“A continental-scale analysis of feral cat diet in Australia”

http://onlinelibrary.wiley.com/doi/10.1111/jbi.12469 A continental-scale analysis of feral cat diet in AustraliaTim S. Doherty1,*, Robert A. Davis1, Eddie J. B. van Etten1, Dave Algar2, Neil Collier3, Chris R. Dickman4, Glenn Edwards5, Pip Masters6, Russell Palmer2 andSue Robinson7 Article first published online: 2 FEB 2015 AbstractAimReducing the impacts of feral cats (Felis catus) is a priority for conservation managers across the globe, and success in achieving this aim requires a detailed understanding of the species’ ecology across a broad spectrum of climatic and environmental conditions. We reviewed the diet of the feral cat across Australia and on Australian territorial islands, seeking to identify biogeographical patterns in dietary composition and diversity, and use the results to consider how feral cats may best be managed. LocationAustralia and its territorial islands. MethodsUsing 49 published and unpublished data sets, we modelled trophic diversity and the consumption of eight food groups against latitude, longitude, mean temperature, precipitation, environmental productivity and climate-habitat regions. ResultsWe recorded 400 vertebrate species that feral cats feed on or kill in Australia, including 28 IUCN Red List species. We found evidence of continental-scale prey-switching from rabbits to small mammals, previously recorded only at the local scale. The consumption of arthropods, reptiles, rabbits, rodents and medium-sized native mammals varied with different combinations of latitude, longitude, mean annual precipitation, temperature and environmental productivity. The frequency of rodents and dasyurids in cats’ diets increased as rabbit consumption decreased. Main conclusionsThe feral cat is an opportunistic, generalist carnivore that consumes a diverse suite of vertebrate prey across Australia. It uses a facultative feeding strategy, feeding mainly on rabbits when they are available, but switching to other food groups when they are not. Control programmes aimed at culling rabbits could potentially decrease the availability of a preferred food source for cats and then lead to greater predation pressure on native mammals. The interplay between cat diet and prey species diversity at a continental scale is complex, and thus cat management is likely to be necessary and most effective at the local landscape level. Media: Feral feast: cats kill hundreds of Australian animals https://theconversation.com/feral-feast-cats-kill-hundreds-of-australian-animals-35555 “Feral cats are estimated to eat tens of millions of native animals each night in Australia. But what kinds of wildlife are they eating? In research published today in the Journal of Biogeography, my colleagues and I show that cats kill hundreds of different kinds of animals, including at least 16 species considered globally threatened. Feral cats are a serious threat to wildlife globally, contributing to the extinction of numerous birds, mammals and reptiles worldwide. In Australia, cats have been implicated in the extinction of at least 20 mammal species and sub-species, including the lesser bilby and desert bandicoot. Cats are widespread across the country, so it’s likely that their diet varies according to the local environment and fauna community – which might be affected by many factors, such as the amount of rainfall that an area receives or the native plant life. Knowing what cats eat can help us decide how best to manage them.” From: halmahera@hotmail.com To: billstent@gmail.com; birding-aus@birding-aus.org; ccgfh@yahoo.com.au Subject: Feral cat nos: “How many are there? The use and misuse of continental-scale wildlife abundance estimates Although research groups would like more money, various groups are tackling cat issues….. “”How many are there? The use and misuse of continental-scale wildlife abundance estimates” http://www.publish.csiro.au/paper/WR14059.htm Jim Hone A C and Tony Buckmaster A B A Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia. B Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT 2601, Australia. C Corresponding author. Email: jim.hone@canberra.edu.au Abstract The number of individuals in a wildlife population is often estimated and the estimates used for wildlife management. The scientific basis of published continental-scale estimates of individuals in Australia of feral cats and feral pigs is reviewed and contrasted with estimation of red kangaroo abundance and the usage of the estimates. We reviewed all papers on feral cats, feral pigs and red kangaroos found in a Web of Science search and in Australian Wildlife Research and Wildlife Research, and related Australian and overseas scientific and ‘grey’ literature. The estimated number of feral cats in Australia has often been repeated without rigorous evaluation of the origin of the estimate. We propose an origin. The number of feral pigs in Australia was estimated and since then has sometimes been quoted correctly and sometimes misquoted. In contrast, red kangaroo numbers in Australia have been estimated by more rigorous methods and the relevant literature demonstrates active refining and reviewing of estimation procedures and management usage. We propose four criteria for acceptable use of wildlife abundance estimates in wildlife management. The criteria are: use of appropriate statistical or mathematical analysis; precision estimated; original source cited; and age (current or out-of-date) of an estimate evaluated. The criteria are then used here to assess the strength of evidence of the abundance estimates and each has at least one deficiency (being out-of-date). We do know feral cats, feral pigs and red kangaroos occur in Australia but we do not know currently how many feral cats or feral pigs are in Australia. Our knowledge of red kangaroo abundance is stronger at the state than the continental scale, and is also out-of-date at the continental scale. We recommend greater consideration be given to whether abundance estimates at the continental scale are needed and to their use, and not misuse, in wildlife management. Additional keywords: feral cat, feral pig, population estimation, red kangaroo, wildlife management