Effects of marsh periwinkle (Littoraria irrorata) size and density on cordgrass (Spartina aterniflora) biomass and dead standing material

Marsh periwinkles (Littoraria irrorata) are common in southeastern US salt marshes, including those on Sapelo Island, GA. They are known to affect the productivity of cordgrss (Spartina alterniflora) and also contribute to its decomposition following senescence. The population struture of Littoraria, in terms of the size and densities of individuals, varies widely in space and time. No previous experiments have, however, attempted to manipulate the density and body size of populations of Littoraria and assessd the response of Spartina. We perforned such an experiment in Airport Marsh on Sapelo Island, using small experimental enclosures and measured Spartina biomass and dead standing material after 3 months (mid July - mid Oct, 2012). We assessed response variables by removing all Spartina material from plots before seperating and drying them in the lab.