Understanding Habitat Use and Activity Patterns of Ornate Box Turtle (Terrapene ornata) in Eastern New Mexico

Abstract. The ornate box turtle (Terrapene ornata) is a terrestrial Emydid, listed as near threatened by the International Union for Conservation of Nature Redlist due to habitat destruction, degradation, habitat fragmentation, commercial harvest, and road mortality. Terrapene ornata is secretive, which can pose a challenge to conducting systematic surveys and assessing species status. Studies on the species' biology have relied on opportunistic encounters on the road and the use of radiotelemetry. The objective of this study was to assess the feasibility of using transect line surveys in single season occupancy surveys for T. ornata in Roosevelt County, New Mexico. We further used radiotelemetry to link turtle activity patterns with environmental conditions to aid in understanding detectability of the species. Our occupancy model showed the detection probability to be influenced by individual observers and the time of day. We found T. ornata to most likely occupy habitats with less dense ground cover and avoid highly altered habitats (i.e., cultivated fields). Radiotelemetry further revealed the effect humidity, time of day, and temperature on turtle activity patterns. The lowest activity occurred between 1200–1700 h, whereas peak activity occurred in early morning hours (0600–0900 h). The peak activity occurred between ∼10–25 C and was promoted by higher humidity. Our study represents the first attempt at using transect line surveys for occupancy modeling framework for the ornate box turtles. We suggest that future studies on box turtle occupancy focus on finer scale habitat assessment that would also include vegetation, invertebrate, and small mammal surveys.