Patch characteristics and domestic dogs differentially affect carnivore space use in fragmented landscapes in Southern Chile

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Rumaan Malhotra, Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, Jaime E. Jimenez, Department of Biological Sciences and Advanced Environmental Research Institute, University of North Texas, Denton, TX and Nyeema C. Harris, Ecology and Evolutionary Biology, Applied Wildlife Ecology (AWE) Lab, Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI

Background/Question/Methods
In an increasingly anthropogenic world, species face multiple interacting threats. Habitat fragmentation and domestic dogs are two perturbations threatening terrestrial mammals globally. Our aim was to determine if (1) the spatial use of domestic dogs increases with habitat destruction and (2) whether domestic dogs and habitat destruction drive the spatial use of native carnivores in a heavily degraded agricultural landscape.
We implemented a camera trap survey in a fragmented landscape comprised of native forest patches amidst a matrix of pastureland in Los Lagos, Chile. We used single-species occupancy models to assess the impact of domestic dogs and habitat destruction on three mesocarnivores – the foxes, culpeo (Lycalopex culpaeus) and chilla (Lycalopex griseus) and the wild cat güiña (Leopardus guigna). Additionally, we compared temporal overlap of all study species (including domestic dogs).
Results/Conclusions
The occupancy of domestic dogs increased with habitat loss. Detection rates for both the foxes increased with domestic dog occupancy, while factors driving occupancy differed for each of the native species. We found that a 12% projected increase in domestic dog occupancy negatively impacted the spatial use of the culpeo. In contrast, domestic dog occupancy had no effect/was positively correlated with chilla spatial use. Fragmentation was a positive driver for chilla occupancy. The güiña did not respond to fragmentation and other habitat covariates or to domestic dog occupancy. All native carnivore species were primarily nocturnal, while the domestic dog was almost entirely diurnal.
We highlight that the effects of domestic dogs or habitat destruction are not ubiquitous across the carnivore guild, with native species showing varied tolerance. However, future conditions of increased fragmentation and habitat loss will likely increase the potential contact between domestic dogs and native carnivores. Our work is an example of how landscape structure may impact native species while also mediating their interactions with an invasive species.