The use of woody debris by the cotton mouse (Peromyscus gossypinus) in a southeastern pine forest

Woody debris, including fallen logs, snags, and stumps, is a feature amenable to management in Southeastern pine forests and may be an important habitat component for the cotton mouse (Peromyscus gossypinus). I examined the use of woody debris by cotton mice in a managed loblolly pine forest and investigated factors proposed to account for the use of fallen logs by mice. The day refuges of cotton mice predominantly were associated with woody debris, including stumps, upturned root boles of wind-thrown trees, fallen logs, and brush. The movement of cotton mice was associated with fallen logs more than expected by chance, indicating selective use. Stumps and logs used by cotton mice were larger than randomly sampled stumps and logs. Many invertebrate taxa were more abundant near logs than on the open forest floor, suggesting that logs could have served as sources of invertebrate foods for small mammals. Large logs were particularly important in providing habitat for invertebrates. The diets of cotton mice and southern short-tailed shrews in this environment consisted largely of invertebrate matter. However, the diet of the short-tailed shrew was more similar to the invertebrate assemblage found on the open forest floor than the invertebrate assemblage found near logs. The use of controlled experiments indicated no effect of invertebrate fumigation on the use of fallen logs by cotton mice in a system of enclosures. Also, the presence of logs did not affect the total number of seeds eaten from a grid of regularly spaced seed trays in enclosures. However, there was a more equitable harvesting of seeds in enclosures with logs. Because the time required to harvest seeds probably increased with the number of seeds eaten, this equitable foraging suggested that mice were able to spend less time eating when logs were present. When logs were absent, mice concentrated foraging activity near the enclosure fencing. Woody debris, particularly in the form of large logs and stumps, may be an important component of cotton mouse habitat in Southeastern pine forests. Fallen logs may provide travel routes that aid cotton mice in exploring their environment.