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Distribution Of The Marsh Periwinkle Littorina Irrorata (Say) In A Virginia Salt Marsh, R. Wyle Crist, William C. Banta

Gulf and Caribbean Research

Littorina irrorata varies over its geographic range in maximum size, preferred elevations relative to tidal datum planes, and in the type of vegetation it inhabits. On Wallops Island, Virginia, postlarvae of Littorina irrorata with shell lengths < 5 mm long live almost exclusively in dead, curled-up leaves of Spartina alterniflora at elevations near mean tide level, below elevations occupied by larger conspecifics. Snails longer than 5 mm in length increase in average size with decreasing elevation. This distribution is opposite to that found by Hamilton (1978) in a marsh in Florida. No difference was found in our study area in growth rate of marked snails at two different elevations, so the size-elevation …