The Iditarod River Lowlands is a large wetland complex within the Innoko National Wildlife Refuge, located in west central Alaska. The 3.8 million acre Innoko Refuge is a relatively flat plain dominated by numerous slow-moving silty rivers, small lakes, streams, and bogs. This region is a transition zone between interior boreal forest and the shrub-land and tundra common in western and northern Alaska. One of the primary reasons for establishment of the Innoko Refuge was protection of the vast wetland complex surrounding the confluence of the Innoko and Iditarod rivers important to waterbirds during many life stages. The unique water regime in this area, characterized by frequent flooding and slow drawdown of lakes, creates excellent habitat for breeding, molting, and migrating birds. The Iditarod River Lowlands is home to molting Greater White-fronted Geese, and breeding populations of several species identified as birds of Conservation Concern (2002) by the US Fish & Wildlife Service: including American Golden-Plover, Solitary Sandpiper, Whimbrel, and Hudsonian Godwit. Landbird species common to the area include Olive-sided Flycatcher, Blackpoll Warbler, and Rusty Blackbird. All three species are recognized to be at risk due to precipitous declines, and while the general ecology and causes for declines are not well known, these species reach some of their highest known breeding densities in riparian habitats in western Alaska.
The Iditarod River Lowlands supports on average 75% of the molting Greater White-fronted Geese (Anser albifrons frontalis) in interior Alaska, including a considerable proportion of the 'Tule' Greater White-fronted Goose (A. a. elgasi) population, a subspecies that numbers less than 8000 individuals. Tule White-fronted Geese radio-tagged during the winter are regularly relocated molting on the Iditarod River Lowlands in mid-summer. Annual breeding pair surveys indicate that approximately 185,000 ducks are found on the regions wetlands in early spring. Shorebirds that occur here include several species identified as species of conservation concern at the continental level including: American Golden Plover, Solitary Sandpiper, Whimbrel, Hudsonian Godwit, and Black Turnstone. Landbird species of conservation concern include the Short-eared Owl, Olive-sided Flycatcher, Blackpoll Warbler, and Rusty Blackbird.
Due to the regions remoteness and lack of human inhabitants, direct threats to the regions bird life are few. The major threat is large-scale ecological shifts due to climate change. A recent study of wetland drying across interior Alaska from 1950 until 2002 documented the highest wetland area loss (31%) on the Kaiyuh Flats, just 150km north of Innoko National Wildlife Refuge.
The Iditarod River Lowlands is entirely federally-owned, and managed by the US Fish & Wildlife Service as part of the Innoko National Wildlife Refuge / Designated Wilderness (National Wilderness Preservation System Act of 1964).
The Iditarod River Lowlands constitutes a large wetland complex and during flooding in early spring river channels are unidentifiable and the region resembles one huge lake. Flood waters rapidly recede, leaving valuable nutrients behind and replenishing the lakes and graminoid and shrub wetlands important to breeding and migrating birds of the region. There are three basic types of wetlands: riverine, muskeg, and drawdown. Riverine and muskeg wetlands are relatively stable, closed-basin systems, while drawdown wetlands are connected to rivers and water levels fluctuate throughout the season with changes in river flow.
National Wildlife Refuge and Designated Wilderness (under the National Wilderness Preservation System Act of 1964). The southern 1/3 of Innoko NWR (Iditarod Lowlands) was designated as Wilderness when the refuge was created in 1980 under the Alaska National Interest Lands Conservation Act (ANILCA).