Introduction

1. Macrohabitat Selection by Eastern Box Turtles (Terrapene c. carolina) Zachary Lunn and Dr. John Roe Department of Biology University of North Carolina at Pembroke Pembroke, NC 28372 Introduction Figures and Tables Results and Conclusions • The most convincing correlation we found was between turtle density and the percentage of hardwood trees at WEWO (Fig. 1C, Table 1). The positive relationship and comparatively high R2 suggests turtles are selecting hardwood forest over other available macrohabitats. The mesic conditions of hardwood forests may provide attractive refuge sites from fires. • Turtle density was also correlated with percentage of longleaf pines at WEWO (Fig. 1A, Table 1), but in this case the relationship was negative. It appears that the longleaf macrohabit at WEWO is being avoided by the turtles, perhaps due to the threat fires pose to box turtles in this xeric forest habitat. • Relationships between turtle density and forest macrohabitat were less pronounced at the LRSP, with turtles only weakly avoiding non-longleaf pine forests and exhibiting no relationship with hardwood forests (Figs. 2A and B, Table 1). The weaker associations with any habitat type at LRSP may reflect the absence of fire in this system and the broader availability of suitable environments at this site. • Overall, the trends support our predictions, as turtles at WEWO demonstrate more habitat selectivity than the turtles at LRSP. For park managers, we suggest targeting longleaf pine forests with prescribed fire poses minimal threat to the population of box turtles. The availability of preferred hardwood forest refuges may explain the persistence of the box turtle population at WEWO despite the historical and current use of fire in managing longleaf pine ecosystems. Prescribed fires are used as a conservation and management tool in longleaf pine ecosystems. This promotes biodiversity and preservation of threatened plant and animal species endemic to the North Carolina Sandhills region (Mitchell, Hiers, O’Brien, Jack & Engstrom, 2006). However, the effects of these fires on Eastern Box Turtles are not well known (Howey & Roosenburg, 2013). This study examines box turtles within two defined study sites: Weymouth Woods-Sandhills Nature Preserve (WEWO), where prescribed burns are utilized, and Lumber River State Park (LRSP), which does not employ fire as a management tool. Biologists recognize that these mesic woodlands contain diverse macrohabitats, and “turtle populations are not distributed evenly throughout” (Dodd, 2001, p. 39). We predict that the impact of fire at WEWO will result in stronger habitat selection and avoidance behavior compared to the LRSP. Examining the degree of macrohabitat selection by box turtles will (1) give biologists insight into box turtle behavior, (2) edify the scientific community on the potential impact of prescribed fires on box turtles, and (3) help guide park and forestry officials when developing burn regimens and schedules. A B C Figure 1: Turtle locations overlaid on basal area density of (A) longleaf pines, (B) non-longleaf pines, and (C) hardwood trees at WEWO. Park borders are outlined in red and watercourses in blue. A B Methods • Forty three turtles (22 from WEWO, 21 from LRSP) were tagged with non-invasive transmitters and tracked using radiotelemetry technology (Fig. 3). • GPS coordinates were obtained on each turtle at least once per week and plotted on maps using ArcMap 10.1. • Basal area of longleaf pines, non-longleaf pines, and hardwood trees was recorded every 50 square meters within the study sites in order to determine the available macrohabitat. • The number of turtle locations within each 50 square meter grid was used as a measure of relative density, or intensity of use. • Regression analysis was used to determine relationships between turtle relative density and percentage of tree type. Figure 3: Eastern Box Turtle with radiotransmitter. Figure 2: Turtle locations overlaid on basal area density of (A) non-longleaf pines, and (B) hardwood trees at LRSP. Park borders are outlined in red and watercourses in blue. Table 1: Results of regression tests describing correlations between relative turtle density and the percentage of longleaf pines (LL), non-longleaf pines (PI), or hardwood trees (HW). References Dodd, C. K. (2001). North American box turtles: A natural history. Norman: University of Oklahoma Press. Howey, C. A. F., & Roosenburg, W. M. (2013). Effects of prescribed fire on the Eastern Box Turtle (Terrapene carolina carolina). Northeastern Naturalist, 20(3), 493-497. Mitchell, R. J., Hiers, J. K., O’Brien, J. J., Jack, S. B., & Engstrom, R.T. (2006). Silviculture that sustains: The nexus between silviculture, frequent prescribed fire, and conservation of biodiversity in longleaf pine forests of the southeastern United States. Canadian Journal of Forest Research, 36, 2724-2736. Acknowledgements This work was supported by: grant #5R25GM077634-04 from the National Institute of General Medical Sciences supporting the UNCP RISE Program and the Lucille F. Stickel Box Turtle Research Award.