Alaska | |
| Overview | | |
| The Alaskan ecoregion has many immense, mostly pristine ecosystems including marine waters and islands; the Arctic Coastal Plain and the Brooks Range; taiga forests and interior rivers; the extensive, treeless lowlands and deltas of the Yukon and Kuskokwim rivers; the rugged coastline with glacier-capped mountains and numerous fjords and tidewater glaciers; and coastal rain forests, bogs, and alpine tundra communities on numerous islands. This section highlights the status and trends of selected mammals and fish that inhabit these pristine ecosystems. Waterfowl, shorebirds, and seabirds are discussed in a separate chapter. |
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| Caribou (Rangifer tarandus), muskox (Ovibos moschatus), and large mammalian predators such as the gray wolf (Canis lupus) and brown bear are vital components in the coastal plain tundra of the Arctic National Wildlife Refuge. All mammal populations on the refuge appear stable and healthy (McCabe et al., this section). Since 1989 the internationally shared (Canada and the United States) Porcupine caribou herd, which uses the narrow coastal plain for calving in June and July, has remained near 160,000 animals. The resident muskox population, reintroduced after being hunted to extinction in the late 1800's, now numbers nearly 720. Almost 100 brown bears (Ursus arctos) and 43 wolves live on the north slope of the refuge in relatively stable populations. |
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| Arctic fisheries, of little significance in terms of commercial harvest and economic value, constitute a significantly large, locally important contribution to rural economies and provide valuable food for Alaskan Natives. Thorsteinson and Wilson document the status of Arctic cisco (Coregonus autumnalis), broad whitefish (C. nasus), least cisco (C. sardinella), and Dolly Varden char (Salvelinus malma) in the nearshore Beaufort Sea north of Prudhoe Bay. |
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| Pacific salmon have always played a major role in the history and economy of Alaska and its commercial, sport, and subsistence fisheries. Burger and Wertheimer (this section) analyze historical and recent salmon harvest information to explore status and trends of Pacific salmon in Alaska. Total salmon harvest in Alaska was estimated at 56,000 salmon in 1878, but rose to over 21 million in 1900. After substantial population declines in the 1920's, 1960's, and 1970's, harvests in most Alaskan populations rebounded, and populations are healthy. Only populations of pink salmon (Oncorhynchus gorbuscha) in Prince William Sound and chum salmon (O. keta) in the Kuskokwim River in western Alaska are experiencing major declines and need attention. |
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| There is a long history of biological studies in Denali National Park and Preserve. Wolves, caribou, brown bears, moose (Alces alces), and Dall sheep (Ovis dalli) all live in this large ecosystem. The park provides scientists the opportunity to study the natural interactions of these species and serves as a baseline for comparison with areas where hunting occurs. Adams and Mech (this section) document the natural fluctuations expected in species inhabiting such a dynamic and variable environment. |
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| Brown bears on the Kodiak Archipelago are renowned for their large size and dense aggregations along salmon-spawning streams. Barnes et al. (this section) estimate a population of more than 2,800 bears on the archipelago. Through intensive management by Alaska and the U.S. Fish and Wildlife Service, the status of the Kodiak bear population is better now than in the early 1900's. |
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| Populations of the three marine mammals for which the Department of the Interior has management authority--polar bears (Ursus maritimus), Pacific walrus (Odobenus rosmarus divergens), and sea otters (Enhydra lutris)--are healthy. The estimated population of polar bears along Alaska's north coast and the Beaufort Sea is nearly 2,000 and probably larger compared to the early 1900's (Amstrup et al., this section). |
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| About 250 years ago, more than several hundred thousand sea otters were continuously distributed from Baja California, north and west along the Pacific Rim to Kamchatka, and south along the Kuril Islands to northern Japan. When the Russian fur harvest was halted in 1911, only a few surviving colonies, likely numbering a few hundred animals or less, remained. Now, Bodkin et al. (this section) estimate more than 100,000 sea otters living throughout about 75% of their original range, illustrating the healthy recovery of a species after protection and active management. |
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| Pacific walruses in the Bering and Chukchi seas of Alaska and Russia are an important source of meat and ivory for Native peoples of Alaska and the Chukotka Peninsula of Russia (Garner, this section). These marine mammals are also a highly visible indicator of the health of the Arctic marine ecosystem. Cooperative U.S.-Russia surveys conducted at 5-year intervals since 1975 provide estimates ranging from 246,000 walruses in 1980 to 200,000 in 1990. Even though the survey estimates have large confidence intervals, some researchers believe these surveys indicate a general decline in numbers between 1975 and 1990. |
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| The Mentasta caribou herd, a small herd that lives in and around Wrangell-St. Elias National Park and Preserve, exhibits typical population trends and management problems found in many mountain herds in central Alaska and the Yukon Territory of Canada. This herd increased from about 2,000 caribou in the early 1970's to 3,200 in the early 1980's (Jenkins, this section). From 1989 to 1993, the herd decreased to 900 caribou, about a 24% decrease per year. |
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| Klein (this section) documents the distribution and abundance of the tundra or Arctic hare (Lepus timidus) in western Alaska. The Arctic hare has long been used for food and clothing by indigenous people living in western Alaska. Arctic hares have declined in number throughout much of their range, though biologists are not sure why. |
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