Content area
Full text
ABSTRACT. - We examined overwintering behavior in gopher tortoises (Gopherus polyphemus) translocated to the northern periphery of their geographic range by using miniature temperature data loggers during 2 winters. All adult and juvenile tortoises monitored with temperature loggers survived overwintering; however, during the course of the study 2 translocated juvenile tortoises without temperature loggers died during winter months. Onset and termination of overwintering were not different between the 2 yrs and were not correlated with mean above-ground air temperature. Mean overwinter duration was 127 ± 9 d SD and 128 ± 13 d SD during 2002-2003 and 2004-2005, respectively. Tortoises experienced temperatures as low as 7°C and as high as 31°C while overwintering; however, most (12 of 15) tortoises experienced very little (<1°C) mean daily temperature fluctuation despite air temperatures regularly dropping below 0°C and exceeding 20°C. The overall mean temperature of overwintering tortoises was 12.4° ± 0.8°C (2002-2003) and 12.6° ± 1.2°C (2004-2005). Large fluctuations in temperature occurred when tortoises actively basked, and half of the monitored tortoises did, particularly juveniles, which accounted for 42% of winter basking events. Our results suggest that, given timely access to suitable refugia at recipient sites, overwinter mortality of translocated adult individuals may be minimal.
KEY WORDS. - Reptilia; Testudines; Testudinidae; thermal ecology; conservation; translocation; gopher tortoise: Gopherus polyphemus; iButtons; dormancy; overwintering
Translocation, defined by Griffith et al. (1989) as the intentional release of individuals of a species to establish, reestablish, or augment a population of that species, is becoming a more widespread management tool and, as such, has garnered rigorous debate (Burke 1991; Dodd and Seigel 1991; Reinert 1991; Germano and Bishop 2008). Although early translocation efforts primarily focused upon game species (e.g., Griffith et al. 1989; Wolf et al. 1996), many projects have recently focused on the translocation of reptiles (e.g., King et al. 2004; King and Stanford 2006; Field et al. 2007; Roe et al. 2010). Ethical animal translocation projects have conservation value when they result in the establishment of new viable populations or help augment depressed populations. Consequently, reptile translocation projects should involve postrelease monitoring to assess the achievement of these goals (Kingsbury and Attum 2009). Frequently, measures of survival and movement (i.e., site fidelity) of individuals are used as the basis for...