Polar Bears In Depth
Denning
Page 8 of 8
In the Beaufort Sea, individual polar bears have strong ties only to general denning areas and substrata. Denning habitat there is widely scattered across broad areas and is not limiting. Where such circumstances prevail, temporal and spatial management of human activities should eliminate most conflicts between those activities and maternal denning (Amstrup 1993; Amstrup and Gardner 1994). For example, proposed human activities can be directed around most of the narrow bands of habitat that are suitable for denning (Durner et al. 2001). Furthermore, initiation of intense human activities in autumn would give bears enroute to land dens the opportunity to den in less disturbed areas. If a bear encountered activities it didn't like, if could move up or down the coast to a place where it is comfortable. Also, bears already in dens could relocate more easily in autumn than after parental investment increases.
Much relocation of denning appears to occur naturally in autumn before bears finally settle down for the winter. Natural fluctuations in areas used for denning (Uspenski and Chernyavski 1965; Uspenski and Kistchinski 1972; Ramsay and Stirling 1986a, 1990) suggest that, even in some concentrated or core denning areas, alternate den sites may be available to bears if they are disturbed. However, data regarding fidelity to denning locales and responses to disturbances of dens are largely unavailable outside of the Beaufort Sea. More importantly, a human activity with potential to disturb denning bears will affect more individuals where dens are geographically clustered than where they are widely scattered. In the Beaufort Sea region for example, even expansive human activities, such as some related to oil exploration, would likely overlap with only a very small number of dens in any given year. In the concentrated denning areas of the world, a similar activity could overlap with dozens of dens. The risks that human activities could have population level effects are greater where dens are geographically clusterred. Clearly, human activities around all maternal denning areas must be managed with utmost caution. Each development scenario must be approached with full understanding of the ecological and behavioral situation, and wherever human activities proceed, outcomes must be carefully monitored so that management can be adjusted as needed.
Much relocation of denning appears to occur naturally in autumn before bears finally settle down for the winter. Natural fluctuations in areas used for denning (Uspenski and Chernyavski 1965; Uspenski and Kistchinski 1972; Ramsay and Stirling 1986a, 1990) suggest that, even in some concentrated or core denning areas, alternate den sites may be available to bears if they are disturbed. However, data regarding fidelity to denning locales and responses to disturbances of dens are largely unavailable outside of the Beaufort Sea. More importantly, a human activity with potential to disturb denning bears will affect more individuals where dens are geographically clustered than where they are widely scattered. In the Beaufort Sea region for example, even expansive human activities, such as some related to oil exploration, would likely overlap with only a very small number of dens in any given year. In the concentrated denning areas of the world, a similar activity could overlap with dozens of dens. The risks that human activities could have population level effects are greater where dens are geographically clusterred. Clearly, human activities around all maternal denning areas must be managed with utmost caution. Each development scenario must be approached with full understanding of the ecological and behavioral situation, and wherever human activities proceed, outcomes must be carefully monitored so that management can be adjusted as needed.