Investigating the Impact of Human Disturbances on Grizzly Bear Population


Photo of a grizzly bear by (

Grizzly bear populations are under increasing threat of mortality due to anthropogenic development in its habitats in western North America and Eurasia. In Alberta, Canada, the rapid landscape modification arising from heavy resource development, particularly forestry and coal-mining, is affecting the abundance of grizzly bear populations. Also, the grizzly bears forage on the regenerating forests and the sites near the roads for high quality diet, an attempt that increases the risk of attack from humans.

A team of researchers from University of Calgary, University of Toronto, and Foothills Research Institute performed a study of the relationship between anthropogenic disturbances and the abundance of grizzly bears in the 8721km2 study area, which coincides with the Yellowhead grizzly bear population unit.

While prior studies focused on features of individual disturbances, the group conducted temporal and spatial study: the cumulative effect of human disturbances in different parts of the study area during the period of 1998-2004. The tools implemented are satellite-imaged time series, candidate model-selection techniques, and zero-inflated Poission regression models.  They analyzed the data by utilizing the three variables: disturbance processes, neighborhood effect, and landscape characteristics.

According to their findings, the areas with lower disturbance exposure over a period of time had greater grizzly bear populations. Also, the areas that were less disturbed by humans’ neighborhoods possessed greater bear population. These indicate that the less anthropogenic pressure can sustain greater population.

Other variables that led to higher abundance are availability of regenerating forest and protected areas such as wild parks. The regenerating forests provide high-quality forage for the bears while the protected areas provide a safe shelter for them.

Creating the environment with less anthropogenic pressure, more protected areas, and more regenerating forests will enable support of larger grizzly bear population.


Source: Linke, Julia. “Relationships between grizzly bears and human disturbances in a rapidly changing multi-use forest landscape.” Biological Conservation. 166. (2013): 54-63. Web. 29 Oct. 2013. <;.

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