Cover December 2025

A study of carnivores in California’s Sierra Nevada, by Martin et al. (2025), shows that species like bobcats, cougars, coyotes, gray foxes, and martens largely avoid each other in space but share surprisingly similar diets—revealing how landscape conditions shape coexistence and how future habitat changes could disrupt these delicate balances.

Abstract: Interspecific competition is a structural force in animal communities and can be particularly influential among species with similar taxonomic or ecological characteristics. In carnivore communities, heterogeneity in resource availability and landscape structure can ameliorate competitive interactions, but it is often difficult to quantify the space- and resource-use of these elusive species. Here, we examined the spatial and diet partitioning of a montane carnivore guild, including bobcats, cougars, coyotes, gray foxes, and Pacific martens, in a 3074 km2 protected area in the Sierra Nevada range of California, USA. We used non-invasively-collected scat samples and remote camera detections to estimate the effects of landscape conditions on carnivore occurrence via an integrated, hierarchical occupancy model. We further analyzed scat samples via DNA metabarcoding to elucidate carnivore diet patterns, overlap, and effects of landscape conditions on foraging of the carnivore guild. We observed limited spatial overlap within the guild, with few species exhibiting high overlap. Conversely, we found strong overlap in diets, with greater overlap than expected among most species including those with different body-sizes and foraging strategies. Importantly, spatial partitioning resultant from landscape conditions appears to facilitate shared exploitation of prey. Through this work, we demonstrate the importance of landscape conditions and species' ecology in influencing space-use and resource partitioning, and we highlight the potential effects of landscape change on species' ecology and distributions in a changing world.

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