New study reveals complex relationships among grizzly bear activity, ecotourism, and salmon availability

A new study “Ecology of fear alters behaviour of grizzly bears exposed to bear-viewing ecotourism” in the journal Ecology finds that some bears will avoid ecotourists on multiple spatial and temporal scales, and can take multiple weeks after encounters to return to their baseline activity levels at the research sites. This surprising result, associated with a non-consumptive activity, requires some unpacking. Ultimately, it’s a good news story for an industry committed to evidence-based and sustainable practices.

The ‘ecology of fear’ concept in the scientific literature allows an understanding of how an animal’s perception of risk may influence its behaviour and use of habitat. Owing to a history of hunting and other harms by humans, it’s well-accepted that wildlife display a healthy fear of humans. It’s an evolved response to a mortality risk, and it’s expressed even in the context of harmless encounters (e.g. with hikers, mountain bikers). 

In any context, this perception of risk by wildlife often relates to habitat structure, the types and intensity of risk cues, as well as an animal’s previous experiences. This study specifically examined how habitat structure and varied risk cues (in the form of various levels of ecotourism influenced grizzly bear activity).

Given the increasing popularity of bear-viewing ecotourism, including their own Spirit Bear Lodge, the Kitasoo Xai’xais Nation was interested in the potential effects of bear-viewing on the bears in their territory. The closure of ecotourism due to COVID-19 in 2020 in the K’ootz/Khutze Conservancy (“Khutze”) on the central coast of BC provided an unprecedented opportunity to monitor bear activity with remote cameras in the absence of humans, and compare it with human activity in 2021 when ecotourism resumed. Bear viewing in Khutze is primarily boat based, with two small land based interpretive sites in the estuary. Owing to their commitment to evidence-based and sustainable practice, other ecotour operators agreed to participate by allowing researchers to track their presence, precise movement tracks (via GPS trackers) and group size. They also respected the half-watershed closures established as part of the research design. We are grateful for their involvement.  

The researchers found that grizzly bear activity in Khutze was influenced by the amount of human activity, habitat structure and salmon availability. We explain some key details below.

After accounting statistically for the variation in daily salmon abundance and other factors, the researchers detected a decrease in grizzly bear activity in 2021 across the remote camera array compared with the 2020 closure year. Within the 2021 ecotourism season bear activity also declined on days with more tourist activity. Finally, bears were more likely to be detected at sheltered, forested camera sites compared with those more exposed, such as the open estuaries where bear viewing usually occurs. 

The variable that had the largest influence on bear detection rates was the number of days since people had last been in the Khutze bear viewing areas. In other words, the researchers found a strong temporal lag in terms of time required for bear activity levels to return to baseline following exposure to humans. Accounting for salmon abundance and other factors that varied between years, it would take ~25 days with no people in the watershed for bears to return to their 2020 levels of activity, revealing that the effects of human presence extended beyond the time that ecotours occurred. This effect was ~7 times as important as variation in salmon biomass in predicting bear activity levels. In other words, bears appear to be more sensitive to people than they were to salmon. 

The study provided important insight not only to scientists but also ecotourism operators and managers. All parties agree that best practice policy and procedures benefit from evidence. 

The various age-sex classes of bears (i.e., adult males, females with young, etc.) showed different responses to combinations of ecotourism levels and salmon biomass. When salmon levels were low, the number of people had little influence on the likelihood of a remote camera detection being an adult male. But when salmon biomass was high, increasing numbers of people were associated with a lower likelihood of a detection being an adult male. This suggests that perhaps when salmon availability is sufficient, adult males opt for alternate feeding areas outside of human activity. The opposite pattern was observed for females with young; when salmon levels were moderate or high, there was a positive association between the number of people and the likelihood of a detection being a female with young. Results from a complementary model presented in the research paper suggested that females with young are not increasing their activity in response to ecotourism, but rather simply may be the age-sex class that is least negatively influenced. 

This study provides valuable, site-specific information for managers within the Kitasoo Xai’xais Nation, the province, and beyond to implement measures to best manage ecotourism to benefit both bears and people. 

Does this research suggest that ecotourism will negatively influence bears over the long-term and sweeping changes to management are required? 

Not in the view of researchers. At the broadest level, the research team emphasizes that the project focused on behavioural measures in one important watershed, not factors relating to survival or reproduction at a population level.  

Whereas it’s clear that there can be surprisingly pronounced effects (that persist for many days), there is broader context to consider. First, ecotourism occurs only in the accessible portions of a very few of the watersheds available to grizzlies. Second, the avoidance behaviour shown by grizzlies is generally consistent with that associated with other human activity typically considered benign (like hiking on popular trails). Third, the behaviour is a natural and important response by bears that underlies coexistence with humans. In an adaptive way, bears are free to use their agency to move to adjacent habitats when others don’t feel safe. Fortunately, in areas like the Khutze, other spaces and times without relatively intense human activity still abound. 

Most importantly, new insight from this research helps local managers – should they want to keep bear behaviour closer to ‘baseline’ levels without ecotourism – consider trade-offs between various management tools (i.e., the number of viewing days in a week/month, times in a day that bear viewing could be open/closed, group sizes and bear viewing durations), other associated uses and effects, and the sustainable economic activity and derived benefits that bear-viewing provides.  Those decisions are beyond the influence of researchers. The science merely provides important information into one side of this ecological and economic balancing act. 

Citation

Short, Monica L.,  Christina N. Service,  Justin P. Suraci,  Kyle A. Artelle,  Kate A. Field, and  Chris T. Darimont. 2024. “ Ecology of Fear Alters Behavior of Grizzly Bears Exposed To Bear-Viewing Ecotourism.” Ecology e4317. https://doi.org/10.1002/ecy.4317

Abstract

Humans are perceived as predators by many species and may generate landscapes of fear, influencing spatiotemporal activity of wildlife. Additionally, wildlife might seek out human activity when faced with predation risks (human shield hypothesis). We used the anthropause, a decrease in human activity resulting from the COVID-19 pandemic, to test ecology of fear and human shield hypotheses and quantify the effects of bear-viewing ecotourism on grizzly bear (Ursus arctos) activity. We deployed camera traps in the Khutze watershed in Kitasoo Xai’xais Territory in the absence of humans in 2020 and with experimental treatments of variable human activity when ecotourism resumed in 2021. Daily bear detection rates decreased with more people present and increased with days since people were present. Human activity was also associated with more bear detections at forested sheltered sites and less at exposed sites, likely due to the influence of habitat on bear perception of safety. The number of people negatively influenced adult male detection rates, but we found no influence on female with young detections, providing no evidence that females responded behaviorally to a human shield effect from reduced male activity. We also observed apparent trade-offs of risk avoidance and foraging. When salmon levels were moderate to high, detected bears were more likely to be females with young than adult males on days with more people present. Should managers want to minimize human impacts on bear activity and maintain baseline age–sex class composition at ecotourism sites, multiday closures and daily occupancy limits may be effective. More broadly, this work revealed that antipredator responses can vary with intensity of risk cues, habitat structure, and forage trade-offs and manifest as altered age–sex class composition of individuals using human-influenced areas, highlighting that wildlife avoid people across multiple spatiotemporal scales.

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Authors and affiliations

Monica Short^1,2, Christina N. Service³, Justin P. Suraci⁴, Kyle A. Artelle^1,2,5,6, Kate A. Field^1,2, Chris T. Darimont^1,2

1. Department of Geography, University of Victoria, Victoria, British Columbia, Canada
2. Raincoast Conservation Foundation, Sidney, British Columbia, Canada
3. Kitasoo Xai’xais Stewardship Authority, Klemtu, British Columbia, Canada
4. Conservation Science Partners, Inc., Truckee, California, USA
5. College of Environmental Science and Forestry, State University of New York, Syracuse, New York, USA
6. Department of Earth, Environmental and Geographic Sciences, University of British Columbia, Okanagan, British Columbia, Canada

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