The Millennium Ecosystem Assessment (MA) published in 2005 represented a major international effort to assess ecosystem changes and the consequences for human well-being, at scales from the global to the local. MA recognized four distinct categories of services:- supporting (nutrient cycling, soil formation and primary production);
- provisioning (food, fresh water, wood and fiber and fuel);
- regulating (climate, flood and disease regulation and water purification) and
- cultural (aesthetic, spiritual, educational and recreational).
Society is exhausting ecosystem services
The MA findings conclusively prove that society is exhausting the planet's ecosystem services, and the current decline of these services presents a serious obstacle in meeting the Millennium Development Goals for many developing countries.
The MA emphasis on ecosystem services and trade-offs and their links to human well-being have been welcomed by the conservation and development community as a bridge to development efforts focused on poverty reduction. Because most ecosystem services are public goods, markets are seldom available to provide clear units of account.
In terms of freshwater services, these have been defined as falling into three broad categories:
- supply of water for drinking, irrigation and other consumptive purposes;
- supply of goods other than water, such as fish; and
- supply of non-extractive 'instream' benefits, such as recreation, transportation, dilution and flood control.
Of the four distinct categories of services that the MA recognized, freshwater is thought of mainly as provisioning various goods and services — such as water for drinking, etc. Simultaneously, though, 'freshwater services' are
- regulating, such as water purification, nutrient and sediment removal, water damage mitigation,
- supporting, in the meaning of underlying, intermediate ecosystem processes such as nutrient cycling, primary production via green water, etc., and
- cultural, that is, giving spiritual, religious and aesthetic services.
