Preliminary Analysis of Habitat Use and Home Range Size in a Long- Lived Ectotherm Vertebrate

Abstract

Habitat loss and fragmentation can create barriers of unusable matrix which can restrict animal movements, potentially impacting population fitness. Invasive plant species contribute to disrupted landscape structure by replacing native vegetation. Changes in habitat composition and resource availability from the presence of invasive plants may have implications for imperiled vertebrate species, particularly long-lived ectotherms given their need for specific thermal conditions influenced by habitat conditions. Thus, long-term research on these species may provide insight into conservation and management practices for invasive-impacted ecosystems. To investigate environmental factors, such as widespread invasive plant species, influencing movement patterns and habitat use, we have conducted a radio-telemetry study on Eastern Box Turtles (Terrapene carolina) since 2013. The study site, a 31-hectare plot in the Northeast Georgia Piedmont, is composed of mixed hardwood-pine uplands, areas dominated by Chinese privet (Ligustrum sinense), beaver-created wetlands, and human maintained areas. Our research includes 36 radio-transmitted turtles located by homing techniques 1-2 times per month, with an average of 60 radiolocations (range: 1 to 199) per turtle. Upon locating, each turtle’s microhabitat use was assessed in a 1.5-meter diameter circular plot by quantifying understory vegetation and other habitat components. Minimum convex polygons were used to estimate annual home ranges, which we relate to microhabitat use. Preliminary analyses show a negative trend between proportion of microhabitat composed of privet and home range size across multiple years. Our data on habitat use, home range and microhabitat structure may help identify factors impacting species persistence and resource use in vulnerable ectothermic populations.