Lexikon

ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving, physical components of the environment with which the organisms interact, such as air, soil, water, and sunlight. It is all the organisms in a given area, along with the nonliving (abiotic) factors with which they interact; a biological community and its physical environment. The entire array of organisms inhabiting a particular ecosystem is called a community. In a typical ecosystem, plants and other photosynthetic organisms are the producers that provide the food. Ecosystems can be permanent or temporary. Ecosystems usually form a number of food webs.

Ecosystems are functional units consisting of living things in a given area, non-living chemical and physical factors of their environment, linked together through nutrient cycle and energy flow.

1. Natural ecosystem

• Terrestrial ecosystem
• Aquatic ecosystems (Lentic, the ecosystem of a lake, pond or swamp; Lotic, the ecosystem of a river, stream or spring

2. Ecosystem of artificial, man-made environments.

ecosystems management is an approach to natural resource management that focuses on sustaining ecosystems to meet both ecological and human needs in the future. Ecosystem management is adaptive to changing needs and new information. It promotes shared vision of a desired future by integrating social, environmental and economic perspectives to managing geographically defined natural ecological systems.

Ecosystems promote human well being through the various services they provide.

One of the six priorities of the UNEP medium‑term strategy for 2010–2013 is that “countries utilize the ecosystem approach to enhance human well-being”. The UNEP Ecosystem Management Programme is centred on the functioning and resilience of the ecosystems and the services they provide. The programme aims to support countries and regions to:

1. increasingly integrate an ecosystem management approach into development and planning processes;
2. acquire the capacity to use ecosystem management tools; and
3. realign their environmental programmes and financing to tackle the degradation of selected priority ecosystem services.

The programme is guided by five major interlinked elements: human well-being, indirect and direct drivers of change, ecosystem functioning and ecosystem services. As ecosystem services are interlinked and cannot be treated in isolation, UNEP promotes a holistic perspective for dealing with bundles of interlinked services to reverse their decline through improved ecosystem functioning and increased resilience. The services fall under the following categories: regulating, provisioning, supporting and cultural services

The UNEP programme focuses on 11 of the 15 degraded ecosystem services mainly comprising:
Regulating services: climate, water, natural hazard and disease regulation, water purification and waste treatment, which are often strongly affected by the overuse of provisioning services;
Provisioning services: freshwater, energy (especially the emerging issues around biofuel production) and capture fisheries;
Cultural services: Recreation and ecotourism service;
Supporting services: nutrient cycling and primary production which underlie the delivery of all the other services but are not directly accessible to people.

Source: http://www.unep.org/ecosystemmanagement/Introduction/tabid/293/language/en-US/Default.aspx

humankind benefits from a multitude of resources and processes that are supplied by natural ecosystems. Collectively, these benefits are known as ecosystem services and include products like clean drinking water and processes such as the decomposition of wastes. While scientists and environmentalists have discussed ecosystem services for decades, these services were popularized and their definitions formalized by the United Nations 2004 Millennium Ecosystem Assessment (MA), a four-year study involving more than 1,300 scientists worldwide. This grouped ecosystem services into four broad categories: provisioning, such as the production of food and water; regulating, such as the control of climate and disease; supporting, such as nutrient cycles and crop pollination; and cultural, such as spiritual and recreational benefits.

Experts currently recognize four categories of ecosystem services. The following lists represent samples of each: