The Bridger Sage-steppe encompasses a broad intermountain valley between the Beartooth and Prior Mountains. It sits in the rainshadow off the Beartooth Mountains and is one of the direst areas of the state. It is dominated by sagebrush shrubs-steppe, with native grasslands on upper hillsides.

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Ornithological Summary

The Carbon Triangle area encompasses significant habitat for Greater Sage-Grouse. It supports the largest concentration of sage-grouse in the south-central portion of the state and roughly 3% of the male grouse surveyed in the state. The IBA encompasses 21 lek sites (2.3% of the known leks in Montana), and at least 632 male sage-grouse, based on lek surveys. Although somewhat isolated to the east and west by the Prior and Beartooth mountain ranges, the area's sage-grouse population is contiguous with, and part of, the grouse population in northern Wyoming.

Conservation Issues

The primary threat to this area is the invasion of noxious weeds, particularly cheatgrass, that replace the native grass and forbs understory and alter fire regimes. Overgrazing is also a significant stress on the sagebrush habitat. There is an active oil field on the Montana/Wyoming border and active exploration in the area, with discussions of potential coal-bed methane development. There is potential for further energy development in the future.


Land ownership is primarily private agricultural lands, secondarily Bureau of Land Management lands, mixed with state lands.


The IBA is dominated by sagebrush shrubsteppe and grassland, mixed with small amounts of agriculture, upland forests, riparian shrubs, and riparian woodland.

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