Untangling wildlife entanglements: patterns represented in rescue data from New South Wales, Australia

Background: Entanglement in man-made materials is reported by wildlife rehabilitators as a common source of injury and mortality in wildlife, however there is limited scientific research on this impact. Aims: To quantify the impact of entanglement on wildlife in terms of entanglement material, taxonomy, and conservation status using New South Wales (NSW), Australia, as a case study. Methods: Wildlife rescue data were sourced from the NSW National Parks and Wildlife Service data repository. All records of wildlife entanglement incidents in NSW between 2011–2012 and 2020–2021 were analysed for trends in relation to entanglement material and taxonomy, and NSW conservation status of affected species. A Mann–Kendall trend test and Augmented Dickey–Fuller test were performed for each data series to identify trends or periodicity. Key results: The annual number of wildlife rescue records in NSW attributed to entanglement has increased between 2011 and 2021. Entanglement in netting and wire represents more than a quarter of reported annual entanglements and has increased over time. The reported number of species impacted each year has increased, with mammals and birds consistently most affected. Across all taxa, the data show that flying-foxes were the most impacted species, representing more than two-thirds of all entanglements annually. The grey-headed flying-fox (Pteropus poliocephalus), listed as a threatened species under both NSW and Australian federal legislation, represented more than 50% of all flying-fox entanglements. Conclusions: We provide scientific evidence that entanglement in netting and wire is a threat to Australian wildlife, and that this threat is likely increasing. The consistent representation of the grey-headed flying-fox in the data, combined with the observed trend of increasing annual entanglements, suggests that this threatened species will continue to be disproportionately impacted. Implications: This paper quantifies the impact of entanglement on wildlife in terms of entanglement materials and impacts on particular species, especially species that are threatened with extinction. Promotion of wildlife-safe netting and fencing materials is common across jurisdictions, with some additionally enacting regulatory changes to prohibit certain netting materials.