An analysis of the long-term trends in the records of Friends of the Koala in north-east New South Wales: II. Post-release survival

Abstract

Context Post-release monitoring of rehabilitated koalas is lacking, meaning that the long-term success rate is unknown. Aims We addressed the question: will a koala released from rehabilitation re-join the wild population and survive for months, if not years? Methods Using ear tag records as unique identifiers of individual koalas, we sifted the 31-year set of 5051 koala admission records (1989–2020) of a koala rehabilitation group, Friends of the Koala, in Lismore, north-east New South Wales for records of koalas that had returned to rehabilitation for a second, third or fourth time. Key results Of the 1771 koalas that were released, most (80%) had a coloured ear tag with a unique number. Of these koalas, 270 were admitted to rehabilitation two or more times and therefore represented an opportunity for post-release monitoring. Re-admission figures mostly fitted the pattern of first admissions, meaning that the released koalas had become part of the local koala population. Of the 270 koalas that were re-admitted into rehabilitation, 66% remained for more than 6 months in the wild, and 33% remained in the wild for more than 2 years. Conclusions We conclude that rehabilitated and released koalas can survive in the wild long-term, even though some koalas were re-admitted after a very brief period post-release. Implications The success of rehabilitation and release, as judged by re-admitted tagged koalas, is a more robust view of success for koala survival after rehabilitation than simply the proportion of released versus non-released koalas.

Health surveillance representative of koala (Phascolarctos cinereus) distribution in Victoria, Australia

“…36 It would benefit WHV:S to work with these practices to establish a protocol of sampling and continue to work with each practice by providing materials to sample wildlife. In addition to aforementioned suggestions, a greater focus should be placed on gathering and utilising data from rehabilitator groups to improve record keeping for disease and causes of premature death, as discussed in a recent paper by Lunney et al 37 …”

“…36 It would benefit WHV:S to work with these practices to establish a protocol of sampling and continue to work with each practice by providing materials to sample wildlife. In addition to aforementioned suggestions, a greater focus should be placed on gathering and utilising data from rehabilitator groups to improve record keeping for disease and causes of premature death, as discussed in a recent paper by Lunney et al 37 Brief specific plans for the immediate future should also include adopting a standardised necropsy procedure, which will assist in the diagnosis of mortality for koalas submitted to WHV:S in future. This can help to detect large clusters of specific diseases.…”

Influences on koala habitat selection across four local government areas on the far north coast of NSW

“…By focusing on the scale of the four LGAs, we have provided the ecological basis for developing a regional approach to koala conservation. There is strong local community support for koala conservation and recovery measures to help ensure koalas continue to survive in the region (Brown et al, 2018;Brown, McAlpine, et al, 2019;Fielding et al, 2022;Lunney et al, 2022). This study has provided an ecological foundation for a koala conservation strategy for the four LGAs, as well as the neighbouring Kyogle and Richmond Valley…”

Reversing the decline of threatened koala (Phascolarctos cinereus) populations in New South Wales: Using genomics to enhance conservation outcomes

“…The collection dates of the samples analysed in this study spanned approximately 28 years, a time period slightly greater than the hypothetical maximum lifespan of a koala in the wild (~18 years; Lunney et al., 2023 ). However, since koalas have relatively long generation times (6–8 years), and because significant shifts in genetic diversity usually take at least several generations to occur, state‐wide allele frequencies were not expected to have changed significantly in this time (Browne et al., 2019 ; Lott et al., 2022 ).…”