Agriculture adjustment, population urbanization and nature conservation in NW Argentina

GRAU, R.; GASPARRI, N.I.; GRAU, A.; MORALES, M.; CARILLA, J.; ARÁOZ, E.; IZQUIERDO, A.

Morelia, México

Congreso; Tropical Biology: Linking Tropical Biology with Human Dimensions; 2007

Association for tropical biology and conservation

We analyzed government statistics and published case studies to assess the trends in human demography and land use change during the last 50 years in NW Argentina, a subtropical region (>50 million ha), which includes different life zones: dry forests (Chaco), montane humid forests (Yungas), high elevation grasslands and shrublands (Puna), and middle elevation desserts (Monte). And, to assess the impacts of these changes on nature conservation. Agriculture intensified and expanded in mesic lowland ecosytems and middle elevation irrigated desserts, favored by international demand for commodity products (soybean, sugar, wine). In these areas, population grew fast and became concentrated in urban centers. In contrast, in the different mountain ecosystems, marginal agriculture and extensive grazing decreased in association to a reduction in rural population. This process favored the recovery of different forest types and the expansion of population of once threatened large mammals (e.g. Vicugnas in the Puna). These opportunities for ecosystem recovery, however, where limited by the existence of different stable and low diversity plant communtities. For example in Yungas ecosystems, peri-urban secondary forests are often dominated by highly resilient monodominant exotic tree stands; and fire-maintained degraded grasslands are not invaded by trees even when grazing pressure decreases. Dry forests combine both expansion of modern agriculture and reduction in extensive grazing over non-deforested areas. Balancing these two processes is the key to ensure the conservation of the Chaco, one of the largest continuous remaining neotropical dry forest ecosystems. Overall, this analysis indicates that ecosystem recovery associated to agriculture adjustment to the most productive soils allows growing food production in association to increasing regional opportunities for nature conservation. However, complex interactions between social and natural systems need to be considered to take advantage of these opportunities and to minimize the threats associated to rapid land use change.