Problems with mitigation translocation of herpetofauna

Abstract

Mitigation translocation of nuisance animals is a commonly used management practice aimed at resolution of human-animal conflict by removal and release of an individual animal. Long considered a reasonable undertaking, especially by the general public, it is now known that translocated subjects are negatively affected by the practice. Mitigation translocation is typically undertaken with individual adult organisms and has a much lower success rate than the more widely practiced conservation translocation of threatened and endangered species. Nonetheless, the public and many conservation practitioners believe that because population-level conservation translocations have been successful that mitigation translocation can be satisfactorily applied to a wide variety of human-wildlife conflict situations. We reviewed mitigation translocations of reptiles, including our own work with 3 long-lived species (Gila monsters [Heloderma suspectum], Sonoran desert tortoises [Gopherus morafkai], and western diamond-backed rattlesnakes [Crotalus atrox]). Overall, mitigation translocation had a low success rate when judged either by effects on individuals (in all studies reviewed they exhibited increased movement or increased mortality) or by the success of the resolution of the human-animal conflict (translocated individuals often returned to the capture site). Careful planning and identification of knowledge gaps are critical to increasing success rates in mitigation translocations in the face of increasing pressure to find solutions for species threatened by diverse anthropogenic factors, including climate change and exurban and energy development.

Trends in lizard translocations in New Zealand between 1988 and 2013

“…Studies overseas have shown that mitigation-driven translocations of reptiles have high failure rates (Germano & Bishop 2009;Germano et al 2015;Sullivan et al 2015). This review has identified some areas of concern about mitigation-driven translocations of lizards in New Zealand.…”

“…If the habitat is at carrying capacity, then it is likely that released animals will either die or displace resident lizards (Sullivan et al 2015). If the habitat is below carrying capacity, but the refuges that offer protection from predation are fully occupied, the translocated individuals will be vulnerable to predation by introduced mammals (Norbury et al 2014b).…”

“…In both scenarios there may be no overall change in the population and no benefit from translocating animals. Mitigation-driven translocations to mainland sites do not undertake disease screening so there is also the risk of introducing disease into resident populations when lizards are moved between sites (Sullivan et al 2015).…”

“…Reptiles are considered suitable candidates for conservation translocation programmes, but there is concern about high failure rates when used in mitigation-driven translocations (Germano & Bishop 2009;Sullivan et al 2015). Germano et al (2015) called mitigationdriven translocations a 'misguided conservation strategy' due to their failure rate and lack of application of scientific principles and best practice.…”

Sustainability of utility‐scale solar energy – critical ecological concepts

“…Other species with high site fidelity and small home ranges within energy installations will be more vulnerable, especially those that are sensitive to disturbance and do not prosper when the subject of translocation efforts (Sullivan et al . , but see Brand et al . ).…”