Movement and space-use are critical components of an animal’s ecology. Movement allows animals to acquire resources, find mates, avoid predators, and to effectively thermoregulate. Understanding animal movement can help ecologists predict rates of disease and parasite transmission, predator-prey interactions, resource needs, range shifts and patterns of speciation. Intraspecific variation in movement has been shown to be an important factor in understanding broader population and species level patterns of movement and space-use. Here, we questioned whether individual movement and ranging patterns are related to macrohabitat temperature variation within the environment. Our hypothesis is that an individual’s home-range size will co-vary with macrohabitat temperature during the animal’s primary active season. To investigate this hypothesis, we used radio telemetry with 39 box turtles (Terrapene ornata ornata, n=38; Terrapene mexicana, n=1) across two populations, one in western Nebraska and one in Northeastern Kansas. To supplement our ranging data of our Kansas population, we used stratified sampling to place 30 thermochrons (digital temperature recording devices) throughout the habitat where the turtles were expected to occupy.
Results/Conclusions
As expected, we found variation in the turtles’ movement and ranging activities both within and across populations. We also found individual differences in microhabitat and macrohabitat associations. In our Kansas population we found that individual range size was independent of ambient temperature within their range over short time frames but significantly influenced by temperature over longer monitoring periods. We also observed variation in daily movement and range overlap among individuals, which combined with sex, explained additional home-range variation among individuals across both populations. We also compared shell morphology across our two populations and found that adult individuals of our Nebraska population to be, on average, smaller than the average adult size of turtles in our Kansas population supporting the inverse Bergmann’s Rule for ectotherms. Our study helps contribute to our growing understanding of the ecological significance of intraspecific variation in movement and space-use both across and within populations of animals. Understanding the space-use of animals in response to environmental temperature will be beneficial for projecting future habitat needs of populations or species. Overall, gaining a better understanding of the variables that contribute to space-use variation can help guide effective habitat and population management plans for species of concern.