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 categories of services, which was popularized in the early 2000s by the Millennium Ecosystem Assessment initiative by the United Nations. How these groups are defined varies dependent on classification system. The MA groups the services into four broad categories of services. These 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.
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 and flood control. Lastly, their cultural services include recreation and tourism. Evaluations of ecosystem services may include assigning an economic value to them.

Definition

Ecosystem services or eco-services are defined as the goods and services provided by ecosystems to humans. Per the 2006 Millennium Ecosystem Assessment, ecosystem services are defined as "the benefits people obtain from ecosystems".
While Gretchen Daily's original definition distinguished between ecosystem goods and ecosystem services, Robert Costanza and colleagues' later work and that of the MA lumped all of these together as ecosystem services.

Categories

The categorisation of ecosystem services varies depending on classification system. The Millennium Ecosystem Assessment groups the services into the four groups: regulating services, provisioning services, cultural services and supporting services, where the so-called supporting services are regarded as the basis for the services of the other three categories.
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 differ in nature and in consequence. In fact, some services directly affect the livelihood of neighboring human populations while other services affect general environmental conditions by which humans are indirectly impacted.
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 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". This was further developed by the Common International Classification for Ecosystem Services, which uses the categories of Cultural and Provisioning, but combines Regulatory and Habitat services into the category Regulation and maintenance services.

Provisioning services

Provisioning services consist of all "the products obtained from ecosystems". The following services are also known as ecosystem goods:
Forests and forest management produce a large type and variety of timber products, including roundwood, sawnwood, panels, and engineered wood, e.g., cross-laminated timber, as well as pulp and paper. Besides the production of timber, forestry activities may also result in products that undergo little processing, such as fire wood, charcoal, wood chips and roundwood used in an unprocessed form. Global production and trade of all major wood-based products recorded their highest ever values in 2018. Production, imports and exports of roundwood, sawnwood, wood-based panels, wood pulp, wood charcoal and pellets reached their maximum quantities since 1947 when FAO started reporting global forest product statistics. In 2018, growth in production of the main wood-based product groups ranged from 1 percent to 5 percent. The fastest growth occurred in the Asia-Pacific, Northern American and European regions, likely due to positive economic growth in these areas. Over 40% of the territory in the European Union is covered by forests. This region has grown via afforestation by roughly 0.4% year in recent decades. In the European Union, just 60% of the yearly forest growth is harvested.
Forests also provide non-wood forest products, including fodder, aromatic and medicinal plants, and wild foods. Worldwide, around 1 billion people depend to some extent on wild foods such as wild meat, edible insects, edible plant products, mushrooms and fish, which often contain high levels of key micronutrients. The value of forest foods as a nutritional resource is not limited to low- and middle-income countries; more than 100 million people in the European Union regularly consume wild food. Some 2.4 billion people – in both urban and rural settings – use wood-based energy for cooking.

Regulating services

Regulating services are the "benefits obtained from the regulation of ecosystem processes". These include:
  • Purification of water and air
  • Carbon sequestration
  • Waste decomposition and detoxification
  • Predation regulates prey populations
  • Biological control pest and disease control
  • Pollination
  • Disturbance regulation, i.e. flood protection

    Water purification

An example for water purification as an ecosystem service is as follows: In New York City, where the quality of drinking water had fallen below standards required by the U.S. Environmental Protection Agency, authorities opted to restore the polluted Catskill Watershed that had previously provided the city with the ecosystem service of water purification. Once the input of sewage and pesticides to the watershed area was reduced, natural abiotic processes such as soil absorption and filtration of chemicals, together with biotic recycling via root systems and soil microorganisms, water quality improved to levels that met government standards. The cost of this investment in natural capital was estimated at $1–1.5 billion, which contrasted dramatically with the estimated $6–8 billion cost of constructing a water filtration plant plus the $300 million annual running costs.

Pollination

Pollination of crops by bees is required for 15–30% of U.S. food production; most large-scale farmers import non-native honey bees to provide this service. A 2005 study reported that in California's agricultural region, it was found that wild bees alone could provide partial or complete pollination services or enhance the services provided by honey bees through behavioral interactions. However, intensified agricultural practices can quickly erode pollination services through the loss of species. The remaining species are unable to compensate this. The results of this study also indicate that the proportion of chaparral and oak-woodland habitat available for wild bees within 1–2 km of a farm can stabilize and enhance the provision of pollination services. The presence of such ecosystem elements functions almost like an insurance policy for farmers.

Buffer zones

Coastal and estuarine ecosystems act as buffer zones against natural hazards and environmental disturbances, such as floods, cyclones, tidal surges and storms. The role they play is to " a portion of the impact and thus its effect on the land". Wetlands and the vegetation it supports – trees, root mats, etc. – retain large amounts of water and then slowly releases them back, decreasing the likeliness of floods. Mangrove forests protect coastal shorelines from tidal erosion or erosion by currents; a process that was studied after the 1999 cyclone that hit India. Villages that were surrounded with mangrove forests encountered less damages than other villages that were not protected by mangroves.

Supporting services

Supporting services are the services that allow for the other ecosystem services to be present. They have indirect impacts on humans that last over a long period of time. Several services can be considered as being both supporting services and regulating/cultural/provisioning services.
Supporting services include for example nutrient cycling, primary production, soil formation, habitat provision. These services make it possible for the ecosystems to continue providing services such as food supply, flood regulation, and water purification.

Nutrient cycling

Nutrient cycling is the movement of nutrients through an ecosystem by biotic and abiotic processes. The ocean is a vast storage pool for these nutrients, such as carbon, nitrogen and phosphorus. The nutrients are absorbed by the basic organisms of the marine food web and are thus transferred from one organism to the other and from one ecosystem to the other. Nutrients are recycled through the life cycle of organisms as they die and decompose, releasing the nutrients into the neighboring environment. "The service of nutrient cycling eventually impacts all other ecosystem services as all living things require a constant supply of nutrients to survive".

Primary production

Primary production refers to the production of organic matter, i.e., chemically bound energy, through processes such as photosynthesis and chemosynthesis. The organic matter produced by primary producers forms the basis of all food webs. Further, it generates oxygen, a molecule necessary to sustain animals and humans. On average, a human consumes about 550 liter of oxygen per day, whereas plants produce 1,5 liter of oxygen per 10 grams of growth.