Trophic matches and mismatches: can polar bears reduce the abundance of nesting snow geese in western Hudson Bay?
Article first published online: 18 OCT 2010
© 2011 The Authors
Volume 120, Issue 5, pages 696–709, May 2011
How to Cite
Rockwell, R. F., Gormezano, L. J. and Koons, D. N. (2011), Trophic matches and mismatches: can polar bears reduce the abundance of nesting snow geese in western Hudson Bay?. Oikos, 120: 696–709. doi: 10.1111/j.1600-0706.2010.18837.x
- Issue published online: 20 APR 2011
- Article first published online: 18 OCT 2010
- Paper manuscript accepted 1 September 2010
Climate change driven advances in the date of sea ice breakup will increasingly lead to a loss of spring polar bear foraging opportunities on ringed seal pups creating a phenological trophic ‘mismatch’. However, the same shift will lead to a new ‘match’ between polar bears and ground nesting birds. This new match will be especially prevalent along the Cape Churchill Peninsula of western Hudson Bay where both polar bears and nesting snow geese are abundant. Easily foraged goose eggs will provide at least some of the earlier arriving polar bears with compensation for the energy deficit accrued through lost seal hunting opportunities. We examine the potential impact of changes in the extent and pattern of polar bear egg predation on snow goose abundance using projection models that account not only for increases in the temporal overlap of the two species but also for autocorrelation and stochasticity in the processes underlying polar bear onshore arrival and snow goose incubation. Egg predation will reduce reproductive output of the nesting lesser snow geese and, under all but trivial rates, will lead to a reduction in the size of their nesting population on the Cape Churchill Peninsula. Stochasticity associated with the asymmetrical advances in polar bear onshore arrival and the snow goose incubation period will lead to periodic mismatches in their overlap. These, in turn, will allow snow goose abundance to increase periodically. Climate driven changes in trophic matches and mismatches may reduce snow goose numbers but will not eliminate this over-abundant species that poses a threat to Arctic landscapes.