Applied Mathematics Colloquium

Abstract: Seed dispersal is the sole method of movement for most plants and, thereby, establishes the initial spatial template of plants. Patterns of seed deposition determine subsequent interactions with neighbors competing for limiting resources, the likelihood of mortality due to natural enemies, and the likelihood of reaching microsites suitable for survival and growth. Vertebrates disperse seeds of approximately half of all flowering plants and more than eighty percent of tropical tree species. Using a spatially-explicit simulation model developed with empirically based functions, I show that three factors are crucial in determining spatial distributions of seedlings around isolated trees; these factors are local-scale clumping of seeds due to vertebrate seed dispersal, natural enemy type (i.e. insect seed predators vs. soil-borne pathogens), and the dispersal distances of seeds relative to those of natural enemies. To further examine the consequences of different scales of clumping in seed deposition and foraging behavior of insect seed predators for populations of plants, I developed a simulation model and an analytical approximation that elucidates the influence of spatial structure created by vertebrates on plant spatial patterns and survivorship. Using mechanistic models, I am examining the potential consequences of global change on plant populations and species coexistence.