Polar bear. USFWS

By John Platt Mammals, birds and fish living in the High Arctic experienced an average 26 percent drop in their populations between 1970 and 2004 due to the loss of sea ice, according to a new report from The Arctic Species Trend Index (ASTI), Tracking Trends in Arctic Wildlife [pdf]. The 2010 report, commissioned and coordinated by the Whitehorse, Yukon–based Circumpolar Biodiversity Monitoring Program (CBMP), was presented Wednesday at the State of the Arctic Conference in Miami. It covers 965 populations of 365 species, representing 35 percent of all known vertebrate species found in the Arctic. The Arctic region is broken into three floristic zones (High, Low and Sub Arctic), referring to the amount of plant life that exists within the regions’ boundaries. … Among the specific findings: Low Arctic fish species such as pollack have benefited from rising ocean temperatures, which is why their populations have increased. Populations of lemmings, caribou and red knot (a shorebird) have all decreased. Migratory birds that pass through the Arctic have decreased an average of 6 percent, although that number is skewed by a “dramatic increase” in some populations of migratory geese. Furthermore, brown bear populations have dropped as much as 50 percent in the last 15 years. …

Study: High Arctic’s biodiversity down 26 percent since 1970