In Sync

Populations of reindeer, ptarmigans, and voles rise and fall in sync in response to extreme weather events on an Arctic island, researchers report.

Climate change is happening fast in the Arctic. Researchers already know that changes in climate can cause populations within a species to become synchronized, and one team wanted to find out if the same phenomenon could happen with entire communities of wildlife.

To investigate, the study authors turned to Spitsbergen, Svalbard, an island in the high Arctic. Plant-eating Svalbard reindeer, Svalbard rock ptarmigans, and sibling voles all make their homes here, as do the arctic foxes that eat these animals.

The team found that the three herbivore species tended to follow similar population trends, with the arctic fox lagging by about a year. The number of reindeer, ptarmigans, and voles dropped during years with a lot of winter rain. The rain causes a layer of ice to accumulate on the ground, making it harder for the animals to eat plants. The populations then swung back up together because fewer animals were competing for food.

The results show that extreme weather events “may have broad ecological implications,” the team writes. These ups and downs may become more common, since researchers expect icing to increase in that part of the Arctic. Roberta Kwok | 17 January 2013

Source: Hansen, B.B. et al. 2013. Climate events synchronize the dynamics of a resident vertebrate community in the high Arctic. Science doi: 10.1126/science.1226766.

Image © Wild Arctic Pictures |