Human presence shifts the landscape of fear for a free-living mammal

Humans may play a key role in providing small prey mammals spatial and
temporal refuge from predators, but few studies have captured the
heterogeneity of these effects across space and time. Global COVID-19
lockdown restrictions offered a unique opportunity to explore how a sudden
change in human presence in a semi-urban park impacted wildlife. Here we
quantify how changes in the spatial distributions of humans and natural
predators influenced the landscape of fear for the California ground
squirrel (Otospermophilus beecheyi) in a COVID (2020) and non-COVID (2019)
year. We used a structural equation modeling approach to explore the
direct and indirect effects of human presence, predator presence, and
habitat features on fear responses [e.g., giving-up densities (GUDs),
number of foragers, and average food intake rate while at food patches].
In 2019, humans and dogs had moderate effects on GUDs; squirrels were less
fearful (lower GUDs) in areas frequently visited by humans and dogs, but
the effects of raptors were weak. In contrast, in 2020, the effects of
humans and dogs on GUDs were weak; squirrels were more fearful of high
raptor activity, open sky, and ground cover. In both years, squirrels
farthest from refuge were the most risk-averse. Overall, our analyses
revealed an increase in perceived risk from natural predators in 2020,
associated with a change in the concentration of human presence. Thus,
risk-sensitive foraging was dynamic across space and time, depending on a
complex interplay between human, dog, and natural predator activity, and
microhabitat features. Our findings elucidate the myriad ways humans,
directly and indirectly, influence animal perception of safety and danger.