Grizzly Bears Isolated by Human Activity

Grizzly bears are not travelling between the southern Selkirk Mountains and adjacent populations, rendering this 70-100 bear population as genetically isolated. The southern Selkirk bears are separated from other grizzlies in British Columbia by highway 3A and associated towns.

Genetic analysis of half the region's bears also reveals that north-south migrations of Purcell and Rocky Mountain grizzlies are severely hampered by human valley-bottom activity. In these populations, no females migrate, and only a small minority of males move between northern and southern bear populations.

In contrast, both female and male grizzly bears of the undeveloped Flathead north fork watershed, move freely across the valley. All four areas have similar ecology and topography, with grizzly populations separated by less than a day's travel distance. The key difference in the Flathead, is bears need not cross a highway or pass by human settlements to reach other bear populations.

Isolation of southeastern BC's grizzly populations raises concern about their conservation, especially for the now genetically-separate southern Selkirk bears.


Michael F. Proctor, Bruce N. McLellan, Curtis Strobeck and Robert M.R. Barclay. 2005. Genetic analysis reveals demographic fragmentation of grizzly bears yielding vulnerably small populations. Proceedings: Biological Sciences. 272(1579): 2409-2416.

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