Effects of tropical forest conversion on soil and aquatic systems in southwestern Brazilian Amazonia: A synthesis.

Southwestern Brazilian Amazonia has suffered intense forest conversion in a short period of time (~60 years) and deforestation is ongoing. Around 70% of the deforested area has been designated for cattle ranching. This forest clearing and pasture establishment is abruptly disrupting the functioning of the ecosystem. In this paper, we provide an overview of the effects of land conversion from forest to pasture on the soil and aquatic systems. Forest conversion to pasture has two clear effects: a) an on-site effect on the hillslope domain and 2) an off-site effect on the river system. The conversion of forest to pasture affects the soil physical-chemical properties, soil carbon content, water resources, and aquatic system. However, many of these changes are not straightforward or obvious. For example, in some conditions, the soil carbon stock increases in pasture. Despite the advances in our understanding of the effects of land conversion on environmental processes, knowledge gaps persist, and we identify some research needs.