An examination of the marsh microhabitats of lymnaea tomentosa and l. Columella (mollusca: Gastropoda) by path analysis

Abstract

Some physical and biological characteristics of marsh microhabitats of the pulmonate snails Lymnaea tomentosa (Pfeiffer) and L. columella (Say), intermediate hosts of Fasciola hepatica in New Zealand, are compared by path analysis. The most significant variable suggested by the various path coefficients is the relative importance of flocculence of mud in the substratum. L. tomentosa was more likely to be found in or on flocculent mud, whereas L. columella appeared to prefer firm mud. Submersion of the substratum was of more direct importance to L. columella than to L. tomentosa; the effect of water on L. tomentosa was mainly indirect, since wetter microhabitats were more likely to contain flocculent mud. Results of an experiment simulating pugging of the muddy substratum by cattle suggest that both snail species are likely to be more numerous in habitats heavily pugged by cattle. © 1977 Taylor & Francis Group, LLC.