A Comparison of the lichen floras of four locations in the Intermountain Western United States.

The Intermountain Region of the western United States has a rich and diverse lichen flora. Various research projects have examined the lichen communities of this region. This study compares the lichen floras of four Intermountain Area locations, Dinosaur National Monument, Utah and Colorado; the Gila Wilderness Area, New Mexico; the Manti La Sal National Forest, Utah; and the San Juan – Rio Grande National Forest, Colorado. A total of 392 species in 122 genera have been identified from these four general locations. The San Juan – Rio Grande National Forest has the highest number of species (313 species in 109 genera). The Dinosaur National Monument and the Manti La Sal National Forest lichen floras were dominated by crustose species; a condition typical of many Intermountain Area locations; however, the Gila Wilderness Area and San Juan – Rio Grande National Forest were dominated by foliose species. Substrate distribution patterns for all four sites indicated a preponderance of saxicolous species. In addition, a total of 69 pollution sensitive indicator species were identified from the four study areas of which 16 species were common to all 4 locations. The relatively high percentage of pollution sensitive species at all study areas generally suggests that air pollution-related impact on this area has been minimal.