Personality and plasticity predict postrelease performance in a reintroduced mesopredator

Reintroductions involve the relocation of animals into their historical range following extinction or extirpation. In this context, individuals with certain personalities may be more successful than others. For example, proactive individuals may dominate by being bolder, exploratory and more willing to take risks in familiar, stable environments (i.e. the source environment). Reactive personalities, in contrast, may thrive in novel, unstable environments (i.e. the release site) by being vigilant and risk averse. In addition, an individual's ability to adjust its behaviours over time (plasticity, or responsiveness) can play a pivotal role in determining postrelease performance. There is uncertainty, however, surrounding which behavioural measures translate to reintroduction success. We conducted behavioural assays and postrelease monitoring for eastern quolls, Dasyurus viverrinus, to determine whether behavioural measures (e.g. latency to emerge, time spent vigilant) could predict postrelease survival and dispersal in a fenced sanctuary. Using the ‘behavioural reaction norm’ approach, we found that personality derived from time spent exposed or vigilant during the assays had significant associations with postrelease den sharing and home range, while plasticity derived from latency (i.e. time delay) to reach food had a significant association with mean distance between consecutive dens. We recommend that proactive and rigid founders be preferred for initial trial reintroductions, and that reactive and plastic founders be used to supplement the population in later translocations. Our study demonstrates that, by including novelty, innovative behavioural assays offer significant value as a conservation tool to provide the fastest pathway to reintroduction success

Coexistence conservation: Reconciling threatened species and invasive predators through adaptive ecological and evolutionary approaches

Invasive predators are responsible for declines in many animal species across the globe. To redress these declines, conservationists have undertaken substantial work to remove invasive predators or mitigate their effects. Yet, the challenges associated with removal of invasive predators mean that most successful conservation programs have been restricted to small islands, enclosures (“safe havens”), or refuge habitats where threatened species can persist. While these approaches have been, and will continue to be, crucial for the survival of many species, in some contexts they may eventually lock in a baseline where native species vulnerable to invasive predators are accepted as permanently absent from the wild (shifting baseline syndrome). We propose an explicit theme in conservation biology termed “coexistence conservation,” that is distinguished by its pursuit of innovative solutions that drive or enable adaptive evolution of threatened species and invasive predators to occur over the long term. We argue evolution has a large role to play but using it to adapt native species to a new environmental order requires a shift in mindset from small, isolated, and short-term leaps to deliberate, staged steps within a long-term strategy. A key principle of coexistence conservation is that predation is treated as the threat, rather than the predator, driving a focus on the outcome rather than the agent. Without a long-term strategy, we face the permanent loss of many species in the wild. Coexistence conservation is a complementary approach to current practice and will play an important role in shifting our current trajectory from continued and rapid invasive predator-driven defaunation to a world where invasive predators and native prey can coexist

Adapting reintroduction tactics in successive trials increases the likelihood of establishment for an endangered carnivore in a fenced sanctuary

Threatened species recovery programs are increasingly turning to reintroductions to reverse biodiversity loss. Here we present a real-world example where tactics (techniques which influence post-release performance and persistence) and an adaptive management framework (which incorporates feedback between monitoring and future actions) improved reintroduction success. Across three successive trials we investigated the influence of tactics on the effective survival and post-release dispersal of endangered eastern quolls (Dasyurus viverrinus) reintroduced into Mulligans Flat Woodland Sanctuary, Australian Capital Territory. Founders were monitored for 42 days post-release, and probability of survival and post-release dispersal were tested against trial, origin, sex, den sharing and presence of pouch young. We adopted an adaptive management framework, using monitoring to facilitate rapid learning and to implement interventions that improved reintroduction success. Founders released in the first trial were less likely to survive (28.6%, n = 14) than those founders released the second (76.9%, n = 13) and third trials (87.5%, n = 8). We adapted several tactics in the second and third trials, including the selection of female-only founders to avoid elevated male mortality, and post-mating releases to reduce stress. Founders that moved dens between consecutive nights were less likely to survive, suggesting that minimising post-release dispersal can increase the probability of survival. The probability of moving dens was lower in the second and third trials, for females, and when den sharing with another founder. This study demonstrates that, through iterative trials of tactics involving monitoring and learning, adaptive management can be used to significantly improve the success of reintroduction programs

Baseline health and disease assessment of founder eastern quolls (Dasyurus viverrinus) during a conservation translocation to mainland Australia

We evaluated the health of 31 (eight males, 23 females) founder eastern quolls (Dasyurus viverrinus), translocated to a fenced reserve in the Australian Capital Territory between February 2016 and July 2017. Quolls were wild caught in Tasmania (16 animals) or captive bred at Mount Rothwell Biodiversity Interpretation Centre, Victoria (15 animals). Quolls were assessed for the presence of selected potential pathogens (Toxoplasma gondii, herpesviruses, Salmonella serovars, hemoprotozoa, and ectoparasites). We assessed the relationships among sex, provenance (captive or free ranging), T. gondii or herpesvirus infection, weight, and hematologic and biochemical variables. Six of 21 quolls (29%) tested were seropositive for antibodies to T. gondii. Seropositive quolls weighed significantly more and had significantly lower potassium levels, anion gaps, and urea and triglyceride levels than seronegative quolls had. Eighteen of 31 (58%) combined conjunctival-pharyngeal-cloacal swabs collected from quolls were PCR positive for a newly identified gammaherpesvirus, tentatively named dasyurid gammaherpesvirus 3. There were no significant differences among hematologic and biochemical variables or body weights from PCR-positive and PCR-negative quolls. Eighteen of 18 (100%) of rectal-swab samples were culture negative for Salmonella serovars. Three species of tick (Ixodes tasmani, Ixodes fecialis, and Ixodes holocyclus), two species of mite (Andreacus radfordi, one unidentified), and four species of flea (Pygiopsylla hoplia, Acanthopsylla rothschildi rothschildi, Uropsylla tasmanica, and Stephanocircus dasyuri), were detected on wild-caught quolls, whereas a fifth species of flea, Echidnophaga myremecobii, was detected only on captive-bred quolls. Five of 15 blood samples (33%) were positive for hemoprotozoan DNA via PCR, a novel Hepatozoon species, a novel Theileria species, Theileria paparinii, and Trypanosoma copemani were detected. Despite the presence of several potential pathogens known to be associated with disease in other marsupials, the quolls were considered to be in good general health, suitable for translocation, and a viable population was subsequently established