The landscape is currently storing about 31.7 tons of carbon per ha as aboveground and belowground biomass, resulting in avoided climate change-related losses of economic output to the world worth US$1.23 billion per year. This offers a potential source of income for Zimbabwe, which is explored in the scenario analysis. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe XVII SUMMARY OF THE CURRENT VALUES OF SELECTED ECOSYSTEM SERVICES ASSESSED IN THIS TABLE E1:  STUDY, US$, MILLIONS PER YEAR Types of services Explanation Value to whom Value per year (US$, millions) Wild resources Value of wild harvested foods, fuel, Rural households 105.7 and raw materials net of human inputs Cultivated production Production value net of human inputs Communal farmers 38.0 Commercial farmers 30.2 Livestock production Production value net of human inputs Communal farmers 43.1 Commercial farmers 21.6 Sediment regulation Cost savings due to vegetation capacity Water utilities and private dam owners 166.3 to hold soil in place or trap eroded soils before entering streams Flow regulation (baseflow Cost savings in water resources Water utilities and/or direct water users 83.9 and groundwater) infrastructure due to facilitation of recharge by vegetation Tourism Net income generated as a result of Tourism sector 42.9 tourism to natural attractions Carbon retention Avoided climate change damages as a Zimbabwe 30.0 result of avoided CO2 emissions from Rest of world 1,230.0 ecosystem degradation KEY MESSAGE 3. Public investment to scale up sustainable landscape management will make economic sense with every $100 invested in landscape management generating $170. FIGURE E2: THE THREE BROAD INTERVENTIONS TO ACHIEVE SUSTAINABLE USE OF MAZOWE CATCHMENT AREA Extension services Land rights and & concessional governance and loans Climate-smart agriculture Investments in alternative energy Tradeable grazing and resource rights Formal protection, Restoration and enforcement Sustainable protection rangeland of key Certification management ecological schemes infrastructure Government restoration programmes Community conservancies & Stewardship, joint venture partners Payments for ecosystem services XVIII Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 18. Conservation and sustainable landscape management practices are needed to sustain the livelihoods and economy of the catchment. Currently, the benefits from the landscape are being undermined by environmental degradation, often for short-term gains such as the expansion of low-yielding agriculture or mining. Several interventions are needed to address and reverse this trend, to sustain these benefits into the future and to improve the local inhabitants’ resilience to climate change. 19. Interventions to maintain soil, vegetation cover, biodiversity, and agricultural productivity are mutually supportive and include supporting, regulating, and/or incentivizing (a) climate-smart agriculture (CSA) practices which increase the productivity of land and reduce rates of land conversion, soil loss, and water consumption; (b) limiting the use of grazing and wild resources to sustainable levels to maintain their productivity as well as other services; and (c) restoring and protecting key natural areas and their biodiversity to capitalize on their regulating and cultural services. Key natural areas include important wildlife habitat and natural riparian corridors that contribute to water security and play a key role in maintaining wild populations in the landscape. 20. The choice of policy measures to achieve these results depends on how critical the outcome is, the relative costs and benefits to the actors versus the rest of society, and who the beneficiaries are. Because CSA interventions are favorable for farmers, they may only need financial and technical assistance in the start-up phase. There are various incentives that can encourage farmers to adopt Climate Smart Agriculture (CSA) practices. Financial incentives such as subsidies for climate-resilient seeds, providing support for agroforestry and other practices that sequester carbon and promoting the adoption of rain harvesting and soil water conservation can motivate farmers to implement CSA practices. Training farmers on CSA practices, providing access to extension and agronomic advisory services, and providing support with marketing CSA products are additional strategies that can help incentivize farmers to adopt CSA practices. Educating farmers about the benefits of CSA can also raise awareness among policymakers and the public and increase its adoption. Lastly, ensuring easy access to CSA input and output markets can further improve its uptake. 21. Curbing the unsustainable use of rangelands, trees, and wild resources and encouraging practices to allow their recovery requires stronger and ongoing regulation and/or incentives. These can include payments for ecosystem services (PES) and supporting measures such as the planting of woodlots and/or investment in alternative or more efficient energy sources. Provision of secure land tenure and resource rights, for example, through conservancy establishment, could be a powerful incentive for the sustainable management of natural resources as well as a lever of private sector conservation funding. 22. While conservation actions will take a number of years to bear fruit, economic analysis shows that this is worth doing. The impact of conservation actions on ecosystem service values was compared to a business-as- usual (BAU) scenario in which further catchment degradation occurs. It was estimated that the increase in natural resource stocks from the full restoration of riparian buffers and degraded natural habitats could eventually increase the value of wild resource harvesting by US$3.5 million per year relative to BAU. These interventions, along with the increased uptake of soil carbon through conservation tillage, could also sequester carbon worth at least US$13.5 million per year, using a conservative estimate of the price of carbon on the voluntary carbon market. Despite the reduction of cropland in riparian areas, CSA interventions could increase small-scale crop production by US$21.1 million per year or 9.5  percent. The proposed interventions would collectively increase groundwater recharge by 4.5  percent, worth around US$11.8 million per year in terms of water supply. Improved erosion and sedimentation control arising from these interventions could reduce erosion across the catchment by 48  percent and sediment export to dams by 62 percent relative to BAU. This results in cost savings of US$10.2 million per year in avoided sediment control costs in reservoirs. Erosion from communal farmland would be roughly halved, bringing erosion rates closer to tolerance levels. Overall, well-implemented restoration and conservation interventions could produce benefits that outweigh their costs. The NPV over 25 years is estimated to be US$288 million, with an ROI of 1.7 over the Mazowe Catchment as a whole. Notably, ROI exceeds parity in all but 2 of the 17 sub-catchments, with the highest ROI of 3 in sub-catchment #5 (Figure I). At the subcatchment level, investment costs are primarily driven by the size of subcatchments, the extent of land degradation of the subcatchments, land cover types, Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe XIX FIGURE E3: ROI PER SUB-CATCHMENT WITH IMPLEMENTATION OF THE PROPOSED LANDSCAPE INTERVENTIONS Data source: This study. and the type of sustainable land management investment relevant for a given subcatchment. On the other hand, ecosystem services benefits at the subcatchment level are driven by positive changes in land resources management following CSA adoption, availability of water resources, presence of intact forests and wetlands, and presence of high biodiversity within the ecosystem. Six sub-catchments have an ROI of 2 or greater, suggesting interventions would be most cost-effective in these parts of the study area. Key recommendations of the study 23. This study has shown that degradation in the Mazowe Catchment is increasing, and this will undermine not only biodiversity but the well-being of its inhabitants and of Zimbabweans in general. It is clear that the environmental issues in the catchment need to be addressed. The study has also identified the priority areas for intervention. However, there are several information gaps that also need to be addressed in moving forward. Bearing this in mind, and the fact that similar issues are threatening livelihoods and the economy across the country, the key recommendations from this study are as follows. Support further adoption of CSA interventions following the recommendations of the Zimbabwe’s CSA 24. (a)  Investment Plan which aims to strengthen the country’s agriculture sector’s resilience to climate change. Priority investments recommended by the CSAIP include on-farm investments in improved crops, fertilizers, irrigation, and animal management to increase farmer production and build resilience; off-farm investments in XX Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe PRESENT VALUE OF COSTS AND BENEFITS OF TABLE E2.  LANDSCAPE INTERVENTIONS IN MAZOWE CATCHMENT $ million Costs 422.0 Restore degraded natural habitats 200.5 Establish conservancies 0.8 Implement climate-smart agriculture (50% adoption) 179.7 Install riparian buffers 41.0 Benefits 709.9 Avoided dredging (sediment) 107.8 Avoided dam costs (change in recharge) 125.0 Gains in wild harvested resources 21.1 Changes in agricultural production 258.7 Revenue from carbon credits 191.9 Tourism gains 5.2 Net present value 287.9 B:C ratio / ROI 1.7 ROI for Farmland interventions 1.44 ROI for natural land interventions 1.86 Duration is 25 years at 4.56%. storage, processing, marketing, and research & development to increase the agricultural value chain’s productivity and efficiency; and cross-cutting investments in land reform and water management to help the country realize its full agricultural potential. Enforce riparian protection. Government should act to enforce the already-existing laws prohibiting use of the (b)  riparian zone. Riparian protection is critical to landscape health and to the persistence of biodiversity across the landscape. This should include protection from in-stream mining activities as well as from agriculture and wood harvesting in the riparian zone. To enforce riparian protection, first there is a need to develop a riparian restoration plan to identify areas that needs ANR, those that can recover naturally, as well as the threats and drivers of degradation. A riparian restoration plan could also inform REDD financing opportunities. Second, develop the riparian zone as a resource to conserve biodiversity and increase tangible benefits to farmers. Third, there is a need to work with farmers and communities to develop local-level solutions and ownership Enable conservancy establishment. Zimbabwe has a comparative advantage in terms of its wildlife heritage (c)  and parts of the study area (as well as many other areas in Zimbabwe) still hold the potential for wildlife-based land use. The government needs to amend its policies and legislation to support the establishment of communal conservancies with land and resource rights that allow for commercially viable joint venture conservation- based business arrangements. Undertake strategic environmental assessments to inform proactive planning. Proper spatial planning (d)  is required to balance conflicting activities such as agriculture, mining, wildlife-based land uses, and the provision of ecosystem services to society. It is recommended that the government undertake detailed strategic environmental assessments for these different activities to plan where they should and should not be allowed to take place. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe XXI Improve and enforce environmental safeguards. Some of the threats to the study area, such as mining, (e)  are difficult to address because of combination of easy access, the promise of a quick return, and the lack of enforcement of environmental standards that would make the operations more costly. Such activities need to be closely regulated and need to involve the use of appropriately specified performance bonds that will fully cover the restoration of environmental damages. The internalization of these costs could go a long way toward addressing the environmental problems in the study area. Environmental safeguards should be set in place for all types of development. Invest in sustainable forest management. The high rate of deforestation observed in this study requires investment (f)  in sustainable forest management to maintain the health and integrity of forest ecosystems, conserve biodiversity, mitigate climate change, and provide livelihoods for communities that depend on forests. Investing in sustainable forest management will also help conserve ecosystem services, provide social and community benefits, and align development efforts with the growing trend of green investments and impact investing for a green economy. Key investments for consideration in this regard include reforestation and afforestation of severely degraded land, conversion, and passive reforestation of marginal agricultural land into silvo-pastoral systems for adapted livestock species or community conservancies, encouraging private investments in commercial forestry for all socioeconomic category of farmers down to smallholder commercial woodlots thereby enhancing household income diversification and resilience Design and pilot payments for ecosystem services (PES). The analysis has generated first-order evidence to (g)  support the design and implementation of two pilot schemes for payment for ecosystem services (PES) based on appropriate global examples. The first is sustainable landscape management to reduce land degradation and soil erosion on catchments of water-supply dams for urban settlements in Mazowe Catchment. Candidate urban settlements include Bindura, Murewa and Mutoko. The second is sustainable landscape management scheme to verifiably generate and sell carbon credits through carbon funds. A carefully selected catchment could include hard investments and governance arrangements to generate and sell carbon credits from an integrated combination of climate-smart agriculture, sustainable forestry management, biodiversity conservation and sustainable landscape management. 25. The private sector has a critical role to play in biodiversity conservation and sustainable landscape management in Zimbabwe by i) financing projects that contribute to the conservation, restoration, and sustainable use of landscape; and ii) directing financial flows away from projects with negative impacts on biodiversity and ecosystem services. However, government holds the key to harnessing the power of the sector to mobilize the needed private finance at scale to protect nature. Government can support the integration of biodiversity criteria in private sector decision making by adopting natural capital accounting and making relevant data available as public good. Second, environmental fiscal policy reforms that value natural capital can provide incentives for the private sector to co-invest in the sustainable use of natural resources and contribute toward net domestic resource mobilization. Third, government can drive the green transition by promoting policies such as greening the supply chain to drive changes in corporate behavior. Lastly, there is a need for multi-sectoral, people centered approach to natural resources management by ensuring the integration of natural capital consideration into planning, budgeting, implementation, and decision-making at the national and local levels will help build resilience. XXII Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 1. Introduction 1.1 Background to landscape management and land degradation, the United Nations Convention to Combat Desertification 26. Healthy ecosystems provide multiple, essential (UNCCD). The latter was ratified by Zimbabwe in services to life on the planet, such as water cycle 1997, leading to the production of the country’s regulation, carbon sequestration, and habitat for first National Action Plan to avoid and reduce land biodiversity. They also sustain livelihoods, providing degradation and restore degraded areas. In 2017, food, fuel, shelter, and jobs. However, the ecological Zimbabwe set ambitious land degradation neutrality integrity of landscapes is under significant and (LDN) targets in a bid to halt and reverse degradation increasing threat due to deforestation and land of cultivated areas and natural habitats and achieve degradation driven by land conversion for agriculture, LDN by 2030 (GoZ 2017). These targets include infrastructure, mining, and other activities and restoration of the tree cover of large areas of forest unsustainable management of natural resources. and woodland, conservation farming and agro-forestry on cropland, improved management and appropriate 27. Like most other African countries, Zimbabwe stocking rates to improve vegetation cover in sparsely has a largely rural population and a high degree vegetated lands, restoration of degraded wetlands, of dependence on natural resources and related and control of alien plant species (GoZ 2017). The sectors for livelihoods and economic growth country’s LDN commitments also include associated (ZIMSTAT 2019). Alarmingly, the country is considered measures such as improvement in the regulation of a land degradation and climate change hotspot. illegal mining, provision of alternative energy sources, These pressures are undermining the very resource expansion of the energy for the tobacco program, base on which most of the nation’s population and other important measures. depends. Land degradation has been particularly prevalent in the country’s densely populated 29. Valuing ecosystem services is an important step communal land areas, due to long-standing and in devising interventions to address land and worsening land shortage issues, unsustainable farming ecosystem degradation in the pursuit of practices and poor natural resource management sustainable livelihoods and climate resilience. practices, including excessive veld fires and a rise Through a detailed analysis of a selected landscape in in mining and gold panning activities. Already, land Zimbabwe, the Mazowe Catchment area, this study degradation costs up to 6.3  percent of the country’s highlights the value of existing ecosystems and the gross domestic product (GDP), with the impacts set potential value that can be gained through supporting to worsen under future climatic conditions (UNCCD effective landscape management interventions that 2018). Zimbabwe is also heavily dependent on its restore and maintain biodiversity and the supply of groundwater, which is also highly vulnerable relative ecosystem services. to other African countries. 28. Zimbabwe is a signatory to several multilateral 1.2 Study objectives agreements concerning land degradation, biodiversity conservation, and climate change 30. The objectives of this study were as follows: issues. This includes the Convention of Biodiversity (CBD); United Nations Framework Convention on Undertake a high-level spatial assessment of (a)  Climate Change (UNFCCC); and, of particular relevance selected ecosystem services and their beneficiaries Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 1 at the national scale to select a focal landscape 34. In Chapter 4: Ecological trends, drivers and impacts, for the study. the ecological pressures and trends in the study area are described as far as possible, based on available Undertake a desk assessment of ecosystem (b)  literature and analysis of satellite data. The chapter changes in the focal landscape over the last 30–40  years, the key drivers of change, and then postulates what the main drivers of ecosystem impacts on local livelihoods. change have been, based on the literature and expert input, and it summarizes some of the impacts that Estimate the value of ecosystem services of the (c)  these changes have had on the local population in focal landscape using a spatial approach. qualitative terms. Identify investment approaches and interventions (d)  that could restore degraded landscapes for 35. Chapter 5: Ecosystem services, beneficiaries, and conservation and production. value begins with an overview of the ecosystem services provided by different ecosystem types in the Assess and recommend possible governance/ (e)  study area and specifies the types of services that the institutional improvements to support improved study is focused on. Each of the selected services is landscape/ecosystem services management. then described, modelled, and mapped across the Mazowe landscape in physical terms, and its value 1.3 Structure of the report is estimated. A summary is provided of the value of each of these services to different beneficiaries in 31. The remainder of report is set out as follows: and beyond the study area. 32. Chapter 2: Selection of the focal landscape 36. In Chapter 6: Enhancing the asset value of describes the high-level spatial assessment of the Mazowe landscape: a scenario analysis, a selected ecosystem services and their beneficiaries range of potentially suitable interventions are that was undertaken at the national scale to inform identified, and a future implementation scenario the selection of a focal landscape for the study by is outlined. The impacts of this scenario are then government stakeholders. modelled and compared with the outcomes of a business-as-usual scenario. A high-level cost- 33. In Chapter 3: The Mazowe Catchment Area, benefit analysis is undertaken to identify which a detailed description of the geographical, ecological, areas should be prioritized for intervention. Finally, and socioeconomic characteristics of the Mazowe recommendations are made for the actions to follow Catchment area is provided as context for the study. this study. 2 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 2. Selection of the Focal Landscape 2.1 Overview will result in a strong case for the feasibility of any subsequent PES schemes in the selected landscape. 37. A screening assessment was performed at a 39. The screening analysis involved the collection of national scale to identify areas that provide a high spatial data that relate to ecosystem condition, level of five key services: food production, erosion including land cover, land productivity, soil types control, water regulation, carbon storage, and and extents, elevation and slope, and climate. In ecotourism potential. The assessment also evaluated addition, proxy data reflecting the users potentially where there are likely to be many beneficiaries benefitting from each service were collected and connected with those services and where recent systematized to reflect the degree of dependence on trends in land degradation are threatening to further ecosystem services. reduce the provision of these services. 40. Selecting a landscape that provides multiple 38. Having a transparent and data-driven process for benefits across sectors will serve to foster selecting the candidate landscape was considered opportunities for intersectoral collaboration on crucial to ensure that the government’s efforts are the topics of agro-ecology, climate resilience, and directed toward a geography where sustainable environmental management in subsequent work land management is likely to significantly affect under the Advisory Services and Analytics (ASA). the provision of (or access to) ecosystem services. PES programs are more likely to be durable when they deliver tangible benefits to payers, and such tangible benefits are more likely to result when activities are 2.2 High-service provision directed to the places where they are most effective. areas Selecting a priority landscape based on technical criteria derived from a national screening analysis 41. The following maps show high-level results of will help ensure that the final outputs of the study the national scale assessment of five ecosystem KEY POINTS • Landscape interventions can be fruitful in (a) areas where services are currently high and where there are a lot of people and other sectors depending on them or (b) where landscapes are currently degraded and not providing a high level of ecosystem services to people and other sectors who depend upon them. • High-service and high-value areas tended to be in the north and northeast of the country. • High degradation areas were widespread, but more in the central, south, and southeastern areas. • Seven candidate areas for intervention were identified. • Based on the broad assessment of ecosystem service values, degradation trends, and local knowledge of the study areas, government stakeholders in the Ministry of Lands, Agriculture, Fisheries, Water and Rural Resettlement (MLAFWRR) and Ministry of Environment, Climate, Tourism and Hospitality Industry (MECTHI) selected the Mazowe Catchment as the focal landscape for this study. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 5 FIGURE 1: RESULTS OF THE NATIONAL SCREENING ANALYSIS OF FIVE KEY ECOSYSTEM SERVICES: FOOD, EROSION CONTROL, WATER, CARBON, AND ECOTOURISM, AND THEIR POTENTIAL BENEFICIARIES Note: The number of services for which each watershed falls in the top 25 percent (left) and the number of beneficiaries that fall in the top 25 percent considering all services (right). services. Indicators for (a) the provision of each ecosystem services and (b) the number of beneficiaries depending on those ecosystem services were summed to the watershed level (see Appendix 1 FIGURE 2: RESULTS OF THE NATIONAL for details). SCREENING ANALYSIS OF FIVE KEY ECOSYSTEM SERVICES: FOOD, EROSION CONTROL, WATER, CARBON, AND ECOTOURISM, AND THEIR 42. The values represent the number of ecosystem POTENTIAL BENEFICIARIES services for which the watershed was in the top 25 percent, compared to all watersheds across the country; in other words, darker colors represent areas that provide the highest level of ecosystem services across all five services considered (food, erosion control, water, carbon, and ecotourism) and across all beneficiaries considered (people, dams, agriculture, livestock, and so on). 43. Figure 1 highlights the areas where ecosystem services are greatest (left) and where sectors are most in need of ecosystem services (right). Figure 2 puts the two together, showing watersheds that provide both a high level of ecosystem services and where sectors depend on those services the most. 2.3 High degradation areas 44. The next set of results focusses on historical trends Note: This map shows the overlap of ecosystem services and in land and water degradation, based on a trends benefit ‘hotspots’ - watersheds that provide the most services and analysis of remote sensing data on productivity where the most beneficiaries potentially rely on them. 6 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 3: COMPARISON OF AREAS IN TOP 50 PERCENT OF LAND AND WATER DEGRADATION INDEXES (LEFT) WITH LAND PRODUCTIVITY DYNAMICS RESULTS FROM THE UNCCD LDN STUDY (RIGHT) Source: Land Degradation Neutrality Report 2017. Note: Degradation indexes (left) are based on the slope of a 20-year trend analysis and indicate a high rate of loss of vegetation productivity (net primary productivity [NPP]), reduction in evapotranspiration, reduction in soil moisture and baseflow, and increasing surface runoff (source: this study). Land Productivity Dynamics (right) are based on data from the Environmental Management Agency. and water use by vegetation, baseflow, surface runoff, and soil moisture (see Appendix 1 for details). 2.4 Selection of focal Results from this study are compared with results from landscape the Land Degradation Neutrality Report (2017) of the Government of Zimbabwe (GoZ). It is clear that while 46. Table 1 presents a set of geographies that emerged some of the areas that are highlighted in Figures  1 from the national screening analysis as candidates and 2 are experiencing land degradation, the for further deep-dive analysis into the benefits, most acute degradation is happening in areas tradeoffs and potential feasibility of a PES program. Feedback from stakeholders in the MLFAWRR, where ecosystem service provision is relatively low MECTHI, and various environment and agriculture (Figure 3, left panel). Therefore, areas in Figure 3 that agencies (that is, Forestry Commission, Environmental show the highest degradation trends are those where Management Agency [EMA], Zimbabwe Parks ecosystem services may need restoration and recovery. and National Wildlife Authority [ZPWMA], Zimbabwe National Water Authority [ZINWA], Community Areas 45. The results also reveal a somewhat different Management Programme for Indigenous Resources pattern than the LDN study (Figure 3, right panel). [CAMPFIRE], and AGRITEX) was solicited to finalize Our analysis used remote sensing data, which reveal the selection of a focal landscape for the next phase patterns in water availability, runoff, and water use by of analysis. The proposed geographies fall into vegetation, as proxies for vegetation health. There is a three main categories: (a) those where ecosystem 51 percent agreement at the watershed level between services are currently high, but there are indications of watersheds with a higher-than-average degradation degradation; (b) those where ecosystem services are (from this study) and those with stressed or declining currently high with less acute threats of degradation; land productivity dynamics (from the LDN study), the and (c) those where ecosystem services are relatively current study results tend to highlight more areas in low, and degradation is acute. the central and eastern part of the country whereas the land productivity dynamics results are more 47. It is interesting to compare the results of this concentrated in the south. analysis with findings reported in the Land Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 7 CANDIDATE PRIORITY LANDSCAPES FOR CONSIDERATION FOR DEEP-DIVE ASSESSMENT OF TABLE 1:  ECOSYSTEM SERVICES BENEFITS AND TRADEOFFS RELATING TO LANDSCAPE MANAGEMENT INVESTMENTS No. Region or Associated district(s) Ecosystem services status and opportunity Degradation trend landscape Type I: Landscapes with high provision of ecosystem services, low to moderate degradation 1 Lower Zambezi Hurungwe Ecosystem services level = HIGH Low but stressed River Valley Opportunity to conserve and enhance existing (Hunyani high-quality ecosystem services in headwaters Catchment) draining into protected areas 2 Hwange-Sanyati Hwange*, Binga, Ecosystem services level = HIGH Low but stressed, Biological Corridor Kariba, and Gokwe moderate decline in Opportunity to conserve and enhance existing North some areas high-quality ecosystem services, scale up existing efforts, and protect headwaters 3 Mazowe Shamva*, Mount Ecosystem services level = HIGH Moderate decline in land Catchment Darwin, Rushinga, and water indicators Opportunity to conserve and enhance existing Mudzi, Murehwa high provision of ecosystem service Uzumba-Maramba- Pfungwe and Bindura Type II: Landscapes with moderate provision of ecosystem services, moderate to high degradation 4 Chimanimani Chimanimani Ecosystem services level = MODERATE Strong decline in land and water indicators Opportunity to enhance and improve ecosystem services in a productive landscape 5 Savé Valley Bikita, Chipinge, and Ecosystem services level = MODERATE Moderate decline in land Chiredzi and water indicators Opportunity to enhance and improve ecosystem services in a productive landscape Type III: Landscapes with low provision of ecosystem services, high degradation 6 Runde and Tokwe Zvishavane*, Insiza, Ecosystem service level = LOW, but high Steep decline in land River Catchments Shurugwi, Gweru, demand. and water indicators Chirumhanzu, Opportunity to restore services of erosion Masvingo, and Chivi* control, water regulation, and soil carbon in productive landscapes, and to benefit downstream dams 7 Umzingwani Gwanda, Umzingwane*, Ecosystem service level = LOW Moderate to steep and Thuli River Matobo, and Beitbridge* decline in land and Opportunity to restore services of erosion Catchments water indicators control, water regulation, and soil carbon in productive landscapes Note: *Districts included in the eight priority LDN hotspots identified for further investment in the GoZ’s Land Degradation Neutrality Report, August 2017. 8 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe Degradation Neutrality Report that the Ministry consistent with the LDN methodology. The other of Environment, Water and Climate released two (Hwange and Shamva) fall into Type I landscapes in 2017. That report highlighted areas where in this study: those with high ecosystem service land productivity is threatened from both natural provision and moderate declines. Because this drivers (for example, changing climate patterns) study focused specifically on ecosystem services and human-driven land degradation (for example, beyond land productivity (namely erosion control, spread of invasive alien species, gullies, illegal water regulation, carbon storage, and tourism mining, and poor land management). Eight priority potential) and incorporated the number and types LDN hotspots were identified for further investment of beneficiaries that depend on these services, our in the Shamva, Mhondoro, Chivi, Zvishavane, results (Table 1) highlight a broader set of landscapes Umzingwane, Hwange, Chikomba, and Beitbridge than those selected in the LDN report. districts (Figure  4). Note that six out of these eight districts also emerged from the current analysis 48. Based on the broad assessment of ecosystem as potential focal areas for this ASA (Table  1). service values, degradation trends, and local Four of these (Zvishavane, Chivi, Umzingwane, knowledge of the study areas, stakeholders from and Beitbridge) correspond with areas of low MECHTI and MLAFWRR selected the Mazowe ecosystem service provision and high degradation, Catchment as the focal landscape for this study. FIGURE 4: SELECTED LDN HOTSPOTS, IDENTIFIED BY THE MINISTRY OF ENVIRONMENT, WATER AND CLIMATE Source: GoZ 2017. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 9 3. The Mazowe Catchment Area 49. The capacity for an area to generate ecosystem Ruya, Ruenya, and Gairezi—join the main stem in services is highly related to its physical features Mozambique, about 40  km upstream of the Zambezi. and climate, while the value of these services The entire catchment has an area of 54,577 km2, relates in part to the way in which the area of which 39,857 km2 is within Zimbabwe. is populated, managed, and used. This section provides an overview of the biophysical characteristics 51. The catchment is relatively hilly and undulating. of the Mazowe Catchment area, the land tenure, Altitude ranges from almost 2,600  m at Mount population characteristics, livelihoods, and economy. Nyangani to 80  m at the Mazowe and Zambezi This provides the background information that confluence (Figure 5). informs the way in which people have changed the landscape and the way in which they depend on 52. The area has warm to hot, wet summers and cool its ecosystem services, which are described in the to mild, dry winters. The highest temperatures are subsequent chapters. in November to January, while July is the coolest month. Mean annual temperature (MAT) increases as altitude declines. The most southerly areas of the catchment have the lowest MAT, between 12°C and 3.1 Topography, drainage 15°C. The low-lying northeast parts of the catchment and climate have an MAT above 22°C. 50. The Mazowe River rises 14 km north of Harare and 53. Rainfall tends to be highest in January and lowest flows into Mozambique, where it joins the Zambezi in August. Mean annual precipitation (MAP) is also River (Figure 5). Its three main tributaries—the closely correlated with altitude, with the highest KEY POINTS • The Mazowe Catchment extends over roughly 40,000 km2 of northeast Zimbabwe. • Natural vegetation varies from miombo woodland in the wet upper reaches of the catchment to mixed Acacia- Terminalia woodland in the drier lower reaches, with small patches of montane forest and grassland in the Nyanga Mountains. • Extensive transformation of natural vegetation has occurred, with cultivation covering 33 percent of the catchment. • Prime agricultural areas in the southwest are mostly commercial farmland, many of which were resettled under the FTLRP. The north and east of the catchment mainly consist of communal land. • Around 2.3 million people live within the catchment, with an average population density of 58 people per km2. Around 93 percent of this population is rural. • Crop cultivation is the most important livelihood activity in the wet upper reaches of the catchment, while livestock is increasingly important in the drier lower reaches. • Numerous small to medium dams are located in the catchment, mostly on commercial farmland in the south and west. However, groundwater is the main water source for most of the area’s inhabitants. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 11 FIGURE 5: THE LOCATION AND GENERAL TOPOGRAPHY OF THE MAZOWE CATCHMENT Source: HydroRivers (Lehner and Grill 2013), Topography/Digital elevation model (Farr et al. 2007), Towns (https://www.openstreetmap.org/) rainfall in the catchment being around 1,000  mm per year. These areas experience among the highest 3.2 Geology, vegetation rainfall in Zimbabwe. The lowest parts of the catchment and land cover experience 620 mm of rainfall per year. 55. The catchment comprises predominantly primarily 54. Like the rest of Zimbabwe, significant changes in crystalline basement rocks that typically have climate are predicted for the Mazowe Catchment, a low permeability and porosity.1 Parts of the though the projected changes are not as severe area, particularly in the north, comprise basic as those predicted for the south and west of igneous rock of the greenstone belt, which is the the country (World Bank 2021). Mean annual oldest geology in the region. Most of the upper temperatures in the Mazowe Catchment could rise by and middle catchment area comprises intermediate around 2°C under the representative concentration igneous granitoid rocks while the lower catchment pathway (RCP) 8.5 emissions scenario. Changes is predominantly made up of acid metamorphic in precipitation are less certain, but modelling rock of the Orogenic belt. There are patches where projections suggest changes will be modest. However, schist and gneiss are the most dominant rocks higher temperatures in the absence of significant (Anderson et  al. 1993; FAO and ISRIC 2013; Wilson increases in precipitation will increase potential and Nutt 1990). evapotranspiration, resulting in greater heat and water stress. The likelihood of severe drought is also 56. Soils are predominantly shallow, greyish brown, expected to increase (World Bank 2021). coarse-grained sands, to similar sandy loams, 1 http://www.zinwa.co.zw/catchments/mazowe-catchment/ 12 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe over reddish browns and clay loams on granitic 58. The landscape has since been extensively rocks. The dominant soils within the catchment are transformed, with many areas having been cleared varied but luvisols, lixisols, arenosols, and cambisols for anthropogenic uses, resulting in a highly are the most widespread (Department of the Surveyor- fragmented landscape with few large, contiguous General 1979; FAO and ISRIC 2013). Soils are primarily areas of natural or near-natural vegetation between 100  cm and 150  cm deep with shallower (Figure 6). Cultivated land accounts for roughly soils in the Ruya and Ruenya/Rwenya river valleys. 33  percent of the study area. Most cultivation is Soil moisture is generally high across the catchment subsistence or small scale (ZIMSTAT 2019). There is (Mantel 1994). Only areas with shallower soils are irrigated cultivation adjacent to major rivers. considered to have a severe soil moisture deficit. 59. Towns such as Bindura and Mutoko, as well as the 57. Historically, the Mazowe Catchment was dominated outskirts of Harare and Marondera which are on by open miombo woodland, particularly in the the catchment watershed, account for the urban/ upper and middle reaches, while mopane shrubland built-up land cover which makes up less than and Acacia-Terminalia savanna occupied most of 1 percent of the total area. the lower reaches. Denser miombo vegetation was primarily found in the upper Mazowe sub-catchment 60. Although they occupy a relatively small surface east of Bindura, while there were fragments of area, there are several mines in the Mazowe indigenous forest in the Nyanga Mountains in the Catchment including some of Zimbabwe’s largest extreme southeast. The area includes many wetlands. mining operations (Chandiwana 2016). These FIGURE 6: HABITATS, INCLUDING LAND COVER AND VEGETATION TYPES IN THE MAZOWE CATCHMENT Source: Ecosystem (vegetation), types (Olson et al. 2001), and land cover (Buchhorn et al. 2020). Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 13 include Bindura Nickel Corporation, Trojan, Mazowe, (Mutami 2015). Plot sizes are small, with landholdings Ashanti, Arcturus, and Madziwa mines. The dominant typically 2 ha or less (Chimhowu and Woodhouse minerals mined in the catchment are nickel and 2008). Much of the south and west of the catchment gold (contained largely in the greenstone belt and consisted of large-scale private commercial farms extracted primarily through alluvial mining). before 2000. Under the FTLRP of 2000–2009, many of these farms were subdivided into small (±20 ha) A1 family farming units and medium-scale (±300 ha) A2 commercially oriented farming units (Moyo 2011; 3.3 Administrative areas, Scoones et al. 2011; Sukume, Mahofa, and Mutyasira land tenure, and 2022).2 The intensity of production of these farms varies, with some having converted to smaller-scale protected areas operations (Scoones et al. 2018).3 61. The catchment lies mainly within Mashonaland 63. Many of these areas still have insecure and East, Mashonaland Central, and Manicaland uncertain land tenure arrangements. For example, (Figure 7). Within these provinces, 15 rural districts fall A1 households cannot use their land as collateral inside the study area. security, which affects their access to credit (Mugabe et al. 2014). 62. Much of the area is under communal land tenure, particularly in the lower reaches (Figure 8). These 64. This, combined with other financial constraints and areas generally have lower rainfall and crop production limited agricultural training of the new tenants, FIGURE 7: PROVINCES AND DISTRICTS INTERSECTING THE MAZOWE CATCHMENT. DISTRICTS ARE LABELLED 2 A1 farms have individual family farm of 6 ha plus a common livestock grazing area (ZIMSTAT 2019). 3 Large-scale farms are said to have declined in area from 15.5 percent of the country’s surface area in 1980 to 3.4 percent in 2010 (Scoones et al. 2011). 14 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 8: LAND TENURE IN THE MAZOWE CATCHMENT Sources: GOZ-SADC-FANR (2003); UNEP-WCMC (2022). has often resulted in low crop production and dense settlements, grazing areas and crops (Muposhi underutilization of land, with many areas falling et  al. 2016) and has at least one commercial mine fallow (Godwin et al. 2011; Mugabe et al. 2014). within its boundary. The southern part of the A survey of Mazowe District estimated that 50 percent catchment includes part of the Nyanga National of resettled small-scale commercial farmland was Park, which protects areas of montane grassland, fallow in 2013. woodland, and small indigenous forest patches. Two state forest areas, York and Nyangui, also fall within 65. Nevertheless, A1 farmers now account for the southern part of the catchment. Although listed 26 percent of marketed maize and 41 percent as protected areas by UNEP-WCMC4, these areas are of registered flue-cured tobacco producers used primarily for plantation forestry production. (MoLAWFRR 2021; Sukume, Mahofa, and Mutyasira 2022; TIMB 2020). 67. There are also several wildlife management areas (WMAs). The mapped WMAs represent wards 66. The study area also contains some state-owned participating in CAMPFIRE, which helps communities to and communal conservation areas. The largest benefit from wildlife-related tourism activities such as protected area is the Umfurudzi Safari Area on the hunting. In Mazowe, the largest of these (Karamba, western side of the Mazowe River. This is the largest Chimukoko, and Mukota A) are in the relatively remote contiguous area of natural or near-natural land cover lowest parts of the catchment (Figure  8) and border in the study area (ESA 2017), but it is surrounded by the Nyatana Game Park, a community conservation 4 https://www.protectedplanet.net/ Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 15 area overseen by the three regional district councils (annual growth of approximately 15  percent) to of Mudzi, Rushinga, and Uzumba Maramba Pfungwe about 2.3 million (Bondarenko et al. 2020). This is just (Amon 2011). Other WMAs are Gairezi situated near under 17 percent of the country’s total population. Nyanga National Park and Masiyandima adjacent to Umfurudzi Safari Area. Although they are classified as 69. The average population density of the catchment protected areas, they function as multi-use landscapes is around 58 people per km2, with most areas rather than being strictly focused on biodiversity above 25 people per km2 and very few sparsely conservation. populated areas. The largest towns wholly within the catchment are Bindura, Mutoko, and Murewa, which had populations of around 46,000, 17,000, and 12,000 in 2012 (ZIMSTAT 2012). Notably, all of these towns 3.4 Population are located near or on one of the main rivers. These towns and the outskirts of Harare had the greatest 68. The Mazowe Catchment area, encompassing the population density increase from 2000 to 2020. outskirts of the capital city, Harare, and the nearby town of Marondera, is one of the most densely 70. Approximately 93 percent of the people living in populated regions of Zimbabwe (Figure 9). In 2000, the catchment area are in rural areas,5 with the the population of the catchment was approximately communal land areas being the most densely 1.58 million. By 2020, this had increased by 45 percent populated. FIGURE 9: POPULATION DENSITY OF MAZOWE CATCHMENT Source: WorldPop (Bondarenko et al. 2020) 5 Calculated using the number of people as per Bondarenko et al. (2020) dataset intersecting with land cover classified as anything aside from urban/built-up. 16 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 71. The main ethnic group and language in the study 73. Subsistence or small-scale farming is the area is Shona. Manyika, a Shona subgroup with a main livelihood, particularly in communal and slightly different dialect, is dominant across some resettlement areas, with maize being the dominant of the catchment’s eastern parts. Finally, a small food crop (ZimVAC 2021). Small-to medium-scale population of Nsenga people lives in part of the commercial farming has become more prevalent catchment along the Mozambican border (Eberhard, in the south and west of the catchment (that is, the Simons, and Fennig 2022; Muturzikin 2007). Highveld Prime Cereal and Cash Crop Resettlement Zone). Overall, over 80 percent of rural households in the study area grow maize, while tobacco is the most important cash crop (Sukume, Mahofa, and Mutyasira 3.5 Livelihoods and 2022; ZimVAC 2021). Many farmers also practice socioeconomic status agropastoralism, though livestock ownership is not as widespread as crop cultivation. According to the most 72. Most people in the study area are rural and recent ZimVAC assessment, around 30–40  percent relatively poor. The study area has four main of households in the constituent provinces of the livelihood zones—Central and Northern Semi- catchment own cattle or goats (ZimVAC 2021). Market Intensive Farming, Highveld Prime Communal, access, ecosystem degradation, and natural hazards, Highveld Prime Cereal and Cash Crop Resettlement, combined with the weak national economy, are the and Greater Mudzi Communal (ZimVAC 2011, main inhibitors of improving agricultural livelihoods Figure 10, Appendix 1). (GoZ and WFP 2017). FIGURE 10: LIVELIHOOD ZONES IN THE MAZOWE CATCHMENT Source: Zimbabwe Rural Livelihood Baseline Profiles (ZimVAC 2011). Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 17 74. Poorer households depend on multiple sources of the study area, followed by Makoni District (38 percent) income including sale of handcrafts, petty trading (ZimVAC 2021). Food insecurity becomes even more (fish sales and beer brewing), and artisanal serious in lower rainfall seasons, with 75 percent of mining (GoZ and WFP 2017; Myambo 2017; households in Mudzi estimated to be cereal insecure ZimVAC 2011). Mining in particular has become in the drier 2019/2020 season (ZimVAC 2020). In an increasingly prevalent livelihood strategy in the same season, a further nine districts within the recent years, particularly in gold-rich areas such as study area (Rushinga, Mutoko, Mazowe, Uzumba Mazowe District, due to a combination of poverty, Maramba Pfungwe, Mount Darwin, Muzarabani, unemployment, and declining agricultural yields Goromonzi, Shmava, and Marondera) experienced (Nyavaya 2021). The majority of formal employment cereal insecurity rates above 50  percent, highlighting is in agriculture (including forestry), followed by the extent of food poverty issues in the catchment. retail trade, mining, and quarrying. The Makaha/ Benson mine is a key employer in the rural Mudzi 77. Based on information collected by the EMA, illegal District (ZimVAC 2011). There is also a small degree mining is most prevalent in the mineral-rich of employment in ecotourism around protected Highveld Prime Cereal and Cash Crop Resettlement areas (Chirenje 2017). Zone, particularly north and east of Harare and around Glendale and Bindura. There is also significant 75. Average monthly income among rural households illegal mining in the northern parts of the Greater in the study area ranges around US$30–80 (ZimVAC Mudzi Communal Zone around Kotwa. Gully erosion 2021). According to ZIMSTAT data, poverty generally recorded by the EMA is almost entirely limited to increases moving from southwest to northeast in the communal livelihood zones, with highest incidences catchment (ZIMSTAT 2019), mirroring the decline in of gully erosion around Murewa (Highveld Prime rainfall and agricultural suitability. Over 60 percent of Communal Zone) and Mutoko (Central and Northern households live below the poverty line across all Semi-intensive Farming Zone). rural districts in the catchment, with Rushinga District having the highest poverty levels in the study area, 78. Household energy sources are not available at a as well as being one of the poorest districts in the detailed level, but the Poverty Income Consumption country. Over 90 percent of households in Rushinga and Expenditure Survey report of 2017 indicates live in poverty and 59  percent in extreme poverty that at a national level, wood accounts for (ZIMSTAT 2019). At an aggregate level, Mazowe District 93.8 percent of rural households’ energy for cooking was estimated to have the highest number of poor (ZIMSTAT 2018). In urban areas, the main source of households in the catchment, due to a combination energy for cooking is electricity (64.5  percent), wood of a high poverty rate (82 percent) and large number (16.7 percent), and gas (10.8 percent). At the provincial of households living within it. Despite the high levels of level (rural and urban households combined), reliance poverty, literacy rates are high by regional standards, on wood as the primary cooking source ranges from at over 85  percent (UNESCO 20226; ZIMSTAT 2018), 82  percent to 90  percent across the constituent and at least a primary school level of education has provinces within the catchment. been attained by more than 85percent of adults in the intersecting provinces (ZimVAC 2021). 79. Sanitation in Zimbabwe is vastly different between urban and rural areas. On average, 91.5 percent of 76. Of the provinces within the study area, urban dwellers have access to a flush toilet, compared Mashonaland Central (half of which is in the to only 4 percent of rural dwellers (ZIMSTAT 2018). northern Mazowe Catchment) has the worst food poverty levels, with the highest incidences of 80. Access to ‘improved’ drinking water, that is, water hunger out of any province in the country (ZimVAC protected from fecal contamination, ranges from 2021). However, according to projections of district- 80 to 85 percent in the study area provinces, which level cereal insecurity data for the 2020/2021 season, is above the national average. The proportion of Mudzi (Mashonaland East) had the highest proportion households relying on water from wells, springs, or (about 50  percent) of cereal-insecure households in directly from surface water source (for example, rivers, 6 http://uis.unesco.org/ 18 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe ponds, or streams) is between 15 and 19 percent, irrigation to surrounding citrus estates. Presently, which is among the lowest in the country (ZimVAC the dam supplies various agricultural crops and 2021). orchards as well as water for livestock (Ernettie 2014; Nhedzi 2008). 3.6 Water supply 83. Reservoir levels have declined over the last few decades due to increased demand and regular 81. The Mazowe Catchment contains a number of intense droughts which at times left the dam man-made reservoirs. The total dam storage capacity almost completely empty (Downing 2013; Viriri is approximately 543.6 Mm3 in 260 reservoirs and Musariri 2006). Abstraction from elsewhere (Messager et  al. 2016). However, dams are not evenly has also affected groundwater flow into the reservoir. distributed across the catchment, with most falling The Rushinga and Mudzi districts in the lower within commercial farming areas in the south and catchment have been particularly hard hit by west of the study area. Dams in the catchment droughts in the last few years (GoZ and WFP 2017; supply water to Harare and other towns, as well as ZimVAC 2021). to several irrigation schemes, namely Kanhukamwe, Naymaropa, Marondera, Nyanga, and Glendale 84. While dams provide an important source of (ZINWA 2022). Nevertheless, there is an annual water water for agriculture, particularly in commercial supply deficit of 143 megaliters (ML) for the Mazowe farmland, groundwater is the main water source supply area. for rural communities in the catchment. The proportion of households depending on boreholes 82. There are seven medium-to-large dams (>10 Mm3) and wells as their main source of drinking water in the Mazowe Catchment, all located in the across the constituent provinces of the catchment southwest of the study area. The 39.4 Mm3 Mazowe (excluding Harare) ranges from 74 to 89  percent, Dam (the catchment’s second largest dam by surface while use of surface water ranges from 3 to 9 percent of area) was built in 1920, initially to supply water for households (ZIMSTAT and UNICEF 2019). Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 19 4. Ecological Trends, Drivers, and Impacts 4.1 Overview poor land management, uncontrolled mining and industrial activities, and poor sanitation. 85. This section provides an analysis of how the ecological status of the study area has changed 87. These problems find their roots in a set of over the past two or three decades, focusing on interrelated underlying drivers, including a low aspects relating to ecosystem health and the level of government services, insecure land tenure landscape capacity to deliver ecosystem services. and weak governance, poverty, and population Ecological trends were analyzed using satellite growth. In particular, lack of secure property rights data, including changes in land cover, tree cover, takes away any incentive to invest in land and protect and land productivity. The chapter also mentions one’s assets. Resulting persistent poverty drives up some environmental pressures that have not been fertility rates and fuels a downward spiral. quantified in any way, but which are known to have affected ecosystems or pose a threat to them in future. 88. The pressures on the environment are also certainly exacerbated by global climate change 86. The environmental trends observed in the Mazowe (IPBES 2018; IPBES and IPCC 2021), but at this Catchment have been brought about by a complex stage, it is clear that poor land and ecosystem array of factors. Some of the well-known proximate management is the bigger problem. If this is not causes of ecosystem degradation and loss have addressed, then the additional stress imposed by been land use change, overexploitation of resources, increasing climate change will have particularly severe KEY POINTS • Based on land cover data, the study area lost over 1,100 km2 of its dense woodland and over 90 percent (400 km2) of its wooded grassland, mostly to dryland cultivation, in the last 25 years (1992–2018). • According to Forest Watch data, some 594 km2 of forest and woodland (above 10 percent tree cover) experienced a loss of tree cover between 2001 and 2020. • Some 9 percent of remaining natural areas have experienced significant losses in productivity, while 29 percent have shown an increase between 2001 and 2017. • Commercial and artisanal mining is having a serious impact on surface and groundwater quality and causing significant sedimentation problems. • Catchment productivity is seriously affected by the invasion of lantana, alien grasses, and water weeds. • Climate change will have a direct impact on ecosystem condition and water supply and will indirectly increase all of these pressures. • Environmental problems in the catchment are primarily due to expansion of cultivated lands, tobacco curing, and small-scale mining. Ultimately, they are due to the related problems of poverty, population growth, and lack of secure property rights. • The combination of the above trends with future climate change will likely be catastrophic for the well-being of catchment inhabitants. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 21 consequences for livelihoods in the coming decades, 91. Using a land cover change matrix (see Appendix 2), including worsened food insecurity from higher it is possible to determine the different transitions frequency of drought and other extreme events, that have taken place within the landscape. higher risks of water scarcity, and contraction of Dense woodland, for example, has lost over 580 km2 areas suitable for rainfed crop production (IPCC 2020; to cultivation while over 1,200 km2 shifted to World Bank 2019). shrubland or herbaceous vegetation, indicative of a loss of tree cover in these areas. Rainfed cultivation has also replaced over 260 km2 of wooded grassland. 4.2 Ecological status Urban/built-up land cover has increased primarily at the expense of dense woodland, followed by and trends rainfed cultivated land and shrubland. 4.2.1 Land cover change 4.2.2 Deforestation and vegetation loss 89. Habitat loss through anthropogenic changes in land cover is the primary driver of biodiversity 92. Deforestation is a major concern, particularly in loss worldwide, reducing the ability of landscapes tropical and sub-tropical environments. The loss to sustain ecosystem services (CBD 2020). For this of woody vegetation has repercussions for ecosystem study, land cover changes were quantified for the functioning and affects several processes that underpin 26-year period from 1992 to 2018, using uniformly ecosystem services. It also leads to the emission of developed and classified land cover data from the greenhouse gases that accelerate climate change European Space Agency (ESA 2017). This period globally. According to FAO, Zimbabwe as a whole, has saw significant political changes that, in the early had some of the world’s highest rates of deforestation 2000s, in particular, resulted in major changes in (for canopy cover exceeding 10  percent) with a land tenure which led to changes in land use and forest loss rate of 3,090 km2 per year leading up condition across the country, including the Mazowe to 20107. Between 1990 and 2015, it is estimated Catchment. that 37  percent of the country’s ‘forested’ land was cleared8. Based on Global Forest Watch data (Hansen 90. The detailed changes in land cover are presented et  al. 2013) it was estimated that 594 km2 of natural as land cover accounts for the Mazowe Catchment forest and woodland (above 10  percent tree cover) in Appendix 2. The greatest net losses in this was lost from Mazowe Catchment from 2001 to 2020 period were by far the extents of dense woodland (Figure 11, Figure 12). (−1,226 km2) and wooded grassland (−402 km2). The extent of rainfed cultivation (765 km2) and 93. Tree loss was also examined for each sub- herbaceous vegetation (597 km2) increased the most catchment in the study area.9 The greatest loss in this period. Wooded grassland in the catchment has been in the Upper Mazowe Catchment with just has been almost completely transformed to other over 3  percent of all non-plantation areas showing land cover types, losing 90 percent of its 1992 extent. detected loss in forest or woodland canopy cover The area under irrigated crops tripled, although it (Figure  13). This is followed by the Kairezi sub- is likely that some areas have been misclassified as catchment with 2.8  percent and then the Upper rainfed agriculture and the figure underestimated Rwenya sub-catchment with 1.8 percent. the actual extent of irrigated crops both in 1992 and 2017. Urban/built-up land cover increased by 94. Most vegetation loss has been within miombo 87 percent from 34 km2 to 64 km2. Open woodland woodland areas and is largely from clearing for also increased during this time, by just over one-fifth agriculture. Many vegetated areas were cleared to of its 1992 extent. make way for subsistence and small-scale agriculture 7 www.globalforestwatch.org 8 Unregulated Deforestation May Be Decimating Zimbabwe’s Timber Industry (globalpressjournal.com) 9 As per the HydroSHEDS layer, not administrative sub-catchment councils. 22 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 11: AREAS OF TALL TREE CANOPY COVER (TREES > 5M HEIGHT) LOSS BETWEEN 2001 AND 2020, SHOWN BY YEAR IN YELLOW-RED SCALE, SUPERIMPOSED ON A MAP OF TREE CANOPY COVER AS 2010 Source: Global Forest Watch (see Hansen et al. 2013 for desciption of methods). Note: Grey areas indicate zero tall tree cover. Because of the tree size, this is mainly detected in commercial plantations and is likely to be part of normal harvesting cycles. FIGURE 12: LOSS OF TALL TREE COVER AND ASSOCIATED GROSS GREENHOUSE GAS EMISSIONS IN MAZOWE CATCHMENT BETWEEN 2001 AND 2020 (FOR VEGETATED AREAS WITH 30 PERCENT CANOPY COVER OR MORE) 35 1,600,000 30 1,400,000 1,200,000 25 1,000,000 Emissions Mg 20 Area km2 800,000 15 600,000 10 400,000 5 200,000 0 0 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 Tree cover loss Gross emissions non-CO2 Gross emissions CO2 Source: Hansen et al. 2013. 23 FIGURE 13: MAZOWE SUB-CATCHMENTS AND THE PERCENTAGE OF THE TOTAL AREA THAT HAS BEEN CLASSIFIED AS HAVING LOST TALL TREE COVER BETWEEN 2001 AND 2020 3.5% Upper Rwenya 3.0% Lower Rwenya 2.5% Kairezi 2.0% Nyangui 1.5% Nyadiri 1.0% Upper Mazowe 0.5% 0.0% Middle Mazowe Source: HydroSHEDS, Lehner and Grill 2013; Hansen et al. (2013b). after the FTLRP of the 2000s.10 High rates of 96. Based on the analysis of NDVI trends, some recent deforestation within miombo woodland 9 percent of remaining natural areas exhibited areas of the upper catchment have been confirmed significant losses in productivity, while 29 percent by more localized studies. For example, almost showed an increase from 2001 to 2018 (Figure 14). half of the woodland cover in Ward 32 of Mazowe While areas with increasing NDVI may reflect recovering District was lost between 2000 and 2018 while the vegetation in some cases, it is also likely to represent size of cultivated and bare areas more than doubled the atmospheric fertilization effect, where increased (Matsa et  al. 2020). This has negatively affected carbon dioxide in the atmosphere stimulates increased livelihoods, with the vast majority of local respondents photosynthesis in plants (Nkonya et al. 2016). Areas complaining of a reduction in trees for firewood and experiencing the greatest degradation over this period building materials, loss of wildlife and fruit trees that were around Glendale and Bindura in the west of were previously harvested for food, and increased catchment and near the Mozambique border north conflict over resource access in the face of worsening of Kotwa (Figure 14). The former area includes many scarcity. of the catchment’s largest dams (including Brecon, Umrodzi, Pote, and Jumbo). An analysis of historical 4.2.3 Land degradation satellite imagery indicates that many of the regions exhibiting a decline in NDVI are the result of the 95. Land degradation was assessed using satellite- partial clearance of natural vegetation for agriculture derived trends in land productivity, using the in areas that had not been cultivated previously. Normalized Difference Vegetation Index (NDVI) as the measure of productivity. Areas that exhibited 97. Since the Mazowe Catchment encompasses some of a statistically significant decline in productivity after the wettest parts of the country, the inherent risks accounting for the impacts of precipitation trends of soil erosion by water across much of the Mazowe were considered to be degraded (Nkonya, Mirzabaev, Catchment are among the highest in the country. and von Braun 2016). Due to the availability of According to Berg and Tempel (1995), the water erosion satellite imagery with sufficiently high resolution, risk for most of the catchment is moderate to very high this analysis was limited to the period between 2001 and is particularly high risk for areas under rainfed maize and 2018, and thus only captures relatively recent crops. The mean soil erosion in the Mazowe Catchment degradation. Further methodological details on the has been estimated to be as high as 54 tons per ha per analysis performed are given in Appendix 3. year (Tundu, Tumbare, and Onema 2018), which is well 10 The FTLRP facilitated redistribution of farms owned by white citizens to black Zimbabweans, especially war veterans from the independence wars of the late 1970s. Many of these farms included commercial timber plantations and natural woodland where livestock and game were kept. 24 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 14: PRIMARY PRODUCTIVITY TRAJECTORY IN THE PERIOD 2001–2017 ON A SCALE FROM SIGNIFICANT INCREASE TO SIGNIFICANT DECLINE IN PRODUCTIVITY AS WELL AS AREAS OF RELATIVE STABILITY Source: Conservation International 2018. Note: This excludes agricultural and other modified land cover (shown in grey). above the soil erosion tolerance limit of 10 tons per ha 4.2.4 Water pollution per year for agricultural land. High erosion rates reduce topsoil depth, deplete soil nutrients, and reduce soil 99. Water quality in the Mazowe Catchment has water and organic carbon content. This imposes a cost been affected by mining, agriculture, and human on farmers by forcing them to rely on fertilizer inputs to settlements. Drainage from commercial mining replace lost nutrients, while in extreme cases, the soil activities (tailings) has had a particularly serious may become too shallow to support crop production. impact on surface and groundwater quality through poorly managed wastewater runoff (Chandiwana 98. High erosion rates have not only led to a loss of important topsoil for agriculture but have also 2016; ZINWA 2022). Mining discharges release led to sedimentation that has diminished storage chemicals that do not degrade easily, such as capacity in reservoirs and limited their ability to heavy metals, mercury, and cyanide used for gold provide intended quantities of water for domestic, extraction, into waterbodies (Jackson et  al. 2001). industrial, and irrigation uses (Godwin et al. 2011; Acid mine drainage (AMD) has been reported in Tundu, Tumbare, and Onema 2018). For example, the Pote River in the upper Mazowe Catchment siltation has resulted in a 39  percent reduction in (Lupankwa et  al. 2006; Muposhi et  al. 2015). Lower the capacity of Chimanda Dam in Rushinga District down in the Mazowe Catchment, cyanide, mercury, (Tundu, Tumbare, and Onema 2018) and a 67 percent and other poisonous substances released by loss in storage capacity for Chesa Causeway Dam in mining operations in Mudzi District have been Mount Darwin (Godwin et al. 2011). blamed for causing cattle deaths along the Ruenya Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 25 River.11 Pollution of rivers in the area has become 2018). While some IAPs are relatively benign, certain so serious that Mozambique has reportedly been species, once established, can negatively affect species compelled to lodge a formal complaint to the composition, outcompeting native species due to Zimbabwean authorities. the lack of natural predators or enemies (Keane and Crawley 2002) and eventually reduce ecosystem 100. In addition to the release of toxins into the functioning. environment, small-scale and artisanal mining has resulted in several rivers’ natural flow 104. IAPs can lead to the reduction of stream flows and being disrupted following degradation of rivers groundwater, displace native biodiversity, and and riparian areas by alluvial gold panning. reduce areas available for grazing. The financial Sedimentation and increases in turbidity have also impacts of IAPs on agricultural output in Africa have resulted from artisanal alluvial mining. Artisanal been in the order of the tens of billions of US dollars gold panning is said to be the leading cause of high (Eschen et  al. 2021), while the financial impact on sediment yields in the Middle Mazowe sub-catchment livestock production has been estimated to be in the (Tundu, Tumbare, and Onema 2018). Sedimentation region of US$21 million in South Africa (O’Connor in rivers has also resulted from re-mining of old mine and van Wilgen 2020). dumps and erosion of unused mine dumps. These mine dumps are not well vegetated, resulting in limited 105. IAPs are a problem in the Mazowe Catchment, control of erosion and runoff of chemicals, dust, and with lantana (Lantana camara) invasions being other rock material into riparian areas, river channels, particularly widespread (Masocha 2009, Figure 15), and groundwater. Although there are regulations in with dense thickets along the Mazowe and Mwenje place that require rehabilitation of mine dumps, there Rivers. Lantana is a destructive species with little or is very little compliance (ZINWA 2022). no benefit (Ncube et  al. 2020). It reduces native species diversity, negatively affects wildlife habitats, 101. Effluent from industries, including textile and can reduce rangeland productivity by over manufacturers and smelters, is often above the 50  percent (Shackleton et  al. 2017). Its leaves are stipulated acceptable range of waste disposal poisonous to livestock12. It can also reduce annual regulations. In addition, seepage from landfill sites surface water runoff by as much as 1,250 m3 per contributes to groundwater pollution, while lack of condensed ha13 (Middleton and Bailey 2008). It is water supply and sanitation further contributes to also difficult to harvest for fuelwood. The habitat river pollution and solid waste pollution is also a suitability of lantana is expected to increase under problem (ZINWA 2022). This has led to an increase in climate change (Ncube et al. 2020). chemicals and fecal microbes contaminating rivers. 106. Aquatic weeds, such as water hyacinth (Eichhornia 102. It is likely that there is some runoff of nitrogen and crassipes), red water fern (Azolla filiculoides), phosphorus from the application of fertilizers to and parrot’s feather (Myriophyllum aquaticum) crops in commercial crops in the upper catchment. are problematic in some of Zimbabwe’s larger Even small-scale farming may result in such impacts. reservoirs. These increase evapotranspiration and During the wet season, soil and fertilizers often flow affect dissolved O2 and pH levels in the waterbodies, from subsistence farms in and adjacent to the riparian with detrimental impacts on fish and other aquatic zones into rivers resulting in increased sedimentation life (Chamier et  al. 2012; Mujaju, Mudada, and and eutrophication. Chikwenhere 2021). Up-to-date impacts on dams within the catchment are not available. 4.2.5 Invasive alien plants 107. Most of the country’s focus in terms of IAP management is on biological control of aquatic 103. The presence and spread of invasive alien plants weeds. There is also legislation which specifically (IAPs) can have long-lasting and severe impacts prohibits the cultivation of lantana anywhere and on ecosystem functioning (van Wilgen and Wilson weeding any individual plants of the species is 11 https://www.pressreader.com/zimbabwe/the-standard-zimbabwe/20220710/281590949275389. 12 https://www.cabi.org/isc/datasheet/29771#tosummaryOfInvasiveness 13 IAPs occur at varying densities, so measures are standardized to the equivalent area at 100 percent cover. 26 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 15: LANTANA (L. CAMARA) AND PRICKLY PEAR (OPUNTIA SPP.) DISTRIBUTION AND EXTENT ACROSS ZIMBABWE Source: Environmental Management Agency. compulsory. Certain forestry companies clear 4.3.1.1 Agriculture practices spreading IAPs around timber plantations and there are programs to control IAPs in certain 109. In the Mazowe Catchment, the vast majority vulnerable areas and national parks (Sithole and (67 percent) of tree cover loss since 2001 is Chikwenhere 2003). This is especially worthwhile estimated to be due to the expansion of agriculture for IAPs that are heavy water users (Marais and Curtis et al. (2018). Wannenburgh 2008; Morokong et  al. 2016; The Nature Conservancy 2019). 110. Poor land management has led to widescale erosion and sediment loading into rivers and 4.3 Key drivers reservoirs across Zimbabwe. This includes the clearing of riparian vegetation to grow crops, which 4.3.1 Proximate causes has been particularly evident in communal and resettlement areas in the middle and upper Mazowe 108. The main proximate causes of ecosystem Catchment (GoZ and WFP 2017). Indeed, communal degradation and loss are the conversion of virgin land tenure areas appear to have the worst rates land to cropland, poor cultivated and rangeland of soil loss relative to other land tenure types management, and overexploitation of harvested across Zimbabwe (Tundu, Tumbare, and Onema resources and mining. 2018; Whitlow 1988). Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 27 111. Smallholder farmers in Zimbabwe typically try to mechanical ploughing of land with an animal-drawn compensate for low yields through expanding mouldboard plough, remains prevalent among cropping areas (extensification) rather than most smallholder farmers (ZCATF 2009). While the intensifying production on existing fields practice has benefits, the associated mechanical (Marongwe et al. 2011). Often, the expansion disturbance of the soil structure increases its of cropland into increasingly marginal areas is susceptibility to erosion, though there has been accompanied by very limited investment in erosion some promising progress in the uptake of reduced- control measures. and no-tillage approaches across the country (Marongwe et al. 2011; World Bank 2019). 112. Another factor which contributes to erosion is the typically bare state of fields at the start of the rainy 113. Subsistence farms are also often located near season, which is often characterized by violent, streams and rivers, to reduce watering effort erosive rain storms (Makwara and Gamira 2012). and costs (Figure 16). This reduces the sediment Due to shortages of dry season grazing, crop residues retention capacity of the riparian zone, thus further are typically consumed by livestock, resulting in bare contributing to sedimentation problems. fields by the end of the dry season. Additionally, planting in communal areas typically occurs late, 114. Similarly, wetlands are heavily used for crop resulting in greater exposure of bare soil to rain production and livestock grazing, due to in the early part of the rainy season (Whitlow the enhanced water availability and forage 1988). Conventional tillage, most commonly involving production they provide (Matiza 1994; Musasa FIGURE 16: SATELLITE IMAGE SHOWING THE SUBSISTENCE FARMING AREA ADJACENT TO THE NYADIRE RIVER IN THE MAZOWE CATCHMENT Source: Google Earth. 28 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe and Marambanyika, 2020; Svotwa, Manyanhaire, 4.3.1.2 Fuelwood harvesting for household and Makombe, 2008). While year-round growth of consumption and tobacco crops on wetlands has been an important livelihood strategy since precolonial times, wetland cultivation 117. The inhabitants of the Mazowe Catchment still has expanded to unsustainable levels in recent depend heavily on harvested natural resources decades, undermining the very benefits which make for livelihoods, particularly firewood. Firewood is wetlands attractive for cultivation and grazing in the used as the primary cooking fuel by 94 percent of first place. Crop cultivation tends to increase water rural households, with an additional 0.1  percent abstraction relative to natural wetland vegetation, of households using charcoal (ZIMSTAT and while livestock grazing and trampling further reduce UNICEF 2019). The high dependence on firewood vegetation cover and weaken soil structure, making places significant pressure on woody resources, it prone to erosion (Musasa and Marambanyika particularly in more densely populated parts of 2020). As of 2015, it was estimated that 65  percent the catchment. of wetlands in the Mazowe Catchment were in a moderately degraded state and 21  percent in a 118. Additionally, the rate of firewood exploitation severely degraded state, highlighting the severe has reportedly greatly increased in areas where impact of land management practices (Musasa and people are engaging in small-scale contract Marambanyika 2020). tobacco farming, since firewood is needed for tobacco curing (GoZ and WFP 2017). This is despite 115. There is little information on stocking rates of the fact that harvesting of indigenous fuelwood livestock in relation to grazing capacity. However, for tobacco curing is prohibited. According to it is likely that there is an increasing squeeze on the shrinking area of grazing lands, because livestock the Forestry Commission, tobacco harvesting keeping remains an important aspect of rural is estimated to account for one-fifth of national livelihoods in the region. This will affect grass cover, deforestation each year, with the authority conceding drive invasion of unwanted species, and incentivize that enforcement of restrictions on harvesting burning. indigenous fuelwood has been limited.14 116. Burning is usually carried out to clear lands for cultivation, clear moribund vegetation and crop 4.3.1.3 Mining residue on small-scale farms (Mupotsa 2014), and promote green growth for livestock grazing or 119. Another serious driver is the expansion of poorly hunting at the end of the dry season when fresh regulated and illegal mining in the area, which grass is scarce and crop residues unavailable (World is having devastating impacts on both upland Bank 2019). However, late dry season burning and riparian systems. This is often by outsiders can cause massive increases in runoff once the that have unfettered access to the area. Indeed, the first rains arrive, significantly increasing erosion gold-rich nature of the Mazowe area has resulted in rates (Roose 2008). The Mazowe area has some a significant influx of both locals and people from of the highest incidences of intentional wildfires other parts of the country to mine in the catchment in Zimbabwe, and the issue seems to be increasing in (Nyavaya 2021). Furthermore, the problems are not severity (GoZ and WFP 2017). An upsurge in wildfires limited to small-scale mining. There has also been occurred during the FTLRP period across Zimbabwe, an explosion of commercial mining operations, often presumably to clear land for cultivation, and in view by Chinese-owned firms. These new operations of an underdeveloped social contract for nascent have been notorious for their disregard of both the farming communities. environment and human rights.15 14 https://news.mongabay.com/2022/02/zimbabwes-forests-go-up-in-smoke-to-feed-its-tobacco-habit/. 15 https://www.theguardian.com/global-development/2022/jan/07/zimbabwe-china-mines-pollution-evictions. https://www.pressreader.com/zimbabwe/ the-standard-zimbabwe/20220710/281590949275389. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 29 120. Quarrying and mining involves the direct removal continent, the potential benefits of this investment of vegetation and disturbance of sediments, which could not be realized as a result of a lack of opportunity. contributes to soil erosion and the formation There are few economic opportunities in urban of gullies. This includes sand mining, which is a areas, and without any system of welfare, much of major contributing factor to wetland shrinkage in the population has no option but to make a living off the Mazowe Catchment (Chikodzi and Mufori 2018). the land and grab any opportunities that arise, legal Mining and gully formation are especially serious or illegal. Poverty leaves households in a position of in the Marondera, Mutoko, Goromonzi, and Mount having a short time horizon, in which the need for Darwin Districts (GoZ and WFP 2017). immediate survival obscures any need to plan for a sustainable income. In addition, poor households 121. Mining also has a serious impact on water quality will be more likely to take risks, such as disregarding through pollution as well as sedimentation. The the law, to make ends meet. particular environmental impacts depend on the nature of the ore, the type of mining, and the size 124. Poverty has contributed to an upsurge in of the mining operation (Lupankwa et  al. 2006). uncontrolled harvesting of natural resources. Both nickel and gold, the two most common metals Since the 2000s, the country’s rural poor have mined in the Mazowe Catchment, are associated reportedly increasingly resorted to activities like with AMD (Lupankwa et al. 2004; Pratt 2011). This is hunting wildlife and harvesting and selling firewood the outflow of mine drainage that has a high heavy for sale to urban markets (Miller and Gwaze 2012). metal concentration, making it acidic. AMD can have This places further pressure on woody resources, serious environmental impacts in aquatic habitats, which are already heavily exploited as a fuel source for particularly on fish and other aquatic organisms subsistence use due to poverty and the unavailability (Hogsden and Harding 2012). of alternative energy sources. 122. Artisanal mining also contributes to air pollution; 125. Poverty and the country’s economic collapse erosion; and removal of crops, arable land, and are also key underlying drivers of the upsurge in natural vegetation (Chandiwana 2016; Tundu, small-scale mining within the catchment, which Tumbare, and Onema 2018), all of which exacerbate has become a significant income opportunity in resource scarcity and food insecurity. In addition, the context of high unemployment and low wages it comes with socioeconomic issues such as poor (Chandiwana 2016; International Crisis Group 2020). community relations leading to conflict and mistrust, Declining crop production has been an additional crime, prostitution, and corruption, which are also contributing factor. A further massive jump in illegal common where artisanal mining is practiced. Gang mining occurred with worsened unemployment violence and elaborate patronage networks have resulting from the COVID 19 pandemic (Nyavaya 2021). been reported around Jumbo Mine in Mazowe (International Crisis Group 2020). These issues 126. The initial expansion of small-scale and artisanal are underpinned by an alleged culture of impunity mining followed the closure of several commercial and poor regulation at a state level (Hlungwani, Yingi, mining operations as a result of the economic crisis and Chitongo 2021). between 2000 and 2008, and the opportunity that this presented in a climate of economic decline (Chandiwana 2016; Masocha et al. 2019). These 4.3.2 Underlying Drivers commercial mining operations were generally better regulated and had better technologies to manage the 4.3.2.1 Poverty and economic decline external damages associated with mining than the small-scale operations that followed. Furthermore, 123. The degradation of the catchment is largely driven the many Chinese-owned firms in the commercial by a combination of poverty and population mining sector are also notorious for failing to mitigate growth. Poverty levels in the study area are high negative environmental impacts from their activities. and can be blamed in large part on the country’s In the Mazowe Catchment, informal artisanal mining economic collapse in the 2000s and failure to recover now dominates (both alluvial panning and reef mining) subsequently. Although the population has benefited and is largely unregulated. Of the 1.5 million small- from one of the best education systems on the scale miners estimated to be operating in Zimbabwe, 30 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe only around 50,000 are formally registered according in the catchment. Changes in population density to the Zimbabwe Miners Federation (Nyavaya 2021), across the catchment between 2000 and 2020 are highlighting the difficulty of managing the impacts shown in Figure 17. of the mushrooming small-scale mining sector. This lack of regulations means that provisions for land 128. The expansion of the farming population in the rehabilitation and the development of mine closure catchment is a key underlying factor which has plans are not followed. contributed to the growth of human settlements, conversion of natural land to agriculture, increased harvesting of resources, grazing pressure on the 4.3.2.2 Population growth remaining land, and an increased rate of burning. 127. Between 2000 and 2020, the population of the 129. Issues related to population pressure on land Mazowe Catchment is estimated to have increased resources in communal lands date back to colonial by roughly 717 000 (www.worldpop.org). This land tenure policies which confined the black rural represents a 45  percent overall increase and an population to overcrowded communal areas. As a average annual population growth rate of 15 percent. result, many of these areas have experienced high Most population increases have been in the upper levels of land degradation for some time (Whitlow catchment around Harare and the other main towns, 1988). Indeed, in a nationwide assessment, population as well as in the Mount Darwin District lower down density was one of the key predictors of erosion FIGURE 17: CHANGES IN POPULATION BETWEEN 2000 AND 2020, EXPRESSED IN TERMS OF CHANGE IN THE NUMBER OF PEOPLE PER KM2 Data source: Population density, 2020 (Bondarenko et al. 2020) Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 31 risk in Zimbabwe, contributing to the much higher Mazowe District since 2000, which included the loss levels of erosion in communal land (Whitlow 1988). of almost half of the existing woodland cover in Since many rural households own at least some Ward 32 between 2000 and 2018. livestock, higher population densities also tend to worsen overstocking and overgrazing, which are 133. In some cases, farms have been resettled by new compounded by the increasing scarcity of rangeland owners who lack a background in commercial as cultivation expands to meet local food requirements farming management. For example, a number of (Makwara and Gamira 2012; Whitlow 1988). Intense new A2 farm owners are business people, civil land shortages also mean farmers cannot allow servants, or other people with urban backgrounds depleted soils to rest and recover despite falling (Miller and Gwaze 2012). This has contributed to a yields (Roose 1996). These factors collectively contribute failure to adopt sustainable agricultural practices to significant elevation of erosion rates. on some resettled farms. 130. Most remaining unfarmed land in crowded communal areas is in increasingly sensitive and 4.3.2.4 Lack of secure property rights marginal zones such as steep slopes, riparian 134. In addition to population pressure, tenure areas, and wetlands (Makwara and Gamira 2012). insecurity is a major contributing factor to poor Indeed, population growth is cited as a key reason land management, particularly in areas resettled for the overexploitation of wetlands by agriculture during the FTLRP. According to a study conducted and livestock (Chikodzi and Mufori 2018; Svotwa in Mazowe District, perceived tenure insecurity et al. 2008). All else being equal, the expansion of the following the FTLRP has contributed to reduced rural population will result in further conversion of adoption of soil conservation measures among remaining natural land to agriculture, in the absence Model A1 farmers (Zikhali 2010), which is likely to of sustainable agricultural intensification, have increased erosion in these areas. Farmers who have no ownership of their land and resources 131. Given that 94 percent of rural households depend are not likely to invest in them. There are also no on firewood as their main cooking fuel (ZIMSTAT opportunities to obtain rights over wildlife for investing and UNICEF 2019), population growth has also in wildlife-based land uses which could be more contributed to increased harvesting pressure on viable than farming in some marginal areas. woody resources. 4.3.2.3 Land reform 4.4 Implications for a future 132. Population growth has been accompanied by under climate change widescale deforestation to make way for small- 135. The growth of agriculture and mining in the study scale agriculture, particularly in the early 2000s area has provided important sources of livelihoods. under the FTLRP (Tundu, Tumbare, and Onema However, it has also undermined some of the 2018). Land remains underutilized in many resettled benefits provided by ecosystems. Ecosystems in the commercial farms (Mugabe et  al. 2014). However, study area provide a range of ecosystem services in other cases, the influx of new farmers on to large that benefit not only the local inhabitants but also commercial farms has resulted in the conversion to the rest of the country and world at large. cultivation of natural areas that had been formerly reserved for grazing (Matsa et  al. 2020). In many 136. Communities living off the land are being faced formerly white-owned commercial farming areas, this with increasing scarcity of the natural resources that has significantly increased the pressure on land and they collect or hunt, and also face water scarcity. natural resources (Musasa and Marambanyika 2020). For example, the removal of woody vegetation According to Matsa et  al. (2020), the resettlement has affected provisioning services associated with of commercial farms has been a major driver of the woodlands and forests. Matsa et al. (2020) reported, substantial loss of natural habitats and wildlife in in a local study in the upper Mazowe Catchment, that 32 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe respondents had noted a reduction in high-energy days with a maximum temperature above 35°C and tree species; fewer animals that constitute consumed an increase in the length of dry spells. bushmeat (that is, local extinction); and lower availability of fruit trees, medicinal plants, firewood, 140. These conditions will increase the strain on rural and construction materials. The scarcity of resources communities, the majority of whom depend had also resulted in conflict among community on rainfed crops which are highly vulnerable to members. Loss of grassland and open woodland climate change impacts and account for 80 percent areas has reduced grazing areas and forage quality of Zimbabwe’s agricultural production (World which, in some instances, has resulted in declining Bank 2021). Zimbabwe’s Meteorological Services meat quality, which invariably will limit the potential Department has already noted that warming trends to generate income for livestock farmers. since the 1970s have put stress on the agricultural sector.16 Even the commercial agriculture sector, 137. Ecosystem degradation poses threats to water which is the country’s largest employer, is likely to be security by affecting water supply infrastructure negatively affected. Production of irrigated crops such and treatment costs or by posing direct threats to as tobacco and cotton will also be affected, which human health. The combination of food and water will have a widescale impact on many households’ insecurity also exacerbates human health issues. ability to derive an income (World Bank 2021). Even While food, water, and health are primary concerns, under medium climate change projections, yields of all degradation of the environment also carries a cost to main crops except dry beans are expected to decline human quality of life beyond material benefits. Not by the 2040s, including a 33 percent yield reduction only does it affect local users, but it could affect the for maize (World Bank 2019). Livestock production potential for tourism in the area. At this stage, tourism is also expected to be negatively affected, with development is relatively low, but its potential for income generated from cattle, goats, and sheep development will become more limited with an predicted to decline by 12  percent, 7  percent, and increasingly irreversible scale of degradation. 14  percent, respectively. Overall, in the absence of effective adaption, the impacts of climate change 138. Finally, one of the greatest looming threats on agriculture could cost a decline in Zimbabwe’s to the area is that of climate change. While the GDP of over 2  percent (Benitez et  al. 2018). These degradation of ecosystems in the study area will projected impacts highlight the great need for the contribute to further climate change, an even greater adoption of CSA practices as an adaptation and concern is that their ability to buffer the population mitigation strategy. from the impacts of climate change is being eroded. Maintaining resilience through ecosystem-based adaptation may be one of the most important 141. Natural vegetation is also likely to change. In motivations for addressing ecological degradation Mazowe, mopane woodlands are likely to spread, in the area. largely at the expense of miombo woodlands (INDUFOR/AEMA and MEWC 2017). This will have 139. Climate change is predicted to have a profound repercussions for wood harvesting which is critical impact on ecosystems and livelihoods the world in the Mazowe Catchment owing to the high levels over (IPBES 2019). Zimbabwe is expected to be of fuelwood use for meeting energy needs. These particularly hard hit, even relative to other countries consequences may be beneficial in some areas in southern Africa. Increases in mean annual but would require further evaluation on the growth temperature of up to 2.2°C and up to 4.4  percent and harvesting rates of mopane wood. decrease in annual median precipitation is expected by 2060 (World Bank 2021). Over the same period, 142. Climate change is expected to reduce groundwater the annual probability of Zimbabwe experiencing recharge and surface runoff in the Mazowe severe drought is projected to increase by 21 percent, Catchment. Under a BAU (A2a) global emissions coupled with a substantial increase in the number of scenario, it is estimated that mean runoff in the 16 The National Climate Policy of Zimbabwe (2016). Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 33 Mazowe Catchment will decrease by 15  percent by 143. Degradation of ecosystems in the study area 2050 and groundwater recharge by 7 percent (Davis is already compromising water security, food and Hirji 2014). These declines become much smaller security, human health, and livelihoods. Climate under an ecologically aware (B2a) global emissions change puts pressure on ecosystems in the same scenario (2 percent for surface runoff and 1 percent direction. If the drivers of degradation are not for groundwater recharge), highlighting the large addressed, then the population of the Mazowe impact of global actions on local climate change Catchment could face catastrophic consequences projections. such as famine under future climate conditions. 34 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 5. Ecosystem Services, Beneficiaries and Value 5.1 Overview of concept, Ecosystem Assessment 2003, 2005). These benefits depend on the nature of ecosystems and their key services, and biodiversity. Ecosystem services are typically considered to include provisioning, regulating, and beneficiaries cultural services. 144. The ecosystem goods and services that are 146. Provisioning services are the harvestable resources generated by the natural ecosystems of the Mazowe supplied by ecosystems. These include Catchment contribute to local livelihoods as well as to the economy. The capacity of the area’s ecosystems • Wild foods and medicines; to supply these benefits is strongly linked to ecosystem • Raw materials; characteristics and condition, as described in the previous chapter. This section quantifies and maps • Ecosystem inputs to crop and livestock production; the ecosystem services provided within the Mazowe and Catchment area in physical terms and estimates their • Genetic resources. approximate value to different groups of beneficiaries, within the limitations of a rapid desktop study. 147. Regulating services are the functions that ecosystems and their biota perform that benefit people in surrounding or downstream areas or 5.1.1 Ecosystem services even distant areas. These include • Climate regulation; 145. Ecosystem services are defined as “the benefits people obtain from ecosystems”17 (Millennium • Flow regulation; KEY POINTS • Ecosystem services are broadly defined as the benefits people obtain from natural and man-modified ecosystems. • They can be categorized into provisioning, regulating, and cultural services. • Provisioning services include harvestable resources and land inputs to crop and livestock production. • Regulating services are ecosystem functions that provide downstream benefits as inputs to economic production or cost savings. An example is sediment retention. • Cultural services are the provision of opportunities for a range of experiences. • This study focused on provisioning services (as completely as possible), carbon, flow regulation, soil/sediment retention, and tourism value. • The beneficiaries of these services variously include local households, the tourism sector, water service providers, and society as a whole. 17 An ecosystem is a community of living organisms in conjunction with non-living components of their environment, interacting as a system. The biotic and abiotic components are linked together through nutrient and energy flows. Ecosystems can be defined in space and range in size, for example, from ponds to a large rainforest. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 37 • Sediment regulation; • Water suppliers and users benefit from the reduction of sediment and nutrient inputs into • Water quality amelioration; and reservoirs, as well as from the regulation of the • Pollination. timing of surface flows. These save on both water storage and treatment costs. 148. Cultural services are the ecosystem attributes • The tourism sector and tourists benefit from (for example, beauty and species diversity) that nature-based tourism opportunities. Tourist give rise to the ‘use values’ gained through any expenditure in the country is captured in the value type of activity ranging from adventure sports to of the tourism sector. Note that this study does birdwatching, religious or cultural ceremonies, or not estimate the consumer surplus of tourists, just passive observation or the ‘non-use values’ most of which accrues to non-Zimbabweans. gained from knowing that they exist and can be enjoyed by future generations. • Both Zimbabwean citizens and global society benefit from the avoided climate change costs 149. A fourth category (supporting services) was through retention of intact natural ecosystems. also defined by the (Millennium Ecosystem They also derive satisfaction from knowing Assessment 2003b) to encompass underlying about the existence of conserved biodiversity ecosystem processes such as soil formation, and wilderness areas. Zimbabwe shares in the nutrient cycling, and water cycling, but since these global impacts of carbon emissions on climate are internal to the provision of the other services, change, the extent of its share of the costs being they are no longer included in more recent determined by global climate circulation and classifications of ecosystem services or in the its relative vulnerability to climate change. Its System of Environmental Economics Accounting - share of the existence value of biodiversity is Ecosystem Accounting methods (UN 2021). determined by relative ability to pay among other factors, but it is not valued here. Selection of ecosystem services 5.1.2  for analysis 5.2 Provisioning services 150. This study tackled selected services, based on data availability as well as their relative importance. We 5.2.1 Crop production focused on the provisioning services (as completely 152. The Mazowe Catchment contains some of the as possible but excluding medicinal plants for which prime areas for crop production in Zimbabwe, there were insufficient data), carbon, flow regulation, particularly the wetter south and west of the soil/sediment retention, and tourism value. catchment which fall within agroecological region II. This is the optimal region for intensive production of maize, tobacco, and other key crops (World Bank 5.1.3 Beneficiaries of ecosystem services 2021). The drier northeast of the catchment falls within agroecological regions III and IV, where 151. The main beneficiaries of the selected ecosystem conditions become increasingly marginal for rainfed services in the catchment were identified as crop production. Nevertheless, the area supports follows: large numbers of smallholder farmers. Thus, much of the catchment is under commercial or small-scale • Subsistence/small-scale farmers, who benefit production, with a mixture of food and cash crops from harvesting wild resources and from ecosystem being grown. inputs to cultivated crops and livestock, and from linked regulating services such soil retention and 153. Nature’s inputs to crop production are complex crop pollination. and include the soil and the nutrient and moisture • Commercial farmers and timber producers inputs. As a proxy, the physical measure for the benefit from land inputs to cultivated crops and ecosystem service is the tonnage of crop production. tree plantations. Spatial variation in production of the 10 main crops 38 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe KEY POINTS • The Mazowe Catchment is generally highly suitable for crop production. Some 254,000 tons of food and cash crops are produced on commercial farms and 353,000 tons on communal land. The value of this ecosystem service is estimated to be in the order of US$58 million per year. • The study area has a higher density of cattle than for the country as a whole and average densities of goats and sheep, with total populations of about 840,000, 400,000, and 38,000, respectively. The value of land input to livestock production was estimated to be US$108 million per year. • Households in the Mazowe Catchment are estimated to harvest over 2.2 million tons of wood, thatching grass, and wild foods annually, with a value of approximately US$106 million per year. Natural habitats have an average value of US$42 per ha per year. This does not include medicinal resources or bush meat. • In general, provisioning service values are highest in the areas of high population density due to demand. In some areas, this will have compromised natural ecosystem capacity. in the study area was estimated using the Integrated which covers about 10  percent of Zimbabwe’s Valuation of Ecosystem Service Tradeoffs (InVEST) surface area, accounts for 20  percent or more of Crop Production model and production reported in national production. This indicates its importance Zimbabwe’s Crop and Livestock Assessment Reports to agriculture in the country. The proportional (see Appendix 5). The service was valued in terms of contribution was particularly high for tobacco the gross margin of production. (36.6 percent) and beans (35.3 percent). 155. Since communal and resettlement areas cover 5.2.1.1 Quantification of crop production a larger proportion of the catchment than commercial farming areas, it is not surprising 154. The estimated production of 10 major food and that production of most crops is higher here than cash crops in the Mazowe Catchment is shown in in commercial farmland (Table 2). However, beans Table 2. For most crops, the Mazowe Catchment, and soya were an exception, with higher estimated TABLE 2: ESTIMATED PRODUCTION OF 10 MAJOR FOOD AND CASH CROPS IN THE MAZOWE CATCHMENT Crop Total production % of national Production Production (tons) production commercial (tons) communal (tons) Maize 368,741 25.1 156,718 212,023 Sorghum 26,807 20.7 13,196 13,611 Millet 4,578 7.3 805 3,772 Ground and bambara nuts 40,702 26.7 15,205 25,497 Beans 6,215 35.3 3,163 3,052 Sweet potato 39,751 19.1 8,987 30,764 Tobacco 83,488 36.6 39,435 44,053 Cotton 19,233 15.4 6,710 12,523 Soya 14,579 24.5 8,880 5,699 Sunflower 2,522 25.2 630 1,892 All Crops 606,616 — 253,729 352,887 Source: Based on the Crop and Livestock Assessment reports (MoLAWFRR 2021) Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 39 production in commercial farmland. Conversely, (a good rainfall season) was just 3.5 million ha, or production of millet and sweet potato was estimated around 9 percent of the country (MoLAFWRR 2021). to be several times higher in communal and resettlement areas. This suggests sweet potato 157. Total crop production is generally highest in the is largely grown as a subsistence crop. The higher southwest of the catchment Figure 18, particularly output of millet is because these farming areas in commercial farming areas. This is not surprising also tend to be in drier parts of the catchment. as the southwest of the catchment has the best climatic conditions for agriculture, and indeed some 156. The spatial variation in total crop production per of the most favorable farming conditions in the hectare of all farmlands is shown in figure 18. Note country. Production per hectare declines in the drier that these figures are lower than the yield of planted north and northeast of the catchment. areas. Planted area cannot be differentiated from broader farmland in remote sensing products, which 5.2.1.2 Value of land inputs to crop production includes fallow and abandoned fields, hedgerows, and other landscape features which characterize small- 158. In gross revenue terms, production of the 10 crops scale farming areas in Zimbabwe. At the national considered was estimated to be worth around scale, agriculture was estimated to cover 42  percent US$454.6 million per year, with a gross margin of land area in 2016 (World Bank 2021), whereas of US$68.2 million per year (Table 3). Maize and the total planted area for field crops in 2020/2021 tobacco account for the bulk of this value. For maize, FIGURE 18: ESTIMATED AGGREGATE PRODUCTION OF THE TEN MAJOR CROPS ACROSS THE MAZOWE CATCHMENT (GREY REPRESENTS NON-FARMLAND PIXELS) Source: This study is based on the InVEST Crop Production Model and Crop and Livestock Assessment reports (MoLAWFRR 2020, 2021). 40 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe  STIMATED VALUE OF CROP PRODUCTION BASED ON GROSS REVENUE AND GROSS MARGIN, TABLE 3: E ASSUMING A 15 PERCENT PROFIT MARGIN Crop Producer price Gross revenue Gross revenue Gross margin Gross margin (US$/t) commercial communal commercial communal (US$ millions/year) (US$ millions/year) (US$ millions/year) (US$ millions/year) Maize 341 53.4 72.3 8.0 10.8 Sorghum 341 4.5 4.6 0.7 0.7 Millet 341 0.3 1.3 0.0 0.2 Groundnuts and 341 5.2 8.7 0.8 1.3 Bambara nuts Beans 341 1.1 1.0 0.2 0.2 Sweet Potato 800 7.2 24.6 1.1 3.7 Tobacco 2,970 117.1 130.8 17.6 19.6 Cotton 455 3.0 5.7 0.5 0.9 Soya 780 6.9 4.4 1.0 0.7 Sunflower 935 0.6 1.8 0.1 0.3 All Crops — 199.3 255.3 29.9 38.3 this reflects its areal dominance in the catchment, while gross margin, as an approximation of the residual the high contribution of tobacco to crop value is due value attributed to the environment. For livestock to its much higher value per ton than any other crop. in small-scale farming areas, this incorporated the value of manure, milk, draught power, and hides, all of which are particularly important components 5.2.2 Livestock production of the value of livestock to small-scale farmers. 159. Livestock production is an important component of rural livelihoods in Zimbabwe. Although conditions 5.2.2.1 Quantification of livestock production are favorable for crop production across much of the 161. Communal and resettlement areas account for catchment, particularly the upper reaches, livestock the bulk of livestock in the catchment, with remain an important part of mixed cropping systems. the exception of sheep (Table 4). In TLU terms, In addition to offtake for meat production, they are numbers are about 2.7 times higher in communal kept for a range of other reasons including to exploit and resettlement areas than in commercial farming crop-livestock interactions, provide a store of wealth, areas. Over 70  percent of cattle and goats are in for draught power and lobola payments. communal and resettlement areas. The overall goat population is just under half the cattle population. 160. Ecosystem inputs to livestock production include fodder production and natural water sources. 162. Overall, the study area has a higher density of A suitable proxy physical measure of the service is the livestock (15.9 TLUs per km2) than the national number of tropical livestock units (TLUs) supported. average (11.1 TLUs per km2), and accounts for The spatial distribution of livestock in the landscape 14.6 percent of TLUs nationally and 15.1 percent, was modelled using the Food and Agriculture of the national cattle population. Goat and sheep Organization (FAO) Gridded Livestock of the World densities are similar to the national average. (GLW3) dataset (derived from official government data; Wint and Robinson 2007), and data in the Crop 163. A map of livestock density per km2 in TLU terms and Livestock Assessment reports (MoLAWFRR, 2021) is shown in Figure 19. This reflects the combined (see Appendix 5). The service was valued in terms of effects of land tenure, population density and rainfall. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 41 ESTIMATED POPULATIONS OF CATTLE, GOATS, AND SHEEP IN THE MAZOWE CATCHMENT AND THE TABLE 4:  AGGREGATED NUMBER OF TLUS Livestock Livestock Livestock Livestock Percent of Average Average density species population population combined national density/km2 nationally/km2 commercial communal population Cattle 231,185 609,613 840,798 15.1 21.0 14.2 Goats 98,501 302,527 401,028 10.4 10.0 9.8 Sheep 65,874 48,304 65,874 11.4 1.6 1.5 TLUs 173,436 461,812 635,249 14.6 15.9 11.1 FIGURE 19: MAP OF LIVESTOCK DENSITIES (EXPRESSED IN TLU TERMS) ACROSS THE MAZOWE CATCHMENT Data source: Gridded livestock of the world (GLW3 - Buchhorn et al. 2020). Grey indicates the strictly protected areas of Umfurudzi Safari Area and Nyanga National Park where livestock grazing is not permitted. 42 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe Higher TLU densities are generally associated with 5.2.3 Harvested wild resources communal areas due to the higher densities of households owning livestock, although there are 165. Harvested wild resources are essential to rural exceptions such as Nyanga District in the southeast livelihoods in the Mazowe Catchment, with the vast of the catchment which is noted for low livestock majority of households depending on firewood as ownership. For example, Nyanga’s District Risk Profile their main source of energy (ZIMSTAT and UNICEF estimated that only 40  percent of households own 2019). Most rural households also obtain a range of livestock (GoZ and WFP 2017), significantly lower other products from natural habitats, including wood than most other rural districts. Parts of the district and thatching grass for construction, wild fruits and also have relatively low population densities, as do the vegetables, mushrooms, honey, medicinal plants, dry communal areas north of Kotwa, contributing to and other products. low livestock densities in these areas. TLU densities were highest in the northwest of the catchment, 166. Harvested wild resources were modelled using where rural population densities are high while the methods described in Turpie et al. (2020). greater rainfall allows for higher stocking rates then in These estimate the use of natural resources based the drier northeast of the catchment. on the capacity of the landscape to supply different types of resources on the one hand and the spatial distribution of the human demand for a given 5.2.2.2 Value of livestock production resource on the other. A further factor considered is accessibility, with resources in protected areas 164. Due to much higher offtake levels in the commercial assumed to be less available for harvesting (see farming sector, sales revenue from livestock is Appendix 4). more than double sales revenue from communal areas (Table 5). Total livestock sales revenue in commercial farmland was estimated to be 5.2.3.1 Quantification of wild resource harvesting US$41.8 million per year, with cattle accounting for 92 percent of this value. In communal areas, the 167. Wood is the dominant fuel source for most gross margin from livestock (that is, gross output (94 percent) rural households in Zimbabwe minus variable costs) exceeds sales revenue, due to (ZIMSTAT and UNICEF 2019). The average wood the inclusion of ploughing, hides and milk production usage across various studies consulted was around in the estimate of total livestock output in communal 4.5 tons per household per year (Campbell, Luckert, areas. The total gross margin of livestock production in and Scoones 1997; Campbell, Vermeulen, and the catchment was estimated to be US$64.7 million Lynam 1991; Mabugu and Chitiga 2002; McGregor per year, with cattle again accounting for the vast 1991; Woittiez et  al. 2013). According to census majority (94 percent) of this value. data, 22–38  percent of households across the  STIMATED VALUE OF LIVESTOCK PRODUCTION, EXPRESSED IN TERMS OF SALES REVENUE AND TABLE 5: E GROSS MARGIN (US$ MILLION PER YEAR, LATTER INCLUDES THE VALUE OF PLOUGHING, MANURE, AND MILK PRODUCTION FOR COMMUNAL AREAS) Livestock Sales revenue Sales revenue Sales revenue Gross margin Gross margin Gross margin (commercial) (communal) (combined) (commercial) (communal) (combined) US$ millions/ US$ millions/ US$ millions/ US$ millions/ US$ millions/ US$ millions/ year year year year year year Cattle 27.7 10.7 38.4 20.80 40.2 61.0 Goats 1.4 1.3 3.4 0.80 2.5 3.3 Sheep 0.4 0.1 0.5 0.03 0.3 0.4 All livestock 29.6 12.1 41.8 21.60 43.1 64.7 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 43 provinces of the Mazowe Catchment use traditional This is due partly to the location of miombo woodland wall materials (for example, pole and mud), while a areas in higher rainfall and generally more densely further 36–43  percent of households have a mixture populated parts of the catchment, resulting in higher of modern and traditional structures (ZIMSTAT 2012). demand for resources and thus harvesting levels. Average demand for construction wood was estimated Additionally, miombo woodland was estimated to to be around 1.5 tons per household per year have high stocks of certain natural resources. For (Campbell et  al. 1991; McGregor 1991; Grundy et  al. example, wild plant food stocks per unit area are 1993; Woittiez et  al. 2013). Some 43–56  percent of relatively high due to the presence and abundance of households in the study area have thatched houses multiple prized fruit tree species, including muzhanje/ (ZIMSTAT 2012), with annual demand from user mahobohobo (Uapaca kirkiana) and mobola plum households estimated to be 98  kg per year (Grundy (Parinari curatellifolia). Both species are harvested et al. 2000; Twine et al. 2003). The next most harvested in large quantities by local communities for both resources were estimated to be wild plant foods, consumption and informal sale (Chagumaira et  al. followed by thatching grass, mushroom and honey. 2016; Woittiez et  al. 2013). Miombo woodland Note that this excludes medicinal resources, for was also estimated to have high mushroom which there was insufficient information available. stocks, due to the abundance of tree genera (Brachystegia, Jubelnardia, and Uapaca) associated with ectomycorrhizal fungi. This results in a high 5.2.3.2 Value of wild resource harvesting abundance of edible fungi compared to other 168. The total value of the selected harvested wild woodland types (Degreef et  al. 2020; Mlambo and resources (wood, thatching grass, wild plant foods, Maphosa 2021). In degraded form, the average value mushrooms, and honey) in the Mazowe Catchment of resources harvested from miombo woodland was estimated to be US$105.7 million per year or an declines to an estimated US$40.51 per ha per year. average value of US$42.06 per ha per year of natural habitat (Table 6). Wood harvesting accounts for 170. Plantation forest had a notably low value of around half of this value. Wild plant foods were harvested wild resources per hectare (US$9.78 the next most valuable harvested resource, closely per ha), underscoring the importance of indigenous followed by mushrooms. Thatching grass and honey forest and woodland habitats for resource had relatively low total values. For thatching grass, harvesting. Plantation forests do not support this is the result of lower value per kg than most other important resources such as thatching grass or resources, while for honey it reflects lower household indigenous edible plant foods. In addition, some of consumption and participation in harvesting. the plantation area falls within protected state forest areas, where livelihood activities are more 169. Miombo woodland had the highest value of any restricted. Among natural habitat types, Acacia- habitat type (US$57.48 per ha per year; Table 7). Terminalia woodland and shrubland had relatively ESTIMATED QUANTITIES AND VALUES OF SUBSISTENCE HARVESTING OF SELECTED NATURAL RESOURCES TABLE 6:  IN THE MAZOWE CATCHMENT. PER HECTARE HARVESTING VALUES ARE BASED ON THE TOTAL AREA OF NATURAL HABITATS IN THE CATCHMENT, AS STOCKS OF HARVESTED RESOURCES WERE RESTRICTED TO NATURAL HABITATS ONLY Resource Total harvested Average harvesting Total value Average value (t/year) (kg/ha/year) (US$ millions/year) (US$/ha/year) Wood 2,125,385 845.7 53.1 21.14 Thatching grass 22,927 9.1 9.2 3.65 Plant foods 63,776 25.4 22.3 8.88 Mushrooms 14,383 5.7 17.3 6.87 Honey 1,548 0.6 3.8 1.52 All resources 2,228,019 886.6 105.7 42.06 44 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe  STIMATED QUANTITIES AND VALUES OF SUBSISTENCE HARVESTING OF SELECTED NATURAL TABLE 7: E RESOURCES IN THE MAZOWE CATCHMENT ACROSS DIFFERENT NATURAL HABITATS Habitat Area (ha) Total value of resources Average value of resources (US$ millions/year) (US$/ha/year) Indigenous forest 9,878 0.34 34.64 Plantation forest 12,795 0.13 9.78 Degraded forest 1,423 0.03 19.74 Miombo woodland 1,279,090 73.52 57.48 Degraded Miombo woodland 113,285 9.18 40.51 Acacia-Terminalia woodland 448,086 4.59 20.34 Degraded Acacia woodland 11,501 0.11 9.94 Miombo shrubland 340,769 11.38 33.40 Degraded Miombo shrubland 22,131 4.95 24.62 Acacia-Terminalia shrubland 242,266 0.54 20.43 Degraded Acacia-Terminalia shrubland 4,183 0.05 11.35 Grassland 22,360 0.83 37.29 Degraded grassland 1,966 0.04 20.72 ALL 2,513,022 105.70 42.06 low harvested resource values per unit area. This is partly due to the location of these habitat types in 5.3 Cultural services drier, less densely populated parts of the catchment, 5.3.1 Nature-based tourism as well as lower estimated stocks of certain resources compared to miombo woodland. Overall, the highest 171. The Mazowe Catchment has few major tourist values of wild resource harvesting per unit area attractions, though it does include some notable are generally associated with densely populated nature-based tourism attractions such as the miombo woodland areas, such as the communal northern end of the Nyanga Mountains and areas north of Harare (Figure 20). Natural resource the Umfurudzi Safari Area. As in most areas where stocks are generally more contiguous in the less tourism is not well developed, there are few or no densely populated northeast of the catchment, due statistics available. However, big data which reveals to the larger blocks of natural habitat which remain tourism activity can allow for the estimation of how here. However, harvesting values per unit area tourism value is spread across a landscape. National are generally lower here, due to lower household statistics were used to obtain information on tourism densities as well as the dominance of other vegetation expenditure which was separated into attraction- types (for example, Acacia-Terminalia woodland) based tourism and other forms of tourism. The which have a lower abundance of most harvested InVEST Visitation model was then used to obtain a resources than miombo woodland. The effect of spatial disaggregation of tourism activity, based on protected areas is also reflected in the map, with geotagged photograph densities (See Appendix 4 low harvesting estimated for Nyanga National Park, for further details). Umfurudzi Safari Area, and state forest areas due to the assumption that resources are less available for harvesting here. However, WMAs were not assumed 5.3.1.1 Value of attraction-based tourism to influence the availability of resources, as they do not impose any specific restrictions on the use of 172. In total, the value of attraction-based tourism wild resources. across the catchment was estimated to be Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 45 FIGURE 20: TOTAL VALUE OF SELECTED HARVESTED WILD RESOURCES (WOOD, THATCHING GRASS, WILD PLANT FOODS, MUSHROOMS AND HONEY ACROSS THE MAZOWE CATCHMENT) Note: Grey areas with zero value reflect cultivated and built-up areas, since these land cover types lack harvestable wild resources. Source: Based on Turpie et al. (2022). KEY POINTS • Tourism is not well developed in the Mazowe Catchment. • In total, the value of attraction-based tourism across the rural parts of the catchment was estimated to be US$47 million in 2019 or 4.6 percent of the national attraction-based tourism value. • Attraction-based tourism in natural areas specifically was estimated to have a value of US$36.2 million in 2019. • Natural areas had significantly higher tourism value than areas dominated by cultivation. US$76.5 million in 2019, or 8.2 percent of area, the tourism value of the rural area of Mazowe the national attraction-based tourism value. Catchment was estimated to be US$46.9 million The estimated tourism value per unit area in 2019 or an average of US$1,180 per km2 of non- (US$1,811 per km2) in the catchment is lower than urban land. the national average (US$2,246 per km2), affirming that it is generally not a key region for tourism. 173. The most notable areas of higher tourism value Furthermore, much of this value is attributed to are associated with the outskirts of Harare in the the outskirts of Harare. Excluding this peri-urban southwest of the catchment and popular nearby 46 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe natural attractions such as Domboshawa and 5.3.1.2 Visitor numbers to protected areas Mazowe Dam (Figure 21). Other areas with notable clusters of photographs include around Nyanga in 174. Available data on visitor numbers to parks within the southeast of the catchment, Mutoko in the center the Zimbabwe Parks and Wildlife Management of the catchment, and, to a lesser extent, Umfurudzi Authority (ZPWMA) estate, derived from annual Safari Area. Photographs are generally sparse in the reports produced by the Zimbabwe Tourism north of the catchment, which has no notable tourist Authority (ZTA), corroborate the modest estimates attractions. Using the total number of photo user of nature-based tourism in the catchment. Visitor days (PUDs) taken in grid cells where natural land number data for Umfurudzi Safari Area were provided cover categories were dominant, the value of nature- only for 2007–2010, where annual visitors varied based tourism in the catchment was estimated to significantly from as low as 513 in 2010 to 7,005 in be US$36.2 million in 2019 or US$1,369 per km2 2008, or an average of around 3,000 visitors per year. of natural land cover. This relatively modest value This is less than 1  percent of total visitor numbers again reflects the few major nature-based tourism to the whole ZPWMA estate over this period, attractions in the catchment. Nevertheless, natural highlighting that Umfurudzi is not a major tourist areas still had significantly higher tourism value drawcard. Visitor numbers to Nyanga National Park than cultivated areas. Attraction-based tourism in are higher, averaging around 20,000 per year since grid cells dominated by cultivation was valued at 2010, or about 3.5 percent of all visitors to ZPWMA’s US$13.2 million or just US$851 per km2. Thus, away protected area estate over this period, with a peak from urban areas, the analysis suggests that natural value of 26,408 visitors in 2018. In addition, much of areas are more attractive for tourism than more Nyanga National Park is freely accessible, meaning heavily transformed agricultural landscapes. visitor numbers are likely significantly higher in reality. FIGURE 21: ESTIMATED TOURISM VALUE OF THE MAZOWE CATCHMENT IN 2019 Source: Based on this study. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 47 However, some of Nyanga National Park’s prime 5.4.1.1 Quantification of carbon storage visitor attractions, such as Mount Nyangani and Mtarazi Falls, are not located within the smaller portion of 177. The total aboveground and belowground storage the park which falls within the Mazowe Catchment. of carbon across the Mazowe Catchment was Nevertheless, a concentration of tourist activity was estimated to be 126.8 million tons, or 465.2 tCO2e evident around Nyanga, including areas outside the (Table 8). This amounts to average storage of boundaries of the national park which have high 31.7 tCO2e per ha or 116.3 tCO2e per ha. As the most nature-based attraction tourism value due to their extensive natural habitat type, miombo woodlands high scenic quality (for example, Troutbeck). contain almost half of the carbon stored in the catchment. However, plantation and indigenous forest 5.4 Regulating services had higher values for carbon storage per hectare, reflecting the higher aboveground biomass (AGB) in these denser woody habitats. Acacia-Terminalia 5.4.1 Carbon storage woodland also had notably high carbon storage per hectare, almost equal to indigenous forest. This is 175. Ecosystems store carbon in their biomass and due in part to high estimated belowground biomass continuously add carbon to the soil. The degradation of landscapes releases stored carbon into the (BGB) across much of this habitat type. It also exhibits atmosphere as CO2, thereby contributing to global relatively high AGB, especially in comparison to climate change. Conversely, retention of carbon in miombo woodland. This is because Acacia-Terminalia ecosystems helps to reduce CO2 emissions. woodland is situated in the less densely populated lower reaches of the catchment, where remaining 176. While much of the Mazowe Catchment has low natural areas are generally more intact and less biomass due to historical conversion of natural degraded. This includes parts of Umfurudzi Safari habitat to agriculture, settlement, mining and other Area and densely wooded hilly areas along the uses, there are some notable areas of relatively Mazowe River in the extreme northeast of the dense woody natural habitats remaining, such country. as the Umfurudzi Safari Area and the sparsely populated rural areas in the northeast, which 178. With the exception of bare areas, cultivation do store significant quantities of carbon. Carbon had the lowest carbon storage per hectare, biomass was mapped using datasets derived from about 3 times less than miombo woodland and remote sensing methods (Bouvet et al. 2018; Santoro 4.5 times less than indigenous forest and Acacia- et al. 2018) (See Appendix 5 for more details). Terminalia woodland (Table 8). Carbon storage KEY POINTS • Carbon storage. In total, aboveground and belowground carbon storage across the Mazowe Catchment was estimated to be 126.8 million tons, or 465.2 tCO2e. Retention of this carbon results in avoided climate change-related losses worth US$1.23 billion per year globally. • Flow regulation. Through mediating infiltration, ecosystems can help reduce overall seasonal variation in flows, relative to the seasonal variation in rainfall. This potentially has an important bearing on the cost of supplying or obtaining water. Modelling of flows with and without vegetation cover did not generate a significant benefit for surface infrastructure. However, it was estimated that groundwater recharge would decline by 1263 Mm3 under a bare ground scenario, with a replacement cost of US$84 million per year. • Sediment retention. Vegetative cover prevents erosion by stabilizing soil and intercepting rainfall, thereby reducing its erosivity. It was estimated that landscapes across the Mazowe Catchment retain some 196.5 million tons per year of sediment (49.3 tons per ha per year), relative to a hypothetical landscape where all land cover is converted to bare ground. The value of the sediment retention service within dam catchment areas was estimated to be worth US$166 million per year. 48 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe  OTAL ABOVEGROUND AND BELOWGROUND CARBON STORAGE ACROSS THE MAZOWE CATCHMENT TABLE 8: T Land cover Total carbon stored Mean carbon storage Total CO2e Average tCO2e/ha (million tons) (tons/ha) (million tons) Indigenous forest 0.61 61.7 2.24 226.5 Plantation forest 0.89 69.3 3.25 254.2 Degraded forest 0.05 38.5 0.20 141.3 Miombo woodland 54.46 42.6 199.86 156.3 Degraded Miombo woodland 2.77 24.4 10.16 89.7 Acacia-Terminalia woodland 27.84 61.7 102.16 226.3 Degraded Acacia-Terminalia woodland 0.46 40.0 1.69 147.0 Miombo shrubland 7.96 23.4 29.22 85.8 Degraded Miombo shrubland 0.35 16.0 1.30 58.7 Acacia-Terminalia shrubland 9.07 37.4 33.28 137.4 Degraded Acacia-Terminalia shrubland 0.13 30.8 0.47 113.1 Grassland 0.49 22.0 1.81 80.7 Degraded grassland 0.03 15.1 0.11 55.5 Cultivation 21.19 14.4 77.78 52.7 Sparsely vegetated 0.00 7.3 0.00 26.7 Built-up 0.45 48.0 1.66 176.1 ALL 126.75 31.7 465.19 116.3 per hectare was notably high in built-up areas which and also in terms of potential income from the sale may be somewhat surprising. This can be attributed of carbon credits. For comparability, these values, to the prevalence of large garden and street trees, normally expressed in asset terms, were annualized. particularly in suburban areas. Due to the 100  m resolution of the land cover, treed areas within towns 181. The avoided costs of climate change were based are often lumped with hard infrastructure under the on the World Bank’s median estimate of the social built-up land cover category. value of carbon for 2022 (US$62 per tCO2e (World Bank 2017). At the global level, the asset value of 179. The spatial map of carbon biomass is shown in avoided economic losses through the retention of Figure 22. Areas of low biomass throughout the carbon stocks in the catchment was estimated to study area are associated with cultivation, with the be US$26.7 billion, equivalent to an annual value of lowest values associated with densely cultivated US$1.23 billion per year. The potential to generate communal areas in the south and west of the income from carbon credits is explored in Chapter 6. catchment. Highest carbon storage values are mostly found in the northeast where more extensive woody habitats remain. The Umfurudzi Safari Area is another 5.4.2 Flow regulation area of notably high biomass in the northern central part of the catchment. 182. During rainfall events, some water soaks into the ground, while the balance runs off the surface (herein referred to as ‘quickflow’). Some of the 5.4.1.2 Value of carbon storage former is lost due to evaporation from the soil or evapotranspiration by plants. Of the remainder 180. The retention of ecosystem carbon can be valued (herein referred to as the ‘net infiltration’), some in terms of the avoided costs of climate change emerges at springs to join streams and rivers (termed Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 49 FIGURE 22: CARBON BIOMASS (ABOVE AND BELOW GROUND) ACROSS THE MAZOWE CATCHMENT Source: Based on Bouvet et al. (2018) and Santoro et al. (2018): ‘baseflows’), while some replenishes groundwater or In general, the more variable the runoff, the larger aquifers (termed ‘groundwater recharge’). the built storage capacity required to meet water demands during low flow seasons (for small dams) 183. The balance between quickflow and infiltration or drier years (for large dams, Guswa et  al. 2017; varies considerably across the landscape and is Vogel et al. 1999, 2007). Small dams and run-of-river mediated to some extent by ecosystems. As well as users are particularly sensitive to seasonal variation retarding flood flows, vegetation cover facilitates the in flow. However, the extent to which ecosystems infiltration of rainfall into the ground, reducing the may play a role in smoothing surface flow variability proportion of rainfall that runs off the surface during and/or contributing to groundwater replenishment rainfall events. Depending on the evapotranspiration depends on a range of context-specific factors effects of the vegetation, this has an influence on the such as slope, geology, rainfall pattern, evaporation, contribution of rainfall to groundwater and baseflows evapotranspiration, groundwater depth, etc. in the landscape. 185. Water supply systems are engineered to the way 184. Through mediating infiltration, ecosystems can in which surface and groundwater flows vary therefore help reduce overall seasonal variation in across the landscape, as can be seen from the flows relative to the seasonal variation in rainfall. variation in how water is collected. However, if This can affect the cost of surface or groundwater land use or climate changes led to a decrease in supply by water utilities and/or the cost of collecting infiltration, this can result in increased quickflow, water (for households not supplied by infrastructure). leading to flooding, a reduction in dry season flows, 50 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe and/or the availability of groundwater and increased cover. To obtain the contribution of ecosystems to costs of storing and extracting water. flow regulation, current flows were then compared to those of a hypothetical bare ground landscape. 186. Both surface water and groundwater sources are used in the Mazowe Catchment. There are several 5.4.2.1 Ecosystem effects on flows small-to-moderate-size dams which supply irrigation schemes and bigger settlements. However, most 188. It was estimated that total quickflow (surface rural households in the study area depend on runoff during or shortly after rainfall events) groundwater. Excluding Harare, some 74–89  percent across the catchment is 3,132 Mm3 per year of households rely on boreholes and wells as their (78 mm per year). Net infiltration amounts to some main water source and 3–9  percent rely on surface 3,575 Mm3 per year (89  mm per year; Table  9). Of water (ZIMSTAT and UNICEF 2019). Groundwater is this, an estimated 2,145 Mm3, goes to groundwater still a major source of water for irrigation, mining, recharge, and 1,430 Mm3 is the baseflow contribution and tourism (Davis and Hirji 2014). to streamflow. Thus, total streamflow (quickflow + baseflow) is estimated to be 4,562 Mm3. These 187. A rapid-level estimate of the effects of ecosystems estimates are in line with published values (see on flow was made using the InVEST Seasonal Appendix 5). Water Yield (SWY) tool. This included the impacts of vegetation cover on quickflow, infiltration, and 189. Net infiltration is generally highest in natural land contribution to baseflow and groundwater recharge. cover types with a lower density of trees (Table 9). Flows were first modelled under the current land This reason also underlies the higher values for net  VERAGE QUICKFLOW AND NET INFILTRATION ACROSS DIFFERENT LAND COVER TYPES IN THE TABLE 9: A MAZOWE CATCHMENT Land cover Average Average net Net recharge % Difference quickflow (mm) infiltration (mm) (% of precipitation from bare ground received) Indigenous forest 16.0 −66.7 −7.0 −246.9 Plantation forest 162.9 −9.3 −0.8 −112.6 Degraded forest 29.3 171.3 18.1 169.2 Miombo woodland 38.0 124.0 15.0 276.1 Degraded Miombo woodland 79.4 185.9 22.5 321.8 Acacia-Terminalia woodland 28.1 34.9 5.1 104.8 Degraded Acacia-Terminalia woodland 56.5 79.0 11.7 321.6 Miombo shrubland 64.5 167.9 21.2 347.0 Degraded Miombo shrubland 103.1 238.4 30.1 359.5 Acacia-Terminalia shrubland 48.9 105.6 15.8 398.8 Degraded Acacia-Terminalia shrubland 77.8 141.4 21.1 488.2 Grassland 176.9 254.9 29.5 424.7 Degraded Grassland 220.4 274.6 31.8 438.4 Cultivation 125.0 47.0 6.0 1.4 Sparsely vegetated 290.4 49.1 5.9 −16.2 Built-up 601.8 −10.8 −1.3 −103.7 ALL 76.1 90.0 11.5 143.1 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 51 recharge in degraded land cover classes relative to rainfall and, in some cases, high evapotranspiration their undegraded equivalents. This is in line with due to high tree cover. Throughout the catchment, the meta-analysis of groundwater recharge studies areas where net infiltration is less than 0 mm reflect conducted by Owuor et  al. (2016), which found that areas where evapotranspiration loss exceeds the groundwater recharge rates usually decline when infiltration capacity. bare or degraded areas are restored. 190. Most natural land cover types have higher net Ecosystem contribution to groundwater 5.4.2.2  infiltration rates than cultivated areas, as the recharge and baseflow greater vegetation cover reduces quickflow, 194. Overall, it was estimated that net infiltration allowing more time for infiltration to occur. under the current land cover (3,576 Mm3 per year) However, forest and Acacia-Terminalia woodland had is 2.4 times greater than if the catchment was lower values for net recharge than cultivation, due bare of vegetation (1,470 Mm3 per year; Table 9). to the higher evapotranspiration losses associated Groundwater recharge and baseflow were estimated with these denser vegetation types. Indigenous and to be 1,263 Mm3 and 842 Mm3. higher than under bare plantation forests in fact had negative values for land cover. This is because quickflow runoff increases average net recharge, meaning that on each 30  m drastically at the expense of infiltration when there forest cell, more water is lost to evapotranspiration is no vegetation cover to intercept and slow runoff. that the amount that is left over on the cell after the immediate loss of a portion of rainfall to runoff. This 195. Natural habitats with a lower density of woody indicates that forested areas use surplus groundwater vegetation (shrubland and grassland) had the and subsurface flow coming down from upslope highest recharge capacity, with vegetation cover areas (that is, the upslope subsidy) to meet a portion increasing infiltration by at least 6 times relative of their water requirements. to bare ground in these habitats (Table 9). This is due to their ability to slow runoff as well as 191. The average quickflow in the different natural their lower evapotranspiration losses relative to land cover types reflects the combined effects of denser habitats. Conversely, forest has a lower net vegetation cover and rainfall. The highest values infiltration than bare ground, in line with findings of were associated with built-up and sparsely vegetated experimental studies (Owuor et al. 2016). This is due areas (Table  9), which have hard surfaces and/or little to high rates of evapotranspiration associated with vegetation to slow runoff. Indigenous forest had the trees. Cultivated areas also have lower net infiltration lowest value, as it is the densest land cover type. In than bare ground due to crop water consumption. contrast, plantation forest had a high mean quickflow value due to its sparse understory coupled with its 196. The difference in net infiltration that can be location in high rainfall parts of the catchment. attributed to ecosystems is shown in Figure 23. This map represents the ecosystem service of water 192. Cultivated areas also had relatively high quickflow capture by vegetation. Overall, this map shows values relative to most wooded land cover types that there is significantly higher infiltration under due to sparse vegetation cover. Acacia-Terminalia the current land than would be the case for a bare woodland had the lowest per hectare quickflow value, landscape. Areas where net infiltration would be due to both dense vegetation cover which intercepts higher if existing cover were converted to bare ground and slows runoff and its location in the drier lower are shown in brown. Examples include some of reaches of the catchment. the forested areas around Nyanga, due to the high evapotranspiration of forest vegetation noted earlier. 193. The highest net infiltration rates are found in the There are also some areas in the northeast of the high rainfall Eastern Highlands, especially under catchment where recharge would be increased if more open land cover types (relative to forest) such current cover was converted to bare ground. This as grassland and miombo woodland. The recharge is because evapotranspiration losses from habitats rate is also relatively high in the relatively wet south such as woodland and cultivation account for a higher and west of the catchment. Conversely, it is lowest proportion of the overall water balance equation in the northeast of the catchment reflecting lower in these drier areas. 52 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 23: DIFFERENCE IN NET INFILTRATION BETWEEN CURRENT LAND COVER AND BARE GROUND Note: Darker blue areas indicate a higher value for current land cover. Brown values (that is, <0) indicate areas where net infiltration would be higher if current cover was converted to bare ground. Source: Original calculations from this study. 198. The value of regulating surface water flows was also 5.4.2.3 Value of the flow regulation service explored. Patterns of quickflow and net infiltration 197. The groundwater recharge mediated by ecosystems within dam catchment areas were examined. was valued in terms of the avoided additional Quickflow is strongly linked to rainfall and drops expense that would have to be incurred to to virtually zero from May to September. Reduced meet current demands under a no-ecosystem vegetation increases the difference between wet (bare-ground) scenario. It was assumed that the and dry season flows. The sequential mass curve percentage decrease in net infiltration would have a procedure was used to estimate reservoir capacity similar impact on the combined yield from existing requirement for a series of arbitrary yield ratios for borehole and well infrastructure in each catchment, the dam catchment areas under the current and bare and the deficit would be made up through investment ground scenarios. However, the loss of vegetative in surface water infrastructure. Based on an assumed cover could not be shown to lead to a larger dam storage-yield ratio of 2, an estimated construction capacity requirement. In fact, because of the large cost of US$1.88 per m3 (based on data from eight increase in quickflow, the required dam capacity (for dam projects in Zimbabwe), and a 15 percent cost of all else equal) was smaller under bare ground. The capital, the value of the service for water supply was important caveat here is that, because this study valued at US$84 million per year. Note that this does was trying to isolate the flow regulation effect, this not include the value of maintaining groundwater- does not consider the impact of higher erosion and dependent ecosystems such as wetlands. sedimentation, which can severely reduce reservoir Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 53 capacity. It was concluded that sediment retention sedimentation accounts for about 37percent of the is the more important hydrological service in terms annual costs of reservoirs (Basson 2009). In urban of surface water resources to support existing dams contexts, elevated sediment loads also have to within the catchment. Similarly, in terms of flow be removed from sewerage systems, storm water regulation as a whole, the mediation of groundwater drainage systems, and harbors. recharge appears to be the more important ecosystem service than sustaining dry season flows. This is in 201. Soil loss and the sedimentation of rivers and line with the non-perennial nature of most rivers in the reservoirs is a serious issue in Zimbabwe, including region, which suggests that baseflow does not make in the Mazowe Catchment (Makwara and Gamira a large contribution to sustaining dry season flows 2012; Tundu, Tumbare, and Onema 2018). For (NUST 2019) example, there has been a 39  percent reduction in capacity of Chimhanda Dam (Tundu, Tumbare, and Onema 2018) and a 67 percent loss in storage capacity for Chesa Causeway Dam (Godwin et al. 2011). These Erosion control and sediment 5.4.3  smaller, low-capacity dams in communal areas are retention particularly prone to high siltation rates (Whitlow 1988). It has been estimated that such dams have 199. Soil erosion has been a serious concern in an effective lifespan of just 15  years before being Zimbabwe for some time (Whitlow 1988). High filled with sediment (Magadza 1984). Murwira et  al. soil erosion rates reduce topsoil depth as well as (2014) found a strong negative relationship between reducing soil water content, soil organic carbon and the degree of vegetative cover and the suspended removing nutrients (Roose 2008). This imposes costs sediment loads of rivers in the Mazowe Catchment on farmers, who must increase fertilizer application (Figure 24). to replace lost nutrients. In extreme cases, soils may become too shallow to support crop growth 202. In this study, soil erosion and sedimentation rates (Whitlow 1988). In addition to affecting agricultural were modelled using the InVEST Sediment Delivery productivity, the export of eroded soil to watercourses Ratio (SDR) model to estimate the amount of results in siltation, which can affect river flows and erosion and how much is exported to watercourses reduce the storage capacity of reservoirs. as sediment (See Appendix 5). In this study, we focus on the value of sediment retention by ecosystems 200. Vegetative cover prevents erosion by stabilizing for water supply from reservoirs, recognizing the soil and intercepting rainfall, thereby reducing serious issues caused by reservoir sedimentation its erosivity. Vegetated areas, especially wetlands, discussed above. The sediment retention service may also capture the sediments that are eroded was quantified by comparing sediment export from from upstream agricultural and degraded lands and the current landscape to one where all land cover is transported in surface flows, preventing them from converted to bare ground and the service valued is entering streams and rivers (Blumenfeld et al., 2009). based on the cost of dredging dams to recover lost Thus, vegetation protects downstream areas from storage. the impacts of sedimentation, which can include impacts on water storage capacity, hydropower generation and navigability of rivers (Pimentel et  al. 5.4.3.1 Current erosion and sediment export 2008). While some level of sedimentation of reservoirs is expected under natural conditions, and planned 203. Total erosion across the Mazowe Catchment was for, elevated catchment erosion either incurs dredging estimated to be around 127.9 million tons per costs or shortens the projected lifespan of reservoirs year, or an average of 32.0 tons per ha per year. and related infrastructure. The reduction of natural This estimate is comparable with Tundu, Tumbare, vegetation cover, whether through building roads and and Onema (2018), who estimated soil loss across settlements, mining, resource harvesting, grazing, the catchment ranged from 36 tons per ha per agriculture, or burning, results in elevated levels year to 65 tons per ha per year between 2000 and of erosion and subsequent increases in sediment 2014. Tolerable soil loss rates vary significantly, but loads carried downstream. Globally, anthropogenic generally range from 1 to 12 tons per ha per year, 54 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 24: RELATIONSHIP BETWEEN VEGETATION DENSITY (AS INDICATED BY NDVI) AND THE CONCENTRATION OF SUSPENDED SOLIDS IN RIVERS IN THE MAZOWE CATCHMENT y = 6609.2544 * x(22.2805 + 18.3529*In x) 150 Total Suspended Solids (mg/I) R2 = 0.64 100 50 Sparse Dense Vegetation Vegetation 0 0.35 0.40 0.45 0.50 0.55 0.60 Vegetation density (Mean NDVI) Source: Murwira et al. 2014. or around 10 tons per ha per year for agricultural modelling results underestimated sediment export soils (Roose 1996). Modelled erosion rates thus in the relevant catchments. significantly exceeded tolerance limits over much of the catchment, particularly in small-scale farming areas (69.2 tons per ha per year), as well as degraded 5.4.3.2 Sediment retention natural land cover types (for example, 30.3 tons per 205. It was estimated that landscapes across the ha per year in degraded miombo woodland, 83.5 tons Mazowe Catchment retain some 196.5 million tons per ha per year in degraded grassland). These high per year of sediment (49.3 tons per ha per year), erosion rates are in line with previous works. For relative to a hypothetical landscape where all example, Whitlow (1988) reported soil erosion rates land cover is converted to bare ground (Figure 25). in communal farmland to be 50 tons per ha per year Topography is a major factor determining the potential and 75 tons per ha per year in communal rangelands. for sediment export, with the highest values for These high rates of soil erosion on farmland impose sediment retention associated with hilly areas under costs on farmers who must replace lost nutrients with natural land cover. fertilizers, while in extreme cases, soils may become too shallow to support crop growth (Whitlow 1988). 206. In the catchment areas of dams, total sediment export was estimated to be 2.75 million tons per 204. Of the soil eroded in the study area, around year (2.59 tons per ha per year), while retention 11.6 million tons per year were estimated to by the landscape was estimated to be 43.7 million be exported to watercourses as sediment, with the tons per year (41.1 tons per ha per year) (Table 10). remainder being deposited across the landscape These figures highlight that sediment export form before it reaches streams or reservoirs. This gives natural land cover types is much lower than for an average sediment export rate of 2.9 tons per ha cutlivated areas, with the latter being the major per year. This is somewhat lower than the 6.0 tons contributor to sedimentation in the catchment. For per ha per year estimated by Tundu, Tumbare, and example, sediment export from miombo woodland, Onema (2018). However, comparison with measured the dominant natural land cover in the catchment, sedimentation rates did not suggest that the final is around 16 times lower per hectare than sediment Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 55 FIGURE 25: SEDIMENT RETENTION ACROSS THE MAZOWE CATCHMENT RELATIVE TO A LANDSCAPE WHERE ALL COVER HAS BEEN CONVERTED TO BARE GROUND Source: Calculations from this study. Sediment retained outside of dam catchments has been slightly greyed out. export from cultivated areas. Sediment retention Sediment retention by miombo woodland accounts realtive to a bare landscape is also drastically higher for the majority of the sediment retention value in for natural land cover types than for cultivation the landscape, reflecting its areal extent as well as (Table  10), highlighting the higher value of the the general location of miombo woodland in higher sediment retention service provided by natural land rainfall areas that are more prone to erosion. cover types. This reflects both the greater erosion control provided by natural land cover and that the remaining natural habitats tend to be located 5.5 Summary of ecosystem in steeper areas which are less suited to farming. This results in even greater erosion reduction relative values and their to natural land cover in flat areas. beneficiaries 208. The ecosystem services of the Mazowe Catchment 5.4.3.3 Value of sediment retention benefit a range of stakeholders (Table 11). The way in which these benefits are distributed among 207. Based on the cost of dam dredging, the value the different stakeholders is determined by the use of the sediment retention service within dam of the landscape, the resulting balance between catchment areas was estimated to be worth natural and transformed land cover types, and the US$166.3 million per year, or US$158.0 per ha. condition of those land cover types. 56 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe  STIMATED SEDIMENT EXPORT AND SEDIMENT RETENTION ACROSS DIFFERENT LAND COVER TYPES TABLE 10: E WITHIN DAM CATCHMENT AREAS OF THE STUDY REGION, AND THE ESTIMATED VALUE OF THE SERVICE Land cover Sediment export Sediment retention Sediment retention value (t/ha/year) (t/ha/year) (US$ million/year) Indigenous forest 0.06 88.0 1.0 Plantation forest 0.04 40.1 0.3 Degraded forest 0.74 114.3 0.4 Miombo woodland 0.32 88.4 88.4 Degraded Miombo woodland 1.72 53.3 23.1 Acacia-Terminalia woodland 0.12 64.2 1.4 Degraded Acacia-Terminalia woodland 1.25 27.7 0.1 Miombo shrubland 1.91 69.3 12.7 Degraded Miombo shrubland 5.67 50.5 2.3 Acacia-Terminalia shrubland 0.50 37.3 0.6 Degraded Acacia-Terminalia shrubland 2.68 14.9 0.0 Grassland 1.75 47.4 2.1 Degraded grassland 5.24 22.4 0.2 Cultivation 5.25 29.1 32.9 Sparsely vegetated 1.01 14.6 0.0 Built-up 5.45 37.1 0.8 ALL 2.23 41.1 166.3  UMMARY OF THE CURRENT VALUES OF SELECTED ECOSYSTEM SERVICES ASSESSED IN THIS STUDY, TABLE 11: S IN US$ MILLIONS PER YEAR Types of services Explanation Value to whom Value per year (US$, millions) Cultivated production Production value net of human inputs Communal farmers 38.0 Commercial farmers 30.2 Livestock production Production value net of human inputs Communal farmers 43.1 Commercial farmers 21.6 Wild resources Value of wild harvested foods, fuel, and raw materials Rural households 105.7 net of human inputs Sediment regulation Cost savings due to vegetation capacity to hold soil in Water utilities and 166.3 place or trap eroded soils before entering streams private dam owners Flow regulation (contribution Cost savings in water resources infrastructure due to Water utilities and/or 83.9 to baseflows and groundwater) facilitation of recharge by vegetation direct water users Tourism Net income generated as a result of tourism to natural Tourism sector 42.9 attractions Carbon retention Avoided climate-change damages as a result of Zimbabwe 30.0 avoided CO2 emissions from ecosystem degradation Rest of world 1,230.0 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 57 209. Rural households, who make up most of the that groundwater recharge saves costs in the region population, enjoy the greatest aggregate benefits of US$84 million per year. from ecosystems. These include agriculture and livestock production, worth an estimated US$43 and 212. Finally, there are global benefits from the retention US$38 million per year, respectively, and at least of carbon in the landscape, which helps avoid US$106 million per year from the use of natural further climate change damages, potentially worth resources provided by ecosystems. Commercial billions of dollars. farmers derive over US$50 million per year in benefits from the Mazowe Catchment, in addition to plantation 213. Table 12 shows that natural ecosystems provide forestry (not estimated). a broader range and higher value of ecosystem services compared to croplands per hectare. 210. In addition, all the inhabitants of the catchment Croplands often involve intensive agricultural practices, area benefit from the opportunities for recreational, such as monocultures, intense tillage, and the use cultural, or spiritual fulfilment offered by the area’s of synthetic fertilizers and pesticides, which can natural assets. Rural landscapes of the Mazowe have negative environmental impacts. However, well- Catchment area also make a small contribution to managed agricultural systems through CSA can the tourism sector, in the range of US$43 million per incorporate some ecosystem services, such as soil year. This value is linked to the extent of road conservation practices or agroforestry systems that infrastructure and tourism facilities as well as provide habitat for wildlife. Global carbon benefits attractive scenery and wildlife. account for the highest per hectare ecosystem service value for both natural ecosystem and cropland 211. The water sector is also a major beneficiary. In this ($408 and $147 respectively). Total ecosystem service study, it was estimated that sediment retention by values per hectare provided by natural ecosystem ecosystems generates cost savings of US$166 million increases from $168 to $576 with the consideration per year from avoided dam sedimentation risk alone. of global carbon benefits. For cropland the total Further benefits may be obtained where water is ecosystem service value per hectare is $84, but treated for use. While the regulation of surface flows increases to $231 with the consideration of carbon was not found to be a major factor, it is estimated sequestration in agricultural soils. TABLE 12: SUMMARY OF BASELINE ECOSYSTEM SERVICES VALUE (US$ PER HA) Crop Livestock Wild Sediment Groundwater Carbon Carbon Tourism Total Total production production resource retention (LB) (GB) value value harvesting excluding including GB GB Natural 0.0 25.7 42.1 52.8 33.9 0.1 408.4 13.7 168.3 576.5 ecosystem Cropland 51.6 0.0 0.0 23.8 0.3 0.1 147.0 8.5 84.3 231.2 58 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 6. Enhancing the Asset Value of the Mazowe Landscape: A Scenario Analysis 6.1 Overview as-usual scenario in a high-level cost-benefit analysis to determine the potential ROI. The 214. The previous chapter of the report quantified analysis is also performed at the sub-catchment and valued key ecosystem services provided by scale, to highlight priority sub-catchments and guide landscapes of the Mazowe Catchment in their a phased investment approach. current state. As noted over the course of the report, the full ecosystem service potential of the study area is not being realized due to environmental degradation. 6.2 Potential management actions 215. This chapter evaluates potential landscape interventions to restore, maintain, or enhance 217. Management actions to maintain soil, vegetation the flow of ecosystem services from natural and cover, biodiversity, and agricultural productivity are cultivated lands within the study area. It starts by mutually supportive and include (a) supporting, identifying potentially suitable interventions for the regulating, and/or incentivizing CSA practices various socioecological contexts of the study area which increase the productivity of land and reduce and estimating the impact that these could have on rates of land conversion, soil loss, and water ecosystem conditions and agricultural productivity. consumption; (b) limiting the use of grazing and wild resources to sustainable levels, to maintain 216. The potential outcomes in terms of the supply of their productivity as well as other services; and ecosystem services are compared with a business- (c) restoring and protecting key natural areas KEY POINTS • A range of agricultural and natural habitat restoration interventions are proposed for the study area: CSA, restoration of riparian buffers that have been lost to cultivation, the passive restoration of degraded natural habitats, management of grazing and resource harvesting pressures, and the improvement of community conservation areas. • CSA could increase crop production from small-scale farmland by US$32.8 million per year. • Full restoration of riparian buffers and degraded natural habitats could increase the value of wild resource harvesting by US$3.54 million per year. • The recovery of riparian buffers and degraded natural habitats and increased sequestration of soil carbon through conservation tillage could generate carbon credits worth at least US$13.5 million per year. • Collectively, the three interventions could result in an increase in groundwater recharge worth around US$11.8 million per year and avoided reservoir sedimentation costs of US$10.2 million per year. • A high-level estimation of costs and benefits of the proposed interventions over a 25-year time horizon suggests that implementing the proposed interventions across the whole study area could generate a return of US$1.70 for every dollar spent. • Six sub-catchments had an ROI of 2 or greater. This suggests interventions will be most cost-effective in these sub-catchments. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 61 important for biodiversity and ecosystem services may only need financial and technical inputs in the (Figure 26). start-up phase. On the other hand, curbing the unsustainable use of rangelands, trees, and wild 218. These will act synergistically toward deriving resources and encouraging practices to allow their diverse benefits from the area’s ecological capital. recovery requires stronger and ongoing regulation CSA practices increase productivity, thus reducing and/or incentives (such as payments for ecosystem the pressure to convert natural areas to farmland services) and supporting measures such as the and reducing dependence on grazing and harvested planting of woodlots and/or investment in alternative resources. If such practices are applied well, the rate or more efficient energy sources. Provision of of loss of natural ecosystems within the catchment secure land tenure and resource rights, for example, could be reduced. The recovery of rangelands will through conservancy establishment, could be a ensure the provision of benefits into the longer powerful incentive for the sustainable management term, including during times of economic shocks of natural resources as well as a lever of private or climate stress. The restoration of natural areas sector conservation funding. Current understanding will help sustain water quality and water yields of the potential for these three areas of intervention critical for household livelihoods, as well as provide are discussed in more detail below. alternative income opportunities, such as from biodiversity, carbon, and hydrological services, some of which could be reinvested in land and resource 6.2.1 Climate-smart agriculture management. 220. Earlier discussions highlighted the severe threat 219. The choice of policy measures or interventions posed to agriculture under future climate change to achieve these ecosystem management changes (Benitez et al. 2018; World Bank 2019, 2021) as well depends on how critical the outcome is, the as the serious concerns with erosion, particularly relative costs and benefits to the actors versus in communal areas (Godwin et al. 2011; Makwara the rest of society, and who the beneficiaries and Gamira 2012; Tundu, Tumbare, and Onema are. Some examples are given in Figure 26. Because 2018; Whitlow 1988). The adoption of CSA has the CSA measures are generally a win-win solution, they potential to address both low productivity and land FIGURE 26: THE THREE BROAD INTERVENTIONS TO ACHIEVE SUSTAINABLE USE OF THE MAZOWE CATCHMENT AREA THAT DERIVES MAXIMAL BENEFIT FROM ITS ECOLOGICAL CAPITAL AND THE VARIOUS MEASURES THAT CAN BE USED TO ACHIEVE THEM Extension services Land rights and & concessional governance and loans Climate-smart agriculture Investments in alternative energy Tradeable grazing and resource rights Formal protection, Restoration and enforcement Sustainable protection rangeland of key Certification management ecological schemes infrastructure Government restoration programmes Community conservancies & Stewardship, joint venture partners Payments for ecosystem services 62 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe degradation. Indeed, a Climate Smart Agriculture production and water saving benefits, it has been Investment Plan (CSAIP) has already been prepared estimated that conservation tillage increases the for Zimbabwe (World Bank 2019). uptake of soil carbon by 0.18 tCO2e/year, thus increasing the value of carbon stored by the 221. CSA encompasses a wide range of practices, landscape (World Bank 2019) including conservation agriculture (CA) (which reduces soil and water losses), agroforestry, 223. Zimbabwe officially promotes CA practices improved livestock fodder production, rainwater through the Pfumvudza/Intwasa programme. harvesting, and soil conservation infrastructure. The implementation of CA on 360,000 ha of cropland CSA practices improve land productivity and could and 1.1 million ha of degraded arable land also reduce the rate of loss of natural ecosystem areas forms part of the country’s LDN targets. In the to cultivation (Marongwe et al. 2011). 2020/2021 season, around 200,000 ha of maize was planted under the Pfumvudza/Intwasa programme (MoLAWFRR 2021). Average yields were 5.3 tons per 6.2.1.1 Conservation agriculture ha, nearly five times higher than the national average of 1.2 tons per ha (MoLAWFRR 2021). Within 16 project 222. CA is premised on three main principles: districts, average maize yields in Pfumvudza plots minimum mechanical soil disturbance, improved (4.19 tons per ha) were almost twice as high as those maintenance of ground cover using organic matter, from non-Pfumvudza plots (2.27 tons per ha) (IAPRI and diversification of crop species to move away and FAO 2021). This is a more realistic comparison, from monocultures (Kassam et al. 2009; Marongwe as it effectively controls for selection bias in the et al. 2011). These practices have the potential to bring location of the program within the country. However, multiple benefits to both farmers and ecosystems at large. Conservation tillage (for example, ridge tillage, it should be noted that a key component of the tine tillage18) is estimated to reduce erosion by Pfumvudza concept is the use of small plot sizes 65  percent and no tillage by 75  percent, relative to (around 600 m2). Small fields are generally more conventional ploughing (Panagos et al. 2015; Stone productive per unit area than larger fields (see Ali and and Hilborn 2001). Mulching is estimated to reduce Deininger 2015; Larson et  al. 2014). When comparing evaporation from the soil by 15–24  percent (World small fields only, Pfumvudza plots have a yield Bank 2019) while contributing to further reductions benefit of just 9  percent over similarly sized non- in erosion (Kassam et al. 2009; Panagos et al. 2015). Pfumvudza plots. Nevertheless, the analysis used just All of this contributes to higher germination rates one year of data from areas which received relatively and reduced moisture stress and improves resilience good rainfall and greater relative benefits would be in the face of increased temperatures and rainfall expected in drier areas (IAPRI and FAO 2021). Also, variability under climate change (Marongwe et  al. benefits are likely to increase over time (Twomlow 2011; World Bank 2019). Soil fertility may be enhanced et al. 2008; ZCATF 2009). by intercropping or rotation with legumes and/or agroforestry species, while the precise application of 224. Barriers to adopting CA include higher labor fertilizer reduces input costs and nutrient pollution requirement, and competition with livestock for (Marongwe et  al. 2011; Twomlow et  al. 2008). crop residues (Twomlow et al. 2008; ZCATF 2009). Recommended strategies for the Mazowe Catchment Labor demands could be addressed through the include intercropping or rotation of maize with crops use of low-cost seeding equipment (Marongwe such as soybeans, cowpeas, or green beans to et  al. 2011). Support for purchasing such equipment both enhance soil fertility and increase nutritional could thus be key to increasing adoption of CA. diversity. Collectively, these factors have generated To address competition over crop residues, farmers considerable yield increases, ranging from around could consider using other sources of mulch such as 30 percent to as high as 200 percent across different grass or kitchen compost (ZCATF 2009). Ultimately, regions of the country (Marongwe et  al. 2011; increased production under CA could yield more Twomlow et  al. 2008; ZCATF 2009). In addition to crop residue for both mulching and livestock. 18 Ridge tillage involves creation of raised planting beds (ridges), while tine tillage involves working only the top 5–7 cm of soil Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 63 227. Agroforestry can increase the absorptive capacity 6.2.1.2 Adjusting crop choices of soil, reducing runoff evaporation, improving 225. In addition to rotation and intercropping as soil fertility and nutrient cycling, and providing part of CA, switching to more drought-resistant leaf litter for mulching and fodder and shade for crops like sorghum has also been suggested livestock (Liniger et al. 2011; World Bank 2019). to maintain or improve agricultural production This could be beneficial in the hot and dry northern (World Bank 2019). However, sorghum is generally regions of the catchment. For example, agroforestry lower yielding. According to the National Crop and has been shown to reduce soil evaporation after Livestock Assessment Reports, the average sorghum rainfall by 15–24  percent and increase soil wetness yield across the constituent provinces of the Mazowe by 9–18  percent (Siriri et  al. 2013). Other benefits Catchment is around 0.47 tons per ha, compared include the provision of wood and other non-timber to 0.99 tons per ha for maize (MoLAWFRR 2020, forest products such as fruit, which can be used 2021).19 In this study, an analysis was undertaken to diversify diets and income sources, particularly to investigate whether switching to sorghum would during drought and other challenging times (Liniger yield production gains in the Mazowe Catchment et al. 2011; World Bank 2019). (see Appendix 6). Future suitability ratio layers were generated for maize and sorghum by dividing current suitability by future suitability, using the layers 6.2.1.4 Improved livestock fodder production produced for the CSAIP (World Bank 2019). In all sub- 228. Intercropping of cereal crops with fodder crops catchments, future combined production of maize and/or shrubs has the potential to improve soil and sorghum was lower under the crop switching fertility and reduce fertilizer costs (Marongwe scenario than predicted future production if the et al. 2011) while providing an improved source current maize/sorghum mix remains unchanged. This is because projected maize yields in the study of food for livestock. The CSAIP recommended the area remain higher than sorghum even under climate introduction of velvet beans as an additional food change. Thus, the final intervention scenario did not source for cattle as one of the most promising cost- include any production gains due to crop switching. effective measures for improving the sustainability Nevertheless, it is acknowledged that switching to and productivity of communal cattle (World Bank sorghum may be beneficial for increasing drought 2019). This could help reduce grazing pressures resistance among small-scale farmers in drier parts on natural habitats but only if it is accompanied of the catchment. Switching from sorghum to maize by measures to discourage an increase in stocking is likely to be more beneficial in the south and rates as a result of the availability of supplementary west of the country, where future suitability for food. Since fodder crops provide a more nutritious maize declines more drastically than in the Mazowe food source than natural forage, especially in the dry Catchment (see Appendix 6). season, this could improve livestock production and meat quality (World Bank 2019). It could also reduce the need for dry season burning to stimulate grass 6.2.1.3 Agroforestry growth (World Bank 2019). 226. Agroforestry involves integrating woody perennial species with crops and/or livestock to take 6.2.1.5 Soil and water conservation advantage of a range of benefits and services and harvesting (Liniger et al. 2011). Forms of agroforestry are already traditionally practiced by small-scale farmers in 229. The majority of smallholder farmers in Zimbabwe Zimbabwe, including the retention of indigenous fruit depend on rainfed agriculture, putting them at trees and planting of fruit trees in and around rural high risk of crop failure, especially under climate home gardens (Campbell, Luckert, and Scoones 1997; change (World Bank 2019, 2021). Measures to Maroyi 2009). Agroforestry has also been identified improve conservation and harvesting of water are as a key strategy for improving the agricultural thus a key part of CSA. CA practices like mulching can sector by the Zimbabwean government (GoZ 2013). already result in notable gains in crop water efficiency 19 These estimates are based on the reported yields for the three most recent rainy seasons captured in the National Crop and Livestock Assessment Reports. 64 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe (Marongwe et al. 2011; World Bank 2019). In addition, restoration alone (Kalaba et al. 2013; Williams et al. availability of water for irrigation could more than 2008). This is because the main regeneration strategy double the yields for many crops, particularly in the of miombo species is through coppice regrowth country’s drier agro-ecological regions (World Bank and root suckers, meaning vegetation can recover 2019). Small-scale water harvesting technologies like passively where sufficient stumps and root stock rain barrels or community ponds are cost-effective ways remain (Strang 1974). Passive recovery can be brought of achieving this compared with large-scale irrigation about through adoption of sustainable rangeland infrastructure (World Bank 2019). management and the sustainable harvesting of resources, particularly wood. 230. Enhanced soil and water conservation structures in fields could also lead to further water savings. 233. In communal lands, access to grazing and firewood Contour ridging and hedgerows are already prevalent is relatively unrestricted. Sustainable practices would in communal farmland in the study area (Whitlow require active management on the basis of regular 1988; Zikhali 2010). However, old contour ridges assessments of resource status and following best are often neglected or ridges not dug at all on new practice guidelines (Liniger and Studer 2019). This farmland, partly due to the persistent association of would entail reducing livestock numbers and using contour ridges with forced labor under colonialism, rational grazing, reducing burning practices, and where the practice was made compulsory (Makwara reducing the rate of harvesting of woody resources and Gamira 2012; Whitlow 1988). Low-cost techniques, in rangeland areas. Initially, these pressures would such as adding sisal or vetiver grass to contour ridges/ need to be greatly reduced until forage and woody hedgerows, in combination with improved contour ridge maintenance, could be effective. This will lead to stocks recover to maximally productive levels. improved soil and water conservation (Makwara and Gamira 2012; ZCATF 2009). Protection of key ecological 6.2.3  infrastructure Sustainable rangeland and 6.2.2  234. As shown in Chapter 5, the value of ecosystem resource management services varies across the landscape. Areas that 231. There are extensive areas of the catchment where are of particular importance in terms of regulating natural vegetation persists in a degraded state services are recognized as ‘ecological infrastructure’ and its ecosystem service value is reduced. This since they often complement or save on grey includes areas which have been partially cleared for infrastructure in economic production. These tend cultivation, abandoned fields, areas thinned out to include20 for fuelwood harvesting, and areas where livestock • Higher-rainfall areas, where healthy vegetation overgrazing has reduced woody and/or herbaceous cover is important for mediating rainfall infiltration; biomass. Pressure on these areas needs to be reduced to allow them to recover their productivity and then • Steeper areas, where natural vegetation cover is managed sustainably. This could make a significant important for preventing erosion; contribution to Zimbabwe’s LDN commitment to • Riparian areas, where natural vegetation reforest 6.4 million ha of deforested land (GoZ 2017) cover is particularly important for preventing as well as improve the resilience of the area to climate anthropogenically generated sediments and change. nutrients from entering river systems; and 232. Woodland structure and biomass in abandoned • Wetlands, which contribute to flood attenuation fallows and areas affected by fuelwood harvesting as well as sediment trapping and nutrient can fully recover over 20–30 years, through passive uptake. 20 Note that areas important for carbon sequestration and storage are not typically referred to as ecological infrastructure. Ecological infrastructure is more commonly associated with hydrologically linked services. In the study area, all the interventions address the restoration and retention of carbon in the landscape, and the potential for this is an important driver for rangeland conservation through PES. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 65 238. Riparian buffers also have notable biodiversity 6.2.3.1 High-rainfall areas benefits. They help maintain aquatic habitats by 235. High-rainfall areas are often protected as water regulating stream temperature and providing inputs catchment areas. In the study area, some protection is to woody debris and other organic matter beneficial afforded by the Nyanga National Park, but much of the to aquatic organisms (Wenger 1999). They can also higher rainfall areas is already heavily transformed. help serve as movement corridors for terrestrial wildlife, thus enhancing landscape connectivity. 6.2.3.2 Vegetation on steep slopes 239. In theory, cultivation within 30 m of streams is 236. Steeper areas tend to be less transformed by prohibited in Zimbabwe under the Stream Bank agriculture but are increasingly becoming affected Protection Act of 1952, though this prohibition by woody vegetation removal. Landowners need is commonly ignored (Dube et al. 2018; Zinhiva, to be educated on this, and areas on steep slopes Murwendo, and Rusinga 2017;). Satellite imagery may need to be protected through legislation. reveals that this is the case in the study area too, with riparian buffer areas in parts of the catchment reduced to less than 30  m or removed altogether 6.2.3.3 Riparian buffers (see Figure 27 for an example). 237. Riparian vegetation plays an important role in trapping sediment in runoff and reducing channel 240. Where riparian buffers have been degraded by erosion (Márquez et al. 2017; Tanaka et al. deforestation, livestock watering, and cultivation, 2016; Wenger 1999) and also retains a significant they can be allowed to recover slowly through proportion of the nutrient runoff from agricultural protection, or recovery can be enhanced through landscapes (Anbumozhi, Radhakrishnan, and assisted natural regeneration (ANR). ANR seeks to Yamaji 2005). Indeed, studies have shown that a accelerate natural successional processes through riparian buffer width of 30  m is sufficient to trap removing or reducing barriers to regeneration, such as sediments under most circumstances (Wenger 1999). controlling weeds and/or invasive species, protecting FIGURE 27: AN EXAMPLE OF A HEAVILY CULTIVATED RIPARIAN AREA ALONG THE MAZOWE RIVER NEAR GLENDALE, WITH MINIMAL RIPARIAN VEGETATION REMAINING Source: Google Earth imagery. 66 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe from livestock and fire, and other measures (Shono, greater than those opportunity costs, (b) address Cadaweng, and Durst 2007). the demand for those resources, or preferably both. Addressing demand will help reduce opportunity 241. Restoration of degraded ecological infrastructure costs. These are discussed further below. would also contribute to the country’s ambitious LDN target of reforesting 6.4 million ha of deforested land (GoZ 2017). 6.3.1 Providing positive incentives 244. Creating the incentive for communities to control 6.2.3.4 Wetlands their own use (option a above) could be achieved through a combination of the provision of 242. Wetlands are particularly valuable elements of secure property rights21 and reliable stock the landscape. Their actual roles vary considerably, assessments and management advice and based on how they are formed and how they function. could be further incentivized through PES In general, they are highly productive and have high schemes and/or provisions to set up communal value in terms of provisioning services, ranging from conservancies to generate income from wildlife- harvesting of foods and raw materials to a source based joint venture partners. Secure property rights of dry-season grazing. These same characteristics (whether communal or individual) and ecosystem often make them important refugia for biodiversity. monitoring are both prerequisites for the successful Because of their vegetation and storage capacity, establishment of both PES schemes and joint venture wetlands also play a major role in attenuating flows business arrangements. (quickflow) through the landscape. Their capacity to slow water flows, combined with their high productivity, gives them a high capacity for removing 6.3.1.1 Payments for ecosystem services anthropogenic sediments and nutrients before they enter rivers. The characteristics of wetlands that 245. PES schemes involve making payments to enable them to deliver these services also make ecosystem owners/managers in return for them highly vulnerable to degradation and loss the delivery of ecosystem services or a proxy through overgrazing and cultivation. When this leads management regime. The payments are conditional to development of erosion gullies and consequent on service delivery, and the metrics and rewards for desiccation, the degradation is particularly difficult delivery are clear and transparent. to reverse. 246. Participation is voluntary. Communities are ideally invited to organize themselves and bid to become 6.3 Potential measures to part of the scheme through persuasive marketing rather than being coerced to participate. Payment bring about sustainable terms are negotiated and need to exceed the costs practices incurred by the service providers, to be viable. These costs could include reduced livestock benefits and 243. Achieving the recovery and sustainable use of reduced access to harvested resources as well as the rangeland areas would require motivating protection of the designated area from use by others. communities to establish respected systems of It could also include labor time in ANR and desisting governance that can control the use of resources from expansion of fields into unploughed areas. to the benefit of the community as a whole. From an individual perspective, this would come 6.3.1.2 Riparian stewardship/PES at an opportunity cost, at least in the short term. Interventions to achieve sustainable resources 247. Protecting riparian areas can be difficult because of management therefore need to (a) generate benefits their linear nature. However, engaging communities 21 Note that, in the context of rangelands, by assigning secure property rights we do not mean subdividing or fencing common grazing areas. Large contiguous grazing areas are increasingly necessary in the face of climate change, as they provide opportunity to move in response to local conditions. Rather it means that access and use of rangeland areas is limited and controlled, as opposed to uncontrolled open access. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 67 to do this under a stewardship program can provide directly between private investors and communities. a practical solution. While it is untested in rural Community conservancies would also contribute to areas, there is successful precedent for such a biodiversity conservation and maintaining of wildlife program in urban or peri-urban areas—the Mlalakua populations in the catchment as a whole. River Restoration Project in Dar es Salaam and the Sihlanzimvelo Stream Cleaning Project in Durban. 249. Current opportunities for expanding wildlife- In these programs, sections of rivers or streams are based land uses in the Mazowe Catchment are maintained by cooperatives which are responsible relatively limited due to the highly transformed for removing alien vegetation, rubble, and any solid nature of most of the catchment, particularly in waste blocking the free flow of water down the stream communal areas. Currently, wildlife-based land uses or river. They are also responsible for maintaining in communal land are mainly in the far northeast the grass and other vegetation along the banks of of the catchment, where sizeable areas of natural the waterway. Both projects were initiated with habitat remain in an area of rugged mountainous donor funding (EUR 400,000 in Dar es Salaam and terrain which supports populations of elephant and US$3 million in Durban). The programs have provided other wildlife (Amon 2011; Muchapondwa, Carlsson, employment for hundreds of people. It would not and Köhlin 2008). Due to topography and climatic be difficult to adapt the idea for rural riparian areas. conditions, this is also one of the most marginal parts of the catchment for agriculture. The selected area encompasses the existing Nyatana Game Reserve22 6.3.1.3 Communal wildlife conservancies and adjoining WMAs of Karamba, Chimukoko, and and joint venture partnerships Mukota A. Nyatana is around 75,000 ha and is jointly managed by the three CAMPFIRE districts of 248. Another option that will help recover and maintain healthy rangelands is to switch to wildlife-based Mudzi, Rushinga, and Uzumba-Maramba-Pfungwe. land use. This is potentially feasible where sizeable Elephant trophy hunting has been important in the tracts of the landscape remain untransformed and past, through joint venture partnerships between where agriculture is marginal. As noted in Zimbabwe’s the Nyatana Joint Management Trust and private Biodiversity Economy report (Turpie et  al. 2022), safari operators (Amon 2011). However, there is little there is potential to expand the development of up-to-date information on the status of this area, wildlife-based land uses outside state protected though there are indications that it is experiencing areas, particularly in communal areas and private degradation by poaching, deforestation, mining, and land, and potentially in state-owned fast-track other activities.23 A news article from 2021 also resettlement areas, through a new community stated no hunting partner was currently operating conservancy model similar to Namibia’s community- in the area.24 based natural resources management (CBNRM) program. The main barriers to this are land tenure, 250. Given that its current tourism potential is not lack of rights over wildlife, and start-up costs, being realized, there are opportunities to improve particularly since wildlife has largely been depleted and expand community conservation areas and in these areas. While CAMPFIRE has gone some way associated tourism activities in the northeast toward increasing community involvement and of the catchment. Satellite imagery, land cover, benefits from conservation, this has been limited and aboveground carbon biomass suggests that by the program’s institutional setup under the rural there is also an area with potential for conservation district councils. Allowing communities to form true extending beyond the boundaries of Nyatana Game community-owned conservancies would increase the Reserve. Wildlife tourism could be a particularly attractiveness of wildlife-based land use. Community valuable alternative livelihood strategy here, given conservancies would provide opportunities for joint- that this is the driest and hottest part of the Mazowe venture enterprises and agreements to be made Catchment with conditions poorly suited to rainfed 22 Unfortunately, Nyatana Game Reserve is not included in the World Database on Protected Areas (WDPA) layer of protected areas in Zimbabwe (UNEP-WCMC 2022). A rough map of its boundaries is shown in Amon (2011). 23 https://allafrica.com/stories/201509100267.html. 24 https://www.herald.co.zw/jumbo-attacks-on-the-rise/. 68 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe agriculture. However, significant investments in tourist 6.3.2.2 Replacing traditional functions infrastructure such as roads and lodges, improved protection of the area, marketing, and other 254. Many households keep cattle to fulfil one or more measures would be needed to create an attractive roles such as a form of banking (converting cattle to tourism product. These investments would provide cash when required) or payment (for example, for opportunities for employment of community members bride price) or to provide draught power, manure, as game scouts, guides, or lodge staff. and milk and for status. While small herds will likely remain important to most farmers because of their integral relationship to crop farming, herd size might 6.3.2 Managing resource demands be reduced in the presence of easier access to cash or banking and cheaper credit. 251. Demand for scarce resources can be addressed in several ways, usually through regulation and/or pricing, or the introduction of cheaper or better 6.3.2.3 Improved cookstoves alternatives. For grazing, this can be achieved through grazing taxes or fees or tradeable grazing 255. Improved cookstoves can reduce fuelwood rights.25 For firewood, this can be achieved by consumption through more efficient combustion, introducing cooking technologies that require less with fuel savings of up to 60 percent improvement firewood or by introducing alternative energy sources. over the traditional three stone stove (Urmee and Production of charcoal is illegal in Zimbabwe and can Gyamfi 2014). Reductions in carbon and particulate also be controlled through enforcement of the law. matter emissions also mean improved cookstoves These options are discussed in more detail below. can bring significant health benefits (Ezzati, Mbinda, and Kammen 2000). However, the success of this strategy is varied (Honkalaskar, Bhandarkar, and Sohoni 6.3.2.1 Grazing taxes and rights 2013; Jeuland and Pattanayak 2012). Adoption of 252. Taxes and charges are among the most effective improved cookstoves in Zimbabwe remains limited, instruments for reducing environmental damages. with many programs having collapsed soon after the While they are also useful for raising revenues, they termination of donor funding (Makonese, Chikowore, are understandably unpopular and tend to be and Annegarn 2011). Barriers to sustained adoption used only where it can be shown that they do not include the costs of the stoves, inappropriate have retrogressive effects. Taxes, for example, can technologies, and lack of community training and be justified to reduce carbon emissions, which pose participation in stove design (Roden et  al. 2009; serious threats to humanity. Charges can be justified Urmee and Gyamfi 2014). Designs need to include where these are used to pay for the management of consideration of cultural preferences, convenience, communal areas. and versatility relative to traditional cooking methods (Makonese, Chikowore, and Annegarn 2011). If 253. Tradeable grazing rights can further strengthen the these issues can be addressed, there is potential control of grazing pressure within a communally for meaningful adoption of improved cookstove managed grazing system. This is a cap-and- technology, as demonstrated by the relative success trade arrangement, where the number of grazing of the well-designed Tsotso stove in Zimbabwe in the permits is capped according to grazing capacity and 1980s (Makonese, Chikowore, and Annegarn 2011; production objectives (traditional wealth systems Urmee and Gyamfi 2014). More recently, the United under open access tend to be at full capacity, Nations Children’s Fund (UNICEF) reported that Tsotso commercial production systems focusing on income stoves were rolled out to almost 4000 households in typically optimized at half capacity). Permits are Hurungwe, reducing fuelwood consumption by up freely tradeable. to 39 percent.26 25 Growing feed has been suggested as an option but is likely to have rebound effects (supporting more rather than fewer livestock). 26 https://blogs.unicef.org/blog/improved-cookstoves-cut-illness-not-trees/. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 69 cookstoves are recommended as a more realistic 6.3.2.4 Alternative energy - biogas digesters intervention for widespread household adoption, 256. Biogas digesters have also been introduced in as costs and technical expertise requirements are Zimbabwe as an alternative energy source, much lower than for biogas digesters. with potential to make a significant contribution to reducing household fuelwood use (Kaifa and Parawira 2019; Mshandete and Parawira 6.4 Scenario analysis 2009). The government has established a National Biomass Programme in partnership with donors and 6.4.1 Business as usual nongovernmental organizations and embarked on 258. In the scenario analysis, a full-scale intervention the construction of biogas digesters at rural schools scenario is compared with a BAU scenario. The and hospitals through the Rural Electrification Agency, impact of a BAU trajectory on ecosystem service including a commercial biogas plant in Kotwa in the values was modelled by the extrapolation of the northeast of the Mazowe Catchment.27 Cow dung is natural habitat degradation trends (as measured used in around 90  percent of plants in Zimbabwe, by NDVI) that were estimated in the assessment of with the remainder using human sewage or pig ecological trends in the Mazowe Catchment. This manure (Kaifa and Parawira 2019). While there could projection was performed for a 25-year period, be some competition with the need for manure in to match the period over which restoration costs agriculture, the leftover digestate can itself be used and benefits were modelled. In projecting future as a fertilizer (Kaifa and Parawira 2019). degradation, it was thus assumed that future rates of degradation would be comparable to the annual 257. However, adoption of biogas digesters remains rate of degradation observed between 2001 and low, due in large part to the costs of installing 2018 through the NDVI trend analysis. biogas digesters and insufficient awareness of the technology. Furthermore, poor design, insufficient fuel stock, poor maintenance, and other challenges 6.4.2 Full-scale intervention scenario hinder the long-term success of installed digesters. For example, one Zimbabwean study found that 259. The sustainable land use scenario involved only 11  percent of surveyed biomass digesters were modeling the effects of a range of interventions to still functional (Kajau and Madyira 2019). In this improve land and resource management practices study, appropriately designed, low-cost improved in the study area (Table 13). Based on the rationale  UMMARY OF PROPOSED LANDSCAPE MANAGEMENT INTERVENTIONS AND THEIR RELATIVE TABLE 13: S EXTENTS AND COSTS Sustainable land uses Potential extent Supporting interventions Initial cost Ongoing costs (US$) (US$/year) CSA practices 550,527 ha, Assistance with setup, long-term 120/hh 20/hh 175,000 households (50%) extension services Sustainable rangeland 735,586 ha PES services 10/ha Average 18.8/ha management 515,000 households Rollout of subsidized efficient stove 15/hh — technologies linked to PES scheme Community 53,000 ha Community conservancy development, 1.50/ha 0.40/ha conservancies capacity building, and joint ventures Riparian buffers 9,166 km Stewardship payments/monitoring and 1,200/km 180/km enforcement Note: hh = Household. 27 https://rea.co.zw/biogas_energy/. 70 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe provided in the previous sections, the assumptions resource harvesting controls. This is incentivized for the scenario are outlined below. through provision of support for the formation of community conservancies and through the implementation of a payments for ecosystem services 6.4.2.1 Climate-smart agriculture scheme. 260. CSA is supported in communal lands and 263. The cost of setting up such a scheme was estimated resettlement areas, through provision of extension at US$10 per ha (Bond et al. 2010). Assuming services, equipment, and supplementary labor. that delivery of the objectives is achieved, the These areas generally have more serious land annual payment was estimated to be in the region degradation and soil erosion issues and lower crop of US$18.8 per ha. The precise level of payment at yields than commercial farmland. It was assumed the sub-catchment level varied, based on the current that 50  percent of farmers would adopt CSA levels of wood extraction and values of agriculture. practices, and that their crop yields would increase by 50  percent based on the yield gains reported elsewhere (IAPRI and FAO 2021; Marongwe et  al. 6.4.2.3 Conservancies 2011; World Bank 2019; ZCATF 2009). 264. Opportunities for community conservation 261. Establishment costs for CSA include the costs development were identified in the northeast of of extension and training of communal farmers, the catchment, where conditions for agriculture additional costs of equipment and inputs required are marginal and suitable natural habitat and for CSA (for example, planting equipment to wildlife populations remain. The initial costs of reduce labor burdens), and labor and input improving and expanding community conservation costs associated with upgrading erosion control initiatives in this area would include the transaction structures or small-scale water harvesting costs needed to designate specific areas of the infrastructure. Based on the literature, particularly catchment as community conservation areas through the investment volumes noted in the Zimbabwe public participation processes and negotiation. This CSAIP, establishment costs in the first year were is estimated to be around US$1.50 per ha (based on estimated to be US$120 per household (Dallimer Wise et al. 2012). The communities are assumed to et  al. 2018;; World Bank 2019). Once they are cover the costs of management out of the revenues established and with suitable equipment, most of (rent and royalty) received from joint-venture partners. the CSA practices should be largely self-sustaining. Nevertheless, ongoing support would be required, Additionally, practices like CA can often become which based on figures from Namibia, could amount less labor-intensive than conventional practices with to some US$0.4 per ha per year (MEFT/NASCO 2021). the right equipment (Liniger et  al. 2011; ZCATF 2009). Hence, maintenance costs are limited to the additional labor associated with the improved 6.4.2.4 Riparian buffers maintenance of soil erosion control structures, management of water harvesting infrastructure, 265. The legal protection of the 30 m riparian buffer zone and ongoing extension support, as well as some is enforced along all streams and rivers throughout incentives for farmers to not expand their fields. the study area. This involves the cessation of Ongoing costs for CSA were thus estimated to be existing cultivation and mining activities within these US$20 per household. areas. Degraded and cultivated areas are allowed to regenerate to riparian woodland vegetation. 6.4.2.2  Recovery and sustainable use of 266. It was assumed that some riparian buffer areas rangelands and harvested resources would recover passively once cultivation was stopped while others would require ANR, 262. Degraded habitats throughout the catchment are depending on the amount of natural vegetation restored to a more natural and productive state remaining. It was estimated that a mix of passive through improved rangeland management and restoration and ANR would have an establishment Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 71 cost of around US$200 per ha in the first year or 6.4.3.2 Harvested wild resources US$1,200 per km of river (Brancalion et al. 2019; Dugan 2011). Costs would gradually decline over the next 269. Changes in the use of harvested wild resources two years to reach a long-term maintenance cost with full restoration of the study area were of US$30 per ha per year or US$180 per km of river. generally estimated to be fairly modest. Due to This is based largely on the estimated costs of the way harvested resource use is modelled, increased monitoring and enforcement to ensure riparian use in the restored scenario would only occur in areas buffers are being left to recover, drawing on estimates where current demand exceeds supply in the BAU of the cost of guarding and patrolling nature reserves scenario. By increasing natural resource stocks through (Chardonnet 2019; Frazee et al. 2003; James, Green, restoration of habitats, the supply constraint in some and Paine 1999). of these areas can be overcome in the restored scenario. 270. Overall, the value of the five harvested resources 6.4.3 Impacts on ecosystem services considered (wood, thatching grass, wild plant foods, mushrooms, and honey) was estimated 6.4.3.1 Crop production to increase by US$3.54 million per year in a 267. About 94,000 ha of cultivation was converted fully restored catchment, with a total value of to natural vegetation through the restoration US$107.6 million per year compared to the BAU of riparian buffers, representing 6.9 percent of value of US$104.0 million per year. Changes in the the current extent of cultivation in the study total value of wild resource harvesting at the sub- area. Despite this, overall crop production with catchment level are shown in Figure 29. The greatest implementation of CSA was estimated to increase by changes in value (dark green) are associated with the 7.2 percent (Table 14). Crop production in communal Upper Mazowe (#17) and Nyangui sub-catchments and resettlement areas, where the interventions (#15), both located in the southwest of the study area. were focused, was estimated to increase by Restoration of both these sub-catchments increases 17.9  percent. Overall, it was predicted that the value natural resource stocks significantly relative to BAU. of crop production in the study area would increase They also have large rural populations and thus high by US$21.2 million, with production from communal demand for resources. and resettlement areas specifically increasing by US$32.8 million per year. 6.4.3.3 Carbon storage 268. The highest increases in production are associated with sub-catchments with large areas 271. Carbon storage in the restored scenario is increased of farmland within communal and resettlement by the restoration of degraded natural habitats areas, particularly the Ruya sub-catchment (#4) and conversion of cultivation in riparian zones to in the far north of the study area and the Nyadiri riparian woodland, as well as a smaller addition sub-catchment (#7), which includes heavily from the increased uptake of soil carbon by areas cultivated communal areas around Mutoko under conservation tillage. It was estimated that (Figure 28). full restoration would increase carbon storage by CROP PRODUCTION WITH FULL RESTORATION OF THE STUDY AREA AND CHANGES RELATIVE TO TABLE 14:  THE BASELINE SITUATION Farming type Production (t) Change in production (t) % change Production change (US$ million/year) Communal/resettlement 411,361 58,473 17.9 32.8 Commercial 239,094 −14,365 −7.2 −11.6 All 650,454 43,838 7.2 21.2 72 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 28: CHANGES IN THE GROSS MARGIN OF CROP PRODUCTION AT THE SUB-CATCHMENT LEVEL WITH FULL RESTORATION OF THE STUDY AREA (SUB-CATCHMENTS NUMBERED ON MAP) Source: Original calculations from this study. 16  percent relative to a BAU scenario. The current is assumed that all households living within 1 km of value of avoided climate-change related losses restored areas are potential beneficiaries of carbon for the world rises to US$1.46 billion per year, credit sales, then annual benefits per household a US$225 million increase from the baseline landscape. could be around US$25 per year. Notably, the value By 2047 (in 25 years), the value of avoided climate- that could be generated through carbon credit sales change related losses would increase to US$2.58 billion would increase significantly with likely future increases per year, based on the values projected by World in carbon credit pricing. Bank (2017). Using a relatively low estimate of US$4.5 per tCO2e (Ecosystem Marketplace 2021), full 272. The total change in carbon storage with full restoration of the study area could generate a total restoration of the study area is shown at the sub- of US$325.5 million in carbon credits for Zimbabwe catchment level in Figure 30. This reflects the at current prices. Given that studies have shown full area of degraded habitat being restored within each recovery of biomass in miombo ecosystems takes sub-catchment, as well as the area of riparian around 25  years (Kalaba et  al. 2013; Williams et  al. cultivation being converted to riparian buffers. The 2008), the annual value of carbon credits generated largest changes are in the Ruya sub-catchment (#4) in by the recovery of natural vegetation in the study the far north of the study area and the Upper Mazowe area would be around US$13.5 million per year. If it sub-catchment (#17) in the southwest. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 73 FIGURE 29: CHANGES IN THE ANNUAL VALUE OF WILD RESOURCE HARVESTING AT THE SUB-CATCHMENT LEVEL WITH FULL RESTORATION OF THE STUDY AREA, RELATIVE TO BAU (SUB-CATCHMENTS NUMBERED ON MAP) Source: Original calculations from this study. northwest of Nyanga, all of which are characterized 6.4.3.4 Flow regulation by dense communal farmland. 273. Groundwater recharge is predicted to increase by 99.2 Mm3 per year or 4.5 percent relative to the Erosion control and sediment 6.4.3.5  BAU scenario. CSA interventions significantly reduce retention runoff and evapotranspiration from cultivated areas while increasing infiltration, as found elsewhere 274. Erosion would be reduced by 47.8 percent relative (Marongwe et  al. 2011; Nyamadzawo et  al. 2012; to BAU (from 34.1 to 17.8 tons per ha per year) World Bank 2019). This makes a large contribution and sediment export by 63.2 percent (from 3.1 to the overall increase in net recharge at catchment to 1.1 tons per ha per year). CSA interventions on scale. In contrast, the restoration of degraded farmland in communal and resettlement areas habitats decreases net recharge in some cases, due roughly halve erosion in these areas, with mean to the increased evapotranspiration losses. These erosion declining from 69.2 to 36.8 tons per ha differences are evident in the results summarized per year. The latter still exceeds the suggested soil by sub-catchments (Figure 31). The largest increases erosion tolerance rates of 1–12 tons per ha per year in recharge are seen in Nyangui sub-catchment (Roose 1996), suggesting that 50 percent adoption (#15) near Murewa, Nyadiri sub-catchment (#7) near of CSA is not sufficient for totally addressing soil Mutoko, and Upper Rwenya sub-catchment (#12) erosion issues from communal farmland. 74 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 30: INCREASE IN TOTAL CARBON STORAGE AT THE SUB-CATCHMENT LEVEL WITH FULL RESTORATION OF THE STUDY AREA, RELATIVE TO BAU (SUB-CATCHMENTS NUMBERED ON MAP) Source: Original calculations from this study. 275. In dam catchment areas, total sediment export prime farming area, resulting in large reductions in is reduced by 61.7 percent, or 2.04 million tons sediment export to waterbodies with restoration of relative to BAU. This has an estimated cost saving degraded natural habitats, conversion of riparian of US$10.2 million per year. Notably, the reduction in cultivation to woodland, and/or improved erosion sediment export from small-scale farmland accounts control on small-scale farmland. for over half of the overall sediment reduction in dam catchment areas. The overall reduction in sediment export to dams at the sub-catchment 6.4.3.6 Tourism level is shown in Figure 32. 277. As noted earlier, opportunities for expanding 276. The spatial patterns shown are closely tied to the nature-based tourism in the Mazowe Catchment number of dams in each sub-catchment, with seem fairly limited. The main area where avoided sediment export generally higher in the opportunities for growth were identified is in the west of the study area. The sub-catchments with far northeast of the catchment, where there is an the highest reduction in sediment export fall within opportunity to enhance and expand the Nyatana the Upper-Mazowe around Glendale and Bindura Game Reserve, which is currently not fulfilling its (#17 and #18) as well as the Nyangui sub-catchment tourism potential. The potential value that could be (#15). The southwest of the Mazowe Catchment generated with improvement of tourism facilities has a high density of dams due to its location in a in this area was calculated from averaging the Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 75 FIGURE 31: CHANGES IN GROUNDWATER RECHARGE AT SUB-CATCHMENT SCALE WITH FULL RESTORATION OF THE STUDY AREA, RELATIVE TO BAU (SUB-CATCHMENTS NUMBERED ON MAP) Source: Original calculations from this study. tourism value per hectare of the well-established 6.4.4 Cost-benefit analysis Umfurudzi Safari Area and the Muzarabani Wildnerness Area located just west of the Mazowe Catchment. 279. A high-level cost-benefit analysis was conducted The latter was selected as its rugged terrain is to evaluate the potential of the proposed comparable to the proposed focal area in the interventions to generate positive ROI in the northeast of the catchment. form of enhanced ecosystem service delivery. The analysis was performed at the sub-catchment level. 278. Extrapolating from the tourism value per unit area of comparable areas, it was estimated that 280. Costs and benefits were converted to present improvement and expansion of community value using a time horizon of 25 years and a conservation areas in the northeast of the social rate of discount of 4.56 percent. Costs were catchment could generate around US$0.5–1 million assigned to the proposed interventions based per year of additional tourism value. While this on estimates from the literature for comparable value is relatively modest, it could make a meaningful interventions in Zimbabwe and the broader region contribution to diversifying livelihoods in this area, where local estimates were scarce. These included as it encompasses the hottest and driest regions of both one-off establishment costs and ongoing the catchment where most conditions for rainfed maintenance costs. Benefits were assumed to be agriculture are particularly marginal (agroecological realized gradually over time for most of the services region IV). assessed. Crop production benefits from CSA began 76 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 32: AVOIDED SEDIMENT EXPORT TO DAMS AT THE SUB-CATCHMENT LEVEL WITH FULL RESTORATION OF THE STUDY AREA, RELATIVE TO THE BASELINE LANDSCAPE Source: Original calculations from this study. in year 2, plateauing from year 5 to 25 based on benefits that outweigh their costs over the Mazowe the assumption that it would take 5 years for the full Catchment as a whole (Table 15 and 16). The NPV benefit to be realized. For carbon and harvested over 25  years is estimated to be US$288 million, resources, a linear increase in benefits was assumed, with an ROI of 1.7. In other words, a US$1 investment with benefits starting in year 2 and reaching their in the interventions could generate US$1.70 of maximum value by year 25, based on studies of benefits. ROI exceeds 1 in all but 2 of 18 sub- miombo woodland recovery after disturbance (Kalaba catchments, reaching up to 3 (Table  15, Figure  33). et  al. 2013; Williams et  al. 2008). The benefits of Notably, six sub-catchments have an ROI of 2 or the hydrological regulating services (groundwater above, suggesting interventions would be most cost- recharge and soil erosion control) were modelled effective in these parts of the study area. using an initial sharper increase up to year 5, reflecting the spread of CSA. Hydrological benefits 282. At the whole Mazowe catchment level, restoration increased more gradually thereafter to reach their of degraded habitats is estimated to cost maximum value by year 20, due to the slower $200.5 million over a 25-year period, whereas recovery of natural habitats. CSA implementation will cost $168.2 million. Installation of riparian buffers will cost $41 million, 281. Theresults of the cost-benefit analysis while establishment of conservancy will cost demonstrate that well-implemented restoration $0.4 million. Changes in land management following and conservation interventions could produce adoption of CSA is estimated to generate the Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 77  RESENT VALUE (PV) COSTS AND BENEFITS AND ROI OF THE LANDSCAPE INTERVENTIONS TABLE 15: P FOR EACH SUB-CATCHMENT AND FOR MAZOWE CATCHMENT AS A WHOLE (US$, MILLIONS, 25 YEARS, 4.56 PERCENT) Sub-catchment Total PV costs Total PV benefits NPV ROI (US$, millions) (US$, millions) (US$, millions) 1 10.6 23.9 13.3 2.3 2 27.1 56.0 28.9 2.1 4 77.2 118.1 40.9 1.5 5 2.8 8.2 5.5 3.0 6 13.8 24.4 10.6 1.8 7 64.6 154.6 90.0 2.4 8 21.7 31.9 10.3 1.5 9 15.1 22.5 7.4 1.5 10 5.4 8.6 3.2 1.6 11 15.9 31.5 15.6 2.0 12 35.3 55.0 19.7 1.6 13 6.2 11.1 4.9 1.8 14 13.3 23.1 9.8 1.7 15 47.2 117.7 70.5 2.5 16 4.1 −6.4 −10.5 −1.6 17 44.8 −2.4 −47.3 −0.1 18 17.0 32.0 15.1 1.9 Mazowe Catchment 422.0 709.9 287.9 1.7 largest ecosystem services benefits for the whole subcatchment 7 (Nyadire) noted for a preponderance Mazowe catchment ($258.7 million), followed by of subsistence farmers growing maize, sunflower, revenue from carbon credits ($191.9 million), water millet, groundnuts, and vegetables. The cost of recharge ($125 million), avoided sedimentation installing riparian buffers varies from $0.1 million for ($107.8 million). while tourism development yields subcatchment 5 to $6.9 million for subcatchment 7. the lowest benefit of $5.2 million (Appendix 7). 284. At the subcatchment level, ecosystem services 283. At the subcatchment level, investment costs are benefits are primarily driven by positive changes primarily driven by the size of subcatchments, the in land resources management following CSA extent of land degradation of the subcatchments, adoption, availability of water resources, presence land cover types, and the type of sustainable land of intact forests and wetlands, and presence management investment relevant for a given of high biodiversity within the ecosystem. subcatchment. The cost of restoring degraded natural These drivers are reflected in the location of habitats range from $1.7 million for subcatchment 5 to the largest ecosystem services benefits: for CSA $38.9 million for subcatchment 4, while the cost of adoption, subcatchment 7 ($95 million); avoided implementing conservation agriculture ranges from dam costs, subcatchment 15 ($43.6 million); carbon $0.5 million for subcatchment 16 to $32.5 million for revenues, subcatchment 4 ($32 million); harvested 78 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe  RESENT VALUE OF COSTS AND BENEFITS OF TABLE I6: P LANDSCAPE INTERVENTIONS IN MAZOWE $ million Costs 422.0 Restore degraded natural habitats 200.5 Establish conservancies 0.8 Implement climate-smart agriculture (50% adoption) 179.7 Install riparian buffers 41.0 Benefits 709.9 Avoided dredging (sediment) 107.8 Avoided dam costs (change in recharge) 125.0 Gains in wild harvested resources 21.1 Changes in agricultural production 258.7 Revenue from carbon credits 191.9 Tourism gains 5.2 Net present value 287.9 B:C ratio / ROI 1.7 ROI for farmland interventions 1.44 ROI for natural land interventions 1.86 Duration is 25 years at 4.56% SDR. wildlife resources, subcatchment 15 ($8.5 million); other subcatchments, these higher crop yields and tourism, subcatchment 1 ($4.3 million). Crop from communal and resettlement land resulted in production results in losses in subcatchments 16 an overall increase in crop production, despite the and 17, a phenomenon driven by overall losses in loss in farmland area within riparian buffer zones. crop production due to the conversion of sizeable This was not the case in subcatchments 16 and 17 areas of high-yielding commercial farmland to riparian because the extent and relative contribution of buffers. communal and resettlement areas to overall production here is small. As a result, any increases 285. The negative ROI for cropland in subcatchments in production from communal and resettlement 16 and 17 is driven by overall losses in crop areas in these subcatchments was not enough to production due to the conversion of sizeable compensate for the losses in production resulting areas of high-yielding commercial farmland to from the loss of higher-yielding commercial farmland riparian buffers. The proposed interventions to along rivers. This is reflected in the negative ROIs improve agricultural production focused on lower- for the two subcatchments. On the other hand, yielding communal and resettlement farmland other subcatchments have positive ROIs ranging from areas, rather than commercial farmland. In all 1.5 for subcatchment 8 to 3.1 for subcatchment 5. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 79 FIGURE 33: ROI PER SUB-CATCHMENT WITH IMPLEMENTATION OF THE PROPOSED LANDSCAPE INTERVENTIONS (NUMBERS CORRESPOND WITH SUB-CATCHMENT NUMBERS USED IN TABLE 15) 80 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe Conclusions and Recommendations 286. This study has shown that degradation in the IPM, farmers, can effectively manage pests while Mazowe Catchment is increasing and that this minimizing risks to the environment and human will undermine not only biodiversity but the well- health, promoting ecological balance, and ensuring being of its inhabitants and of Zimbabweans in the long-term productivity and sustainability of general. It is clear that the environmental issues in agricultural landscapes. the catchment need to be addressed. The study has 2) Enforce riparian protection. Government should also identified the priority areas for intervention. act to enforce the already-existing laws prohibiting However, there are several information gaps that also use of the riparian zone. Riparian protection is need to be addressed in moving forward. Bearing critical to landscape health and to the persistence this in mind, as well as the fact that similar issues of biodiversity across the landscape. To enforce are threatening livelihoods and the economy across riparian protection, first there is a need to develop the country, the overall recommendations from this a riparian restoration plan to identify areas that study are as follows. needs ANR, those that can recover naturally, as well as the threats and drivers of degradation. 1) Support the upscaling of CSA interventions in A riparian restoration plan could also inform the Mazowe Catchment without delay since REDD financing opportunities. Second, develop these have already been demonstrated to be the riparian zone as a resource to conserve effective. There is an urgent need to implement biodiversity and increase tangible benefits to Zimbabwe’s CSAIP which aims to strengthen the farmers. Third, there is a need to work with farmers country’s agriculture sector’s resilience to climate and communities to develop local-level solutions change. Priority investments recommended and ownership. As farming is a key driver of by the CSAIP include on-farm investments in riparian loss, it is important to consider how improved crops, fertilizers, irrigation, and animal riparian zones could be part of the overall farm management to increase farmer production management. This should include protection and build resilience; off-farm investments in from instream mining activities as well as from storage, processing, marketing, and research & agriculture and wood harvesting in the riparian development to increase the agricultural value zone. chain’s productivity and efficiency; and cross- cutting investments in land reform and water 3) Enable conservancy establishment. Zimbabwe management to help the country realize its full has a comparative advantage in terms of its agricultural potential. These investments should wildlife heritage and parts of the study area be backed up by strengthening the policy and (as well as many other areas in Zimbabwe) regulatory environment for CSA and building still hold the potential for wildlife-based the capacity of extension agents, farmers and other land use. The government needs to amend stakeholders through training and resources they its policies and legislation to support the need to adopt climate-smart practices. Grain establishment of communal conservancies loss account for about 25–30% of their crop with land and resource rights that allow for due to high moisture, pest damage, fungal commercially viable joint venture conservation- or bacterial infections, and rodent damage. based business arrangements. Increasing Integrated Pest Management (IPM), an approach environmental management problems such as that utilizes various pest control methods, including land-degradation, forest fires, water pollution biological, cultural, physical, and chemical and wildlife poaching suggest considerable controls, to manage pest populations effectively scope for further decentralization within the and economically, is crucial for ensuring the new devolution thrust of the new constitution, success of Climate Smart Agriculture (CSA) to improve resource allocation and decision- interventions in Zimbabwe. By implementing making making at lower levels of Government Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 81 to strengthen stakeholder and community is a key component of sustainable landscape participation in natural resources management management to address land degradation and in Zimbabwe. restore ecosystem health in the catchment. Key investments for consideration in this 4) Undertake strategic environmental assessments regard include reforestation and afforestation to inform proactive planning. Proper spatial of severely degraded land, conversion, and planning is required to accommodate conflicting passive reforestation of marginal agricultural activities such as agriculture, mining, wildlife- land into silvo-pastoral systems for adapted based land uses, and the provision of ecosystem livestock species or community conservancies, services to society as a whole. It is recommended that the government undertake detailed strategic encouraging private investments in commercial environmental assessments for these different forestry for all socioeconomic category of farmers activities, to plan where they should and should down to smallholder commercial woodlots thereby not be allowed to take place. enhancing household income diversification and resilience. Other SFM investments include 5) Improve and enforce environmental safeguards. the strengthening of value chains for timber Some of the threats to the study area, such and non-timber forestry products as well as the as mining, are difficult to address because commercial promotion of efficient cook-stoves. of a combination of easy access, the promise of quick returns, and the lack of enforcement of 7) Design and pilot two schemes for payments environmental standards that would make the for ecosystem services (PES). The analysis has operations more costly. Such activities need to generated first-order evidence to support the be closely regulated and need to involve the design and implementation of two pilot schemes use of appropriately specified performance for payment for ecosystem services (PES) based bonds that will fully cover the restoration of on appropriate global examples. One scheme will environmental damages. The internalization be based on sustainable landscape management of these costs could go a long way toward to reduce land degradation and soil erosion addressing the environmental problems in the on catchments of water-supply dams for urban study area. Environmental safeguards should settlements in Mazowe Catchment. Candidate be set in place for all types of development. urban settlements include Bindura, Murewa and Mutoko. These local authorities care about 6) Invest in Sustainable Forestry Management and could logically be willing to pay appropriate (SFM) across the Landscape: The high rate of sums of money for incentivising sustainable land deforestation observed in this study requires management practices in upstream catchments investment in sustainable forest management to regularize and guarantee portable water- to maintain the health and integrity of forest supply as well as reduced siltation in feeder ecosystems, conserve biodiversity, mitigate dams. The quality and regularity of bulk water climate change, and provide livelihoods for supply is important for reducing the cost and communities that depend on forests. Investing efficient functioning of water-treatment and in sustainable forest management will also help pumping equipment, in turn to guarantee public conserve ecosystem services, provide social and health of urban residents. On the other hand, community benefits, and align development private investment in sustainable watershed efforts with the growing trend of green management by distributed actors in the investments and impact investing for a green landscape is fraught with and discouraged by economy. A complex array of anthropogenic significant external costs and benefits. A well- and climate-change related drivers have led to designed pilot scheme for sustainable watershed severe land degradation in Mazowe Catchment. management in a focused catchment is one Land degradation manifests in large scale key investment and nature-based solution to deforestation of previously dense woodland and consider for securing sustainable urban water wooded grasslands, loss of other groundcover, supply. reduced agricultural productivity, as well as soil erosion, sedimentation, and pollution of Another pilot PES scheme could be built on water bodies. Sustainable forestry management a sustainable landscape management scheme 82 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe to verifiably generate and sell carbon credits of landscape; and ii) directing financial flows through carbon funds. The path to sustainable away from projects with negative impacts on development in Zimbabwe lies in the effective biodiversity and ecosystem services. However, management of its natural resources, particularly government holds the key to harnessing the power its forests and agricultural lands. With forests of the sector to mobilize the needed private finance being a source of livelihood for 1.5 million at scale to protect nature. Government can support people and agriculture accounting for the largest the integration of biodiversity criteria in private share (50  percent) of employment in the sector decision making by adopting natural capital country, adopting sustainable practices has accounting and making relevant data available as the potential to not only conserve resources, public good. Second, environmental fiscal policy but also boost the economy and uplift the living reforms that value natural capital can provide standards of smallholder farming households. incentives for the private sector to co-invest in the By promoting sustainable agriculture and sustainable use of natural resources and contribute reducing deforestation, the country can break toward net domestic resource mobilization. Third, the cycle of poverty, create jobs, and contribute government can drive the green transition by to a more inclusive and resilient future. In promoting policies such as greening the supply chain addition, sustainable landscape management to drive changes in corporate behavior. Encouraging will enable the country to tap into the potential the certification of products or enhancing the of carbon finance and generate and trade commercial and entrepreneurship skills of producers emission reductions in the carbon markets. could serve for example as an incentive to reduce A carefully selected catchment could include deforestation while increase revenues at the same hard investments and governance arrangements time. Efforts to protect the landscapes should also to generate and sell carbon credits from an prioritize gender equality to deliver a more sustainable integrated combination of climate-smart future. Integrating gender equity into policies and agriculture, sustainable forestry management, practices in sustainable landscape management biodiversity conservation and sustainable will address entrenched and systemic traditions and practices, which have significant implications for landscape management. Initial conditions on how women access and contribute to improvements existent land-uses will determine the form and to landscape management and commodity value portfolio of carbon-generating activities. chains. Lastly, there is a need for multi-sectoral, 287. The private sector has a critical role to play people centered approach to natural resources in biodiversity conservation and sustainable management by ensuring the integration of natural landscape management in Zimbabwe by capital consideration into planning, budgeting, i) financing projects that contribute to the implementation, and decision-making at the national conservation, restoration, and sustainable use and local levels will help build resilience. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 83 References Addicott, E. T., E. P. Fenichel, and M. J. Kotchen. 2020. “Even the Representative Agent Must Die: Using Demographics to Inform Long-Term Social Discount Rates.” J. Assoc. 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Such factors were not considered Overview and selected indicators in this rapid screening; therefore, the results should be interpreted as potential, rather than The analysis proceeded along the following steps: as realized, demand. 1. Identify indicators of the provision of ecosystem 3. Perform an assessment of trends in land and services considered in this study. Ecosystem water degradation over the last 20 years. services included food provision (crops and Indicators included vegetation productivity (NPP), livestock production), erosion control, water, evapotranspiration, soil moisture, baseflow, and carbon storage, and ecotourism potential. surface runoff (table  18). For each indicator, Indicators were selected for rapid assessment a linear regression was applied to the values over based on data availability, their relevance to the a 20-year period to determine the slope of the ecosystem services in question, and whether trend. they could be applied consistently at a national 4. Summarize indicators of services, beneficiaries, scale. Selected indicators are given in table 17. and land and water degradation at the watershed For sediment retention and water yield, InVEST scale. For each service, the indicator(s) were models (Sharp et  al. 2020a) were applied to aggregated to the watershed level, and then a derive pixel-level estimates of these parameters, binary variable was assigned indicating which based on detailed input data on topography, watershed/service pair fell into the top 25 percent soils, land cover and management, and climate. of values (top quartile) or the top 50 percent of 2. Identify relevant indicators on the beneficiaries values (values above the median). For degradation of ecosystem services, where appropriate. indicators, the slope of the pixel-level trends was Beneficiary proxies were selected that represent averaged to arrive at the watershed-level trend, the potential demand on an ecosystem services, and the same binary variable was assigned. The and data were selected using the same criteria final land and water degradation indicator is the as for ecosystem service indicators (availability, total number of sub-indicators for that watershed relevance, consistency for application at a national that fall into the top 50 percent of values. For the scale; Table 17). Croplands, grazing lands, and dams service and beneficiary indicators, it is the total were considered to be the beneficiaries of erosion number of services/beneficiaries that fall into control. People and dams were considered to be the top 25 percent or 50 percent of values for that the beneficiaries of water provision. Croplands and watershed. livestock were considered to be the beneficiaries of biomass produced on the landscape (resulting in food for people). For carbon and ecotourism, Summary of InVEST models no beneficiary indicators were used. In the case for sediment and water of carbon, the beneficiaries are global, and in the case of ecotourism we were limited by the Water flows lack of spatially disaggregated data on visitation at a national scale. Note that the ability of Watersheds capture and store water, thereby contributing beneficiaries to take advantage of the provision to the quantity of water available and the seasonal flow of of ecosystem services is based on many local water. The so-called ‘albedo’ effect refers to the process 96 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe TABLE 17: INDICATORS UTILIZED FOR PROVISION OF ECOSYSTEM SERVICES AND THE BENEFICIARIES OF SERVICES Ecosystem service Indicator of service Method or source Beneficiary Beneficiary data source provision indicator Erosion control Soil retained by InVEST SDR model Croplands Copernicus 2019 vegetation (ton/ha) (Sharp et al. 2020a) 100 m land use land Cover data (Gilbert et al. 2018) ‘Cropland’ class Grazing lands Gridded livestock of the world (GLW3 - Buchhorn et al. 2020), areas with >1,000 animals/km2 Percent of area Global Reservoir and Dam Database contributing to (GRanD) v1.3 (Lehner et al. 2011) dam(s) GlObal geOreferenced Database of Dams (GOOD2) Dams Dataset (Mulligan, van Soesbergen, and Sáenz, 2020) Water regulation Annual water yield InVEST SWY model Population Population density, 2020 (mm) (Sharp et al. 2020a) (Bondarenko et al. 2020) Water yield Same as ‘dams’ above contributing to reservoirs Food production Mean annual biomass MOD17A3HGF.006 Population Population density, 2020 production in croplands MODIS/Terra Net Primary (Bondarenko et al. 2020) Production V006, 500 m Mean annual biomass Number of GLW3 (Gilbert et al. 2018), sum of (Running and Zhao 2019) production in grazing grazing animals animals/watershed lands Ecotourism Percent of area in WDPA (IUCN and UNEP-WCMC 2016) protected status Carbon storage Total aboveground and NASA ORNL Global Aboveground and Belowground Biomass Carbon Density, belowground carbon 300 m (Spawn and Gibbs 2020) TABLE 18: METRICS UTILIZED AS LAND AND WATER DEGRADATION INDICATORS Indicator Data source Method Net primary productivity MOD17A2H MODIS/Terra Gross Primary Productivity V006, 20-year trend analysis, using linear 500 m (Spawn and Gibbs 2020) regression to derive slope of trend for each parameter Surface runoff (‘quickflow’) Famine Early Warning Systems Network (FEWS NET) Land Data Assimilation System (FLDAS) (McNally et al. 2017) Baseflow Evapotranspiration Soil moisture Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 97 by which vegetation increases evaporation of water from 2018). Soil erosion in terrestrial ecosystems is therefore a the earth’s surface to cause increased cloud formation global environmental problem, and it significantly affects and rainfall (Myers 1997). Through this effect, ecosystems environmental quality and social economy. Ecosystems dominated by vegetation, such as forest ecosystems, such as forests, wetlands, and mangroves help stabilize play a significant role in determining rainfall patterns at a soils, reducing erosion. The vegetative cover shelters soil regional scale. Vegetation also acts as a ‘sponge’, soaking from the force of rain by intercepting rainfall while roots up and storing water when abundant and releasing it slowly help maintain the soil structure (Myers 1997). By protecting during the dry periods. This system of water regulation soil from wind and water erosion, terrestrial ecosystems reduces the impacts of flood and drought on downstream supply human beings with soil erosion control service, communities (Myers 1997). one of the fundamental ecosystem services that ensure human welfare (Fu et al. 2011). In this study, we used the InVEST SWY model (Sharp et al. 2020) to look at water flows as a function of landscape The InVEST SDR model (Sharp et al. 2020) was used in this characteristics and land cover and management. The study to evaluate erosion rates and overland sediment model estimates the amount of water produced by a transport. The SDR model highlights areas where higher watershed that arrives in streams over the course of a levels of erosion are occurring, highlights areas providing year. The two primary outputs of the model are quickflow the service of retaining some of that erosion, and quantifies and baseflow—quickflow represents the amount of the amount of sediment that arrives in streams and precipitation that runs off of the land directly, during reservoirs. The model is based on an implementation and soon after a rain event, and baseflow is the amount of the Revised Universal Soil Loss Equation (RUSLE1; of precipitation that enters streams more gradually Renard et al. 1997) for the calculation of annual soil loss through subsurface flow, including during the dry season. and a sediment delivery function on the hydrological Data inputs to the SWY model include rainfall, potential connectivity of each pixel in the landscape. evapotranspiration, topography, soil, and land cover. The SDR model requires input datasets of biophysical To understand which areas of the landscape are contributing parameters for the calculation of erosion dynamics, more or less water to streams over the course of the year, sediment export, and retention across the landscape. we combined the quickflow and baseflow results from the For the erosion component, data on land cover, rainfall model to produce a total annual water flow map, given erosivity energy (EI30), soil texture erodibility, length-slope in cubic meters per year. Total annual mean water flows derived from topography, soil cover fraction by vegetation, were summed by watershed, to provide input to the water and assumptions regarding soil conservation practices are ecosystem services map for the national screening. required. For the transport of sediment and retention on the landscape, a hydrologically corrected DEM is required. Erosion and sediment retention For assessing the national-scale assessment of the erosion control service, the soil retention model was used. This Soil erosion is the movement or displacement of the output represents the amount of sediment (tons per year) upper layer of soil, and it is a naturally occurring process that would otherwise be eroded but is currently retained that affects all landforms. Certain human activities greatly by the landscape, preventing it from entering streams enhance this process and contribute to a significant soil and potentially affecting downstream users. loss. This matters significantly because topsoil contains the highest amount of organic matter and is best suited for agricultural activities. In the last 150 years, as much as half of the world’s topsoil has been lost. Detailed results However, the effects of soil erosion go far beyond the Ecosystem services loss of fertile land and include increased pollution and sedimentation in streams and rivers. As a result, these The following figures present the detailed results for soil waterways are prone to clogging, which causes declines retention (Figure  34), water yield (Figure  35), carbon in fish and other species. Furthermore, degraded land can storage (Figure 36), and primary productivity (Figure 37), often hold less water, which can worsen flooding (RUVIVAL as well as the location of protected areas (Figure 38). 98 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe FIGURE 34: SOIL RETENTION BY VEGETATION (LEFT) AND THE TOP WATERSHEDS FOR PROVIDING SEDIMENT RETENTION SERVICE IN THE CURRENT LANDSCAPE (RIGHT) Source: This study, calculated from data sources given in Table 16. FIGURE 35: WATER YIELD (LEFT) AND THE TOP WATERSHEDS FOR PROVIDING WATER FLOW ECOSYSTEM SERVICE IN THE CURRENT LANDSCAPE (RIGHT) Source: This study, modelled from data sources given in Table 16. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 99 FIGURE 36: TOTAL ABOVEGROUND AND BELOWGROUND CARBON STORAGE IN THE CURRENT LANDSCAPE (LEFT), AND THE TOP WATERSHEDS IN TERMS OF STORING CARBON (RIGHT) Source: NASA ORNL Biomass Carbon Density. FIGURE 37: NPP (BIOMASS), USED AS A PROXY FOR FIGURE 38: PROTECTED AREAS, USED AS A PROXY FOR CROP AND LIVESTOCK PRODUCTIVITY ECOSYSTEM SERVICES RELATING TO ECOTOURISM Source: MODIS/Terra Net Primary Production V006. Source: IUCN WDPA. 100 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe Beneficiaries of ecosystem services Figures 39 to 41 show the location of dam catchment areas and spatial spread of human populations and grazing animals. FIGURE 39: DAMS AND THEIR CATCHMENT AREAS, FIGURE 40: POPULATION, CONSIDERED AS DIRECT CONSIDERED AS BENEFICIARIES FOR SEDIMENT BENEFICIARIES OF CROP PRODUCTION AND WATER RETENTION AND WATER FLOW ECOSYSTEM SERVICES REGULATION SERVICES Source: GRanD and GOOD2 Dams datasets. Source: Worldpop 2020. FIGURE 41: NUMBER OF GRAZING ANIMALS PER WATERSHED, CONSIDERED AS BENEFICIARIES OF BIOMASS PRODUCTION IN LIVESTOCK GRAZING AREAS Source: GLW3. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 101 Appendix 2.  Rural Livelihood Zones in Mazowe Catchment DESCRIPTION OF THE FOUR MAIN RURAL LIVELIHOOD ZONES THAT OCCUR WITHIN THE TABLE 19:  STUDY AREA Zone Description Central and Northern Dominated by maize and small grain crops for both food requirements and as cash crops. Poorer Semi-Intensive Farming households depend on multiple sources of income including sale of handcrafts, petty trading (fish sales and beer brewing), and artisanal mining. An important income source is remittances from relatives. Livestock sales are not common but are a source of income for some middle-income households. The main chronic hazards are malaria, crop pests, and human and animal disease. Fluctuating markets for agricultural produce also place a strain on commercial farmers. Drought (roughly every 1–3 years out of 10), land degradation, deforestation, and wildfires are the main periodic natural hazards to livelihoods. Conflicts around water accessibility in dry years and water quality (reduced by siltation) have also been noted. Highveld Prime Communal Both food and cash crops, dominated by maize production. Wide variety of other crops grown. Favorable rainfall but soils not particularly arable. Own food production is important. Livestock and grazing are limited due to densely populated areas and crops. Sales of harvested resources are common by poorer households. Following the FTLRP, there was significant outflow of labor to urban areas resulting in a decline in commercial crop production. An important source of cash is remittances. Illegal artisanal mining is common among households unable to sell cash crop produce. Stock and crop theft is the main chronic threat. Low market prices are also a key chronic threat. Besides animal diseases and crop pests as periodic threats, degradation, especially in the form of deforestation for tobacco curing, is also a key issue. Uncontrolled veld fires are a major threat. Highveld Prime Cereal and Mostly agricultural resettlement land that changed hands following FTLRP, mostly food secure but Cash Crop Resettlement food production has declined. Many farmers have abandoned farms to work in urban areas, leaving farms to caretakers. Key crops are maize, soya, tobacco, and groundnuts, often supplemented by livestock production. Production of crops and livestock is either for subsistence or commercial output with substantial differences in income and food security between these groups. Following redistribution of land, many commercial farmworkers lost both their livelihoods and homes or job security. This has resulted in similar income earned by resettlement and subsistence farmers. Remittances and food aid have been important for the poorest residents. Crop pests and hailstorms are key chronic hazards. Land degradation is also widespread, particularly through harvesting of firewood for tobacco curing, as is increased abundance of invasive species such as Spropobulus, which spreads in overgrazed rangelands. Animal diseases are the main periodic hazard while wildfires and theft from farms (of stock, crops, and equipment) are also periodic threats. 102 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe TABLE 19: (Continued) Zone Description Greater Mudzi Communal Extensive rainfed maize crops as well as smaller areas of small grain crops, cotton, and groundnuts. Incomes supplemented by cotton production, animal husbandry, and increasingly through artisanal gold panning along rivers in the dry season. Poorer households rely on a more diverse range of food and income sources as compared to more well-off farmers who can satisfy most of their food requirements from their own crops. Livestock sales (particularly cattle and goats) to agents (predominantly from Harare) are relatively important for supplementing income in this zone, especially in low rainfall years. Fishing is also an important income and food supplement. There is some outmigration of workers to work on potato farms further south in the Nyanga district on a seasonal basis. Fairly significant food aid has been received over the last few decades. The fluctuating price of cotton is regarded as a chronic hazard. This makes it difficult for farmers to plan and devote land to cotton crops, which would reduce the availability of land for food crops. Malaria and landmines (nearer the Mozambique border) are chronic threats. Droughts occur roughly every 3 years. Inaccessibility of the area creates challenges for market access. Several animal diseases are periodic threats while human-animal conflict is an issue around the WMAs and protected areas. Source: Based on GoZ and WFP 2017; ZimVAC 2011. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 103 Appendix 3.  Land Cover Accounts 104 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe TABLE 20: CHANGES IN EXTENT IN LAND COVER CLASSES BETWEEN 1992 AND 2018 IN MAZOWE CATCHMENT Forest Dense Open Shrubland Wooded Herbaceous Grassland Natural- Crop- Cultivated Cultivated Bare Urban/ Waterbodies Wetland No Total woodland woodland grassland vegetation dominant dominant (irrigated) (rainfed) ground built-up data mosaic mosaic with with natural crops areas 1992 extent 45 9,458 176 5,032 448 10,38 777 160 239 <1 12,299 297 34 95 22 37 39,857 (km2) Additions to 0 822 63 702 5 760 107 28 75 0 931 16 30 1 3 2 3,544 stock (km2) Reductions in 0 2,048 26 537 407 163 71 90 14 0 166 20 0 0 2 1 3,544 stock (km2) Net change in 0 21,226 37 165 2402 597 35 262 61 0 765 24 30 1 1 1 stock (km2) Net change 0 213 21 3 290 6 5 239 25 — 6 21 87 1 4 3 as percent of opening Unchanged 45 7,410 150 4,495 41 10,575 706 70 225 0 12,134 277 34 95 20 36 (km2) Unchanged 100 78 85 89 9 98 91 44 94 100 99 93 100 100 89 99 as percent of opening (km 2) Turnover 0 2,869 88 1,239 412 923 178 118 89 0 1,097 35 30 1 6 2 (additions + reductions) (km2) Turnover as 1 30 50 25 92 9 23 74 37 200 9 12 88 1 26 6 percent of opening 2018 extent 45 8,232 213 5,196 46 11,335 813 98 300 <1 13,065 293 64 95 23 38 39,857 (km2) Note: Values are rounded to the nearest integer. TABLE 21: LAND COVER CHANGE MATRIX FOR MAZOWE CATCHMENT SHOWING LAND COVER CHANGE PATHWAYS BETWEEN 1992 AND 2018 Land cover Forest Dense Open Shrubland Wooded Herbaceous Grassland Natural- Crop- Cultivated Cultivated Bare Urban/ Waterbodies Wetland No Total Total 1992 woodland woodland grassland vegetation dominant dominant (irrigated) (rainfed) ground built-up data reductions area mosaic mosaic 2018 Land cover (with (with 2018 crops) natural areas) Forest 45 — — 0 — — — — — — — — — — — — 0 45 Dense — 7,410 27 683 3 526 102 26 71 — 580 9 15 1 3 0 2,048 9,458 woodland Open — 4 150 1 — 9 — — 0 — 8 — 3 — — — 26 176 woodland Shrubland — 388 5 4,495 1 71 5 2 3 — 54 6 3 — — 0 537 5,032 Wooded — 2 1 — 41 136 — — 1 0 267 — 0 — — 0 407 448 grassland Herbaceous — 137 14 10 0 10,575 — — — — — 0 1 — — 0 163 10,738 vegetation Grassland — 39 1 0 — 9 706 — — — 21 — 1 — — 0 71 777 Natural- 0 86 0 2 — 0 — 70 0 — — — 1 — — — 90 160 dominant mosaic (with crops) Crop- 0 13 0 — — — — — 225 — — — 1 — — — 14 239 dominant mosaic (with natural areas) Cultivated — — — — — — — — — 0 — — — — — — 0 0 (irrigated) Cultivated — 141 15 4 1 1 — — — — 12,134 0 3 0 — 0 166 12,299 (rainfed) Bare ground — 9 0 0 — 8 — — — — 2 277 1 — — — 20 297 Urban/ — — — — — — — — — — — — 34 — — 0 0 34 built-up Waterbodies — — — — — — — — — — — — — 95 — — 0 95 Wetland — 2 — — — — — — — — — — — — 20 — 2 22 No data — 0 — — — 0 0 — — — — — — — — 36 1 37 Total 0 822 63 702 5 760 107 28 75 0 931 16 30 1 3 2 additions Total area 45 8,232 213 5,196 46 11,335 813 98 300 0 13,065 293 64 95 23 38 39,857 2018 (km2) Note: Cells with zero indicate a change of less than 0.5 km2 while dashes indicate no change between the respective classes. Appendix 4.  Assessment of Land Degradation Satellite data can reveal changes in primary productivity, desertification, restore degraded land and soil, including which can be indicative of land degradation. Primary land affected by desertification, drought and floods, and productivity refers to the rate at which energy is converted strive to achieve a land degradation-neutral world.” As to organic substances by vegetation in croplands, pastoral part of calculating SDG 15.3.1, three sub-indicators are areas, and natural ecosystems. It is, however, difficult and calculated: productivity, land cover, and soil carbon. The costly to estimate at large scales, requiring surrogate indexes productivity sub-indicator is useful for deriving general such as NDVI. degradation impacts and uses three measures of NDVI change: trajectory, performance, and state. Trajectory NDVI is a simple quantification of vegetation vigor or indicates the rate of change of NPP between 2000 and greenness, often used as an indicator of vegetation health. 2015 using NDVI. NDVI data are generated globally and made available on a biweekly basis, making it well suited to analyzing changes A positive significant trend in NDVI indicates potential in land productivity over time. improvement while a negative significant trend points to potential degradation of land and ecosystems (Conservation Using the Trends.Earth software plugin (Conservation International 2018). It is important to note that crop International 2018), degradation metrics were derived areas will potentially result in false indication of land or for the Mazowe Catchment. The plugin allows for making ecosystem improvement where they in fact do not allow calculations to derive the UN Sustainable Development for the provision of as many ecosystem services as that Goal (SDG) Indicator 15.3.1, which aims, by 2030, to “combat in a natural or near-natural state. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 107 Appendix 5.  Methods for Quantifying and Valuing Ecosystem Services Harvested wild resources specified distance of the demand source. To estimate and map harvesting at a high resolution, the running mean A natural habitats layer, generated through combining method developed by Turpie et al. (2020) in KwaZulu-Natal, land cover (Buchhorn et al. 2020) and World Wide Fund for South Africa was used. Nature (WWF) ecoregions layers (Olson et al. 2001), formed the basis for mapping the supply of natural resources. Each habitat was assigned a stock estimate per unit area for the Ecosystem inputs to crop different wild resources considered, based on remotely sensed woody biomass data for woody resources (Bouvet production et al. 2018; Santoro et al. 2018), and stock estimates derived from literature studies for other resources (Campbell 1987; Crop production was modelled using the InVEST Crop Campbell, Luckert, and Scoones 1997; Degreef et al. 2020; Production model, with correction factors applied based Frost 1996; Garcia et  al. 2013; Jaffé et  al. 2010; Mlambo on production from Zimbabwe’s Crop and Livestock and Maphosa 2021; Ngadze et al. 2017; Ngulube, Hall, and Assessment reports (MoLAWFRR 2020, 2021). Production Maghembe 1996; Poilecot and Gaidet 2011; Pritchard et al. was modelled for six food crops/food crop groupings 2018). The demand for natural resources was estimated (maize, sorghum, millet, ground and bambara nuts, beans, based on household density, the proportion of households and sweet potatoes) and four cash crops (tobacco, cotton, using a particular resource, and the average consumption soya, and sunflower). The InVEST Crop Production model per user household. Population density was obtained from was used to estimate production of each crop per hectare of the WorldPop 100 m constrained population density map cultivated land (as per the land cover layer), thus generating (www.worldpop.org). Information on household usage of an estimate of the spatial variability in production based particular natural resources was derived from literature on Monfreda, Ramankutty, and Foley (2008), which is studies and the most recent intercensal survey (ZIMSTAT the input dataset for the InVEST model. The modelled 2017). The latter provides figures for the proportion production was then summed at a provincial level and of households using wood as a cooking fuel and the compared with mean production at the provincial level proportion of traditional dwelling types (that is, those between 2019 and 2021, as per the Crop and Livestock using thatch for roofing and wooden poles in their walls) at Assessment reports. Correction factors were then applied the provincial level. Household use of all other modelled to the InVEST crop production maps to ensure alignment resources was obtained from literature studies (Campbell with modelled and reported production at the provincial et  al. 1991, 1997; Chagumaira et  al. 2016; Dowo, Kativu, level and the InVEST model data were updated to reflect and de Garine-Wichatitsky 2018; Grundy et  al. 1993, 2000; recent production levels. Kupurai, Kugedera, and Sakadzo 2021; Mabugu and Chitiga 2002; Mahlatini et al. 2020; Mashapa et al. 2021; McGregor Crop production was valued using the most recent producer 1991; Mudekwe 2007; Shackleton and Shackleton 2004; prices derived from the Grain Marketing Board, Tobacco Twine et al. 2003; Woittiez et al. 2013). Industry and Marketing Board, and Cotton Company. None of these sources provide a producer price for sweet potato. Once resource demand, stocks, and accessibility had been However, an estimate was sourced from a recent article mapped, the quantities of resources harvested were published by the Alliance for Science, which reported a calculated from the minimum of the estimated demand price of US$800 per ton for sweet potato production in and the estimated available stocks of resources within a Zimbabwe.28 Prices were converted from Z$ to US$ using 28 https://allianceforscience.cornell.edu/blog/2021/11/sweet-potato-farmers-profit-from-climatic-protection/. 108 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe the mean of the interbank and official exchange rates according to the Reserve Bank of Zimbabwe as of mid- Tourism value May 2022. To arrive at a more realistic estimate of the value Nature-based tourism value was estimated using the InVEST of crop production, gross revenue was converted to gross Visitation: Recreation and Tourism model in combination margin. While gross margin is likely to vary significantly with land cover data and national tourism statistics. across the catchment, both spatially and from year to year, The InVEST model estimates the relative tourism value a gross margin of 15 percent was assumed for this study. across a landscape from the density of PUDs derived from This is because the government aimed to ensure farmers geotagged photos uploaded to the website Flickr. PUD realize at least a 15 percent profit margin when it set these densities are calculated across a user-specified grid size. producer prices.29 A 300 m grid size was chosen, as the model failed to run using smaller grid sizes due to the higher number of calculations required. Ecosystem inputs to livestock production The national value of tourism was obtained from ZTA (2020). This was the most recent pre-COVID-19 year, thus providing The quantification of livestock production employed a a more representative estimate of tourism value before similar approach to crop production. In this case, correction the pandemic and a better indication of potential value factors from Zimbabwe’s Crop and Livestock Assessment as international travel continues to recover. Estimating reports were applied to the FAO GLW3 dataset (Wint and the value of nature-based tourism involved isolating Robinson 2007). The analysis focused on cattle, goats, tourism expenditure on visiting attractions from visitors and sheep, which are the major free ranging livestock spending on other purposes (for example, business or in Zimbabwe (particularly cattle and goats). The 10 km2 visiting friends and family). Data on the expenditure and resolution FAO data were first downscaled to give livestock proportion of different visitor categories were obtained density per km2 and then summed at the provincial level. from ZTA and World Travel and Tourism Council (WTTC) This was again compared with livestock numbers reported reports (WTTC 2021; ZTA 2020). in the Crop and Livestock Assessment reports, allowing for correction factors to be calculated and applied to the Attraction-based tourism across the Mazowe Catchment FAO data. Livestock numbers were also expressed and was isolated by clipping the InVEST PUD density map to mapped in terms of TLUs. Following other studies from the extent of the catchment, and the proportion of national Zimbabwe and the broader region, a value of 0.7 was used PUDs which fall within the catchment was calculated. to convert cattle numbers to TLUs, while a 0.1 conversion This was then applied to the national attraction-based factor was used for goats and sheep. estimate for Zimbabwe to arrive at the value of attraction- based tourism in the Mazowe Catchment. To isolate the Livestock were valued in terms of revenues from livestock value of nature-based tourism specifically, PUD data were sales and gross margin terms. Due to significant differences disaggregated across broad land use categories (natural in the production systems, the valuation was conducted vegetation, plantation, cultivation, and urban) based on separately for commercial farmland areas on the one the dominant land cover within each 300 m PUD grid cell. hand and resettlement areas and communal land on the The proportion of PUDs taken within grid cells dominated other. Livestock sale is the primary aim of production in by natural land cover was then again applied to the overall the commercial farming sector, resulting in much higher attraction-based tourism value to obtain an estimate of livestock offtake rates and thus sales revenues. In contrast, nature-based tourism in the catchment. livestock (particularly cattle) serves a wide range of roles in small-scale farming systems, with draught power, lobola payments, and milk and manure production regarded Carbon storage more important than sale for meat by small-scale farmers in Zimbabwe (Mukhebi et al. 1999; Scoones 1992). Given the Carbon storage by landscapes of the Mazowe Catchment low importance of livestock sales, these other factors were was estimated from the total of AGB and BGB. For AGB, incorporated in the estimates used for gross revenue and the study primarily used the AGB map of African savannas margin of livestock in communal and resettlement areas. and woodlands (Bouvet et  al. 2018), as this dataset has 29 http://www.gmbdura.co.zw/index.php/grain-producer-prices-go-up. Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 109 been specifically designed to give more accurate biomass and baseflows. While quickflow only occurs during or assessments for African woodland and savannah habitats. shortly after rainfall events, baseflow provides a more However, it is less accurate for higher biomass forest areas, sustained source of water during dry periods. Higher which are masked out and given a uniform biomass value quickflow can also result in elevated flood risks. The model by Bouvet et al. (2018). In such areas, the GlobBiomass calculates quickflow using a curve number (CN)-based AGB layer generated by Santoro et  al. (2018) was approach. used instead. For BGB, the global belowground carbon density map (Spawn et al. 2020) was used. All datasets The study drew on available CN estimates for land cover were reprojected and resampled to 100  m resolution as class and hydrological soil group combinations (Baker necessary. Biomass values were converted to carbon and Miller 2013; Beatty et al. 2018; Descheemaeker et al. equivalent using a 0.5 conversion factor. Carbon was 2008; Wischmeier and Smith 1978). For monthly rainfall, converted to equivalent tons of carbon dioxide using a the finest-scale data (1 km) available from WorldClim were 3.67 conversion factor. used (Fick and Hijmans 2017). To calculate the amount of water left for infiltration and recharge, the model requires Carbon stored in the catchment was valued using the information on reference evapotranspiration and the water social cost of carbon (SCC), which is the value of avoided requirements of different land cover and vegetation types. climate change-related damages through the retention For monthly reference evapotranspiration, the Global of carbon by the landscape. Carbon was valued both in Reference Evapotranspiration (Global-ET0) dataset was used terms of avoided damages to Zimbabwe (country-level (Zomer and Trabucoo 2022). The water requirements of SCC) as well as to the rest of the world (global SCC). Values different vegetation/land cover types are measured by of the country-level and global-level SCC were obtained the plant evapotranspiration coefficient (Kc) parameter. from Ricke et al. (2018). As it is the dominant crop throughout the catchment, monthly Kc values for cultivation were based on the Kc The SCC is a net present value of avoided costs, typically values for maize and typical planting and harvesting times over 100 years. However, for accounting purposes, values in Zimbabwe (Allen et al. 1998; Igbadun et al. 2006; Mhizha must be determined for the year in question. Thus, et al. 2012). Kc values for natural land cover types drew on the annualized social cost of carbon (ASCC) was then studies of leaf area index (LAI) from similar natural habitats estimated as in the region (Pfeifer et  al. 2012; Ribeiro et  al. 2008). LAI estimates were converted to Kc by dividing by three. (d # SCC) Urban land Kc values were assigned using the equation ASCC = , (1 - (1 + d)) -t F × 0.1 + (1 − F) × 0.6, where F is the fraction of impervious cover and evapotranspiration from pervious areas is where δ is the discount rate and t is the time period of assumed to be 0.6. There is significant uncertainty around the SCC calculation in years. For this study, we assumed setting the Kc of bare soil. Following the SWY user guide t = 100  years and used a social rate of discount of and other studies, Kc for bare ground was set at 0.5 (Belete 4.56  percent. This is the mean social rate of discount et al. 2018; Sharp et al. 2020b). for all Southern African countries based on Addicott, Fenichel, and Kotchen (2020) who did not provide a figure As recommended in the InVEST user guide, the model was for Zimbabwe. refined by comparing modelled actual evapotranspiration (AET) with remotely sensed measured AET. The Kc values for different land cover types were then adjusted accordingly to Flow regulation improve alignment between modelled and measured AET. Hydrological regulating services were quantified using Monthly variation in average flows was calculated from the InVEST SWY model. This was done at a finer scale the quickflow and net infiltration. A sequential mass than in the preliminary assessment report through the curve procedure (Rippl method) was used to estimate use of a 30  m DEM. The InVEST SWY model estimates reservoir capacity requirement for a given yield (defining the contribution of the landscape to both quickflow and a yield capacity relationship) for the reservoir catchment infiltration. Quickflow is surface runoff associated with areas under the current and bare ground scenarios. Since a rainfall event. Precipitation that does not run off as infiltration is given as a single quantity and the proportion quickflow or get lost through evapotranspiration can which ends up as surface flow was unknown, it was infiltrate the soil and contribute to groundwater recharge treated in three ways in a sensitivity analysis: as a constant 110 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe flow (assuming all infiltrated water eventually reaches by Davis and Hirji (2014). There was also an opportunity to dams), distributed in relation to rainfall with a 1-month lag compare modelled flows with measured flow data from (again assuming all infiltrated water eventually reaches two gauging stations (D27 and D28) in the Upper Mazowe dams), and omitted (that is, no infiltration reaches dams). Catchment reported by Nhedzi (2008). For D28, measured Reservoir storage capacity is valued in terms of average annual river discharge between 1987 and 2006 varied from costs of dam construction per m3. 5 to 27 Mm3. The InVEST estimate for total flows was 17.7 Mm3/year, close to the median measured value of river The impact of ecosystems on net infiltration was presented discharge at station D28. For gauging station D27, measured in terms of the absolute difference in net infiltration river discharge ranged from <1 to 8 m3 between 1987 and between the current land cover and bare ground scenario. 2006. In this case, the modelled estimate of total streamflow In the absence of detailed field data on hydrological (9.5 Mm3) is relatively high, though still reasonably close to fluxes, from which the relationship between infiltration, the observed flows. groundwater table levels, and the cost of extracting groundwater could be inferred, as well as uncertainties There is some uncertainty around the estimation of the with estimating Kc for bare ground, no estimate has been evaporation coefficient for bare ground (Kc), and the model made of the monetary value of this service. results for the bare ground scenario are sensitive to this parameter. For example, the InVEST user guide notes that Kc The InVEST model does not partition net infiltration into for bare ground can range from 0.3 to 0.7 and recommends water that contributes to long-term aquifer recharge and using a value of 0.5 (Sharp et  al. 2020b), as done in this water that is eventually discharged into streams to form study. However, other studies have used lower estimates baseflow. This requires more detailed hydrological study. (for example, Nistor and Porumb 2015). Indeed, this is in line Groundwater dynamics remain poorly studied in Zimbabwe with the metanalysis of 75 groundwater recharge studies in as a whole (Davis and Hirji 2014). However, some guidance semi-arid and subtropical environments by Owuor et  al. was obtained from a preliminary report on groundwater (2016), who found that groundwater recharge generally dynamics within the Zimbabwean portion of the Zambezi declined where bare ground is converted to cropland Basin (encompassing the Mazowe Catchment), which used or restored natural land cover. Unfortunately, since there a factor of 60 percent of net infiltration to estimate the are no extensive bare ground areas in the catchment, ‘safe yield’ of groundwater, after accounting for discharge it was not possible to calibrate Kc values by comparing to streams and other losses (NUST 2019). Applying this modelled AET with remotely sensed AET, as was done for assumption to modelled net infiltration suggests annual other land cover types. A clearer understanding of relative groundwater recharge is around 2,145 Mm3. Assuming that changes in groundwater recharge and baseflow following the remaining 1,430 Mm3 contributes to baseflow, total more realistic land cover changes (for example, woodland streamflow (quickflow plus baseflow) is estimated to be to cultivation) will emerge from the scenario analysis, as 4,562 Mm3. The baseflow index (that is, the contribution of there is less uncertainty associated with the Kc estimates baseflows to total streamflow) of the catchment was thus for these land cover types. estimated to be 0.31. This estimate aligns with NUST (2019), which reported that ZINWA estimated baseflow indexes across the Zambezi River range from 0.05 to 0.40, with values in the upper Mazowe Catchment toward the high Sediment retention end of the range. This lends confidence to the assumptions used to partition net infiltration into groundwater recharge The sediment retention service was quantified using the and baseflow. InVEST SDR model and a 30 m resolution DEM. The model estimates sediment retention and export through combining Due to limited availability of flow monitoring data, the soil loss, calculated using the RUSLE with an SDR, that estimates are not extensively calibrated. However, flow data is, the proportion of soil loss actually reaching a stream. that could be found do lend confidence to the modelling Inputs required by the InVEST SDR model for calculation of estimates. First, the modelled annual streamflow (4,562 Mm3) the RUSLE include a soil erodibility (K-factor) layer, which is close to the reported mean annual runoff of the Mazowe estimates the inherent vulnerability of soil in an area to Catchment of around 4,582 Mm3 (ZINWA 2007, in World erosion based on various soil properties. In the absence of Bank 2021). The modelled value for groundwater recharge such a layer for Zimbabwe, a K-factor map was generated (2,145 Mm3) is also close to the value of 1,918 Mm3 estimated from various soil property layers obtained from the Africa Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 111 SoilGrids dataset (Hengl et  al. 2015). Soil erodibility was dataset. Hence, dam wall locations were updated and calculated using the following equation: missing dams added using a combination of GOOD2, HydroLAKES data (Messager et  al. 2016), and satellite 2.1 # 10 -4 (12 - OM) M 1.14 + 3.25 (s - 2) + 2.5 (p - 3) imagery. Once dam locations had been accurately mapped, K= , 759 catchment areas were modelled using the 30  m DEM through the InVEST DelineateIT watershed creation tool. where M is a parameter linked to particle size, OM is organic matter content (percent), s is soil structure class, and Erosion and sediment modelling was validated and refined p is soil permeability class. For rainfall erosivity (R), the using sediment yield data from Van Den Wall Bake (1985), Global Rainfall Erosivity Database (GloREDa) (Panagos et al. who reports average sedimentation rates of the Mazowe Dam 2017) was used, which provides a global map of rainfall and three other small dams in the study area (Masunswa, erosivity at 250 m resolution. The land cover management Nyamasa, and Nyamembwe), as well as the sediment (C) component of the RUSLE equation accounts for how yield for Chimanda Dam catchment from Tundu et  al. different land cover types affect soil erosion relative to (2018). This was the most recent sediment yield data bare fallow areas (Wischmeier and Smith 1978). A C-factor that incorporated the study area in the comprehensive value was assigned to each of the land cover and habitat review of African sediment yield studies conducted by types through reference to values used in the literature Vanmaercke et  al. (2014). Our own literature search also for comparable vegetation and land cover types (Angima did not reveal any more recent reliable sediment yield et  al. 2003; Fenta et  al. 2020; Panagos et  al. 2015; data. For the four small dams (Chimanda, Masunswa, Wischmeier and Smith 1978). As different crops have Nyamasa, and Nyamembwe), modelled rates of sediment different C-factor values, the C-factor value for cultivated export from the respective catchment areas were within land was calculated from the proportional area of different 4−25 percent of measured sediment accumulation rates. crop types in the constituent provinces of the Mazowe For Mazowe Dam, modelled sediment export was over Catchment. The support practice (P) factor in the RUSLE twice the measured estimate. However, the sediment equation is primarily relevant to agriculture lands and accumulation value for Mazowe Dam was an old long- indicates the ratio of soil loss after implementation of term average between 1920 and 1984. It is quite likely soil conservation measures. Different P-factor values were that the greater loss of natural habitats to cultivation assigned to large-scale commercial farmland on the and urbanization and expansion of artisanal mining has one hand and communal, resettlement, and small-scale increased sediment export rates in recent years, as has commercial farming areas on the other, due to the significant been reported by Tundu et  al. (2018). Furthermore, one differences in field sizes and farming practices. The would expect sediment export to be somewhat higher P-factor estimate for the latter recognized that contour than reservoir accumulation rates, as dams do not trap all ploughing and contour hedgerows are widely practiced exported sediment. Overall, the available data on reservoir in small-scale farming areas, while the P-factor estimate sedimentation rates thus appear to lend confidence to for large-scale commercial farmland incorporated the the validity of the modelled sediment export rates. adoption of conservation tillage, cover cropping, and other soil conservation measures on some farms. The service was only valued within the catchment areas of existing dams. Options for valuation include estimating the Since reservoir sedimentation is one of the major negative cost of preventing sedimentation of dams by constructing impacts of sediment export to watercourses, mapping of sediment check dams or estimating the replacement dams and their catchment areas was conducted. While cost of lost storage capacity through building additional the GOOD2 (Mulligan, van Soesbergen, and Sáenz 2020) water storage. For this study we used an estimated cost of does map the location and catchment areas of 38,000 dams check dam construction, obtained from Mekonnen et al. globally, it was found that dam wall locations were not (2015). The volume of sediment was estimated from mass always corrected, resulting in incorrect catchment areas. using a density of 1.35 t/m3 (Haarhoff and Cassa 2009; Additionally, certain dams were not captured in the GOOD2 Rooseboom 1992). 112 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe Appendix 6.  Relative Future Potential for Maize and Sorghum This appendix provides further details on the analysis scenario, with particularly large declines in southern and that was performed to evaluate the potential benefit of western Zimbabwe (Figure  42). Future suitability for switching from maize to sorghum, particularly under maize is projected to be less than 30 percent of present a hotter and drier future climate scenario. Modelling suitability over much of this region. Notably, the southern conducted as part of the CSAIP found that suitability for and western boundaries of the Mazowe Catchment are maize is low over much of the Mazowe Catchment and some of the only areas where suitability for maize is could decline further under future climatic conditions projected to remain stable or increase. Future suitability (World Bank 2019). The CSAIP recommends considering for sorghum is also projected to decline over much of the switching from maize to more drought-resistant crops country, though the declines are generally less drastic such as sorghum. However, sorghum is generally lower than for maize. Furthermore, suitability for sorghum is yielding than maize under current conditions. Across the projected to increase over the northern and eastern parts constituent provinces of the Mazowe Catchment, the of Zimbabwe’s central watershed, including over the average sorghum yield over the most recent three rainy southern and western parts of the Mazowe Catchment. seasons for which data are available was 0.47 tons per ha, compared to 0.99 tons per ha for maize (MoLAWFRR 2020, 2021). This yield gap is mirrored even in the drier provinces Estimating future yields of maize and sorghum of the country such as Matabeleland. However, future in the Mazowe Catchment declines in maize suitability in parts of the catchment could be severe enough that sorghum becomes a higher yielding To estimate future maize and sorghum yields, current yields option. Thus, the analysis described below aimed to in the Mazowe Catchment were first obtained by averaging evaluate whether there would be any parts of the Mazowe the yield values recorded in recent National Crop and Catchment where declines in future suitability for maize Livestock Assessment reports (MoLAWFRR 2020, 2021). would be severe enough that switching to sorghum would The future suitability ratio layers for maize and sorghum result in an increase in aggregate production. were then used to adjust the current yield values, to give an indication of predicted yields under a hotter and drier climate scenario. To evaluate the potential benefit of Future suitability ratios for maize and sorghum increasing the adoption of sorghum in the catchment, future production under the current maize/sorghum mix The below maps (Figure 42) indicate the FSRs for maize and was compared to a scenario where 50  percent of maize sorghum. This was obtained by dividing future suitability fields are converted to sorghum. This analysis was done by current/historical suitability, as per the layers produced at a sub-catchment scale. for the CSAIP (World Bank 2019). The CSAIP modelled future suitability by 2050 under a hot and dry future climate The projected future yields of maize and sorghum at sub- scenario. In the figures below, an FSR value of 0.5 indicates catchment after adjustment of current yields by the future an area where future suitability is projected to be 50 percent suitability ratio layers are shown in Figure  43. Predicted of current suitability. Values in green (that is, FSR > 1) yields for both maize and sorghum exhibit a similar spatial thus indicate areas where future suitability is similar to or pattern, with higher yields in the wetter south and west of higher than present suitability. the catchment. Notably, even though declines in future suitability for maize are generally more drastic than for Future suitability for maize is predicted to decline over sorghum (Figure 42), predicted maize yields remain higher most of the country under a hot and dry future climate than predicted sorghum yields in all sub-catchments Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 113 FIGURE 42: FSR VALUES FOR MAIZE (LEFT) AND SORGHUM (RIGHT) Source: CSAIP (World Bank 2019). FIGURE 43: PROJECTED FUTURE YIELDS OF MAIZE (LEFT) AND SORGHUM (RIGHT) BASED ON ADJUSTMENT OF CURRENT YIELD BY THE ESTIMATED CHANGE IN FUTURE SUITABILITY Source: Original calculations from this study. Numbers indicate average yield per sub-catchment in tons per ha per year. (Figure  43). In other words, the modeling suggested that sorghum may be beneficial for increasing drought resistance there is no part of the Mazowe Catchment where a switch from among small-scale farmers. On a similar note, the modeling maize to sorghum would increase aggregate production. estimates were based on average yields over three previous The difference in projected yields is generally smallest rainy seasons. In drought years, switching to sorghum may in the dry northeast of the catchment, where conditions result in higher overall grain production in certain parts of for maize are most marginal. In these areas, switching to the catchment, contrary to what was modelled. 114 Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe Appendix 7.  Benefits and Costs of Sustainable Landscape Investments in the Subcatchments Mapping and Valuing Ecosystem Services for Sustainable Landscape Management in Zimbabwe 115 All values in $ millions PV costs and benefits, 25 years @ SDR of 4.56% SubC 1 SubC 2 SubC 4 SubC 5 SubC 6 SubC 7 SubC 8 SubC 9 SubC 10 SubC 11 SubC 12 SubC 13 SubC 14 SubC 15 SubC 16 SubC 17 SubC 18 Mazowe catchment overall Costs 10.6 27.1 77.2 2.8 13.8 64.6 21.7 15.1 5.4 15.9 35.3 6.2 13.3 47.2 4.1 44.8 17.0 422.0 Restore degraded natural 5.3 11.1 38.9 1.7 5.4 22.7 12.8 6.0 2.1 6.4 9.3 3.6 6.0 19.7 2.9 36.1 10.6 200.5 habitats Establish conservancies 0.6 — — — — 0.1 0.1 — — — — — — — — — — 0.8 Implement conservation 3.9 13.3 31.6 1.0 7.0 35.0 7.4 7.6 2.7 8.2 21.1 2.2 6.0 21.6 0.6 5.7 4.9 179.7 agri (50% adoption) Install riparian buffers 0.8 2.8 6.7 0.1 1.4 6.9 1.4 1.4 0.6 1.3 4.8 0.4 1.3 5.9 0.6 3.0 1.5 41.0 Benefits 23.9 56.0 118.1 8.2 24.4 154.6 31.9 22.5 8.6 31.5 55.0 11.1 23.1 117.7 26.4 22.4 32.0 709.9 Avoided dredging 0.6 1.0 14.0 0.0 1.2 2.9 0.6 0.0 — 5.4 4.8 1.0 3.8 17.0 4.5 30.4 20.5 107.8 (sediment) Avoided dam costs (change — 13.4 10.9 — 2.1 35.9 — 2.2 — 2.1 7.6 — 2.4 43.6 — — 4.7 125.0 in recharge) Gains in wild harvested 0.2 1.5 2.4 0.0 0.4 1.3 0.2 −0.1 0.1 0.8 1.3 0.1 0.6 8.5 0.1 3.1 0.6 21.1 resources Changes in agricultural 12.1 32.1 58.5 1.2 7.5 95.0 20.0 13.5 2.5 15.6 24.1 3.8 10.4 33.7 −13.0 − 58.9 0.5 258.7 production Revenue from carbon credits 6.7 8.0 32.2 6.9 13.2 19.1 10.6 6.9 6.0 7.6 17.1 6.2 6.0 14.9 1.9 23.0 5.7 191.9 Tourism gains 4.3 — — — — 0.4 0.5 — — — — — — — — — — 5.2 Net present value 13.28 28.91 40.87 5.46 10.63 89.97 10.26 7.43 3.23 15.57 19.68 4.92 9.83 70.53 210.49 247.27 15.06 287.87 B:C ratio/ROI 2.3 2.1 1.5 3.0 1.8 2.4 1.5 1.5 1.6 2.0 1.6 1.8 1.7 2.5 21.6 20.1 1.9 1.7 ROI for farmland 3.12 2.42 1.85 1.31 1.07 2.71 2.70 1.77 0.93 1.90 1.14 1.74 1.72 1.56 222.42 210.35 0.10 1.44 interventions ROI for natural land 1.75 1.73 1.30 3.84 2.49 2.01 0.84 1.21 2.25 2.05 2.17 1.82 1.75 3.29 1.87 1.44 2.61 1.86 interventions