Assessing stream grazer response to stress: A post-exposure feeding bioassay using the freshwater snail Lymnaea peregra (Muller)

摘要

Snails are important prey items for fish, crayfish and leeches (Lodge 1986) and are an integral component of freshwater communities Their grazing activities strongly influence the dynamics of the macrophyte epiphyte system by reducing shading and competition for nutrients (Bronmark 1989), through a reduction in biomass (Dillon and Davis 1991) and through significant shifts in algal species composition (McCormick and Stevenson 1989). The removal or reduction of snail populations fiom freshwater could therefore have significant consequences for community structure and function.