Edge influence on composition and structure of a Pinus palustris woodland following catastrophic wind disturbance
Forest edges are an important legacy of natural and anthropogenic disturbances. Edges of forest fragments are influenced by adjacent non-forested ecosystems, resulting in compositional and structural differences at the edge. Edge influence is the altered biotic and abiotic interactions that occur along the edge-to-interior gradient in disturbed forests. Few studies have analyzed natural disturbance created edges, particularly in woodland forest structures, which contain fewer trees ha-1 than forests and are typically less light limited. The goal of our study was to examine edge influence of a tornado created edge in a longleaf pine (Pinus palustris Mill.) woodland. In 2011, an EF-3 tornado impacted a restored longleaf pine woodland, resulting in a distinct woodland edge. To quantify distance of edge influence into the stand, nine transects were installed perpendicular to the tornado swath, with 11 plots on each transect at variable distances from the edge. Biotic and abiotic response variables were measured at the appropriate spatial scales. To determine the distance of edge influence, the magnitude of edge influence was calculated at each distance, and compared to the reference forest using a non-parametric randomization test. Edge influence on forest structure was negative, with a maximum distance of 70 m. Ground flora richness and diversity experienced a positive edge influence, with higher richness and diversity in the tornado swath and edge, however, ground flora communities at the edge were not compositionally distinct from the tornado swath or the interior. Results of this study add to our understanding of edge influence on woodland forest structure and naturally created edges.