Microhabitat differences surrounding a pond affects the distribution of trematode parasites among a pulmonate snail community

Anthropogenic disturbance associated with clear-cutting and changing the environmental landscape can lead to distinct microhabitat structure surrounding aquatic habitats. The transmission dynamics of trematode parasites in their snail first intermediate hosts were examined to determine if these alterations affect trematode parasite distribution. This was accomplished by examining 2,771 pulmonate snails belonging to two species (Physa gyrina and Lymnaea columella) over a three month period in a pond surrounded by distinct microhabitats as a result of anthropogenic changes to the environmental landscape. Trematode parasite distribution in the snail first intermediate hosts was largely tied to the microhabitat preference of their vertebrate definitive hosts. Autogenic species were found further away from the center of the open microhabitat and allogenic parasites were closer to the centralized point, most likely as a result of habitat preference by their frog and waterfowl definitive hosts, respectively. Additionally, there was increased parasitism in the molluscan hosts at the edges of the wooded environments due to habitat overlap of autogenic and allogenic species hosts, indicating that microhabitat structure can have profound effects on parasite distribution.