Scale-dependent controls on ecological functions in agroecosystems of Argentina

Agricultural managers that operate at different levels (plot, farm, landscape, region) need to understand how ecological functions (energy, nutrients and water flows and cycles) are controlled by scale-dependent factors. Using cross-level data from the Argentine pampas, analyzed by simple and multiple regression analysis, we demonstrate that controls differ from one spatio-temporal level to the other, but they can be altered by humans. In the Argentine pampas, environmental controls (climate, landform, soil quality) seem to have a strong top-down influence on lower levels. But the bottom-up aggregated effect of anthropogenic controls seems to scale-up to upper levels and counteract such influence. Thus, the more intense use of land and technology in small units, the larger the up-scaling human influence on ecological functions. We suggest that a discrimination among farming intensity levels is useful and necessary to understand and predict human controls on ecological functions across scales.