Sustainability & Environment (Agri-Food Systems) · Natural Resources & Biodiversity · also Ecosystem Services, Natural Capital, Functional Biodiversity in Agriculture
The services nature provides to farming and farming provides back: pollination, pest control, soil formation, water regulation, carbon storage. The economics of valuing them (contingent valuation, travel cost, hedonic pricing) is taught in the Agribusiness subject natural-resource-environmental-economics; this subject covers the ecology, the classification systems, the mapping tools and natural-capital accounting.
In the exams: ICAR AICE subject 71 Unit 2 (values of biodiversity); UGC NET Unit 3; TNFD-related professional work; PG research
Farms are ecosystems. They depend on services that nature provides — pollination by bees and other insects, control of pests by their natural enemies, fertile soils built and maintained by organisms, clean and reliable water, a stable climate — and they in turn produce food and other services while affecting the services that others receive downstream and in the future. Understanding these flows is essential for productive and sustainable farming, for landscape planning, and for companies and governments that must now measure and disclose their dependence on nature.
This subject covers ecosystem service frameworks (the Millennium Ecosystem Assessment, TEEB, CICES and IPBES's nature's contributions to people); the categories of services; ecosystem disservices to and from agriculture; pollination services, pollinator decline and pollinator-friendly farming; natural pest control and functional agrobiodiversity; soil and water regulating services; mapping and modelling of services; natural capital accounting under the SEEA Ecosystem Accounting standard; payments for ecosystem services; and corporate assessment of nature dependencies and impacts. The economic methods for valuing services (contingent valuation, travel cost, hedonic pricing) are taught in the Agribusiness subject natural-resource-environmental-economics; biodiversity science and conservation in biodiversity-conservation; the CBD and Kunming-Montreal framework in environmental-law-policy; forest ecology in the forestry subject forest-ecology; and corporate disclosure in sustainability-reporting-esg.
The subject supports national postgraduate entrance, research-fellowship and university-teaching eligibility examinations in environmental sciences (where the values of biodiversity form a standard unit), civil-service environment papers, postgraduate research in agroecology and landscape ecology, and professional work on nature-related risk and disclosure. Quantitative estimates — of pollination value, threatened pollinators or nature-dependent GDP — come from cited assessments and carry wide uncertainty; they are given with their sources.
Ecosystem services are the benefits people obtain from ecosystems. The idea that nature provides services goes back to early ecologists, but it entered policy in the 1990s with Daily's book Nature's Services (1997) and a widely cited estimate by Costanza and colleagues (1997) of the global value of ecosystem services, which argued that this value exceeded global GDP. The Millennium Ecosystem Assessment (MA), a UN-sponsored assessment by over a thousand scientists published in 2005, made the concept mainstream. It classified services into four categories — provisioning (food, fibre, fuel, fresh water, genetic resources), regulating (climate, water, erosion, pollination, pest and disease regulation), cultural (spiritual, recreational, aesthetic, educational) and supporting (soil formation, nutrient cycling, primary production) — and found that about 60 % of the ecosystem services it examined (15 of 24) were being degraded or used unsustainably, while gains in provisioning services such as food had come at the cost of regulating services.
The Economics of Ecosystems and Biodiversity (TEEB), launched by the G8+5 environment ministers in 2007 and hosted by UNEP, produced reports in 2008–2010 on the economic significance of biodiversity loss and ways to make nature's values visible in decisions, and later TEEB for Agriculture and Food (2018), which applies a systems framework to the visible and invisible costs and benefits of food systems (see sustainable-food-systems). The Common International Classification of Ecosystem Services (CICES), developed for the European Environment Agency and used in environmental accounting, groups final services into three sections — provisioning, regulation and maintenance, and cultural — and deliberately omits 'supporting' services, because these are ecological processes whose benefits are already counted through the final services they underpin; including them would double count. The ecosystem service 'cascade' (Haines-Young and Potschin) links biophysical structures and processes to ecosystem functions, then to final services, then to benefits to people and finally to their values, making clear which step is being measured.
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), established in 2012, broadened the concept into nature's contributions to people (NCP): all the contributions, positive and negative, of living nature to people's quality of life. Díaz and colleagues (2018) described 18 categories grouped as material (such as food and feed, energy, materials), non-material (learning and inspiration, physical and psychological experiences, supporting identities) and regulating (such as habitat creation, pollination, regulation of air quality, climate, freshwater quantity and quality, soils, hazards and detrimental organisms), and stressed that the value of these contributions depends on culture and context, including indigenous and local knowledge. In practice the frameworks are complementary: the MA categories remain common in teaching and exams; CICES is used for accounting and mapping; IPBES's NCP framework emphasises plural values and the knowledge of different communities. For agriculture, all three highlight that farms both depend on services (pollination, pest control, soil fertility, water) and produce or degrade them (food, carbon storage, water quality, landscapes).
Provisioning services are the products obtained from ecosystems: crops, livestock, fish, timber, fuelwood, fibre, fresh water, medicinal plants and genetic resources. Agriculture is designed to maximise some provisioning services, often at the expense of others. Supporting services in the MA scheme are the underlying processes that make other services possible: soil formation, nutrient cycling, primary production, water cycling and the provision of habitat. They operate over long time scales — soil formation is typically measured in millimetres per decade or less — and are not used directly by people. Recognising this, accounting frameworks treat them as ecosystem functions or intermediate services rather than as final services, to avoid counting their value twice (once in the soil-formation service and again in the crop that depends on the soil).
Regulating services are the benefits obtained from the regulation of ecosystem processes: climate regulation through carbon storage and sequestration and through local effects on temperature and humidity; water regulation (timing and magnitude of runoff, flooding and aquifer recharge); water purification and waste treatment; erosion control; pollination; pest and disease regulation; air quality regulation; and natural hazard regulation (mangroves and coral reefs buffering storms, forests stabilising slopes). Regulating services are often invisible until lost: when wetlands are drained, flood damage increases; when pollinators decline, fruit set falls; when hedgerows are removed, wind erosion and pest outbreaks rise. Many regulating services operate at the landscape scale, beyond a single farm, which creates collective action problems — one farmer's hedgerow benefits neighbours' pollination and pest control as well as his own.
Cultural services are the non-material benefits people obtain through spiritual enrichment, cognitive development, reflection, recreation, aesthetic experience, a sense of place and cultural heritage. Agricultural landscapes are rich in them: terraced rice paddies and agroforestry systems, traditional orchards and sacred groves, agricultural fairs and food traditions, and rural tourism. FAO's Globally Important Agricultural Heritage Systems (GIAHS) programme recognises such systems, including the Ifugao rice terraces of the Philippines, the rice–fish culture of Qingtian in China, the oasis systems of the Maghreb, Chiloé agriculture in southern Chile, Maasai pastoralism in northern Tanzania and the Kuttanad below-sea-level rice system on India's south-west coast. Services rarely occur alone: they form bundles that co-occur in landscapes, and management that increases one service often changes others. Trade-offs arise when increasing one service reduces another (more food, less water quality or habitat), while synergies arise when practices enhance several services at once (cover crops improving soil carbon, water infiltration and nutrient retention). Mapping bundles helps identify where land management can deliver multiple benefits (chapter 7).
Ecosystem disservices are functions of ecosystems that are perceived as negative for human well-being. Zhang and colleagues (2007) set out a framework of services and disservices to agriculture, recognising that farms receive harmful as well as beneficial flows from surrounding ecosystems. Disservices to agriculture include crop pests and pathogens that arrive from natural or semi-natural habitats; weeds; competition for water from natural vegetation; damage by wildlife (crop raiding by elephants, wild boar, monkeys, nilgai, birds and rodents); shading of crops by trees; and the spread of livestock diseases from wildlife. Human health disservices include allergenic pollen, disease vectors such as mosquitoes breeding in wetlands and zoonotic diseases. Recognising disservices helps explain why farmers may clear hedgerows, drain wetlands or kill wildlife, and why conservation programmes must address real costs rather than only advertise benefits.
Agriculture also generates disservices to the wider environment and society: loss of habitat and biodiversity, nutrient runoff causing eutrophication and dead zones, pesticide poisoning of non-target organisms and people, soil erosion and sedimentation of reservoirs, greenhouse gas emissions, water depletion, and the spread of antimicrobial resistance from livestock. These are externalities borne by others, often downstream or in the future (see water-quality-nonpoint-pollution and pesticides-environment). The same habitat can produce both services and disservices: a forest patch next to a farm can provide pollinators and natural enemies but also harbour crop-raiding animals and pests; a wetland can purify water and breed mosquitoes. Net effects depend on species, landscape configuration and management.
Practical management aims to increase net benefits. For wildlife damage, options include crop choice (crops less attractive to raiders), guarding, fencing and trenches, early warning systems, insurance and compensation schemes, and land-use planning that maintains corridors away from fields. For pests, habitat management can be designed to favour natural enemies more than pests, for example by choosing flowering plants that feed parasitoids but not pest moths (chapter 5). Assessments should include disservices explicitly: an analysis that counts the pollination benefit of a forest edge but ignores crop raiding will mislead farmers and policy makers. Human–wildlife conflict around protected areas is a major issue across much of Africa, South and South-East Asia and parts of Latin America, and is discussed further in the forestry subject wildlife-management-protected-areas.
Animal pollination — by bees, flies, butterflies, moths, beetles, birds and bats — is needed for the reproduction of most flowering plants. Klein and colleagues (2007) found that 87 of the 115 leading global food crops (about three-quarters) benefit from animal pollination to some degree, although these crops account for about a third of global food production volume, because staple cereals such as wheat, rice and maize are wind-pollinated or self-pollinated. The IPBES pollination assessment (2016) estimated that between 5 and 8 % of global crop production is directly attributable to animal pollination, with an annual market value of 235 to 577 billion US dollars (in 2015), and that pollinator-dependent crops supply much of the vitamins A and C, folate and other micronutrients in human diets. Fruits, vegetables, nuts, oilseeds such as mustard and sunflower, coffee and cocoa are pollinator-dependent; the degree of dependence varies from little to essential. A common method (Gallai and colleagues) values pollination as production × price × dependence ratio: 1000 t of a crop worth 2000 per tonne with a dependence ratio of 0.65 represents 1300000 in pollination value.
There are more than 20000 species of bees, and wild bees and other insects often pollinate more effectively than managed honey bees; diverse pollinator communities increase fruit set even where honey bees are abundant (Garibaldi and colleagues, 2013). The IPBES assessment found that wild pollinators have declined in occurrence and diversity in many regions, that 16.5 % of vertebrate pollinators are threatened with global extinction, and that where regional assessments exist, often more than 40 % of invertebrate pollinator species, particularly bees and butterflies, are threatened. Drivers include land-use change and loss of flower-rich habitat and nesting sites; intensive agricultural management including monocultures and pesticides — neonicotinoid insecticides have lethal and sublethal effects on bees, and the EU banned outdoor use of three of them (imidacloprid, clothianidin and thiamethoxam) in 2018; pathogens and parasites such as the Varroa mite, which spread from the Asian honey bee to the western honey bee; invasive species; and climate change, which shifts ranges and can mismatch flowering and pollinator activity. Managed honey bee colony numbers have increased globally, but beekeepers in some regions suffer high winter losses, and reliance on a single managed species is risky.
Measures that support pollinators include: maintaining or creating flower-rich habitat (wildflower strips, flowering hedgerows, field margins, cover crops such as mustard and clover, and trees on farms) that provides food throughout the season; protecting nesting sites (bare ground for ground-nesting bees, dead wood and stems for cavity nesters); reducing pesticide risk through integrated pest management, avoiding spraying during flowering and at times when bees forage, choosing less toxic products and protecting field margins from drift; diversifying crops and landscapes; managing pollinators responsibly, including honey bees (Apis mellifera and the native Apis cerana in Asia), stingless bees, bumblebees and solitary bees in some crops, with typical stocking rates of a few colonies per hectare for crops such as apples and mustard; and landscape-level planning that connects habitat. Apple growers in parts of the Himalaya and in south-west China have had to rent honey bee colonies or pollinate by hand where pollinators declined, and many governments now run national beekeeping programmes that promote colonies for both honey and pollination. Pollination deficits — where yield is limited by insufficient pollination — can be measured by comparing yields under open and supplemented pollination, and closing them can raise yields and quality substantially for small farmers.
Farm-level assessment of pollination combines three kinds of evidence. Pollinator surveys — timed observations of flower visitors, pan traps and transect walks — show which species visit the crop and how often. Exclusion experiments compare fruit or seed set on flowers that are bagged to exclude visitors, flowers left open, and flowers hand-pollinated to saturation; the difference between open and hand-pollinated flowers measures the pollination deficit, and the difference between open and bagged flowers the contribution of animal pollinators. Landscape analysis relates pollinator visitation and yield to the amount of semi-natural habitat within the foraging range of key species, typically a few hundred metres for small solitary bees and a few kilometres for honey bees. Across Asia, Africa and Latin America, studies on crops such as mustard, sunflower, pigeonpea, cucurbits, coffee and apple have found that wild bees, including native Apis cerana, A. dorsata and A. florea and many solitary bees, contribute substantially to yield and quality. Such measurements allow farmers and advisers to decide whether to add managed colonies, create habitat or change pesticide practice, and give policy makers evidence beyond global averages.
Natural pest control is the regulation of crop pests by their natural enemies — predators (ladybird beetles, lacewings, ground beetles, spiders, birds, bats), parasitoids (small wasps and flies whose larvae develop inside or on pests) and pathogens (fungi, bacteria, viruses, nematodes). Biological control has three forms: classical biological control introduces natural enemies from a pest's native range against an invasive pest (see biodiversity-conservation); augmentative control releases mass-reared enemies such as Trichogramma egg parasitoids against lepidopteran pests; and conservation biological control manages habitats and practices to support enemies already present. The value of natural pest control is large but rarely counted; an early estimate for the United States (Losey and Vaughan, 2006) put the value of pest control by native insects at about 4.5 billion US dollars a year. Integrated pest management (see pesticides-environment) uses natural control as its foundation and treats pesticides as a last resort guided by economic thresholds.
Functional agrobiodiversity is the component of biodiversity on and around farms that provides services such as pest control, pollination and nutrient cycling. Practices that increase it include: flower strips and field margins that provide nectar, pollen and alternative hosts for parasitoids and predators; beetle banks — raised grassy strips within fields that shelter ground beetles and spiders through winter; hedgerows and trees; intercropping and crop diversity; reduced tillage that protects ground-dwelling predators; and reduced use of broad-spectrum insecticides that kill natural enemies and can cause pest resurgence (as seen with brown planthopper outbreaks in rice after heavy insecticide use in Asia). The push-pull system, developed in East Africa by the International Centre of Insect Physiology and Ecology, intercrops maize with a repellent legume (Desmodium) and borders it with an attractive trap grass (such as Napier or Brachiaria), pushing stemborer moths away from the crop and pulling them into the border, while Desmodium also suppresses the parasitic Striga weed and fixes nitrogen.
Natural enemy populations often depend on habitat beyond the field: complex landscapes with more semi-natural habitat generally support more natural enemies, and many studies have found better pest control in such landscapes. However, a large global synthesis (Karp and colleagues, 2018) found that landscape effects on pest abundance and crop damage were highly variable — sometimes positive, sometimes negative or absent — because pests can also benefit from non-crop habitat and because outcomes depend on the species involved and on local management. Practical lessons are to design habitat for the specific pest–enemy system, provide resources at the right time, combine habitat with reduced insecticide use, and measure outcomes (pest densities, parasitism rates, crop damage and yield) rather than assume benefits. Agroecology and conservation agriculture subjects in this track (agroecology-principles, conservation-regenerative-agriculture) place these practices within whole-farm design.
Soils provide a suite of services that underpin agriculture: formation of soil from parent material, organic matter and organisms; nutrient cycling and decomposition; biological nitrogen fixation by rhizobia in legumes and free-living bacteria; maintenance of soil structure by roots, fungi and earthworms, which governs water infiltration and storage; regulation of greenhouse gases and storage of carbon (see soil-carbon-sequestration); and suppression of soil-borne diseases by diverse microbial communities. Soil formation is slow — commonly well under one millimetre per year — whereas erosion on bare, sloping cropland can remove several millimetres a year, so soil is effectively non-renewable on human time scales where erosion is high. A millimetre of soil over a hectare with a bulk density of 1.3 t per cubic metre weighs 13 t, which is why erosion rates of tens of tonnes per hectare per year represent losses that formation cannot replace (see land-degradation-soil-conservation).
Ecosystems regulate the quantity, timing and quality of water. Vegetation and soil determine how rainfall is partitioned between infiltration, runoff and evapotranspiration; forests, grasslands and wetlands can reduce peak flows and maintain dry-season base flows, though forests also use water, so their effect on total annual yield depends on climate and species. Wetlands and floodplains store floodwater and recharge aquifers. Riparian buffers — strips of trees, shrubs or grass along streams — trap sediment and phosphorus and remove nitrate through plant uptake and denitrification; removal efficiencies vary widely with width, vegetation, soil and hydrology. As an illustration, if fields upstream lose 40 kg of nitrate-nitrogen per hectare per year from 100 ha and a buffer removes 60 % of the load reaching it, 2400 kg N a year is retained. Constructed wetlands treat farm and village wastewater. Vegetation cover reduces erosion: in the Universal Soil Loss Equation (A = R K LS C P), reducing the cover-management factor C from 0.3 to 0.05 by keeping residue or cover crops cuts predicted soil loss by about 83 %.
Practices that enhance soil and water services include cover cropping, residue retention and reduced tillage (protecting soil structure and organic matter), diverse rotations including legumes, agroforestry and contour hedgerows, buffer strips and grassed waterways, restoration of wetlands and floodplain connectivity, and careful nutrient management to avoid surpluses (see nutrient-stewardship). Payments and regulations increasingly target these services (chapter 9). Measurement remains a challenge: infiltration rates, aggregate stability, soil organic carbon, nitrate leaching and sediment yields vary in space and time, so monitoring designs must be robust, and models are often used to estimate effects at catchment scale. Community watershed management in South Asia, East Africa and the Andes — through programmes that combine soil and water conservation works with vegetation and community institutions — is an example of managing these services at landscape scale (see water-conservation-governance).
Mapping ecosystem services shows where services are produced, where they are used and how they move between the two. Service supply is the capacity of an ecosystem to provide a service (for example the area of pollinator habitat or the water purification potential of a wetland); demand is the need for the service by people (crops needing pollination, towns downstream needing clean water); and flow is the service actually used. Service-providing areas and service-benefiting areas are often separated: upland forests regulate water for downstream cities; pollinators nest in field margins and forage in adjacent crops within their flight range. Mismatches between supply and demand identify priorities for protection or restoration, and the people who benefit may differ from those who manage the land, which motivates payments (chapter 9).
Mapping methods form a hierarchy of complexity. Lookup-table or benefit-transfer approaches assign service values or scores to land-cover classes from literature or expert judgement and multiply by area: 50 ha of wetland with a transferred value of 2000 per hectare per year gives 100000 a year. They are quick and widely used but ignore local conditions and can be badly wrong. Expert and participatory mapping capture local knowledge and cultural services. Statistical and machine-learning models relate measured service indicators to environmental variables. Process-based models simulate the mechanisms: hydrological models for water yield and sediment, soil erosion models based on the Universal Soil Loss Equation, crop and soil models for carbon and nutrient cycling, and pollination models that combine nesting and floral resources with bee flight distances to estimate visitation to farms. Open-source ecosystem service modelling suites developed by universities and NGOs combine many such models in a GIS environment and are widely used for spatial planning, environmental assessment and natural capital accounts.
Mapping several services together reveals bundles and trade-offs: Raudsepp-Hearne and colleagues (2010) showed that landscapes cluster into types with characteristic bundles, such as intensive agriculture with high crop production but low regulating and cultural services. Scenario analysis compares bundles under alternative land-use futures — for example agricultural expansion versus restoration of riparian buffers — to inform planning. Model results carry uncertainty from input data (land cover maps, soil maps, climate data), model structure and parameters, and from benefit transfer; good practice validates models against field measurements where possible, reports uncertainty ranges, and involves stakeholders in defining which services and beneficiaries matter. Maps support environmental impact assessment, strategic environmental assessment and conservation planning, and provide the spatial basis for ecosystem accounting (chapter 8).
Conventional national accounts measure economic production (GDP) but not the depletion and degradation of natural assets that support it, so a country can grow its GDP while running down forests, soils, fisheries and water. Natural capital accounting extends national accounts to include nature. The UN System of Environmental-Economic Accounting (SEEA) has two main parts: the SEEA Central Framework, adopted as an international statistical standard in 2012, which records individual environmental assets (water, timber, land, energy and mineral resources) and flows of materials, energy and emissions; and the SEEA Ecosystem Accounting (SEEA EA), adopted by the UN Statistical Commission in March 2021, which records ecosystems as spatial assets and the services they provide. The Dasgupta Review on the Economics of Biodiversity (2021), commissioned by the UK Treasury, argued that nature is an asset and that measures of inclusive wealth should replace sole reliance on GDP.
SEEA EA organises information into five core accounts. Ecosystem extent accounts record the area of each ecosystem type (forests, croplands, wetlands, grasslands, urban) within an accounting area at the start and end of a period, with additions and reductions: opening extent + additions − reductions = closing extent. Ecosystem condition accounts record the quality of ecosystems using indicators of physical, chemical and biological state compared with reference conditions (such as soil organic carbon, water quality, species composition). Ecosystem services flow accounts in physical terms record the quantity of each final service supplied by each ecosystem type to each user (households, industries, government) — tonnes of crops, cubic metres of water purified, tonnes of carbon sequestered, visits for recreation. Ecosystem services flow accounts in monetary terms, and monetary ecosystem asset accounts, value these flows and the net present value of expected future services. The extent, condition and physical flow parts are the agreed statistical standard; the monetary valuation parts were adopted as internationally recognised principles and recommendations, reflecting continuing debate about valuation. Agricultural ecosystems appear as cropland and grassland ecosystem types, and the services recorded include crop and livestock provisioning, pollination, soil retention, water regulation and carbon storage.
Dozens of countries have compiled SEEA accounts, usually through the national statistical office working with environment agencies; examples range from Australia, the Netherlands and the United Kingdom to South Africa, Colombia, China and India, and many publish ecosystem extent, condition and service accounts on land, water, forests and biodiversity alongside their annual environment statistics. Accounts help track progress towards national targets, such as the Kunming-Montreal monitoring framework (which uses SEEA indicators), inform land-use and investment decisions, and provide data for corporate disclosures and natural capital assessments. Challenges include data gaps (especially for condition and regulating services), the complexity of spatial modelling, institutional capacity, and the risk that partial monetary values crowd out other values. A simple extent example: if a district begins the year with 1200 ha of wetland, gains 50 ha through restoration and loses 180 ha to conversion, the closing extent is 1070 ha, a net reduction of about 11 %.
Payments for ecosystem services (PES) reward land users for managing their land to provide ecosystem services that benefit others. Wunder's (2005) widely used definition describes PES as a voluntary transaction in which a well-defined ecosystem service, or a land use likely to secure it, is bought by at least one buyer from at least one provider, if and only if the provider secures the service (conditionality); a later revision (2015) defines PES as voluntary transactions between service users and providers that are conditional on agreed rules of natural resource management for generating off-site services. In economic terms, PES addresses a positive externality: upstream land users bear the costs of conservation while downstream beneficiaries gain, so payments align private incentives with social benefits. A viable payment must at least compensate the provider's opportunity cost (the income forgone from the alternative land use) and should not exceed the value of the service to the buyer: if conserving a hectare costs a farmer 120 a year in forgone income and the downstream benefit is 300, any payment between 120 and 300 can make both better off.
Costa Rica's national programme of payments for environmental services, created by the Forestry Law of 1996 and run by its national forestry financing fund, pays landowners for forest protection, reforestation and agroforestry, financed partly by a fuel tax and water charges; it is often credited with contributing to the recovery of forest cover. New York City chose, from the 1990s, to protect and manage the Catskill–Delaware watersheds — buying land, paying farmers for best management practices and upgrading wastewater plants — instead of building a filtration plant estimated to cost several billion dollars, at a fraction of that cost. Mexico's national payments for hydrological services (from 2003) pay forest owners in priority watersheds. China's Sloping Land Conversion Programme ('Grain for Green', from 1999) paid farmers to convert steep cropland to forest and grassland to reduce erosion and flooding, one of the largest such programmes in the world. In France, a mineral water company paid dairy farmers in its catchment to change practices to protect groundwater from nitrate and pesticides. The EU's Common Agricultural Policy pays farmers for agri-environment-climate commitments and, since 2023, eco-schemes; India's Green Credit Programme (2023) creates tradable credits for environmental actions such as tree planting and water conservation. Carbon markets (see carbon-markets-offsets) and biodiversity credits are related market-based mechanisms.
PES effectiveness depends on design. Additionality asks whether the service would have been provided anyway without payment — many programmes have paid for forests at low risk of clearing. Conditionality requires monitoring and enforcement of agreed management or outcomes. Targeting directs payments to places where services are high, threats are real and costs are low. Leakage occurs when protection in one place displaces damaging activity elsewhere. Permanence concerns what happens when payments stop. Baselines define what would happen without the programme. Payment level, transaction costs, secure land tenure (to know who can be paid), equity (whether poor land users can participate and benefit) and the choice between paying for actions (input-based) or results (outcome-based) all shape outcomes. Evaluations using rigorous comparison groups have found PES impacts ranging from substantial to negligible, often small on average because of poor targeting, which has pushed programmes towards better targeting and result-based designs.
In agriculture, payment schemes often take the form of agri-environment programmes that pay farmers to adopt or maintain practices — buffer strips, reduced fertiliser, wetland restoration, extensive grazing, flower strips, agroforestry — rather than for measured services, because measuring services on each farm is costly. Result-based schemes, which pay for outcomes such as the number of indicator plant species in a meadow or measured nitrate reductions, have been piloted in Europe and can improve effectiveness and farmer engagement where outcomes are measurable and largely under farmers' control. Collective or landscape-scale schemes pay groups of farmers to coordinate actions across a catchment, matching the scale at which many regulating services operate. In many low- and middle-income countries, watershed development programmes, community-based natural resource management and schemes supporting agroecological farming and agroforestry provide incentives that resemble PES, and public and corporate programmes have experimented with payments for protecting catchments of drinking water reservoirs. Smallholders face barriers to participation — insecure tenure, high transaction costs, delayed payments and complex rules — so intermediaries such as cooperatives and NGOs often aggregate farmers and handle monitoring.
Businesses depend on nature and affect it. The World Economic Forum (2020) estimated that about 44 trillion US dollars of economic value generation — over half of global GDP — is moderately or highly dependent on nature and its services, with construction, agriculture and food and beverages the most dependent sectors. Agri-food companies depend on pollination, water supply, soil fertility, climate regulation and genetic diversity, and they drive nature loss through land conversion, water use, pollution and greenhouse gas emissions. Nature loss therefore creates physical risks (supply disruption from pollinator decline, drought or soil degradation), transition risks (regulation such as deforestation rules and pesticide limits, changing consumer preferences, litigation) and systemic risks, as well as opportunities in restoration, regenerative agriculture and sustainable products.
Several frameworks guide corporate assessment. The Natural Capital Protocol (2016), developed by the Natural Capital Coalition (now the Capitals Coalition), sets out a four-stage process — frame, scope, measure and value, apply — for identifying, measuring and valuing a company's impacts and dependencies on natural capital. The Taskforce on Nature-related Financial Disclosures' LEAP approach (Locate, Evaluate, Assess, Prepare) guides assessment and disclosure (see sustainability-reporting-esg). The Science Based Targets Network provides methods for companies to set targets for freshwater and land, starting with assessing pressures across the value chain and prioritising locations. Free databases developed with UNEP's World Conservation Monitoring Centre map typical dependencies and impact drivers by economic sector and production process, helping companies screen which ecosystem services and pressures are material before detailed assessment. A typical agri-food assessment maps sourcing regions, identifies dependencies (for example cocoa on pollinating midges and shade, almonds on managed honey bees, rice on irrigation water) and impacts (deforestation, nutrient runoff, pesticide use, water abstraction), evaluates their significance in sensitive locations, and sets responses.
Responses follow the mitigation hierarchy — avoid, reduce, restore and regenerate, transform — applied across the value chain: avoiding sourcing from recently converted natural ecosystems (see sustainable-supply-chains), reducing pesticide and fertiliser use, restoring habitat on and around farms, supporting landscape and jurisdictional programmes, and transforming business models and products. Measuring outcomes requires metrics of pressure (hectares converted, nitrogen surplus, pesticide toxic load, water withdrawn in stressed basins) and of state (species abundance, habitat condition, pollinator diversity), and is complicated by the location-specificity of nature and the lack of a single metric comparable to carbon dioxide-equivalent. Biodiversity footprint metrics and credits are emerging but contested. For farms and agri-food firms, investing in pollinator habitat, natural pest control, soil health and water stewardship can reduce dependency risks while delivering benefits to the wider landscape — the logic at the heart of this subject.
A student should be able to compare the MA, TEEB, CICES and IPBES frameworks, classify services and disservices with agricultural examples, explain why supporting services are excluded from accounts, describe pollination dependence and the drivers of pollinator decline, design pollinator-friendly and pest-suppressive farm habitats, explain soil and water services with the USLE cover factor and buffer arithmetic, describe mapping methods, set out the five SEEA EA accounts, and define PES with its design issues. Numerical skills include pollination value, buffer retention, extent accounts and PES payment bounds.
An agronomist, extension officer, landscape planner or sustainability analyst designs flower strips, hedgerows and buffers; measures pollination deficits and natural enemy activity; advises on pesticide timing to protect bees; maps ecosystem services for land-use plans and impact assessments; compiles natural capital accounts for districts or companies; designs or evaluates PES and agri-environment schemes; and screens supply chains for nature dependencies for TNFD-aligned disclosure. They must explain to farmers why a strip of flowers or a buffer is worth the land it occupies, using local evidence rather than global averages.
A senior official, programme director or head of sustainability decides how ecosystem services are integrated into agricultural policy, payments and investment: which schemes to fund and how to target them, how to build natural capital accounts into planning, how to manage nature-related risks in sourcing, and how to balance food production with regulating services across landscapes. They negotiate with farmers, buyers and governments and judge the evidence for scaling practices. They must also decide how to measure success and how to keep programmes funded beyond short project cycles.
A professor or principal scientist studies the ecology of pollination and pest control in agricultural landscapes, the links between biodiversity and ecosystem functioning, ecosystem service modelling and its uncertainty, natural capital accounting methods, and the effectiveness and equity of PES. They contribute to IPBES assessments and SEEA methodological work, design long-term experiments, supervise doctoral research and set examination questions that test mechanistic understanding of services rather than lists of categories. Their field experiments on pollination deficits and natural enemies supply the local evidence policy needs.
Valuation methods are left to natural-resource-environmental-economics. Estimates of pollination value, pest-control value and nature-dependent GDP are wide-range global figures and should not be applied to specific farms without local data. Software tools and commercial databases are described generically, not named. The manual does not cover marine and coastal ecosystem services, urban ecosystem services, detailed hydrological or erosion modelling, or the full SEEA EA technical guidance. Evidence on landscape effects on pest control and on PES impacts is mixed and evolving.
Original practice questions written to the syllabus and pattern of the exams named in each question's examTags. They are not past papers and do not reproduce any board's questions. Every numerical answer was computed in a script. Global value estimates are quoted from cited assessments and carry wide uncertainty.
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