ter Steege, H.;Pitman, N.;Sabatier, D.;Castellanos, H.;Van der Hout, P.;Daly, D. C.;Silveira, M.;Phillips, O.;Vasquez, R.;Van Andel, T.;Duivenvoorden, J.;De Oliveira, A. A.;Ek, R.;Lilwah, R.;Thomas, R.;Van Essen, J.;Baider, C.;Maas, P.;Mori, S.;Terborgh, J.;Vargas, P. N.;Mogollon, H.;Morawetz, W.
A spatial model of tree alpha-diversity and tree density for the Amazon
Biodiversity and Conservation
2003
Journal Article
12
11
2255-2277
Parque Nacional del Manu Guayana shield inventories diversity density terra firme floristic composition floodplains distribution Brazil ecology Parque Nacional del Manu Cocha Cashu Pakitza Los Amigos Diamante latitudinal gradients large spatial scales ecology climate seasonality plants trees Madre de Dios Bibliography
Large-scale patterns of Amazonian biodiversity have until now been obscured by a sparse and scattered inventory record. Here we present the first comprehensive spatial model of tree alpha-diversity and tree density in Amazonian rainforests, based on the largest-yet compilation of forest inventories and bolstered by a spatial interpolation technique that allows us to estimate diversity and density in areas that have never been inventoried. These data were then compared to continent-wide patterns of rainfall seasonality. We find that dry season length, while only weakly correlated with average tree alpha-diversity, is a strong predictor of tree density and of maximum tree alpha-diversity. The most diverse forests for any given DSL are concentrated in a narrow latitudinal band just south of the equator, while the least diverse forests for any given DSL are found in the Guayana Shield and Amazonian Bolivia. Denser forests are more diverse than sparser forests, even when we used a measure of diversity that corrects for sample size. We propose that rainfall seasonality regulates tree alpha-diversity and tree density by affecting shade tolerance and subsequently the number of different functional types of trees that can persist in an area.