Polar Bears, Sea Ice, and Climate Change
Page 4 of 4
Effects of Sea Ice Conditions on Individual Bears
Because of their reliance on the sea ice for all aspects of their survival, polar bears are especially vulnerable to changing climate patterns. In addition to polar bear movement patterns, the five-year study will look at how climate-induced changes to sea ice affect the body conditions of all polar bear sex/age groups (as reflected in weight-length ratios). In addition, the team will evaluate the effects of changing sea ice on cub production and the survival rates of cubs, yearlings, and juveniles. Their analyses will focus on the survival rates of younger polar bears because they expect them to be more sensitive to short-term environmental changes than adults.
The scientists hypothesize that longer ice-free or ice-melt seasons will minimize summer foraging by polar bears. They expect that minimal foraging opportunities will result in lighter weights of pregnant bears entering the den in the autumn, smaller litter sizes, and lower weights of cubs leaving dens in the spring. Spring cubs that are lighter-weight would be expected to have poorer survival rates, and the survival rates of yearlings and juveniles would also be expected to be lower if they have reduced opportunity to forage.
Future Plans
Because the study is still in its initial stages, Durner has been focused on gathering data and preparing for the upcoming field season. He expects the team to produce preliminary results on some aspects of the study in another year's time.
Because of their reliance on the sea ice for all aspects of their survival, polar bears are especially vulnerable to changing climate patterns. In addition to polar bear movement patterns, the five-year study will look at how climate-induced changes to sea ice affect the body conditions of all polar bear sex/age groups (as reflected in weight-length ratios). In addition, the team will evaluate the effects of changing sea ice on cub production and the survival rates of cubs, yearlings, and juveniles. Their analyses will focus on the survival rates of younger polar bears because they expect them to be more sensitive to short-term environmental changes than adults.
The scientists hypothesize that longer ice-free or ice-melt seasons will minimize summer foraging by polar bears. They expect that minimal foraging opportunities will result in lighter weights of pregnant bears entering the den in the autumn, smaller litter sizes, and lower weights of cubs leaving dens in the spring. Spring cubs that are lighter-weight would be expected to have poorer survival rates, and the survival rates of yearlings and juveniles would also be expected to be lower if they have reduced opportunity to forage.
Future Plans
Because the study is still in its initial stages, Durner has been focused on gathering data and preparing for the upcoming field season. He expects the team to produce preliminary results on some aspects of the study in another year's time.
Page 4 of 4