Animals in the Arctic have increased in number over the last 40 years, but populations closest to the North Pole are shrinking, a new international study says.
The report, commissioned by the Circumpolar Biodiversity Monitoring Program (CBMP) and funded by the government of Canada, found that overall, the number of mammals, birds and fish in the Arctic has increased by 16 per cent since 1970.
The Arctic Species Trend Index, released Wednesday at a conference in Miami, credited hunting restrictions in place for decades with the animals' recovery. The number of geese, for example, has doubled, and certain species of whale are also recovering.
The biggest recovery was in the southernmost parts of the Arctic, where the number of animals was up 46 per cent from 1970 to 2004.
In sharp contrast, though, is the High Arctic, the area closest to the North Pole. The number of animals dropped by 25 per cent in the same time period, while the number of caribou was down by about one-third.
"What we're seeing is that there's winners and losers with rapid changes in the Arctic," said Mike Gill, a Canadian government researcher and study co-author. Gill is also chair of the CBMP.
Louise McRad of the Zoological Society of London said the decrease near the North Pole is most worrisome because the effects of climate change are most dramatic in that area and are expected to worsen. The pressure brought by the loss of sea ice will only increase, she said.
Gill said there isn't enough evidence to blame climate change directly for the loss of animals, but it is "largely in line with what would be predicted with climate change."
The report found the areas associated with the biggest drop in the number of animals also saw a faster-than-expected loss of sea ice, and species such as polar bears and narwhals are dependent on sea ice to survive.
The study tracked 965 populations of 306 species, representing 35 per cent of all known vertebrate species found in the Arctic.
The animals with the biggest recovery include bowhead whales, white-tailed eagles and the Atlantic Puffin. The biggest drops were seen in Atlantic cod, lemmings and the brown bear.
Polar bears in the western Hudson Bay also experienced a large drop in numbers. The report said there wasn't sufficient data to make any conclusions on polar bear numbers elsewhere.