Predation impacts of free-roaming animals on terrestrial wildlife species.

Abstract

Escalating populations of free-roaming dogs (Canis familiaris) and cats (Felis catus), driven primarily by owner abandonment and unrestricted activity, exert pervasive predatory pressures on wildlife. Predation represents their most direct and destructive ecological impact, contributing significantly to global biodiversity decline. However, a comprehensive understanding of the global spatial patterns and environmental drivers of this threat is lacking, impeding the development of targeted conservation strategies. To address this gap, we conducted a systematic global assessment by analyzing 8933 documented predation events on wild mammals, birds, reptiles, and amphibians, compiled from 53 peer-reviewed studies employing a meta-analysis approach. Results showed pronounced geographical heterogeneity across continental, country, and ecosystem scales. Africa recorded the highest number of dog predation events (1698), whereas Europe was a hotspot for cat predation (2900). Populations of critically endangered (CR) species in Australia and Japan's Okinawa Islands face exceptionally high predation pressure. Dogs' predation impacts varied little across taxonomic levels. Cats, in contrast, had a taxonomically broader prey spectrum than dogs, and their impacts differed significantly among families, with Leporidae (28.49%), Procellariidae (14.79%), and Muridae (10.05%) being the most affected. Moreover, cat predation rates declined significantly with increasing human population density, longitude, and latitude and varied markedly among climate types, whereas dog predation showed no significant correlation with these environmental covariates. Collectively, our findings demonstrated a fundamental divergence in the ecological impacts, foraging behaviors, and adaptive strategies of free-roaming dogs and cats. Our study underscores the necessity for developing differentiated management strategies tailored to geographical hotspots (e.g., dog aggregation zones, islands, and regions with CR species) and to species-specific behavioral traits to mitigate predation risk and help reverse biodiversity loss.