Warm, rainy winters cause the populations of several animal species at a remote Norwegian Arctic outpost to drop at the same time, a new study finds.

The work, published yesterday in Science, is one of the first analyses to document the influence of climate change on a single community of intertwined species.

The Arctic fox. Photo courtesy of Brage Bremset Hansen.

Researchers working in Norway's Svalbard archipelago, a chain of islands above the Arctic Circle, found that winter rains caused populations of three plant-eating animals to plunge in unison. That is followed the next year by declines in the population of Arctic foxes, which feast on the carcasses of those plant-eaters.

The study provides "clear community-level climate signals in a simple system," said lead author Brage Bremset Hansen, an ecologist at the Norwegian University of Science and Technology in Trondheim.

Because just a few animal species spend their winters in Svalbard, and the winter weather there varies greatly from year to year, it was easier for scientists to track the community's response to a changing climate, he added.

The cycle of dramatic population declines kicks off when rain falls on snow. That creates an icy crust that makes it difficult for Svalbard's plant eaters -- reindeer, rock ptarmigans and sibling voles -- to eat grasses and other plants that cover the Arctic tundra.

So populations of those three animals decline, creating a feast for scavenging Arctic foxes. Their population balloons, but it's a short-lived gain.

The next year, the number of foxes declines dramatically because there are fewer reindeer carcasses and other carrion for the increased number of foxes to feed on.

"In some areas of Svalbard where you have heavy rainfall, it is not uncommon to have a [4-to-8-inch-thick] solid ice layer on the ground" after rains, Hansen said. That buries most tundra plants, which are generally no taller than 2 inches high.

Scientists are concerned because warm, rainy, icy winters are becoming increasingly common in Svalbard and other parts of the Arctic. That could give Svalbard's reindeer, ptarmigans, voles and foxes less time to recover from population drops caused by rainy winters.