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Small mammal communities

Emily Vincent, Michael Britton, Curt Hardacre, Michael Tobin
Conservation Biology class, BIO 345, Biology Department, DePauw University
Fall semester 2013

The DePauw Nature Park is an excellent site to study the effects of land use on ecosystems.  The recent construction of a small farm and the recent restoration of farmland into a prairie provide sites to study how changes in land use affect ecosystems.  We studied the effects of land use changes on small mammal communities at the campus farm, an old field next to the campus farm, and a restored prairie. 

We hypothesized that the abundance and diversity of small mammals would be highest in the restored prairie and lowest in the campus farm.

We used Sherman traps to capture and release small mammals.  At each site we set up two parallel transects of 12 traps spaced 5 meters apart.  We trapped small mammals on three dates:  October 15, October 29, and November 5, 2013.  At each trap site, we estimated ground cover using six categories:  tall grasses, medium grasses, short grasses, bare ground, herbaceous plants, and woody plants.

We caught four species of small mammals:  meadow jumping mouse, meadow vole, white-footed mouse, and short-tailed shrew.  We caught the highest number of individuals in the old field and the lowest number of individuals in the campus farm.  The vegetation composition differed among the three sites.  The farm had 98% short grass or bare ground, the old field had 61% tall or medium grasses, and the prairie had 66% tall or medium grasses.  

Small mammals are highly dependent on vegetative cover and tend to avoid open areas.  Small mammals were relatively abundant in the old field next to the farm, but the recent conversion of part of this field to farmland has made it unsuitable for small mammals.  We expected small mammals to be more abundant and diverse in the prairie, but we observed higher numbers in the old field.  We are not sure why these results occurred.  Both sites had similar proportions of tall and medium grasses, which provide adequate cover for small mammals.  We recommend that future studies of small mammals be conducted over longer time periods with more transects per site.