Seed Banks of Carolina Bays: Potential Contributions from Surrounding Landscape Vegetation

Abstract

-We used the seedling emergence method to evaluate the influence of the dominant vegetation (herbaceous, shrubby, forested) and the surrounding landscape on seed bank composition in seven Carolina bays. Landscape influence was evaluated indirectly by determining whether seed banks in wetlands close to clearcuts had more upland weedy species than those farther from clearcuts. Seed bank species composition and richness differed among forested, shrubby and herbaceous bays. DECORANA ordination identified a gradient of species composition from herbaceous bays, to shrubby bays, to forested bays. Bays near clearcuts had significantly more upland weedy species in their seed banks, with bays 20 m from clearcuts containing 79% more weedy species on average than bays 100 m from clearcuts. Within a bay, drier vegetation zones had 2.4 times more weedy species than did deep water zones. These results illustrate the potential contributions from surrounding landscape units to bay seed banks and highlight the need for further studies directly assessing the impact of adjacent clearcuts on bay vegetation dynamics.