Ecosystem services are the benefits derived by people from nature (Scholes and Biggs 2004). These services have been classified into the following four categories by the Millennium Ecosystem Assessment (2004):
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Provisioning services - products obtained from ecosystems such as freshwater, food and wood;
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Regulating services - regulating benefits obtained from ecosystem processes such as disease regulation, pollination, flood protection, and water purification;
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Cultural services - non-material benefits obtained from ecosystems such as aesthetic, educational and spiritual benefits; and
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Supporting services - services necessary for the production of all other ecosystem services such as soil formation, primary production and nutrient cycling.
Water is an essential ecosystem service.
Source: Stieglitz 2000
( click to enlarge )
These services contribute both directly and indirectly to human welfare. However, over-use of resources and the pollution of ecosystems can jeopardise the health of ecosystems that provide the basis for human well-being. Therefore, it is important that people living in and around the ecosystems of the Kunene River basin do not exceed the capacity of the ecosystem's ability to withstand pressures. This could lead to collapse of ecosystem functions, destroying sources of food, removing the valuable services that the river provides, and reducing the ability of local people to maintain a livelihood.
The table below illustrates how ecosystems contribute to human well-being, using the example of ecological processes supported by the flow regime of water.
Links between Ecosystem Services, Ecological Processes Supported by the Flow Regime and Human Well-being
|
Ecosystem services |
Human well-being |
Environmental flow component
and ecological processes |
Provisioning
|
|
The flow regime supports the delivery of a range of different provisioning services such as clean water, plants, building materials and food. |
Basic material for good life. |
Fish supply: the life cycle of many fish species depends on the natural variability in river flows e.g. large floods are important for fish to be able to migrate as well as spawn.
Medicinal plants, fruits: drought levels enable recruitment of certain floodplain plants. Large floods disburse seeds and fruits of riparian plants.
Water supply: large floods recharge floodplain water tables.
|
Regulating
|
|
The environmental flow regime helps controlling pollution, pests and floods. |
Security, health. |
Flood control: riparian vegetation stabilises river banks. Flows that maintain soil-moisture levels in banks and deposit nutrients and seeds on the bank maintain riparian vegetation.
Pollution control: high pulse flows restore normal water quality conditions after prolonged low flows, flushing away waste products and pollutants.
Pest control: a river with environmental flows is more resistant against the intrusion of exotic species. Dammed, diverted and modified rivers that create permanent standing water and more constant flow regimes provide favorable environment for exotic species.
|
Cultural
|
|
Spiritual, recreational, aesthetic services. |
Good social relations. |
Sufficient flows to maximise aesthetic values and contribute to cultural services are an important component of the environmental flow regime. |
Supporting
|
|
Biodiversity, nutrient and sediment cycling. |
Basic material for good life, security, health, good social relations. |
Large floods can maintain balance of species in aquatic and riparian communities. They can also maintain diversity in floodplain forest types through prolonged inundation (different plant species have different tolerance). |
Adapted from: Forslund et al. 2009
The following chapter describes the contribution of ecosystem goods and services to the livelihoods of the rural people in the riparian states and the basin.
