Be nimble with threat mitigation: lessons learned from the reintroduction of an endangered species

Abstract

Reintroductions are increasingly being used to restore species and ecosystems. However, chances of successful establishment are often low. Key to improving success is careful consideration of threats, threat mitigation, monitoring, and subsequent improvement to management. We demonstrate this planning, implementation, and review process using the reintroduction of an endangered mesopredator, the eastern quoll Dasyurus viverrinus, in the first attempt to reestablish it in the wild on mainland Australia. In March 2018, 20 captive-bred quolls (10 male, 10 female) were released into Booderee National Park and monitored via telemetry, camera, and cage trapping. There were many unknowns and, despite thorough consideration of threats, there were surprising outcomes. Within 3 months, 80% of animals had died; half due to predation, an expected threat. Other threats were unexpected yet, due to good monitoring and responsive management, were quickly detected and effective mitigation implemented. These learnings have been incorporated into revised translocation procedures. One year later, four founder quolls remained and had successfully bred. We highlight lessons applicable to other reintroductions. These are, the importance of: (1) conducting a thorough review of threats and implementing appropriate mitigation; (2) targeted monitoring and responsive management; (3) effective communication, education, and engagement with the local community and stakeholders; and (4) ensuring learnings are disseminated and incorporated into future translocation plans. Threat assessment is an important step in identifying potential reasons for failure. However, actual threats can be realized only via experimentation and monitoring. Applying this knowledge to future reintroduction attempts can increase their chance of success. Implications for Practice• Reintroductions often fail; yet, we demonstrate how quick, reactive, malleable, fact-based management techniques, guided by robust real-time monitoring, can effectively enhance the likelihood of success, and support founding populations undergoing reintroduction to new habitat. • Using the eastern quoll Dasyurus viverrinus as our case study, we outline a template for planning, implementation, and review that includes a pre-release threat assessment and post-release threat evaluation. • We advise reintroductions programs to conduct a thorough review of threats, implement appropriate mitigation, have targeted monitoring and responsive management, ensure good engagement, disseminate findings, and incorporate them into future planning.

Can evolutionary theories of dispersal and senescence predict postrelease survival, dispersal, and body condition of a reintroduced threatened mammal?

“…The eastern quoll was once common throughout south‐eastern Australian states, including Tasmania (Peacock & Abbott, 2014; Robinson et al, 2020). Prior to reintroduction to BNP, the last confirmed sighting of a wild quoll alive on mainland Australia was in 1963 (Dickman et al, 2001).…”

“…Declines and extinctions on mainland Australia are attributed to a combination of disease and predation by the introduced red fox (Peacock & Abbott, 2014). Predation by the red fox, as well as the domestic dog Canis familiarus , continue to threaten the re‐establishment of the quoll on the mainland, along with collisions with vehicles (Robinson et al, 2020). The species is listed nationally and internationally as Endangered (Australian Government 2020, Burbidge & Woinarski, 2016).…”

“…Yet, captive‐bred individuals are often used for conservation‐orientated translocations, especially for endangered animals, as wild source populations are small or nonexistent (Jule et al, 2008). It is important to consider how to improve the success of animal translocations as such operations are resource intensive and ethically questionable if not justified by good planning, monitoring, threat mitigation, and evaluation (e.g., IUCN/SSC, 2013; Robinson et al, 2020). Central to improving animal translocations is understanding what factors contribute to enhanced survival and establishment in the released area.…”

“…Following release into a new environment, translocated animals are often found to disperse away from a release point (Le Gouar et al, 2012; Stamps & Swaisgood, 2007). Large movements can compromise the success of a program if animals fail to establish at the release location (Le Gouar et al, 2012; Robinson et al, 2020). At the individual level, overdispersal can hinder breeding as chances of interacting with conspecifics declines (Le Gouar et al, 2012).…”

Improving Restoration Programs Through Greater Connection With Ecological Theory and Better Monitoring

“…One way to avoid excessive risk aversion is to facilitate a change of culture within resource management agencies and ensure there are well developed approaches for learning from failures and, conversely, avoiding repeatedly making the same mistakes. Indeed, reintroduction biology -a sub-discipline of restoration ecology -has a well developed framework for rapid learning from failures and mistakes (e.g., Ewen et al, 2011;Robinson et al, 2019). Another approach to tackling problems with risk aversion is to provide ways to better document what activities did not work.…”