The vast majority of all plants have seeds modified for dispersal, movement away from the parent plant. The pattern of seed dispersal has the potential to affect both the survival of individual plants and characteristics of plant populations. Since plants are immobile once rooted, the quality of the site into which a plant is dispersed as a seed has a major effect on its survival. Patterns of seed dispersal also affect the spatial arrangement of genetically related individuals. This spatial genetic structure has important consequences for the plant population. The investigators wil document the effects of seed dispersal on plant fate and population genetic structure by following the movement and subsequent survival of seeds in natural populations, using the dispersal of seeds of the native wildflower, Trillium grandiflorum, by ants as a model system. Seeds will be marked with a radio label that will allow them to be relocated after dispersal by ants or other animals. The survival and growth of plants resulting from dispersed and undispersed seeds will be followed for 3 years. The genetic identity of plants will be determined using electrophoresis. In order to document the role of dispersal in the development of spatial genetic structure, the genetic structure of the study population will be determined at four stages of the plant life cycle: undispersed seeds, dispersed seeds, seedlings, and adult plants. The results of this study will be of a value to conservation biologists involved in the preservation or restoration of plants in their natural habitats. An understanding of the effects of seed dispersal on plant survival is critical to such efforts. This study will also explore the importance of seed dispersal by animals in the development of population genetic structure and in the maintenance of population genetic diversity, two factors that may be important in the long-term conservation of viable populations.
