XVI International Botanical Congess

The past dynamics of Amazonian vegetation are poorly known, with no published studies for lowland Bolivia. We present data describing the current and past dynamics of the forest-savanna boundary at a pristine site in eastern Bolivia. The vegetation is a mosaic of semi-deciduous tropical forest and cerrado-type savanna. Stable carbon isotope ratios from soil indicate that the forest-savanna boundary has shifted back and forth over time and that the amount of shift varies by site. To examine contemporary shifts, we inventoried strip plots that cross the forest-savanna boundary for trees and shrubs. In less than 2 years stem density in the savanna increased by 22.3% (n=866) at one site, indicating a possible current reversion to forest.