Climate change can alter the ecology of natural systems through various mechanisms, such as direct thermal effects on a consumer. However, consumers may employ behavioral mechanisms in response to warming. Among these may be spatial or temporal shifts in activity, making use of thermal heterogeneity on the landscape. Despite this, few studies consider the role of behavioral plasticity and spatial or temporal heterogeneity in the context of climate change. I conducted experiments to evaluate the importance of behavior in mediating the net effects of warming at the population and the individual level using captive white-tailed deer (Odocoileus virginianus). I created thermal heterogeneity over feeding stations using opaque and translucent roofing material. Feeding activity and consumption were monitored at these feeders. Activity patterns revealed deer disproportionally used the shaded feeder during the daytime and the unshaded feeder during crepuscular periods. I found that deer consumed less feed in group and individual experiments when feeders were unshaded. My results suggest that deer can use heterogeneity in the environment that may mediate the net effects of climate change. Furthermore, maintaining thermal heterogeneity may mitigate the direct effects of climate change on the consumer, but may lead to indirect effects at the community level.

Population genetics of white-tailed deer (Odocoileus virginianus) have been influenced through human actions including the translocation of deer from across the United States in the 1900s and, recently, the creation of the captive-cervid industry, which uses animal husbandry to manipulate genetic variation. To assess the effects of these actions, I studied the genetic variation of free-range and captive populations of deer across the southcentral U.S. using a 14 microsatellite panel. In free-range populations I found genetic structure that divided deer west to east along the Mississippi River. Additionally, I found that captive populations were genetically distinct from geographically proximate free-range populations. However, after 2 generations of hybridization, this distinction disappeared. Finally, using both Bayesian clustering and multivariate approaches, I was able to identify a non-native individual from local free-range populations in southern Mississippi. Using these methods, wildlife managers can further investigate cases of hybridization between non-native deer and free-range populations.

Factors associated with rank position are poorly understood whereas even fewer studies assessed if benefits were associated with increased rank position when resources were unlimited. I assessed whether age, body mass, size, and testosterone levels were important in rank establishment among 132 captive female white-tailed deer (Odocoileus virginianus). I also assessed if the benefit metrics of improved body condition, decreased stress level, and earlier parturition date were related to rank position. Deer in each of 9 study pens had a linear hierarchy with a mean h Πof 0.39 (SD = 0.09). Rank position was moderately related to age (P < 0.1) and was strongly related to body mass and size (P < 0.01). There was no relationship between benefit metrics and rank position (P < 0.1). Although increased body mass, size, and age improved rank position there were no benefits associated with increased rank when resources were unlimited.

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Declining oak (Quercus spp.) dominance across the eastern U.S. is often attributed to fire exclusion and abundant white-tailed deer (Odocoileus virginianus). Fire restoration can negatively affect acorn germination and survival directly but also indirectly through impacts on seed predation. Similarly, masting events could influence oak regeneration success by altering deer behavior. To date, virtually no information exists assessing indirect effects of acorn consumers on oak regeneration. I developed two experiments to address this knowledge gap. In the first experiment, I determined if burning acorns affects predator removal rates. In the second experiment, I assessed the indirect effects of mast seeding on plant communities mediated by deer. Burning acorns decreased acorn removal rates. This could increase survival to spring for acorns that survived exposure to fire. Mast seeding increased local deer use, decreased the competitive advantage of local oak seedlings, but increased beta diversity in the understory.

The reproductive timing and success of white-tailed deer are important to managers. I evaluated the reproductive variability of pen-raised deer and wild populations within Mississippi and investigated effects of age, body condition and moon phase on conception dates. I also examined the reproductive potential of doe fawns from 3 regions of Mississippi. Individual conception dates varied more than expected and were not related to moon phase. Age affected individual conception date, although the effect may have been confounded by estimated gestation length. Population level variation was less than reported and could not be explained by moon phase or late-winter body condition. One of 65 doe fawns bred. The critical mass for reproduction may be lower in Mississippi than previous reports for the northern U.S. Regional variation in fawn breeding based on yearling lactation rates warrants additional research.

Previous research documented that white-tailed deer body mass and antler size varied across physiographic regions of Mississippi. Deer from regions with greater soil fertility had greater body mass and antler size; however, this information is known only for individuals 6 months of age and older. I monitored birth mass and skeletal size of fawns produced by bred, adult, female white-tailed deer transplanted from the Delta, Thin Loess (Loess), and Lower Coastal Plain (LCP) soil regions to fawn in the Mississippi State University Rusty Dawkins Memorial Deer Unit. I evaluated the effect of soil region of origin, litter size, and fawn gender on mass and size of fawns at birth. Birth mass was not as variable as mass of older animals, but LCP fawns were lighter and shorter than loess and/or delta fawns. Twins were lighter and shorter than singletons. Males were heavier than females. Differences between regional birth dates within the pens and estimated regional birth dates based on a fetal growth curve raises questions about the wide-spread application of this method of estimating deer breeding and fawning dates.

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White-tailed deer (Odocoileus virginianus) in the Big Cypress Basin of South Florida must cope with top-down and bottom-up forces, including frequent pyrogenic and hydrological disturbances and the threat of predation. These forces affect their space use, behavior, and survival. Recent changes to the regional hydrology and increased abundances the Florida panther (Puma concolor coryi), their primary predator in this system, call for a renewed look at how these forces affect this deer herd. To assess the effects of these forces on seasonal space use, behavior, and survival of deer, I analyzed GPS telemetry and camera trap data, highlighting the factors influencing deer space use across hydrological and biological seasons, and connected behavioral data captured on camera traps to female deer survival. Space use is primarily a function of intrinsic sex affects and landscape composition and configuration, and varies as resources and reproductive cycles fluctuate across seasons. Disturbance has little effect on space use, suggesting deer are well adapted to these disturbance regimes. Temperament in foraging behavior in female deer impacted survival, influencing prey catchability and potentially buffering prey populations against cycles of predation. / Master of Science / White-tailed deer (Odocoileus virginianus) in the Big Cypress Basin of South Florida must cope with a changing landscape of resources caused by frequent fire and flooding, while avoiding predation by their primary predator in this system, the Florida panther (Puma concolor coryi). Recent changes to water flow across this landscape and increasing numbers of Florida panthers call for a renewed look at how disturbance, landscape features, and predation influence the seasonal space use, behavior, and survival of deer in this system. Differences from sex and landscape features most explain seasonal space use of deer, while the influence of fire and flooding is limited. Variability in vigilance of female deer led to differences in female survival, suggesting a tradeoff between acquiring resource and safety when foraging under predation risk.