Neotropical lowland forests mainly affected by climate

4 June 2010

WOTRO researcher Marisol Toledo de Vroomans showed that climate is the most important factor in shaping tropical lowland forests in Bolivia. The results suggest that with future climate change drastic shifts can be expected in the species composition, structure, and dynamics of these tropical forests. Marisol received her PhD on June the 1st, 2010 from Wageningen University.

Neotropical lowlands feature an extraordinary display of forests, especially in Bolivia where three biogeographical regions meet: the Amazon, Brazilian-Paranaense and Gran Chaco. The objective of this research was to evaluate how environmental factors shape lowland forests in Bolivia, using a network of 220 1-ha permanent sample plots. For each plot, all stems of more than 10 cm diameter were measured; climatic data were interpolated from weather stations and soil samples were collected.

Annual rainfall, rainfall seasonality and temperature were the most important factors shaping forest structure. Composition and dynamics, whereas soil fertility played, surprisingly, a minor role. 91% of the species were affected by climate factors, while just 47% of the species were affected by soil factors. The large variation found among these forests has to be taken into account when developing forest-specific management plans. The results of the gradient approach suggest that with future climate change (predicted decreases in rainfall and increases in temperature), drastic shifts can be expected in the species composition, structure, and dynamics of these tropical forests.

Dissertation: Neotropical lowland forests along environmental gradients
Promotor: prof.dr. F.J.J.M. Bongers
Co-promotors: Dr.ir. L. Poorter, Dr. M. Peña-Claros

Source: Wageningen UR (2010)