ABSTRACT
It has been recognized that land users can provide a variety of environmental services ranging from biodiversity conservation to the control of hydrological flows and carbon sequestration (Daily et al. 2000). While ecosystem services are important, and often essential to human welfare, they tend to be undervalued and lack protection. An average of almost 15 million hectares of forest, for example, was lost every year during the 1990s, mostly in the tropics (FAO 2001). Soil erosion also drives land degradation; Eswaran et al. (2001) suggest an annual loss of 75 billion tonnes. Other causes and symptoms of land degradation include nutrient mining, salinization, overgrazing of native rangeland species and much else. GEF (2003) states that about two-thirds of agricultural land has been degraded to some extent during the last 50 years, and this has a strong link to deforestation as farmers seek to replace exhausted land.
