Freshwater Molluscs of the United States Military Academy Drainages (West Point, NY) and Comparative Regional Biodiversity of Gastropods

Abstract

Thirty-four species of molluscs have been found in the drainage systems of the United States Military Academy at West Point, NY. A few rare species were found as well as a single specimen of a presumed new gastropod taxon. Only two species of unionids, Pyganodon cataracta and Elliptio complanata, were found within the drainages. The largest drainage system, Popolopen Brook, contained the highest diversity of molluscs. Species redundancy between drainages aligned well as a function of the extent of lentic and lotic habitats with brooks and streams having a Bray-Curtis similarity index of ≈ 64.0 when compared to lakes and ponds. On the other hand, a number of species collected were found in only a single drainage. Total drainage area did not correspond well with diversity unless determined as total predicted usable habitat. Thus the drainages with the greatest number of discernible lakes, ponds, streams, and creeks, also had the highest molluscan diversity. On the whole, molluscan diversity of these drainages compared favorably to those of other regional New York sites, but relative abundance or population densities varied, with variations reflecting survey effort, time or season of collections, and incorporation of historic museum collections.