The effect of spatial and temporal changes in water velocity on the density of a stream population of the fresh water snail Potamopyrgus antipodarum

Abstract

The effects of spatial and temporal changes in water velocity on the introduced freshwater snail Potamopyrglls mztipodarulll (Gray) (Gastropoda: Hydrobiidae) were studied in an artificial stream and in Main Creek, Victoria, Australia. The water velocity at which P. nlltipodarum became dislodged in the artificial stream was in agreement with their distribution in Main Creek. In Main Creek the density of P. mltipodarwll on a standard substrate (half bricks) was negatively correlated with water velocity. However, no evidence was found that increases in water velocity associated with floods affect the densities of P. (Illtipodarul11.