Developing a definition for a mildly-abstract concept such as ecosystem services is never an easy task. Although loose concepts of the definition of ecosystem services are more easily agreed upon than more nebulous concepts such as sustainability, varying constituencies and fields of research define ecosystems in their own terms out of interest and necessity. Below are a number of definitions of ecosystem services and lists of examples of individual services.
Ecosystem services-the goods and services supplied by the natural environment.
Gretchen C Daily as quoted in a Lents Study Technical Memo from ECONorthwest:
"Ecosystem services are the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life…"
Issues in Ecology - Spring 1997 - Gretchen C. Daily et al
Human societies derive many essential goods from natural ecosystems, including seafood, game animals, fodder, fuel wood, timber, and pharmaceutical products. These goods represent important and familiar parts of the economy. What has been less appreciated until recently is that natural ecosystems also perform fundamental life-support services without which human civilizations would cease to thrive. These include the purification of air and water, detoxification and decomposition of wastes, regulation of climate, regeneration of soil fertility, and production and maintenance of biodiversity, from which key ingredients of our agricultural, pharmaceutical, and industrial enterprises are derived.
This array of services is generated by a complex interplay of natural cycles powered by solar energy and operating across a wide range of space and time scales. The process of waste disposal, for example, involves the life cycles of bacteria as well as the planet-wide cycles of major chemical elements such as carbon and nitrogen. Such processes are worth many trillions of dollars annually. Yet because most of these benefits are not traded in economic markets, they carry no price tags that could alert society to changes in their supply or deterioration of underlying ecological systems that generate them. Because threats to these systems are increasing, there is a critical need for identification and monitoring of ecosystem services both locally and globally, and for the incorporation of their value into decision-making processes.
Ecological Society of America
An ecosystem is a community of animals and plants interacting with one another and with their physical environment. Ecosystems include physical and chemical components, such as soils, water, and nutrients that support the organisms living within them. These organisms may range from large animals and plants to microscopic bacteria. Ecosystems include the interactions among all organisms in a given habitat. People are part of ecosystems. The health and wellbeing of human populations depends upon the services provided by ecosystems and their components - organisms, soil, water, and nutrients.
Ecosystems provide "services" that:
- moderate weather extremes and their impacts
- disperse seeds
- mitigate drought and floods
- protect people from the sun’s harmful ultraviolet rays
- cycle and move nutrients
- protect stream and river channels and coastal shores from erosion
- detoxify and decompose wastes
- control agricultural pests
- maintain biodiversity
- generate and preserve soils and renew their fertility
- contribute to climate stability
- purify the air and water
- regulate disease carrying organisms
- pollinate crops and natural vegetation