Animal populations in different parts of the Far North fluctuated substantially from 1970–2004, according to a 2010 assessment from the Arctic Council’s Circumpolar Biodiversity Monitoring Program. Covering about 300 species of mammals, birds, and fish, the report found that high-Arctic species numbers have fallen by about 26 percent. Sub-Arctic species (mostly terrestrial and freshwater) showed a small decline since peaking in the mid-1980s, but overall there was no significant change, while low-Arctic species populations rose by an average of 46 percent. However, the report cautions that this last category is dominated by marine species and heavily biased by data from the Bering Sea, where some fish populations increased sharply due to increasing water temperatures, and some marine mammals are recovering from past hunting pressure.
The main environmental problems facing Arctic ecosystems and human residents today are chemical pollution, the overexploitation of some species, habitat disturbance, and climate change (see Climate Change section).
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