The influence of water presence and understory cover on Sorex cinereus populations in northern lower Michigan.

Abstract

The effects of water presence and understory cover on the local distribution of Sorex cinereus and S. hoyi in northern lower Michigan were addressed. Pitfall traps were set in three wet and two dry ecosystems. Shrew density was significantly greater in wet than dry habitats. Percent cover estimates were made at each trapsite and were compared with shrew abundances on a small and large scale. On the small scale, understory cover seemed to be a determining factor since shrew abundances varied significantly across traplines with different amounts of cover. On the large scale, however, shrew abundances and percent cover were positively correlated but not significant, suggesting understory cover was a secondary factor.