identified mates, spatial locations, microsatellite and mitochondrial data, candidate parents for parentage analysis

identified mates, spatial locations, microsatellite and mitochondrial data, candidate parents for parentage analysi

Radiotracking_records

Radiotracking_record

Interactions_per_day

Interactions_per_da

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

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

Transition to density dependence in a reintroduced ecosystem engineer

When does a reintroduced population of animals become self-regulating? Quantifying this is critical in determining when interventions can be tapered off, or when they may need to be reinstated. We tracked the growth trajectory of a reintroduced population to establish whether it was irruptive and/or had transitioned to self-regulation. In 2012, we reintroduced 32 eastern bettongs (Bettongia gaimardi), a potoroid marsupial from Tasmania, Australia, to a 485 ha exotic predator-proof fenced reserve in the Australian Capital Territory. We established a 92 cage trap monitoring network to track population growth between the Austral Autumn 2014 and Summer 2018. We used capture-recapture models to track changes in the population through time, and modelled ‘bettong weight’, ‘pouch occupancy’ and ‘age of pouch young’ with population variation, to establish potential associations with changes in population size. The estimated population grew from 32 individuals in 2012 to 100 in 2014, 192 in Autumn 2016, and then declined to 151 in Summer 2018. Estimated survival of adults was high—above 92% between most sessions. Adult female weights ranged between 0.485 and 2.428 kg, and adult males between 0.470 and 2.775 kg. Our study showed density dependence was achieved over the 6 year period. Low adult mortality, and variable pouch occupancy related to female weight, suggested that food availability had influenced lactation in females, with flow-on impacts on juvenile survival. Long-term, broad-scale population dynamics were probably driven by a mix of direct (e.g. disease, harvesting for other reintroductions), and indirect (i.e. climate dependent availability of nutritious food) influences on population size