Coexistence of an endangered endemic species with a non-native competitor

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Distinguishing between non-native species that coexist with native species and those that threaten their persistence is critical for conservation and management. We investigated this distinction for a non-native terrestrial snail (Succinea sp.) (Sp. B) that occurs with the closely-related Chittenango ovate amber snail (Novisuccinea chittenangoensis) (COAS), an endangered species that is restricted to a single, known site. We examined the effects of density and body size of Sp. B on growth and mortality of COAS using ex situ competition experiments. We also conducted mark-recapture surveys to document trends of the in situ population of COAS and to identify spatio-temporal factors that may mitigate any competitive interactions between COAS and Sp. B. The results of this study were published in Biological Invasions (PDF).