Vehicle collisions and dog attacks on Victorian koalas as evidenced by a retrospective analysis of sightings and admission records 1997 – 2011

Abstract

Koalas moving across open ground risk dog attacks and collisions with vehicles when crossings roads. Historical records from a resident survey, two regional wildlife carers and a state government department wildlife shelter returns database for Victoria, Australia, were examined to determine the importance of certain admission types. Koala Vehicle Collisions (KVCs) and dog attacks were important contributors to the overall intake of injured koalas. However, KVCs were the most numerous recorded cause of koalas entering a wildlife shelter, and the most frequently assigned cause of death. There were relatively high rates of admission into care, and of death, for male koalas. Furthermore, almost twice as many individuals were admitted during the breeding season; sex ratio was not a differentiating characteristic of road-kills between breeding and non-breeding seasons, or by individual months. Comprehensive, accurate and detailed data gathering are essential for effective evaluation of the success of rehabilitation and release, as well as post release survival rates. This, together with population studies would determine whether admission rates reflect the sex ratio of local populations, and whether the high number of injured or killed females has an impact on their viability. Analyses of wildlife carer databases have great potential for decision making in koala conservation.

Factors that drive koala roadkill: an analysis across multiple scales in New South Wales, Australia

“…Gonzalez-Astudillo et al (2017) examined the causes of the decline of koalas in south-east Queensland, and 26% of the 20 250 koala hospital admissions in their study comprised otherwise healthy koalas that had been hit by vehicles. Schlagloth et al (2021) report a similar finding for Victoria, Charalambous and Narayan (2020) for NSW, and Lunney et al (D. Lunney, I. Sonawane, H. Cope, E. Stalenberg and R. Haering, unpubl. data) have identified that it has been an ongoing issue for koalas in north-east NSW, as recorded by the local wildlife rehabilitation group Friends of the Koala.…”

An 8-year long retrospective analysis identifies the major causes of morbidity and mortality in rescued koala joeys

“…These results are similar to a study by Griffith et al (2013), which concluded that vehicle collision (21.2%) was the primary reason for admission for koalas in the Port Macquarie region of NSW, and when combined with animal attack (19.8%), contributed to 41% of trauma admissions. Both vehicle collision and animal attack are well-recognised threats to koalas in Australia (Beyer et al 2018;Charalambous and Narayan 2020;Lunney et al 2022b;Melzer and Black 2022;Schlagloth et al 2022;Kerlin et al 2023). Trauma caused by vehicle collision and animal attack were among the top five major reasons for admission for koala joeys in our study.…”

“…vehicle collision (Englefield et al 2018), pet attack (Rasmussen et al 2021), lawn mowing (Scheelings 2015)] on wildlife, and for recommending potential measures to improve urban planning to ameliorate the negative consequences of such activities (Taylor-Brown et al 2019). The vast wealth of information contained in wildlife rescue databases is increasingly being recognised as a valuable scientific resource that has the potential to yield information on animal biology and reform conservation efforts (Molina-L ópez et al 2011;Griffith et al 2013;Gonzalez-Astudillo et al 2017;Pyke and Szabo 2018b;Narayan and Vanderneut 2019;Taylor-Brown et al 2019;Charalambous and Narayan 2020;Lunney et al 2022a;Schlagloth et al 2022). Although there are notable issues with bias and accuracy of this information, records from wildlife care facilities can provide a wealth of information to reform conservation and management practices (Kerlin et al 2023).…”

“…The study by Taylor-Brown et al (2019) highlights that koalas are more frequently rescued and brought into care than any other wildlife species. The continuous increase in koala rescues is a result of several synergistic factors, ranging from habitat clearance and fragmentation (Seabrook et al 2003;Gordon et al 2006), to disease (Speight et al 2016;Grogan et al 2018;McCallum et al 2018), to dog attacks and vehicle collisions (Charalambous and Narayan 2020;Schlagloth et al 2022). Furthermore, the key results from these studies highlight that the clinical outcome for the majority of koalas admitted at wildlife hospitals is that they either succumb to their injuries and/or debilitating diseases, or have to be humanely euthanased due to their critical condition (Burton and Tribe 2016;Gonzalez-Astudillo et al 2017;Taylor-Brown et al 2019).…”

The Effect of Disease and Injury on Faecal Cortisol Metabolites, as an Indicator of Stress in Wild Hospitalised Koalas, Endangered Australian Marsupials

“…In South East Queensland (SEQ), in particular, there is significant loss of koala habitat for housing developments and for the expansion of the road and rail networks. The increased traffic volume and larger distances between areas of koala habitat are causing koalas to travel long distances and to cross roads, with a high chance of being attacked by dogs or hit by vehicles [ 15 , 16 , 17 , 18 , 19 ]. These human-driven pressures are further compounded by anthropogenic climate change manifesting itself through high temperatures, more frequent and prolonged droughts and floods and catastrophic bushfires.…”