September 11, 2009

Climate Change Impacting Arctic Ecology

Rapid change is underway in the Arctic due to the effects of climate change, researchers reported on Thursday.

"The Arctic as we know it may soon be a thing of the past," said Eric Post, associate professor of biology at Penn State University, whose study is published in Friday's edition of the journal Science.

Post lead an international team in a broad study of the ecological changes occurring in the Arctic during the fourth International Polar Year, which ended in 2008.

Researchers analyzed the responses of plants, birds, animals, insects and humans to global climate change.

Over the past 20 to 30 years, Post's team found that seasonal minimal sea ice coverage has decreased by 45,000 square kilometers each year, in addition to a decline in terrestrial snow cover, resulting in an earlier start to growing season.

"Species on land and at sea are suffering adverse consequences of human behavior at latitudes thousands of miles away," said Post.

"It seems no matter where you look -- on the ground, in the air, or in the water -- we're seeing signs of rapid change."

Additionally, researchers noted a decline in Arctic animals such as the ivory gull, Pacific walrus, ringed seal, hooded seal, narwhal, and polar bear.

They found that polar bears and ringed seals are losing newborn pups at a faster rate due to collapses in the lairs in which they give birth. Researchers say polar bears and ringed seals could be on the path to extinction.

The study also shows that caribou calves are having a tougher time surviving because their mothers are unable to adjust calving season due to sooner than normal plant growth seasons.

"Inuit hunters at my study site in Greenland have all but given up on hunting caribou there," said Post. "What will be the next component to disappear from their traditional lifestyle, a lifestyle that has worked for thousands of years?"

The changes in plant growth have also caused an increase in insect and parasite populations that threaten migratory animals.

"The presence of more shrubs and trees promotes deeper snow accumulation, increasing soil temperatures during the winter, and more microbial activity in the soil, which in turn makes the habitats more suitable for shrubs. Increasing the shrub cover may lengthen the period during the plant growing season when the tundra acts as a carbon-dioxide sink," researchers said in a statement.

It appears that the warmer temperatures are displacing Arctic foxes, while red foxes are increasing in number.

"The results of our studies so far reveal widespread changes, but also a surprising heterogeneity in biological responses to warming," said Post.

"The broad, rapid, and in some cases devastating changes documented in this paper remind us of why it's important to give consideration to the consequences of rising temperatures."


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