Beaver dam and pond

 Showing little evidence of human habitation, the refuge reflects a transition zone between the boreal forest of Interior Alaska and tundra common in western and northern Alaska. These natural ecosystems provide the food, shelter, and water that wildlife need to survive.

Upland Habitats: birch and spruceInnoko Refuge is located in a transition zone between the forested taiga interior of Alaska and the treeless tundra of the Yukon-Kuskokwim Delta. The vegetation of the refuge is strongly influenced by fire and extensive flooding. In 1987, Bureau of Land Management fire history records indicated an average of 8.5 lightning caused fires burned an average of 45,000 acres per year on the refuge. This was one of the highest frequencies in Alaska at the time.

Evergreen, or conifer forests on the Innoko Refuge are generally dominated by both white and black spruce. Tamarack larch are present in lower elevations where soils are poorly drained. Mixed conifer/deciduous forests are dominated by white spruce, birch, aspen, and balsam poplar, and cover approximately 1.1 million acres (28%) Tamarack of the Refuge. Deciduous forests mixed with tall shrubs such as mountain alder and wild rose occupy another 375,000 acres (10%) of the refuge.

Non-forested upland habitats are a mixture of low shrub/grass (in low-lying, poorly drained soils) and willow (in areas with frequent flooding). These habitats occupy another 249,000 acres (6%) of the refuge.

Wetland Habitats:

Water is an essential element on all refuges, this is especially true for the Innoko Refuge.  Since much of the refuge is lowlands adjacent to rivers, spring flooding is often lily pads and flowerextensive. The flooding of the rivers and inundation and replenishing of wetlands encourage plant diversity. The scouring action of spring floods and ice floes allows for regeneration of willows and other wetland plants that provide nutrition for many animals throughout the year. The U.S. Fish & Wildlife Service, Division of Water Resources has been monitoring the water levels and inflow of major streams on the Innoko Refuge in an attempt to quantify the volume of water moving through this natural system.

Over half the land mass of the Innoko Refuge is wetlands. Wetland types range from small ponds that are seasonally flooded to large permanent and semi-permanent lakes; from streams that are not much more than a trickle to the Yukon River, which forms the western boundary of the refuge for over 100 miles. These wetlands are rich in the number and diversity of wildlife they support. Tens of thousands of ducks, geese, and swanssundew migrate to the nutrient rich lakes and ponds each year in search of safe breeding rearing, and molting areas. Many species of migratory birds, resident species, shorebirds and songbirds, grouse, beaver, and moose utilize these same areas.

Many of the wetlands are unique areas unto themselves. Vast areas are covered by bogs. These wetlands are thick with sphagnum moss that form floating islands and when you walk on these islands you can feel them move under your feet. The bogs are interspersed with open water, which is very acidic, and are ringed with stunted black spruce. Unique plants, such as the carnivorous sundew, inhabit the mossy islands.


fire_high_in_spruce_110x110The Innoko Refuge is a dynamic landscape shaped by fire and flood. Lightning-caused fires occur in most summers and generate a mosaic of habitat types, ideal for wildlife. In dry summers, fires may exceed several hundred thousand acres. Fires can have vastly different effects on the landscape depending upon several factors including; fuel moisture, topography, and weather. These factors can result in fires that only burn off dried grasses and leaves, to more extreme crown fires that burn large areas.  

The Innoko Refuge has three categories of fire protection:
-Full provides protection of cultural and historical sites, private property, and high value natural resource areas;
-Limited areas where fire suppression may do more damage than the positive effects of fire or the cost of suppression exceeds the benefit;
-Modified provides a higher level of protection when fire danger is high and a lower level when fire danger decreases.

Fires can have vastly different effects on the landscape depending upon several factors including fuel moisture, topography, and weather. These factors can result in fires that just burn off dried grasses and leaves to crown fires that can cover large areas. This results in a mosaic of vegetation and age classes which, in most cases, is beneficial to wildlife.

Fire in Alaska is managed by the Alaska Fire Service, an interagency organization developed to assist land management agencies in an effective and efficient manner. Alaska Fire Service manages a number of Remote Automated Weather Stations (RAWS) thoughtout Alaska, one of which is located on the Innoko Refuge. The RAWS takes hourly weather readings and records this data.

Forest Disease:

USDA Insects and Diseases report cover imgAnother major forest modifier is insects. Innoko Refuge works with the U.S.D.A. Forest Service Forest Health Laboratory to monitor outbreaks of insects on the Innoko Refuge. Two of the insects affecting the forest health are the Spruce Bark Beetle and the Larch Saw Fly.  Read the full USDA Insects and Diseases of Alaskan Forests report (2008, 9.6 mb pdf file).