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Arctic birds in decline

Posted on behalf of Hannah Hoag.

A stock-market index of Arctic animals shows that populations of marine birds are shrinking.

Although overall trends for all Arctic animals remain stable, some species are undergoing “interesting” changes, says Mike Gill, chairman of the Circumpolar Biodiversity Monitoring Program (CBMP) in Whitehorse, Canada, which released the report on 23 April at the International Polar Year 2012 scientific meeting in Montreal, Canada.

The Arctic Species Trends Index (ASTI) tracks 890 populations of 323 vertebrate species across the entire Arctic region. The 2011 report covers the years 1970–2007 and adds three years of data to the 2010 assessment. It makes up the Arctic component of the Living Planet Index under development by the Zoological Society of London and the World Wildlife Fund based in Washington DC.

When lumped together, the abundances of Arctic fishes, birds and mammals increased from 1970 to 1990, then levelled off and have since remained relatively stable. “There has been recovery in the past years, but it is too early to say if it will be sustained,” says Gill.

But when the data are separated into ecozones — high-, low- and sub-Arctic regions — or when marine and terrestrial species are compared, new trends emerge.

Arctic marine birds have undergone a slow and steady decline in their populations since 1998. Some population trends may be results of changes in climate and sea-ice extent, which can determine food availability.

Other birds have been affected by changes outside of the Arctic, says Gill, who also heads up the Biodiversity and Species at Risk Section at Environment Canada in Whitehorse. Shorebirds that breed in the Arctic and travel along the East Asia–Australasian flyway to the river deltas of the Yellow Sea, for example, have seen dramatic declines, largely caused by development of the intertidal mudflats for industry, agriculture, aquaculture and urban expansion.

The report also shows that there are more pelagic fish (those living in open water) during peaks in the Arctic Oscillation, a large-scale climate cycle. “This is an extremely important finding, which can help with the management of commercial fish stocks and give better predictions of what they’re doing over time,” says Gill. Commercially important fish species, including Pacific herring, ocean perch and Arctic cisco, were linked to these climate shifts.

The maps produced by the report show existing information gaps. Northern Russia, northern Greenland and the islands in the Canadian High Arctic have been sparsely monitored since the 1950s.

Data from the ASTI are being used in models to predict changes in mammal, bird and fish populations under future climate scenarios, and to inform policy decisions. They will contribute to the Artic Biodiversity Assessment, which is scheduled for release in Spring 2013, along with a suite of policy recommendations, says Tom Berry, executive secretary of Conservation of Arctic Flora and Fauna biodiversity working group of the Arctic Council. “The CBMP allows us to detect trends sooner rather than present policy makers with what was,” says Berry.

Photo: Garry Donaldson


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