XVI International Botanical Congess
Fragmentation of forest ecosystems is a common feature of tropical landscapes. We have used nuclear and chloroplast markers to ascertain the effect of fragmentation and selection on gene flow and population structure of several species of tropical trees in Costa Rica. Gene flow, neighborhood size, and genetic diversity have been assessed at both regional and local scales. Neighborhood sizes and patchiness are influenced by a variety of factors that alter gene flow including asychronous flowering, age structure of forest stands and disturbance. Regional patterns of diversity are influenced strongly by pollination system, species abundance and anthropogenic factors. We discuss the implications of results on conservation of biological diversity.