Demography and Ecology of an Ornate Box Turtle (Terrapene ornata) Population in South-Central Wisconsin

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Abstract
We studied a population of ornate box turtles (Terrapene ornata) during 1977-87 in south-central Wisconsin, and intensively monitored (.gtoreq. 20 relocations) 53 radio-marked individuals during 1986-87. Egg laying occurred mainly in June; eggs in four nests hatched after 79-84 d. Twenty-one of 37 adult females (57%) laid during 1986-87, mean clutch size was 3.5, and hatchlings per adult female averaged 0.7. Mean annual survival of marked adults (age .gtoreq. 10 yr) was 0.81 during 1977-87 (Jolly-Seber analysis). We estimated a total of 54-56 adults on four occupied sites within our 8 km2 study area. Adult densities at these sites ranged from 2.9-5.0/ha. Most (84%) turtles entered hibernation during Sept.; all emerged during April. Known periods of hibernation averaged 216 d (n = 9); burrow depths were between 0.5-1.8 m (n = 26). Mean home range size of adults was 8.7 ha (n = 47) annually, but varied greatly among individuals and did not differ significantly with sex or year. Home ranges of juveniles and subadults were much smaller. Areas of remnant prairie on deep sandy soil were frequented disproportionately, whereas agricultural cropland was clearly avoided. We compared demographic parameters of this and othe turtle populations, and explored requisites for numerical stability with observed and hypothetical survival and recruitment rates. Our study area population will likely continue to decline because the average rate of adult survival (0.81 annually) is well below that (about 0.95) which would, with normal recruitment, stabilize numbers. Results of this study are discussed from a management perspective.