Figure 1From: Dynamics of natural populations of the dertitivorous mudsnail Potamopyrgus antipodarum (Gray) (Hydrobiidae) in two interconnected Lakes differing in trophic stateGeographic location of the Maarsseveen Lake system in The Netherlands (from Swain et al .1987). I. Meso-oligotrophic lake I; II. Eutrophic lake II. 1. Locations of population analysis; 2. locations of snails used for brood pouch analysis.Back to article page