Ecosystem services are the benefits people obtain from ecosystems, or, in frameworks that distinguish services from their resulting benefits, the contributions ecosystems make to human well-being. They include food production, water purification, flood regulation, and opportunities for recreation and spiritual experience. The concept connects ecology with economics by identifying how ecological processes support human activities, including contributions that lack market prices. Its scope includes natural, semi-natural, and intensively managed environments. (millenniumassessment.org)
Development and classification
The Millennium Ecosystem Assessment, whose principal reports appeared in 2005, established an influential classification with four broad categories. These distinguish material products, regulation of environmental processes, nonmaterial benefits, and the ecological processes underpinning other services. (millenniumassessment.org)
- Provisioning services supply products such as crops, fish, timber, fibers, freshwater, and genetic resources. Their use often also requires human labor, equipment, and infrastructure.
- Regulating services arise from regulation of ecosystem processes. Examples include water purification, climate regulation, pollination, erosion control, and moderation of natural hazards.
- Cultural services provide nonmaterial benefits, including recreation, aesthetic appreciation, spiritual significance, learning, and connections to cultural heritage.
- Supporting services underpin other services through processes such as soil formation, nutrient cycling, and primary production. Their benefits are generally indirect. (millenniumassessment.org)
The Common International Classification of Ecosystem Services instead emphasizes final services: ecosystem outputs most directly connected to people's well-being. It groups these into provisioning, regulation and maintenance, and cultural services, while treating supporting processes separately. This distinction helps prevent double counting—for example, adding the value of nutrient cycling to a crop value that already incorporates its contribution. Whether a contribution is final depends partly on the beneficiary and assessment context. (cices.eu)
Ecological processes and beneficiaries
A service is not simply an ecological process considered in isolation. Assessment connects an ecosystem characteristic or process with an identifiable human use or appreciation. The same environment may therefore provide different services to different beneficiaries. A water body, for example, can supply irrigation water, support fishing, or provide recreational experiences; each relationship calls for different measurements. (assessments.epa.gov)
Biodiversity supports many of these relationships through organisms' traits, ecological interactions, and ecosystem functioning. Photosynthesis produces organic matter, while decomposition contributes to nutrient recycling. Vegetation and soils influence the water cycle and carbon cycle. However, biodiversity and ecosystem services are not interchangeable: measuring one service does not capture every ecological characteristic or value of a place. (millenniumassessment.org)
Services also differ in spatial reach. Recreation may depend on access to a particular site, downstream water benefits connect locations within a drainage basin, and climate regulation can benefit people far from the ecosystem producing it. Assessments consequently distinguish ecosystem capacity, realized service flows, demand, and beneficiaries rather than assuming that ecosystem area alone determines benefits. (epa.gov)
Measurement and valuation
Biophysical assessment uses indicators suited to individual services, such as quantities of supplied water, carbon retained or sequestered, or opportunities for recreation. Mapping and modeling can combine information about ecosystem condition, service production, human demand, and environmental pressures. A rigorous assessment specifies its geographical boundary, time period, beneficiaries, and causal relationships between ecological change and benefits. (seea.un.org)
Economic valuation is grounded in welfare economics. It can investigate both use values and non-use values, such as the importance people attach to an ecosystem's continued existence. Revealed-preference methods infer values from observed behavior, whereas stated-preference methods ask people about choices or willingness to pay. Economic values are often expressed monetarily, but monetary expression is not essential to every valuation exercise. (ipbes.net)
A price is not a complete measure of nature's importance. IPBES distinguishes instrumental values, intrinsic values, and relational values associated with meaningful relationships among people and nature. Spiritual attachment, responsibilities toward a landscape, and cultural identity may require qualitative or participatory assessment rather than reduction to a single monetary figure. Different valuation approaches answer different questions and need not yield directly comparable results. (ipbes.net)
Ecosystem accounting
Ecosystem accounting organizes information about ecosystem assets and the services flowing from them. The United Nations Statistical Commission adopted the System of Environmental-Economic Accounting—Ecosystem Accounting in March 2021. Its framework links spatial information about ecosystem extent and condition with physical and monetary service accounts and monetary ecosystem asset accounts. (seea.un.org)
Accounting distinguishes stocks from flows: an ecosystem asset has an extent and condition at a particular time, whereas a service is supplied over a period. These accounts complement national accounts by showing environmental contributions and changes that conventional economic measures do not fully describe. Physical accounts remain useful even where monetary valuation is unavailable or inappropriate. (seea.un.org)
Pressures and trade-offs
The 2019 IPBES Global Assessment identified five major direct drivers of change in nature: land- and sea-use change, direct exploitation of organisms, climate change, pollution, and invasive alien species. Their relative effects vary among ecosystems and regions, altering the conditions that sustain services. (ipbes.net)
Management can increase one service while diminishing others. Agricultural expansion may increase food output while reducing water purification, habitat, or cultural benefits. Service assessments make such trade-offs explicit, including differences between immediate gains and longer-term losses and between beneficiaries in different locations. They are used in conservation, ecological restoration, and land-use planning, but do not by themselves determine which competing values should take priority. (millenniumassessment.org)
IPBES's broader concept of nature's contributions to people includes both beneficial and detrimental contributions and gives explicit attention to cultural context and diverse knowledge systems. It recognizes that the same ecological relationship may be experienced differently across communities, places, and times. (ipbes.net)