Do Livestock Injure and Kill Koalas? Insights from Wildlife Hospital and Rescue Group Admissions and an Online Survey of Livestock-Koala Conflicts.

Alex Jiang,Clive J C Phillips,Andrew Tribe,Peter J Murray

doi:10.3390/ani11092684

Abstract

Simple SummaryKoala populations in Australia are declining and the species is vulnerable to extinction. In the past decade, grazing livestock emerged anecdotally as a threat to koala survival; cattle and horses were reported to have trampled koalas to death when encountered on the ground. In this study, we investigated the scale, frequency, and outcome of livestock-inflicted incidents to koalas via an online survey, and analysed koala admission records from Queensland wildlife hospitals and a wildlife rescue group (Wildlife Victoria) in Victoria. The results provide evidence of both livestock-inflicted injuries and deaths to koalas, especially as these have been confirmed by witness statements. The outcomes for the koala victims of the incidents were severe, which had a 75% death rate. The reported frequency of livestock–koala incidents was low but increasing, with 72 cases (0.14% out of 50,873 admissions) in Queensland wildlife hospitals during 1997–2019, and 59 cases (0.8% of 7017 rescue records) in Wildlife Victoria during 2007–2019, but it is recognised that this was likely to be under-reported. Future research is encouraged to explore the causes of livestock–koala incidents and to develop management strategies to minimise the livestock threat to koalas.Koala populations in Australia are declining due to threats such as chlamydiosis, wild dog predation and vehicle collision. In the last decade, grazing livestock emerged anecdotally as a threat to koala survival in areas where koala habitat and livestock grazing land overlap. This is the first study investigating the significance of livestock-inflicted injuries and deaths in koala populations over a large spatial and temporal scale. We investigated the outcome, scale, and frequency of livestock–koala incidents via an online survey and analysed koala admission records in Queensland wildlife hospitals and a wildlife rescue group (Wildlife Victoria) in Victoria. The results provide evidence of both livestock-inflicted injuries and deaths to koalas, especially as these have been confirmed by witness statements. The outcomes for the koala victims of the incidents were severe with a 75% mortality rate. The reported frequency of livestock–koala incidents was low but increasing, with 72 cases (0.14% out of 50,873 admissions) in Queensland wildlife hospitals during 1997–2019, and 59 cases (0.8% of 7017 rescue records) in Wildlife Victoria during 2007–2019. These incidents were likely to be under-reported due to the remoteness of the incident location, possible mis-diagnoses by veterinarians and the possible reluctance of farmers to report them. Future research is encouraged to explore the mechanics and causes of livestock–koala incidents and to develop management strategies to minimise the livestock threat to koalas.

Highlights

As an iconic, cryptic species in Australia, koalas (Phascolarctos cinereus) live in eucalypt forests
The first media report about the threat of livestock to koalas [14] appeared soon after a mother koala was witnessed being trampled to death by cattle in Victoria, which left the joey orphaned, and alleged incidents of wildlife killed by cattle were apparently known by farmers and wildlife carers
We received 92 completed survey forms, i.e., 11.9% of a total of 775 respondents who started the online survey but did not finish it. This relatively low completion rate may be due to the low occurrence of livestock–koala incidents, with which most survey recipients had little relevant experience

Summary

Introduction

Cryptic species in Australia, koalas (Phascolarctos cinereus) live in eucalypt forests. The reasons include the historical hunting and pelt trade [4], habitat loss and fragmentation [5,6], disease [7], wild and domestic dog predation [8], collisions with vehicles [9], climate change [10] and bush fires [11]. In line with these major threats to the survival of wild koalas, a new threat has emerged recently—livestock. Later more livestock-inflicted deaths to koalas were reported in northern New South Wales, with at least eight koalas killed by livestock over 15 months during 2016 and 2017 [15], and in the Darling Downs region of Queensland “dozens of koalas” have been reported to be injured by cattle and horses every year [15,16]

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