Mammal responses to global changes in human activity vary by trophic group and landscape.

Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amount and timing of animal activity varied widely. Under higher human activity, mammals were less active in undeveloped areas but unexpectedly more active in developed areas while exhibiting greater nocturnality. Carnivores were most sensitive, showing the strongest decreases in activity and greatest increases in nocturnality. Wildlife managers must consider how habituation and uneven sensitivity across species may cause fundamental differences in human-wildlife interactions along gradients of human influence.

Badgers remain fearless in the face of simulated wolf presence near their setts.

Many mesocarnivores are fossorial and use burrow systems to avoid predators. But fossorial animals cannot stay safely underground forever; they must also risk emerging overground to forage and find mates. To make this trade-off effectively and maximise their own fitness, it is imperative they assess how risk varies in space and time and adapt their denning behaviour accordingly. We used the badger in Bialowieza Forest, Poland, as a model for investigating how the denning behaviour of a fossorial mesocarnivore varies in response to short-term large carnivore risk. To this end, we experimentally simulated perceived wolf presence outside 10 badger setts using audio playbacks of wolves (their howls). We assayed two behavioural measures of fear: badger emergence time from setts on the day playbacks were broadcast and their presence in setts on the day after. We found that neither badger emergence time nor next-day sett use varied in response to wolf playbacks. The results of the present study contrast with a previous study of ours that found badgers used setts in areas with high landscape level perceived wolf risk less often than those in lower-risk areas. Together, these papers' findings suggest that different spatiotemporal scales of perceived risk can have differential effects on badger behaviour. We conclude that rather than take risk avoidance measures at all risky times and places, badgers likely display a diversity of reactions to large carnivore presence that depend on the context and spatiotemporal scale of the risk being perceived.

Wolf risk fails to inspire fear in two mesocarnivores suggesting facilitation prevails.

Large carnivores not only supress mesocarnivores via killing and instilling fear, but also facilitate them through carrion provisioning. Hence, mesocarnivores frequently face a trade-off between risk avoidance and food acquisition. Here we used the raccoon dog and red fox in Bialowieza Forest, Poland as models for investigating how large carnivores shape mesocarnivore foraging behaviour in an area with widespread large carnivore carrion provisioning. Using a giving up density experiment we quantified mesocarnivore foraging responses to wolf body odour across a landscape-scale gradient in wolf encounter rates. At locations with higher wolf encounter rates, raccoon dogs depleted feeding trays more than at plots with lower wolf encounter rates. Simulating wolf presence by adding wolf body odour caused raccoon dogs to deplete feeding trays more at locations with low wolf encounter rates, but less at locations with high wolf encounter rates. Fox foraging costs did not vary with the application of wolf body odour or wolf encounter rates. The frequency that the mesocarnivores visited experimental foraging patches was unaffected by wolf body odour or landscape level encounter rates. These results provide further evidence that large carnivore suppression can play a subordinate role to facilitation in determining mesocarnivore behaviour. The varying raccoon dog response to wolf odour across the landscape-scale gradient in wolf encounter rates shows how mesocarnivore-large carnivore interactions can be context-dependent. We suggest that rather than testing the effects of single risk cues on prey behaviour, future studies should focus on understanding how context modifies the ecological impacts of large carnivores.

Brown world forests: increased ungulate browsing keeps temperate trees in recruitment bottlenecks in resource hotspots.

Plant biomass consumers (mammalian herbivory and fire) are increasingly seen as major drivers of ecosystem structure and function but the prevailing paradigm in temperate forest ecology is still that their dynamics are mainly bottom-up resource-controlled. Using conceptual advances from savanna ecology, particularly the demographic bottleneck model, we present a novel view on temperate forest dynamics that integrates consumer and resource control. We used a fully factorial experiment, with varying levels of ungulate herbivory and resource (light) availability, to investigate how these factors shape recruitment of five temperate tree species. We ran simulations to project how inter- and intraspecific differences in height increment under the different experimental scenarios influence long-term recruitment of tree species. Strong herbivore-driven demographic bottlenecks occurred in our temperate forest system, and bottlenecks were as strong under resource-rich as under resource-poor conditions. Increased browsing by herbivores in resource-rich patches strongly counteracted the increased escape strength of saplings in these patches. This finding is a crucial extension of the demographic bottleneck model which assumes that increased resource availability allows plants to more easily escape consumer-driven bottlenecks. Our study demonstrates that a more dynamic understanding of consumer-resource interactions is necessary, where consumers and plants both respond to resource availability.