Relationships between white-tailed deer (Odocoileus virginianus) browsing intensity, slope aspect, and understory plant communities in Kansas cross timbers woodlands

Abstract

Thesis (M.S.)-- Wichita State University, College of Liberal Arts and Sciences, Dept. of Biological SciencesIncreases in white-tailed deer (Odocoileus virginianus) densities in eastern and central North America have caused concern about their impacts on forests and woodlands. It is well documented that deer have robust negative impacts on woody species recruitment; however, little is known about how deer affect understory herbaceous plant communities. My study investigates the relationship between deer browsing intensity and species composition of herbaceous plant communities in Kansas Cross Timbers oak woodlands. Further, I address how slope aspect affects understory species composition and mediates effects of deer browsing intensity. I conducted a regional survey across 19 woodland understory plant communities on northeast and southwest facing slopes. In each community, deer browsing intensity was quantified using damage to juvenile post oaks and blackjack oaks. Data collection quantified plant species composition, litter depth, slope aspect and slope steepness. Surprisingly, results show a significant positive relationship between deer browsing intensity and Shannon Diversity Indices, over a range of low to moderate browsing intensities. However, deer browsing did not increase exotic species cover as predicted and was not a strong driver in plant species composition. Further, slope aspect, steepness and canopy cover appear as the strongest explanatory variables for differences in plant community composition. This study suggests there is minimal effect of deer on Cross Timbers woodland understory plant community composition. My findings illustrate that landscape features, such as slope aspect and steepness, play a role in shaping these plant communities and perhaps influencing the relationship between plants and animals