Quantifying Genetic Diversity Among Ammophila breviligulata Populations on Beaver Island to Determine Dispersal Routes
Long-distance dispersal events play an important role in determining the structure of ecological communities. In species of sessile reproductive individuals, as with plant species, dispersal is the only method for the genetic code of an individual to reenter the gene pool and allow for increased gene flow. However, quantifying long-distance dispersal, such as wind, water or animal dispersal, has proven extremely difficult to observe or quantify. The purpose of our study was to identify dispersal routes around Beaver Island. Located in Lake Michigan, Beaver Island is the largest island in its archipelago and is home to unique plant communities partially pioneered and supported by the native, key plant species Ammophila breviligulata, or American beachgrass. Using Random Amplified Polymorphic DNA (RAPD) analysis, we compared polymorphic bands within and between five populations on Beaver Island of A. breviligulata. Hierarchal cluster analyses used our identified banding patterns for all sampled individuals to cluster individuals based on genetic similarity rather than population. The analyses suggested a general route of dispersal down the west shoreline, dispersal west to east across the island, and an isolating factor around the Cable’s Bay population. This study provides an insight into population connectivity of this plant species through genetic diversity in order to quantify long-distance dispersal routes around Beaver Island.