Date of Award

Summer 2011

Document Type


Degree Name

Master of Science (MS)


Biological Sciences



Committee Director

Robert K. Rose

Committee Member

A. Scott Bellows

Committee Member

Alan H. Savitzky

Call Number for Print

Special Collections LD4331.B46 N33 2011


The hispid cotton rat (Sigmodon hispidus) is a common field rodent throughout the southeastern US, where volunteer loblolly pine trees (Pinus taeda) invade open space and begin the process of ecological succession from field to pine forest. Recent analysis of the diet of S. hispidus indicates that loblolly pine bark is stripped and eaten during the winter months. In this study, we explored the extent of rodent girdling on a 1.23 ha grid in a successional pine forest in southeastern Virginia. During the winter of 2005 we observed damage to 65% of trees in our study area, with 98% of tree mortality due to girdling by rodents. Cotton rats preferentially damaged trees 11-40 mm in diameter and were most actively damaging trees during March and April 2005. Cotton rats also girdled more in areas with a high density of small trees. Damage to loblolly pines was highest in winters directly following autumn cotton rat population peaks. We conclude that our loblolly pine stand was vulnerable between the ages of three and five years, when an understory of herbaceous vegetation was still dense. Girdling by cotton rats was a significant source of mortality in a five-year-old loblolly pine stand, and girdling may influence the rate of succession from old field to pine forest in Virginia.


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