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American Association for the Advancement of Science

Animals in the Arctic linked by climate

An arctic fox in Svalbard.
[Image courtesy of Brage Bremset Hansen]

Few creatures call the high Arctic home year-round. But, for four animals—reindeer, birds known as rock ptarmigans, small rodents called sibling voles, and arctic foxes, which eat the other three—Norway's tiny Spitsbergen island is home, even during the freezing winters. Now, researchers have shown that extreme weather, like icy winter rains, can bring the birth and death rates of all four species into sync with one another.

Previous studies have shown that extreme weather can sync up these population dynamics within the same species. But, until now, it's been unclear whether climate could also match up birth and death rates among different species in a community. Brage Hansen and colleagues studied years of data on these high-Arctic reindeer, ptarmigans, voles, and foxes, and then compared their data to climate events that were recorded at a local weather station during the same time period.

The researchers confirmed that extreme weather had indeed brought the population dynamics of this small ecosystem into sync, although the birth and death rates of the arctic fox—the sole predator, which depends on the others for food— lags behind the others animals' rates by one year. Hansen and his colleagues suggest that heavy rain on top of snow, which freezes plant life and prevents the herbivores from foraging in the winter, has been the main driver of this phenomenon.

And since more icing is predicted for the high Arctic, the researchers also suggest that extreme weather events could have more profound and unpredictable effects on Arctic animal populations in the future.