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American black bears (Ursus americanus)
Large carnivore response to human road use suggests a landscape of coexistence. Kautz TM, Fowler NL, Petroelje TR, Beyer DE, Svoboda NJ, Belant JL. Global Ecology and Conservation. 2021 Aug
Coexistence between humans and large carnivores may depend on carnivore adaptations to use developed landscapes while reducing human encounters. Roads are a widespread form of human development that carnivores may perceive as efficient travel routes or centers of human activity and associated risk. We compared the spatio-temporal responses of carnivores to human road use with high-resolution tracking of a large carnivore guild including American black bears (Ursus americanus), bobcats (Lynx rufus), coyotes (Canis latrans), and wolves (C. lupus) in Michigan, USA. All carnivores selected for roads when traveling at night but avoided roads during the day when human activity was greatest. Human activity explained 90% of temporal variation in road use across carnivore species, with a 3.2–3.7-fold increase in road use at times of low human activity which reduced carnivore activity overlap with humans by 27–42%. Similar but less pronounced activity changes occurred in areas up to 500 m from roads. Bears and wolves increased nocturnal activity with more roads in their home range, but not bobcats or coyotes. Despite increased diurnal activity in areas farther from roads, temporal overlap among carnivores was high regardless of road proximity. Our results suggest that spatio-temporal responses to roads were similar among carnivores and emphasized avoidance of humans over other carnivore species. Further, we provide support that carnivores can be diurnally active while avoiding humans by using areas farther from roads. However, carnivores which are primarily diurnal (e.g., black bears) or have a strong proclivity for using roads (e.g., wolves) likely require greater behavioral changes to avoid humans. Behavioral adaptations allowing multiple species to use and cross roads while avoiding humans are encouraging for human-carnivore coexistence.