PATTERNS OF NICHE PARTITIONING IN TEMPERATE ECOSYSTEMS OF OHIO

Terrestrial gastropods provide essential ecosystem services through their diet by contributing to organic matter decomposition and nutrient cycling. Despite their crucial role in their ecosystems, these organisms are threatened globally, comprising nearly 25% of recorded modern animal extinctions. However, with upwards of 30 sympatric species living in any given ecosystem, it is possible that multiple species may fill the same ecological niches, potentially reducing the risk to ecosystem services posed by the loss of individual species. Understanding the potential impacts of this biodiversity loss, therefore, requires a greater understanding of the driving forces behind the organization of gastropod communities.

Recent geochemical investigations of the diets of sympatric land snails have produced mixed results, with communities in different temperate woodlands exhibiting varying degrees of niche partitioning between species. The studied communities appear to be structured similarly, with most species overlapping in isotope values. However, much of this previous work has been conducted in deciduous forests, and little data is available for other ecosystems. To that end, this work investigates the diets of gastropods from a range of temperate ecosystems using stable isotope analyses to determine if previously detected patterns of community organization hold true in all ecosystems.

Three communities of terrestrial gastropods from Ohio’s East Fork State Park, Cedar Bog Nature Preserve, and Hocking Hills State Park, have been selected for analysis, and represent communities in deciduous forest, wetland, and coniferous forest ecosystems, respectively. We test the following hypotheses: (1) species in each ecosystem will partition food resources to avoid competition, and (2) each ecosystem will be similarly structured. Five to seven species have been collected from each site, and though the species composition of each site is different, there is some overlap between sites; for instance, Deroceras laeve was found in all locations. Preliminary results suggest statistically significant differences (Kruskal-Wallis, P <0.01) in the diets of species from East Fork, which is indicative of niche partitioning within the community. Stable isotope results for Cedar Bog and Hocking Hills are forthcoming.