Ecosystems1 – natural, but also manmade – provide us with many services which may be valuable from an economic, financial, ecological or cultural point of view. Forested land in a watershed may protect water quality or reduce siltation while wetlands filter pollutants, thus improving water quality. Yet, the conservation of ecosystems’ health has traditionally been seen as a cost – either direct costs for protection activities, or indirect costs in terms of forgone investment opportunities. As a consequence, ecological and environmental services (EES) provided by ecosystems are often taken for granted, and their value and importance is only recognised in decision making processes when they cease to exist.
The term ecosystem services2 refers to a wide range of conditions and processes through which natural ecosystems help to sustain life on earth. We can classify EES into four broad categories, according to the final use of the service provided (MEA, 20033): (a) provision services refer to goods which are used directly for consumption or production, such as food and water. (b) regulating services that are used indirectly, and that refer to those services which perform regulation activities, for instance, regulation of floods by a forest, or protection of land from degradation, (c) supporting services that sustain underlying processes which maintain productive assets and ecosystems, such as soil formation, nutrient cycle and (d) cultural services that refer to recreational, spiritual, religious, and other non-material benefits which we may derive from ecosystems.……
