White-tailed deer use of overstory hardwoods in longleaf pine woodlands

Restoration of the longleaf pine ecosystem is a conservation priority throughout the southeastern United States, but the role of hardwoods in providing food and cover for wildlife within this system is poorly understood. We investigated white-tailed deer (Odocoileus virginianus) movement and habitat selection relative to overstory hardwood distribution in a longleaf pine ecosystem at Fort Bragg Military Installation in the Sandhills physiographic region of North Carolina from March 2011-July 2013. We monitored GPS-collared female white-tailed deer and used generalized linear mixed models and step-selection functions to determine the influence of overstory composition and understory cover on seasonal white-tailed deer habitat selection. During fall and winter, deer selection increased with increasing upland hardwood overstory until reaching an upper threshold (12% and 7%; respectively) where increasing cover of upland hardwoods no longer increased selection. Also, in the fall and winter, deer selected areas with greater bottomland hardwood overstory until an upper threshold of 33% bottomland hardwood overstory was reached. In the spring, deer selected areas with < 22% upland hardwood overstory. The effect size of understory cover, defined as lidar-classified vegetation with height < 2 m, was larger than any other variable, regardless of season, and deer consistently selected areas with 20-75% understory cover. When managing longleaf pine woodlands for white-tailed deer, our results indicate maintaining a well-developed woody understory with 20-50% canopy closure is important, ideally with mature upland hardwood overstory cover between 4 and 12% to ensure mast production in fall and winter.