ANTHROPOGENIC AND ENVIRONMENTAL INFLUENCE ON LAND SNAIL SHELL ASSEMBLAGES IN WOODLANDS FROM SW OHIO

Anthropogenic (human) disturbance significantly impacts species composition of animal and plant communities. In particular, animals with low dispersal abilities, like land snails, which exhibit reduced mobility, non-migratory behavior, and high-habitat specialization, are suspected to be highly vulnerable to anthropogenic modification. Land snail diversity from woodland areas are often linked to the density of coarse woody debris. It is hypothesized that old growth forests (or low human-impacted woodlands) will exhibit high abundance of woody debris and high soil organic content, which would result in high diversity of land snails. In contrast, second-growth forests (or high human-disturbed woodlands) are expected to display low concentration of wood debris and low soil organic content, which might cause a decrease in snail diversity. The present study investigates for the first time in Southwest Ohio if and how the diversity of land snails changes along an urban-to-rural gradient. Three main forests with a gradually decreasing degree of human disturbance were sampled, including Mt. Airy Forest (within the city of Cincinnati), East Fork Wildlife Area (39 km east of Cincinnati), and Edge of Appalachia (124 km east of Cincinnati). A total of 27 species and 564 individuals (both live and dead) were collected using a standard visual search method. Multidimensional scaling ordination of species abundance data indicates that snail communities from the three investigated forests exhibit significantly different species compositions despite overall similarities in climate, geology and habitat type. Even after sampling standardization, the number of snail species increases with increasing distance from Cincinnati, supporting the hypothesis that temperate woodlands closer to the urban center harbor lower snail diversity. Even though snail diversity responds to multiple environmental and human drivers, this pilot study suggests that shell assemblages may be affected by human influence in temperate forests in a predictable fashion.