Most of the refuge is bulrush and cattail marsh, with associated sedge, rush, and salt grass meadows. A small portion of the area includes part of Merkley Ridge (mountain brush habitat), which is used as deer winter range. The refuge is primarily a waterfowl production area; it is also a fall staging ground for [Sandhill] Cranes and migration stop for waterfowl. Utah Power and Light Co. owns the right to store water on the refuge. Utah Power and Light is sympathetic to wildlife needs and cooperates well with the refuge to minimize adverse and maximize beneficial effects of their water management. Efforts are underway to introduce Trumpeter Swans as a nesting species.
This site contains exceptional diversity and concentrations of waterbirds. Primarily nesting waterfowl, with dense populations of Canada Geese, Mallards, and Redheads. Also significant numbers of colonial breeders, including White-faced Ibis, Franklin's Gulls, California Gulls, Double-crested Cormorants, Caspian Terns, Black Terns, Forster's Terns, Snowy Egrets, Black-crowned Night-herons, Great Blue Herons, Western and Clark's Grebes, and Eared Grebes. Other breeding species include: Sandhill Crane, Killdeer, American Avocet, Black-necked Stilt, Willet, Spotted Sandpiper, Long-billed Curlew, Wilson's Phalarope, American Bittern, Virginia Rail, Sora, and American Coot. This site may contain the densest breeding population of American Bitterns in Idaho.
Bear Lake is a fall staging area for 300-500 Sandhill Cranes. American White Pelicans, although not breeding, are present throughout the spring and summer. Shorebirds and 10,000-20,000 waterfowl are found here during migration.
Colonies: Eared Grebe (10-12 nests), Western and Clark?sGrebe (40-50 nests), Double-crested Cormorant (50-60 nests), Great Blue Heron (15-50 nests), Black-crowned Night Heron (75-80 nests), Snowy Egret (70-80 nests), Cattle Egret (10 pairs?), White-faced Ibis (largest colony in ID; 150-3,000 pairs), California Gull (120 nests), Franklin?s Gull (4,000 nests), Forster?s Tern (30-40 pairs), Black Tern (20-30 nests), Caspian Tern (6-10 pairs)
Introduced Carp and noxious weeds are management problems. Mechanical, chemical, and biological control measures have been implemented to combat both the weeds and carp. The diversion of the entire Bear River through the refuge is adding nutrients, chemicals, and sediment to the marsh. There also is an inactive mine portal on the edge of the refuge, though the ore body (phosphate rock) is not on refuge property. The refuge manager has implemented use of diking and strategic timing of water intake to reduce this influx of nutrients and sediments into the refuge. Efforts are also being made upstream to reduce non-point nutrient and sediment input in Bear River. Utah Power and Light have water storage rights on the refuge and if they were to change their storage regimes it could affect the marsh negatively. Cooperation and negotation with this company are ongoing to minimize the negative impacts of water storage on the refuge.
Refuge is in a valley bottom and is the remnant of a large natural marsh called Dingle Swamp. The Bear River was diverted through the refuge in order to store water for irrigation use in the early 1900's. A number of dikes separate the marsh into management units. The marsh is a mix of hardstem bulrush, cattail, and open water. Wet meadows surround the marsh, which provide conditions for sedges, rushes, beardless wild rye, and salt grass. Drier areas have sagebrush, greasewood, and a few cottonwoods. Merkley Ridge has sagebrush, and serviceberry.
Bear Lake is used for environmental education, and hunting, fishing, and birding is allowed in open areas. Water that is stored on the refuge and in Bear Lake is used for generating hydroelectric power and irrigation. Permit haying on the refuge benefits both the refuge and local ranchers.