Abstract

Land occupation patterns and the ecological structure and diversity of woody and herbaceous strata were studied at two scales in the anthropogenic savannas (espinales) occupying unirrigated portions of the subhumid and semiarid regions of central Chile (ca. 30°to 36°S). This anthropogenic formation is dominated by the spiny legume tree Acacia caven (Mol.) Mol. and a wide variety of Eurasian annual grasses and forbs, and is the basis for rainfed farming and agroforestry systems that appear outmoded and increasingly unproductive. The current study forms part of a larger effort to determine causes for this trend and to ascertain ways and means for reversing it. Vegetation mapping was carried out along a representative transect of espinales covering 22 970 ha, in the subhumid region. The botanical composition and primary productivity of each stratum was studied for seven vegetation types, in both the occasionally inundated plains (llanos) and the well-drained hillsides (lomas). Complementary data were obtained on community structure, total cover, and tree shape and size in relation to coppice age since last cutting. Degradation patterns in the lomas and llanos, and the various alternatives to ongoing degradation that could replace current land and resource use practices are discussed.