Files
Abstract
The Saltmarsh Periwinkle (Littoraria irrorata) is a common grazer in southeastern marshes dominated by the smooth cordgrass, Spartina alterniflora. I quantified Littoraria density, size structure, microhabitat use, and diet along elevational gradients within eight marshes ranging from Florida to Maryland. Littoraria density and size increased with increasing elevation within southern marshes, but size did not vary and density decreased with elevation in northern marshes. Snails in southern marshes were more likely to occur on sediments, although this habitat pattern was not reflected in their diets. Instead, stable isotope ratios of δ13C and δ15N, showed that δ15N of resources and snails increased from southern to norther marshes and that small snails shifted diet from sediments to Spartina-based sources as snail densities increased; diets of large snails were primarily associated with Spartina. Understanding Littoraria diet and population structure will allow us to better predict its effects on salt marsh food-web dynamics.