TOWARDS AN INCREASED AND SUSTAINABLE PRODUCTION IN SEMIARID RANGELANDS OF CENTRAL ARGENTINA - 2 DECADES OF RESEARCH

The Caldenal or Southern Espinal is a temperate, semi-arid region cove ring about 40,000 km(2) in central Argentina. Cattle raising on natura l vegetation is the major economic activity in this region. Mostly bec ause of overgrazing after the introduction of domestic livestock in th e early 1900s and fire prevention by ranchers, the physiognomy of the vegetation has changed from a grassland with isolated shrubs and trees to a shrubland, with visible signs of soil erosion in the system. Thi s paper presents an up-to-date synthesis of major findings obtained in the Caldenal during the last 20 years, as well as ongoing research, t owards a common objective: to develop management guidelines conducive to a greater, sustainable rangeland productivity while preserving the renewable natural resources in the region. Research has mainly been co nducted to study the effects of the major stresses at the Caldenal (fi re, drought, defoliation) on grass and/or shrub responses, as well as more basic studies on the ecophysiology of these species. (C) 1997 Aca demic Press Limited.