Important Bird Areas

Upper Tanana River Valley

Alaska

The Upper Tanana River Valley lies north of the Alaska Range and extends from the Alaska-Canada border west to the Delta River. The site encompasses the flats and lowlands of the Tanana River and the region generally referred to as the Upper Tanana Valley. The site also contains a portion of the Yukon-Tanana Upland to the north. Two glacial rivers, the Nabesna and Chisana flow from the Wrangell Mountains and join to form the Tanana River. Several other glacial rivers and streams feed the Tanana as it flows west through the valley.

The southern boundary of this site is designed to capture the known Trumpeter Swan nesting habitat, while the northern boundary is the known extent of the Sandhill Crane migration corridor.

Ornithological Summary

The Uppert Tanana Valley is widely known as an important migration corridor for birds that travel to and from Alaska and western Siberia to breed each year. Hundreds of thousands of migratory brds including swans, geese, ducks, cranes, and raptors pass through the valley each spring and fall. More than 3/4 of the entire mid-continental population of Lesser Sandhill Cranes pass through the proposed site annually in addition to thousands of swans. An accurate estimate of swans by species is difficult because migrating flocks of white swans (Trumpeter and Tundra) are difficult to identify to species. The site also encompasses important breeding and post-breeding habitat for Trumpeter Swans, a species on the Alaska WatchList. Recent state-wide late-summer surveys located nearly 10% of the Trumpeter Swan population within the proposed site.

Conservation Issues

Threats to this area include increasing pressures from urbanization and commercial development, the establishment of communication towers (e.g. 700 ft. Loran Station towers) and wind turbines, natural events that may be related to climate change, such as late spring flooding and wetland drying, and increased hunting. Future threats include the potential impacts associated with construction of a proposed natural gas pipeline that would run through the center of the site, such as an increase in contaminants.

Ownership

The vast majority (>75 %) of the land in this site is owned by the State of Alaska or managed by various federal land management agencies. Native tribes and corporations own nearly 19 %, and the remainder is owned by municipalities, ommercial interests (which are primarily agricultural), and private landowners.

Habitat

Vegetation communities range from closed black spruce forests to alpine tundra and shrublands. Most of the area is interspersed with wetlands, ponds, and muskeg. Conifer forests are the predominant feature with black spruce common in low-relief wet terrain. White spruce, somtimes growing with paper birch and aspen, can be found on warmer, better drained areas and are often found in river corridors. Paper birch, willow, and aspen may dominate in areas that have recently burned, especially on southern exposures.

Willow, arctic dwarf birch, lowbush cranberry, cottongrass, and Labrador tea are common throughout the area. Feathermoss covers the ground in well-drained forest. Poorly-drained wetlands consist primarily of tussocks of cottongrass and sedges. A portion of the site near Delta Junction has been developed for agricultural use, primarily barley and hay production.

Land Use

Land use designations generally follow land ownership patterns, but are confounded because most lands in the area have multiple uses. Because vast areas of the site are undeveloped and in a relatively natural state, most land use focuses on land conservation and the subsistence needs of rural residents e.g. hunting. Most commercial activity and development is found in the Alaska Highway corridor that runs through the center of the area.

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