%0 Journal Article
%T How many reptiles are killed by cats in Australia?
%A A. Nankivell
%A B. P. Murphy
%A C. R. Dickman
%A D. Stokeld
%A G. Edwards
%A J. C. Z. Woinarski
%A J. L. Read
%A R. Palmer
%A S. M. Legge
%A T. S. Doherty
%J Wildlife Research
%D 2018
%R 10.1071/WR17160
%X Abstract Context: Feral cats (Felis catus) are a threat to biodiversity globally, but their impacts upon continental reptile faunas have been poorly resolved. Aims: To estimate the number of reptiles killed annually in Australia by cats and to list Australian reptile species known to be killed by cats. Methods: We used (1) data from >80 Australian studies of cat diet (collectively >10ˋ000 samples), and (2) estimates of the feral cat population size, to model and map the number of reptiles killed by feral cats. Key results: Feral cats in Australia＊s natural environments kill 466ˋmillion reptiles yr每1 (95% CI; 271每1006ˋmillion). The tally varies substantially among years, depending on changes in the cat population driven by rainfall in inland Australia. The number of reptiles killed by cats is highest in arid regions. On average, feral cats kill 61 reptiles km每2 year每1, and an individual feral cat kills 225 reptiles year每1. The take of reptiles per cat is higher than reported for other continents. Reptiles occur at a higher incidence in cat diet than in the diet of Australia＊s other main introduced predator, the European red fox (Vulpes vulpes). Based on a smaller sample size, we estimate 130ˋmillion reptiles year每1 are killed by feral cats in highly modified landscapes, and 53ˋmillion reptiles year每1 by pet cats, summing to 649ˋmillion reptiles year每1 killed by all cats. Predation by cats is reported for 258 Australian reptile species (about one-quarter of described species), including 11 threatened species. Conclusions: Cat predation exerts a considerable ongoing toll on Australian reptiles. However, it remains challenging to interpret the impact of this predation in terms of population viability or conservation concern for Australian reptiles, because population size is unknown for most Australian reptile species, mortality rates due to cats will vary across reptile species and because there is likely to be marked variation among reptile species in their capability to sustain any particular predation rate. Implications: This study provides a well grounded estimate of the numbers of reptiles killed by cats, but intensive studies of individual reptile species are required to contextualise the conservation consequences of such predation.
%U http://www.publish.csiro.au/WR/fulltext/WR17160