Evaluating mitigation translocations for better biodiversity outcomes

Abstract

<p>The expansion of urban areas and associated loss of natural areas due to development are greatly contributing to global biodiversity loss. Furthermore, development produces direct harm to wildlife and their habitat. In New Zealand, lizards and their habitat are legally protected and damage due to development of a natural area must be avoided or mitigated whenever possible. Mitigation translocations, the intentional relocation of individuals from the site to be developed to a receptor site, have become commonly used to meet legal obligations; however, mitigation translocations do not guarantee survival of individuals or population success at the receptor site. I aimed to evaluate the success of a mitigation translocation case study, proactively plan receptor sites for a mitigation translocation, and develop a framework for selecting and preparing receptor sites to provide better mitigation translocation outcomes, particularly for herpetofauna. I evaluated the short-term success of a mitigation translocation case study using results from post-release monitoring at receptor sites. This is one of the first studies to provide multiple post-release monitoring sessions and detail recapture rates and body condition changes of lizards at receptor sites with and without resident populations following mitigation translocation. I expanded upon commonly used receptor site selection criteria and translocation data management systems by proactively studying and preparing receptor sites in regional parks, including conducting pilot surveys to evaluate resident populations. Recapture rates were similar between receptor sites (9% and 11.8%) and the limited number of recaptured individuals showed an increase in body condition from the time of salvage to intervals of one- and two-years post-release. Presence of residents was not found to have an effect on recapture rates or body condition changes. Implementation of enhanced site selection criteria resulted in approval of six sites within three protected areas for future mitigation translocations. These sites had low numbers of resident lizards present, if at all. A geodatabase was developed to store results from receptor site evaluations before and after translocation. Together, the improved criteria and geodatabase fit into a framework for selecting and preparing receptor sites to improve outcomes of mitigation translocations of herpetofauna. The framework produced has potential to be used at a national level, in collaboration with ecologists, iwi, and community groups, and for a variety of species. Mitigation translocations should be re-evaluated as the go-to method to mitigate damage to lizards due to development; however, if they must continue, it is essential that best practices are used, and results are published so that outcomes can improve for biodiversity.</p>