Estimates of wildlife killed by free-ranging cats in China

Abstract

Throughout much of the world, growing populations of free-ranging domestic cats pose an increasingly serious threat to biodiversity. However, no study has estimated the magnitude of wildlife mortality caused by cats in China, one of the largest and most biodiverse nations on earth. We used a novel, survey questionnaire-based approach to estimate annual predation on wildlife by cats in China; we separately considered predation rates in urban and rural areas and by both owned free-ranging cats and unowned cats (e.g., feral and semi-feral cats including those associated with feeding and trap-neuter-return (TNR) activities). Using statistical simulations based on 2187 questionnaire responses that included direct observations of prey returns to owners and predation events by unowned cats, we estimate that the minimum annual amount of predation by all free-ranging cats in China is: 1.61-4.95 billion invertebrates, 1.61 -3.58 billion fishes, 1.13-3.82 billion amphibians, 1.48-4.31 billion reptiles, 2.69-5.52 billion birds, and 3.61-9.80 billion mammals. Thus, we show that free-ranging cats cause a tremendous death toll that may be profoundly impacting China’s wildlife populations and biodiversity. Our results indicate that there is an urgent need for increased research into the impacts of cats on wildlife in China, and for management and policy that reduces numbers of free-ranging cats and thus mitigates their harmful effects on China’s wildlife.