Disturbances in Subtropical Dry Forests across contrasting social contexts

JOBBÁGY, ESTEBAN G.; BALDI, GERMÁN; VERÓN, SANTIAGO R.; DI BELLA, CARLOS MARÍA

Bariloche

Congreso; VI Southern Connection Congress; 2010

Southern Connection

Increasing human control over ecosystems claims for a better projection of ecological knowledge across social gradients. How are disturbance regimes and impacts affected by population density, welth, industrialization or connection to markets? By spanning diverse social contexts, subtropical dry forests (STDF) offer a valuable arena to explore this question. Based on remote sensing tools we characterized cultivation and fire patterns and their influence on vegetation structure and net primary productivity (NPP) across precipitation gradients under contrasting social contexts. STDF regions of convergent climate and original vegetation structure were identified in five continents. Cultivation introduced higher crop diversity and more complex landscape patterns in Asia and Africa were denser rural populations rely on local production. The opposite occurred in Australia and the Americas were production targetted national/global markets. Fire density was higher in forests than in croplands and maximum in areas with intermediate cultivation (1-10% coverage). Fires consumed ~5% of the NPP of STDFs in Africa, South America and Australia, but <1 % in Asia and North America. In most regions croplands had lower NPP than natural vegetation, particularly towards humid zones. Preliminary generalities about the role of the social context shaping fire and cultivation regimes as well as ecosystems structure and function can be established.