The goal of this project is to determine consequences of seed dispersal by birds to composition and genetic structure of shrubs in a tropical rain forest. The research involves two phases. The first phase (planning activities) will determine plant species diversity, seed density, and genetic relatedness of seeds within droppings from five species of common fruit-eating birds. Seeds passed by these birds are identifiable and the relatedness of seeds within droppings can be estimated using starch gel electrophoresis. During phase two the consequences occurring with related or unrelated seeds to plant survival and growth will be examined through competition experiments using three light environments characteristic of tropical rain forests. In tropical rain forests, most seeds of understory plants are dispersed by birds. This study will be the first to examine relatedness of seeds in bird droppings and consequences to plants of having seeds eaten and dispersed by different birds. Information on genetic and species composition of seeds in droppings of birds (planning activities) and results from competition experiments (phase two) will be used to develop models that predict genetic structure and composition of rain forest shrubs. This research will contribute substantially to understanding tropical rain forests by testing ecological and evolutionary theories of plant-animal interactions.
