Ecosystem service

Ecosystem services are the various benefits that humans derive from ecosystems. The interconnected living and non-living components of the natural environment offer benefits such as pollination of crops, clean air and water, decomposition of wastes, and flood control. Ecosystem services are grouped into four broad categories of services. There are provisioning services, such as the production of food and water; regulating services, such as the control of climate and disease; supporting services, such as nutrient cycles and oxygen production; and cultural services, such as recreation, tourism, and spiritual gratification. Evaluations of ecosystem services may include assigning an economic value to them.

For example, estuarine and coastal ecosystems are marine ecosystems that perform the four categories of ecosystem services in several ways. Firstly, their provisioning services include marine resources and genetic resources. Secondly, their supporting services include nutrient cycling and primary production. Thirdly, their regulating services include carbon sequestration (which helps with climate change mitigation) and flood control. Lastly, their cultural services include recreation and tourism.

The Millennium Ecosystem Assessment (MA) initiative by the United Nations in the early 2000s popularized this concept.

Ecosystem services or eco-services are defined as the goods and services provided by ecosystems to humans. Per the 2006 Millennium Ecosystem Assessment (MA), ecosystem services are "the benefits people obtain from ecosystems". The MA also delineated the four categories of ecosystem services into provisioning, regulating, supporting, and cultural.

By 2010, there had evolved various working definitions and descriptions of ecosystem services in the literature. To prevent double-counting in ecosystem services audits, for instance, The Economics of Ecosystems and Biodiversity (TEEB) replaced "Supporting Services" in the MA with "Habitat Services" and "ecosystem functions", defined as "a subset of the interactions between ecosystem structure and processes that underpin the capacity of an ecosystem to provide goods and services".

While Gretchen Daily's original definition distinguished between ecosystem goods and ecosystem services, Robert Costanza and colleagues' later work and that of the Millennium Ecosystem Assessment lumped all of these together as ecosystem services.

Four different types of ecosystem services have been distinguished by the scientific body: regulating services, provisioning services, cultural services and supporting services. An ecosystem does not necessarily offer all four types of services simultaneously; but given the intricate nature of any ecosystem, it is usually assumed that humans benefit from a combination of these services. The services offered by diverse types of ecosystems (forests, seas, coral reefs, mangroves, etc.) differ in nature and in consequence. In fact, some services directly affect the livelihood of neighboring human populations (such as fresh water, food or aesthetic value, etc.) while other services affect general environmental conditions by which humans are indirectly impacted (such as climate change, erosion regulation or natural hazard regulation, etc.).

The Millennium Ecosystem Assessment report 2005 defined ecosystem services as benefits people obtain from ecosystems and distinguishes four categories of ecosystem services, where the so-called supporting services are regarded as the basis for the services of the other three categories.