Moved frogs don’t settle: Evaluating the impact of translocation on the movement behaviour of a threatened frog

Abstract

The deliberate movement of wildlife is an accepted mitigation measure to manage the impact of anthropogenic activities. A presumption is that moved individuals settle at recipient sites that possess appropriate habitat. However, translocations have a low rate of success, with many projects unable to identify the cause of failure. We studied the translocation of a threatened amphibian, the green and golden bell frog, Litoria (=Ranoidea) aurea, over short distances within a metapopulation in Australia. Individuals were removed from a fenced area of contaminated habitat earmarked for remediation (donor site) and translocated to nearby ponds (recipient sites) to maintain the breeding population in-situ and allow future natural recolonisation once remediation was completed. The distance between recipient and donor site significantly influenced the chance of translocated frogs being detected back at the fenceline, with the return rate dropping from 35 % to 5 % when the recipient site was moved from 50 to 400 m away. Additionally, translocated frogs exhibited heightened movement from the recipient site when compared to non-translocated frogs. This is one of only a few artificial movement studies of amphibians, with implications for the management of populations undergoing translocation. Our work shows the potential dangers of using translocation to remove individuals from land development and presuming this avoids impacts to threatened species. We recommend monitoring the return of translocated amphibians to donor sites and disturbances to movement behaviour induced by translocation, in order to predict the likely effectiveness of amphibian translocations for mitigating the ecological impacts associated with land development.