Craters of the Moon National Monument was designated an IBA of National Significance by the American Bird Conservancy in 1997. The monument itself was established in 1924 and occupied approximately 54,000 acres until the year 2000. At which time, the boundaries of the monument were expanded, and a preserve was established, resulting in the Craters of the Moon National Monument and Preserve IBA that is now 754,000 acres in size. This site encompasses most of the Great Rift Volcanic Rift System. The Great Rift is the largest terrestrial volcanic rift system in the Western Hemisphere and contains the largest Holocene basalt fields in the contiguous 48 states. The park?s often harsh geologic setting has produced a surprising diversity of flora and fauna. An ongoing inventory project has identified over 900 vascular plants, 58 mammals, 10 reptiles, 3 amphibians, 212 birds, and over 2000 insect species at this site. This includes 41 animals and 3 plants listed as sensitive species by the BLM. The Great Rift is a National Natural Landmark and the IBA itself contains 4 Research Natural Areas in recognition of their undisturbed nature. The site is near or adjacent to 3 other IBAs, which together likely represent the largest complex of protected sagebrush in North America at approximately 1.3 million acres.

Ornithological Summary

This site is utilized by a wide variety of birds. More than 300 migrating and breeding raptors, including Prairie Falcons, Northern Harriers, Ferruginous Hawks, and Burrowing Owls use the area each year. Numerous cavity nesting birds, such as Mountain Bluebirds and Violet-green Swallows, use crevices and gas bubbles in the lava as nest and roost sites. Hundreds, if not thousands, of Brewer?s Sparrows nest here, along with many other breeding songbirds. Thousands of Gray-crowned Rosy-finches winter here, and large numbers of birds pass through here during migration.

Conservation Issues

On arid lands like those in and around the monument, vegetation is subject to heat, wind, salinity, drought, infertile soils, and animal pressure, as well as natural predation, illness, and disease. In addition, as public interest in the national parks increases, so does visitation, presenting managers with the challenge of maintaining a balance of protection of resources while continuing to provide for visitor enjoyment. However, the greatest threats may actually come from outside the monument boundaries. Bulldozing, agriculture, water diversion, mining, over-grazing, differential shrub removal, and the use of off-road vehicles outside of this IBA may all have an impact on the IBA itself. These activities, plus the threat of increased populations, may impact air and water quality, and help spread invasive species. For example, exotic plants are increasing in abundance and distribution. Species gaining ground include cheatgrass, knapweeds, leafy spurge, and rush skeletonweed. Cheatgrass, in particular, is widespread and has the potential to significantly alter fire regimes and stand structures. There is already concern that gaseous pollutants may be in sufficient amounts to damage vegetation within the monument. To get a handle on all these potential impacts, Craters of the Moon conducts regular monitoring of wildlife, vegetation, geology, air quality, and water quality.

In addition, in November of 2000 approximately 670,000 acres was added to the monument. This action withdrew lands from many of the habitat-altering and extractive uses common in much of the region. Additionally, an Act to Establish Craters of the Moon National Preserve brought approximately 400,000 of those acres under the full protection of the National Park System (with the legislated exemption of hunting). The majority of these acres have been recommended for wilderness designation, and the president?s recommendation have been forwarded to Congress.


Craters of the Moon is dominated by the Great Rift Volcanic system. This system is composed of a series of rift cracks and associated lava flows and cinder cones and deposits. The site contains a wide range of successional states from recently formed bedrock to well developed shrublands and dry coniferous forest. The vast majority of the area is flat to rolling terrain of the Snake River Plain. Most areas covered by Holocene lava have little or no soil. In most areas with soils, the dominant vegetation is one of several taxa of sagebrush Artemesia sp. In many areas, the lava surrounded, but did not overrun, the preexisting landforms. These areas are referred to as kipukas. There are 500 plus kipukas within the monument and preserve, ranging in size from ? acre to several square miles. Most are highly vegetated and several have stands of trees. Tree species include limber pine, Douglas-fir, aspen, Rocky Mountain juniper, and Utah juniper. Observations suggest that many o f these tree islands have heavy use by migrant birds.

Of the 750,000 plus acres, approximately half is sagebrush steppe. Approximately 250,000 acres of this habitat has been grazed in recent decades. The site is near or adjacent to 3 other IBAs. This complex of IBAs and protected lands is probably the largest complex of protected sagebrush in North America (world) and is approximately 1.3 million acres.

Craters of the Moon has a semiarid climate with hot, dry summers and cold winters. Annual precipitation averages 42.6cm, which comes mostly from snowfall in December and January. Snow first falls in November, and except for dry winters, remains on the ground until at least April. The temperature ranges widely both seasonally and diurnally. Average maximum monthly temperature range from ?1.7C to 28.7C. The prevailing winds are from the SW and are most intense in the spring.

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