When Australia won the rights to host the Sydney Olympic Games in 2000, there was one tiny thing that stood in their way when building the Olympic village – the green and golden bell frog.

The green and golden bell frog is just one of seven native frog species at Sydney Olympic Park – and the park’s population of green and golden bell frogs is the largest remaining in NSW. This endangered species was once widespread throughout eastern Australia but today is found only in small patches along the east coast. When the area was earmarked for development for the Sydney Olympics in 1993, the frog became part of a major conservation program which not only saved the original population, but now houses self-sustaining sub-populations in two newly-built habitats through assisted and passive translocations.

Sydney Olympic Park is a good example of what can be achieved for endangered species when conservation scientists and developers work together to implement responsible mitigation-driven translocations; closely monitoring the outcomes and reporting the results. Such examples of mitigation-driven translocations are, however, unfortunately rare. There are two main modes for translocating animals from their natural habitat:

  • mitigation-driven translocation, where animals are moved to mitigate construction projects and other human developments.
  • conservation-driven translocation designed to augment or restore animal populations.

A new study, published in the March edition of Frontiers in Ecology and the Environment says that each year, millions of dollars are spent worldwide on relocating animals to new habitats. However, mitigation-driven translocations far outnumber and receive more funding than science-based conservation translocations. While the conservation-driven translocations are designed by applying scientific principles and best-practice, mitigation-driven translocations are generally not. Conservation-driven translocations are, by definition, needs-based and are designed and managed carefully by conservation biologists who are informed by data reported from past translocation studies (we now know that the success rate of scientifically responsible translocations outside the mitigation context is approximately 26–46%, depending on the definition of success and the taxonomic group involved).

Mitigation-driven translocations, on the other hand, are supply-driven and have largely evaded academic scrutiny. These translocations are generally not subjected to a common set of widely accepted standards expected of conservation translocations, although their success could likely be improved if they were. Because very few records are kept on mitigation-driven translocations, both on the numbers of animals moved, and the success of the move, it’s difficult to determine the exact success of mitigation-based translocation. However, where such data have been able to be accessed they suggest that most fail, with high mortality of translocated individuals occurring or displacement of existing individuals in the resident population due to the release site already being at ecological carrying-capacity.

While often well-intentioned, the reality is that mitigation-driven translocations likely spare wildlife a socially unpalatable death from in front of the bulldozer, only to perish a short time later out of sight. Mitigation translocations thus likely represent a misguided conservation strategy. We should not continue to use the relative success of scientific conservation-driven translocations, which have been carefully devised and researched, to justify the use of mitigation-driven translocations when there is little evidence of success. Rather, it should be up to the developer to demonstrate the effectiveness of translocation as a tool to achieve conservation outcomes that are consistent with the regulatory intent. When translocation as a tool is ill-suited to offsetting the impacts of a planned development on a protected species, then the regulatory framework should be flexible enough to allow other, more strategic approaches, regardless of whether they entail the loss of some individuals.

Perhaps most importantly, in cases where mitigation-driven translocations do occur, the process should be transparent, with clear goals for each translocation and data made freely available for public scrutiny. Only then can we truly understand the full extent and success (or lack of) of mitigation-driven translocations for conserving threatened wildlife.

Mitigation-driven animal translocations are problematic: study indicates importance of science-based animal moves to conservation will be published in the print edition of Frontiers in Ecology and the Environment in March. The study is a collaboration between a group of conservationists from San Diego Zoo Global, the US Fish and Wildlife Service, the University of Newcastle, the University of Kent and Amphibian and Reptile Conservation.

This post was written by Mr Simon Clulow, Biologist at the School of Environment and Life Sciences.