Ecological approach for understanding human-wildlife conflicts

Background/Question/Methods

Human-wildlife conflict threatens both human safety and wildlife conservation worldwide.  Limited food availability is often implicated in causing or exacerbating such conflict: there is a tendency for increased risk taking across taxa in times of food shortages, increasing the likelihood of conflict with humans. Relatively few studies have examined ecological associations that might affect the frequency of such conflicts at the landscape level.  We tested the hypothesis that regional inter-annual variation in frequency of conflicts may be driven in part by changes in food availability. We tested for associations between spatially and temporally explicit measures of bear-human conflict (involving black and grizzly bears), and food availability across British Columbia, Canada, from 1960-2009.  Conflict measures included the frequency of serious attacks on humans and the frequency of “animal control kills”, where animals are destroyed by management authorities in response to conflicts, while food availability measures included spawning Pacific salmon biomass and climatic variables associated with terrestrial availability.  While related studies have focused on conflict events or on periods of high conflict, we took more of a comparative approach by also including areas and years with little or no conflict as information about such periods could be biologically meaningful.

Results/Conclusions

Bear-human conflict frequencies were associated with ecological predictors across our study period and area.  Climate was found to influence conflict, though its effect varied among regions.  Most notably, the yearly frequency of animal control kills was inversely correlated to yearly spawning salmon biomass in coastal regions, where spawning salmon are relatively abundant and constitute a considerable and important proportion of bear diets.  Similarly, the years with the greatest number of bear attacks on humans in coastal regions were those with the lowest available spawning salmon biomass.  Given that both salmon abundance and climate can be predicted, albeit imperfectly, this suggests that the probability of bear-human conflict could also be predicted.  As such, the use of landscape-level ecological metrics could help to inform management actions to prevent or mitigate future human-wildlife conflict.