The effect of deer browsing on forest composition in and around a deer exclosure plot at the University of Michigan Biological Station

Abstract

In 1998, the University of Michigan Biological Station in Pellston, Michigan set up a deer exclosure plot in an outwash plain on the property. The plot was constructed on an old growth forest dating to 1911, while two similar plots were constructed on experimental burn plots dating to 1911 and 1998. We conducted a survey of species abundance and richness in the outwash plain deer plot to determine the effects of deer browsing on an old-growth forest. During our study we looked for differences between species richness, underbrush density and species evenness inside and outside the exclosure plot. We also looked for differences in sapling frequency and signs of recent browsing. We sampled a total of 39 2m x 1m plots inside and 40 2m x 1m plots outside the exclosure. In the plots, we recorded the frequency of all plant species and estimated percent cover of the underbrush. We also catalogued saplings along the transects as we recorded their species, height and whether they showed signs of browsing. We were able to support all of our hypotheses: there was a higher density of underbrush inside the exclosure, species evenness was different, species richness was equal, and there was a higher density and variety of saplings inside the exclosure.