An analysis of the long-term trends in the records of Friends of the Koala in north-east New South Wales: I. Cause and fate of koalas admitted for rehabilitation (1989–2020)

Abstract

Context The koala is a threatened species in New South Wales and long-term datasets of koala rehabilitation provide a valuable source of insight into local threats. Aims To examine the long-term trends of the cause and fate of koalas admitted for rehabilitation to assist monitoring the recovery of koala populations and provide a new outlook on the limitations and strengths of rehabilitation records for koala conservation. Methods We used data from long-term records (1989–2020) of the Friends of the Koala wildlife rehabilitation group in north-east New South Wales to identify spatial and temporal trends in 5051 koala admissions. Key results Chlamydiosis was the most common cause of admission, affecting female koalas more often than males. Admissions of female koalas with chlamydiosis showed a two-fold increase over summer, and admissions for motor vehicle collisions and unsuitable environment increased in spring. The rescue locations of admissions show an increasing geographic spread over time, as well as an increasing density of records. Admission body scores were higher in koalas that were eventually released than in non-released koalas. Other main causes of admission were unsuitable environments, dog attacks, abandonment/orphaning and attacks from other species. Conclusions We have produced an analysis and interpretation of a long-term dataset of the relative importance of various threats facing the koala population in north-east New South Wales. However, admissions to rehabilitation do not capture all the landscape-scale problems confronting koalas locally, particularly climate change and habitat loss. Implications We have provided the baseline necessary to detect future changes in the causes for admission, rates of rehabilitation and post-release survival.