Mallinger, R., 2014. Dune vegetation and insect communities vary with barrier beach geomorphic setting on Sapelo Island, USA.
Coastal geomorphic processes, including shore disturbance events, shape coastal landforms and sand dune ecosystems. The magnitude and frequency of shore disturbance can affect dune vegetation diversity, community composition, and succession. Furthermore, these processes might impact higher trophic levels, such as insects, either directly or indirectly through changes in dune vegetation. The objective of this study was to characterize differences in vegetation and insect communities along sand dunes varying in geomorphic setting and exposure to shore disturbance. Vegetation and insects were sampled along Nannygoat Beach, Sapelo Island, Georgia, United States, in areas historically documented to differ in erosion rates and in exposure to storm surges and overwash. Dune height and beach berm width were measured to describe geomorphic setting. The north end of Nannygoat Beach had taller sand dunes and a shorter beach berm width, indicating less overwash but greater rates of erosion compared to the south end. Plant diversity was significantly greater on the north end of Nannygoat, while insect richness was significantly greater on the south end of Nannygoat beach. Both plant and insect community composition were significantly different between the north and south ends of the beach. Furthermore, the plant community composition was significantly related to the abiotic variables, while the insect community composition was significantly related to the plant community. These results suggest that vegetation communities of barrier islands are strongly influenced by geomorphic processes, while insect communities are, in turn, shaped by the vegetation communities.