The Effects of Rainforest Conversion on Water Balance, Water Yield and Seasonal Flows in a Small Tropical Catchment in Central Sulawesi, Indonesia

The ongoing debate over the causes of deforestation in Indonesia views smallholder production and their growing number as a main cause of deforestation in Indonesia. With the common terminology ‘smallholder conversion’ a broad range of conversion strategies like the shifting cultivation-forest pioneer continuum, smallholder tree crop production and transmigration activities is summarized (Sunderlin and Resosudarmo, 1996). However, after ‘smallholder conversion’ the created landscape along the rainforest margin area is usually characterized by a patchwork of different land use types in ever smaller patches undergoing a gradual change from forest dominated areas via annual crops to perennial plantation interspersed by secondary forest, pasture and annual crops. Since the Indonesian economic crisis in 1997 land clearing increased dramatically for establishing export tree crops. Indonesia is now the third largest producer of cocoa (Sunderlin, 2000, Maertens et al, 2002) with Central Sulawesi as one of the main Indonesian production areas. The question then arises: to what extent do these conversion activities affect the hydrological behaviour of the affected areas ?