XVI International Botanical Congess

The approximately 90 years of human habitation of the Bragantina region, eastern Amazonia has resulted in a complex mosaic of lowland forest fragments, secondary forests of different ages, cultivated lands, and pastures. I studied the effects of repeated cycles of traditional slash-and-burn agriculture on the structure, floristics and nutrient stocks of a range of successional forests. Of particular interest is the rate of which successional forests recover the floristic composition and nutrients of primary forest once they are abandoned. This study reveals that the structure, floristic composition and dominance of woody species of the secondary forests are different from the primary forest. Available soil pools of most nutrients do not vary across a vegetative recovery sequence. I suggest that shifting cultivation exerts a greater impact on species diversity than on stand biomass and nutrient stocks.