title photo by S. Kennerknecht
This page describes my prior research on human-wildlife interactions and the conservation implications of the ecology of fear. For information on active research by myself and team members in the Changing Landscapes Lab, check out the CLL website.
Carnivore ecology in human-dominated landscapes
Puma movement decisions in urbanized landscapes inform habitat restoration
with: Chris Wilmers, Barry Nickel, Peninsula Open Spaces Trust Despite potential threats from people, developed landscapes are increasingly important as movement corridors for many large carnivore populations. We are using high-resolution data on puma movement decisions to understand how pumas manage risks when navigating fragmented, urbanized landscapes and applying these insights to enhancing connectivity for puma populations in central California. Models of large carnivore movement across developed landscapes will allow us to compare multiple habitat restoration scenarios and identify the optimal use of limited restoration funds. |
Comparing human disturbance effects across carnivore communities
with: Chris Wilmers, Barry Nickel, Max Allen, Kaitlyn Gaynor, and collaborators across North America Human impacts on wildlife stem from both our footprint on the landscape (e.g., development, habitat loss) as well as the presence of people in wildlife habitat, which many species perceive as a potential threat. These two forms of disturbance are often conflated, but in fact operate over different spatiotemporal scales and may elicit very different wildlife responses. Recent work, using camera traps spanning a suburban-to-wildland gradient in the Santa Cruz Mountains, shows that human presence and human footprint have non-equivalent and often opposing effects on carnivore activity and habitat use, with responses differing between carnivore species based on habitat requirements and sensitivity to humans. Response are also likely to differ between populations of a carnivore species depending on local ecological and anthropogenic context (e.g., whether the population is actively hunted). Our ongoing work takes a macro-ecological approach, bringing together camera trap data from collaborators across North America to explore the drivers of variation in carnivore community responses to human disturbance and the factors promoting human-wildlife coexistence. |
Behavioral modifications by African lions to coexist in human-dominated landscapes
with: Chris Wilmers, Laurence Frank, Alayne Oriol-Cotterill, Terry Williams, Steve Ekwanga The threat posed by humans can strongly influence large carnivore habitat use, forcing carnivores to avoid high-risk areas near people. Such avoidance may be particularly problematic when human activities such as livestock herding overlap with areas of high prey availability. New research, using high-resolution GPS and accelerometer data to continuously quantify lion behavior, reveals that lions modify their behavior across human-dominated landscapes in ways that may promote coexistence, accessing valuable feeding opportunities while avoiding risky encounters with people. Understanding not just whether but how large carnivores use habitat near humans will be critical to managing vulnerable populations outside of protected areas. |
Fear of humans as apex predators
Fear of humans as apex predators affects wildlife behavior at the landscape scale
with: Chris Wilmers, Michael Clinchy, Liana Zanette Humans are major wildlife predators, and the fear we instill may underly many of the observed impacts of human activity on wildlife populations. Yet fear of humans as predators has proven difficult to disentangle from our myriad other influences on the natural world. We conducted a landscape-scale experiment, using audio playbacks to manipulate the fear of humans across large sections of wildlife habitat. This work demonstrates that the mere presence of people, independently of other anthropogenic influences, shapes the behavior, habitat use, and interactions of wildlife across terrestrial food webs, from mountain lions to mice. Understanding and managing the fear we instill in wildlife will be critical for conservation as human activity continues to expand into even the most pristine habitats. |
Fear of humans impacts carnivore foraging ecology
with: Justine Smith, Michael Clinchy, Liana Zanette, Chris Wilmers, David Macdonald, Devin Roberts, Chris Newman, Christina Buesching Humans kill large carnivores and mesocarnivores at rates far higher than do any non-human predators, and the resulting fear of humans can disrupt carnivore foraging and interactions with their prey. Experimental work demonstrates that European badgers in the UK exhibit a much stronger reduction in forging in response to human presence than in response to any other extinct or extant predator, consistent with humans being far more lethal. In California's Santa Cruz Mountains, pumas are similarly fearful of human predators, reducing feeding time and abandoning kills in response to human presence, which may in turn drive increased kill rates on their ungulate prey to compensate for lost feeding. Recent work indicates that pumas readily distinguish the threat posed by humans themselves from other potential sources of anthropogenic disturbance, namely, domestic dogs. |
Carnivore community ecology and conservation
Fear of large carnivores shapes wildlife food webs
with: Michael Clinchy, Liana Zanette, Larry Dill, Devin Roberts As apex predators, large carnivores play a key role in structure ecosystems by keeping their mesopredator and ungulate prey in check. The fear large carnivores instill in their prey may be a major component of their ecological effects, but the role of fear has proven difficult to demonstrate in nature. In the Gulf Islands of British Columbia, all native large carnivores have been extirpated, freeing mesopredator raccoons to dramatically increase their impacts on terrestrial and marine prey. By experimentally reintroducing just the fear of large carnivores (using month-long playbacks of carnivore vocalizations), we demonstrated that the fear of large carnivores can indeed shape food webs, suppressing mesopredator foraging and thus benefiting their marine prey. Raccoon impacts on prey were largely reversed under fear of large carnivores, highlighting the crucial role of these apex predators, and the fear they instill, in maintaining balanced food webs |
Cross-ecosystem effects of mammalian carnivores
with: Michael Clinchy, Liana Zanette Despite being primarily associated with terrestrial ecosystems, mammalian carnivores can be major predators in nearshore marine communities. Along the Pacific coast of British Columbia, Canada, several species of large carnivore and mesocarnivore exploit marine resources, but the relative impacts of these predators on their marine prey depends on the local history of carnivore conservation. Where native large carnivores persist, mesocarnivores like raccoons are kept in check and black bears are the predominate intertidal predators. However, where people have extirpated large carnivores, raccoons expand to fill the niche of their larger competitors, dramatically increasing their impacts on marine prey, in part through an increase in fearlessness. Understanding the role of mammalian carnivores in nearshore food webs will be crucial to carnivore conservation in coastal ecosystems. |
Quantifying behavioral interactions between elusive large carnivores
with: Michael Clinchy, Liana Zanette, Devin Roberts Large carnivore behavioral responses to the cues of their competitors are rarely directly observed, but may mediate competition between these top predators, providing crucial information for reducing risk or locating resources. Using the Automated Behavioral Response system (described below), we experimentally tested whether black bears recognize and respond to the cues of their competitors, pumas, demonstrating eavesdropping among these solitary large carnivores, which may mediate competition between bears and pumas in shared habitats. |
New tools for wildlife research
Automating experiments in wildlife behavior
with: Michael Clinchy, Liana Zanette, Badru Mugerwa, Michael Delsey, David Macdonald, Justine Smith, Chris Wilmers How animals respond to human disturbance, predators and competitors are central questions in conservation biology and wildlife ecology, but direct observations of wildlife behavior are often difficult to obtain, particularly for rare or cryptic species. My colleagues and I have developed an Automated Behavioral Response (ABR) system that integrates playback experiments with camera traps, allowing researchers to experimentally test the behavioral responses of any wildlife species to any acoustic cue without requiring an observer to be present. |