ICP Detail: Great Basin

Great Basin Region 7*

There are some 1.6 million ha of waterfowl habitat in the Intermountain West - Great Basin region of the U.S. (Sanderson 1980). There are two major subregions west of the Colorado Plateau and east of the Sierra/Cascade crest: (1) Columbia Basin/Snake River Plains and (2) Great Basin (Kadlec and Smith 1989). Precipitation varies widely in this region from >130 cm/yr on the western slope to <5 cm/yr in some parts of the desert. Higher elevations are interspersed with lakes, wet meadows, and streams. Lower elevations in the Great Basin are dominated by rivers with broad, meandering floodplains that typically flow into terminal basins. Springs and/or snowmelt feed most streams. Streams and rivers featuring extensive floodplain habitats that eventually flow into the Columbia River dominate the Columbia Basin, including the Snake River.

Important wetland regions in the Columbia Basin/Snake River Plains include: the channeled scablands and potholes region in eastern Washington, Yakima River floodplain, wetlands created and enhanced by the huge Columbia Basin irrigation project, mid-Snake River region, the mid-Columbia River region on the Oregon/Washington border, and the extensive marshes and floodplains in the upper Snake River basin in eastern Idaho, including the Henry's Fork watershed.

The Great Basin subregion is made up of many unique, expansive watersheds, most of which have no drainage to the sea. Most of the watersheds in this region end in terminal basins. Wetlands in the Great Basin are generally associated with rivers, lakes, or springs, or are formed as terminal basins. Some 45 significant terminal basin lakes exist today in the Great Basin, covering about 1,012,000 ha, of which almost half is the Great Salt Lake and associated wetlands found along the Bear, Jordan and Weber Rivers. Other important wetland habitats for waterfowl in this region include: Ruby Lake and Stillwater/Carson Sink in Nevada; Malheur-Harney Lakes, Upper and Lower Chewaucan Valleys, Warner Valley, Lake Abert and Summer Lake in Oregon; and the Klamath Basin marshes and Goose Lake found along the Oregon-California border.

Water quality and quantity are the chief concerns for Intermountain West and Great Basin wetlands. Competition for water from municipal, agricultural, and industrial uses continues to alter hydrologic functions of western wetlands. Population levels in several areas of the Great Basin are growing at a rate well above the national average. Certain areas in Idaho, Utah, Nevada and eastern Washington are experiencing rapid growth. Human populations in some of these areas have doubled in the last 10 years. This growth has increased the demand for urban water in these areas, often at the expense of both agriculture and wildlife. Competition for water will become more intense as population levels continue to increase. In the Great Basin, both Owens and Winnemucca Lakes had been totally dried by water diversions prior to 1950. Bottoroff (1989) states that 85 to 90% of Klamath Basin wetlands have been lost. A review of the biological, limnological, and historical changes (primarily induced by humans) in eight of the most important saline and alkaline Great Basin lakes describes how these changes may have affected the lakes' ability to support breeding and migratory birds during the past 150 years (Jehl 1994). Based on this review, Jehl (1994) concluded that only Mono Lake, Pyramid Lake and perhaps the Great Salt Lake will likely remain largely unchanged in their ability to support current population levels of migratory birds well into the next century. Surface modifications to intercept precipitation and snowmelt runoff have resulted in the single greatest impact on Great Basin wetlands (Engilis and Reid 1997). Trans-basin water diversions will only increase degradation to Great Basin wetland complexes and aquifers.

Avian botulism is a common and long-standing disease that kills thousands of waterfowl and other waterbirds in the Great Basin annually. Botulism is most common from August through October when waters are hot, stagnant, and of low oxygen content. Consequently, the effects of botulism are most dramatic on breeding, molting, or staging birds. Livestock grazing is a common land use in the Great Basin. Livestock, particularly cattle, can cause a variety of problems for wetlands and waterfowl including degradation of water quality and nesting habitat (Ratti and Kadlec 1992). Solar evaporation operations, primarily for magnesium and potassium, on the east and south end of the Great Salt Lake and other saline basins are having an adverse impact on both hydrology and plant and animal life. The evaporation ponds interrupt the water flows and the elevated mineral levels displace organisms such as brine shrimp, which has an impact on bird use.

Other impacts to waterfowl habitat have occurred as the result of introduced species, such as the common carp introduced from Europe. Historical records from the U.S. Fish and Wildlife Service indicate that Malheur Lake produced 50,000 fledged mallards each year as recently as the 1950s. The lake was also once the most important staging area for canvasbacks in the intermountain west. A dramatic increase in carp numbers in the lake has virtually eliminated vast expanses of sago pondweed and other emergent and submergent aquatic plants. Today, only a handful of waterfowl are produced in Malheur Lake itself and canvasbacks are only seen in very small numbers during migration periods.

Importance to Waterfowl

The importance of the Great Basin and the Columbia/Snake Basin to waterfowl is perhaps best captured by Kadlec and Smith (1989:451) who state: "In contrast to the perception that the Great Basin is a "˜desert' of little value to waterfowl, the reality is that the marshes and wetlands are of higher value to waterfowl than are many areas in wetter regions. In fact, the very rarity of marshes in a dry region adds to their value." Because of limited numbers of wetland stopovers in the Great Basin, large and spectacular concentrations of migrating waterfowl often are found on suitable areas (Chattin 1964, Smith and Kadlec 1986). Prior to transbasin water diversions, both Owens and Mono Lakes held over 1 million ducks at one time in fall migration (Reid et al. 1997), and the Great Salt Lake marshes have recorded similar fall usage. Waterfowl population estimates on Mono Lake in 1948 indicated peak migrant numbers "well over a million ducks" by 1 November, principally northern shovelers and ruddy ducks. Recent estimates during the 1980s-90s indicate that no more than 15,000 ducks use the Mono Basin annually (Reid et al. 1997). The Klamath Basin has attracted greater than 5 million waterfowl during migration, and prior to water diversions and habitat degradation was considered the single most important waterfowl habitat in the U.S. (Gilmer et al. 1982). Great Basin wetlands provide important waterfowl breeding grounds, primarily for mallard, northern shoveler, cinnamon teal, gadwall, and redhead.

From 1966-90, the ten-year average for total ducks produced in the Columbia Basin alone was over 535,000 birds. Other divers with significant breeding populations include ruddy duck and canvasback. Some 18 species of waterfowl nest at Malheur, Klamath, Great Salt Lake, Carson Sink, and Ruby Lake. Many of these sites are also critical staging areas for ducks, especially northern pintail and northern shoveler. In addition to waterfowl, millions of shorebirds use these lakes during breeding and migration periods. Great Basin marshes are critical to sandhill cranes, eared grebes, white-faced ibis, American avocet, phalaropes, black-necked stilts, snowy plover, white pelican, California gull, and black tern. Wintering populations of bald eagles are some of the highest in the contiguous 48 states. The Klamath Basin winters 2,000 bald eagles while marshes on the east side of the Great Salt Lake winter 1,000 birds. Golden eagles, peregrine falcons and a host of other raptors forage in Great Basin wetlands throughout the year. These birds regularly nest on cliffs adjacent to the wetlands. The basin and range makeup of the area provides migration corridors for a host of neo-tropical species.

Few areas in the world have more spectacular concentrations of fall migrants than does the Great Basin. Estimates of migrants through the Great Basin include 2 million northern pintail and 1.5 million mallard (Kadlec and Smith 1989). Estimates of American wigeon are 0.7 million and both green-winged teal and northern shoveler are at 0.5 million. The Snake River and Columbia Basin may winter some 32,000 Canada geese and 1.1 million mallards. The entire Rocky Mountain trumpeter swan population winters in the tri-state area, south to Great Salt Lake.

Current Conservation Programs

Currently, DU is assisting a variety of cooperators in the delivery of more than 100 wetland projects in the Great Basin on both private and public lands. These projects will enhance or protect upland and wetland habitats on more than 30,000 ha. Total costs for these efforts will exceed $10 million. Included in this restoration work are several NAWCA funded projects in such widely diverse areas as the Lower Colorado River, Goose Lake Basin in Oregon, Malheur/Harney Lakes Basin, Bear Lake in Idaho, Channeled Scablands of Washington, Henry's Fork in Idaho, and the Great Salt Lake. The Malheur Lake project includes enhancing 4,050 ha of wetlands by excluding carp. The Lower Colorado River project will protect over 1,000 ha of floodplain wetlands and 175 ha of riparian forest. These habitat improvements will directly benefit waterfowl, Yuma clapper rail, willow flycatcher, and several species of indigenous fish. The Great Salt and Bear Lake projects will protect and enhance threatened wetland and upland habitat in southeastern Idaho and northern Utah. The projects will protect and enhance more than 6,400 ha of threatened wetlands and provide habitat for nesting and migrating waterfowl, as well as bald eagles, peregrine falcons, ospreys, and trumpeter swans. The projects in the Channeled Scablands of eastern Washington will restore and enhance several thousand acres of waterfowl breeding habitat. The Goose Lake project in Oregon will protect the largest remnant bulrush marsh in the Goose Lake basin, protecting the nesting habitat for over 9,000 white-faced ibis.

Goals (2005-2009)



* Region 7 - NABCI Bird Conservation Region 9 ( U.S. only - Canada Great Basin is covered in British Columbia Intermountain Region (BCR 9 and 10.)

Revised February 1, 2005 - Region 7

   General Editing and minor improvements throughout the text