The proposed Chapman Bench ACEC (23,326 acres) is north of Heart Mountain National Landmark and east of Highway 120 in an area of predominantly BLM-administered land. The area contains sagebrush habitat used by sensitive bird species and other wildlife.
The proposed ACEC is an Audubon Society-designated important bird area, and the area contains a diverse and abundant bird population. The Chapman Bench area supports at least 12 sensitive species. Greater sage-grouse, long-billed curlew, and mountain plover occur in this sagebrush steppe; all three are BLM sensitive species, and the mountain plover is a proposed threatened species under the ESA. Sagebrush-obligate species in the area also include the sage thrasher, sage sparrow, Brewer’s sparrow, and loggerhead shrike. This area provides nesting habitat for one of the highest concentrations of these species together in the Bighorn Basin. In addition, this area provides pronghorn and mule deer crucial winter range. Visitors travel the area, which provides views of the Absaroka Mountain foothills, on their way to Yellowstone National Park.
At present, the BLM manages this area as VRM Classes II, III, and IV, and motorized vehicle use is limited to existing roads and trails. There has been little development in the proposed ACEC to date.
The proposed Clarks Fork Basin/Polecat Bench West Paleontological Area ACEC (23,895 acres) is west of Powell, Wyoming, in Park County, in the northwestern corner of the Planning Area. The ACEC is proposed to protect the area’s stratigraphic contact zone and the paleontological and geochemical values associated with these rock layers, which are exposed in only a few areas worldwide. The area contains mammalian and botanical fossil resources and its geologic information relates to global warming and paleoclimate change. This stratigraphic boundary represents a transition from the Paleocene Epoch to the Eocene Epoch, and produces fossils and geochemical data used in the study of a major Carbon Isotope Excursion recorded during a period of global warming (the Paleocene-Eocene Thermal Maximum). The area also contains scenic and colorful badlands and eroded features.
Management challenges for this area include soil instability, erosion potential, and fossil occurrence that make it vulnerable to surface disturbance and the loss of its identified resource values. At present, the BLM manages this area as VRM Classes III and IV, with motorized vehicle use limited to existing roads and trails.
The proposed Clarks Fork Canyon ACEC (12,259 acres or 2,724 acres depending on the management alternative) is in the far northwestern portion of the Planning Area. The ACEC is proposed to protect the area’s geologic, wildlife and special status species habitat, open space, and recreational resources and uses. The geology of the Clarks Fork Canyon, the Canyon Mouth Anticline, and glacial features in the area are of scientific and educational value. The area contains crucial winter range for mule deer, elk, and moose, one of only two ranges for mountain goats in the state, and one of the largest bighorn sheep ranges in the country. The area provides habitat for several species of raptors and contains caves with bat hibernacula and roost sites. Special status species in the proposed ACEC include plant species (such as Shoshonea and Ute ladies’-tresses), habitat for BLM sensitive wildlife species (such as greater sage-grouse, mountain plover [also a candidate for listing under the ESA], long-billed curlew, sage thrasher, Brewer’s sparrow, Baird’s sparrow, and loggerhead shrike), and BLM sensitive Yellowstone cutthroat trout. The Clarks Fork area provides opportunities for recreation on large unbroken tracts of public land, including a segment of the Clarks Fork of the Yellowstone River WSR eligible waterway.
At present, the BLM manages this area as VRM Class II, and motorized vehicle use is limited to existing roads and trails with seasonal management restrictions.
The proposed Foster Gulch Paleontological ACEC (27,302 acres) is 10 miles south of Lovell, Wyoming, in Big Horn County. The ACEC is proposed to protect the area’s stratigraphic contact zone and the paleontological and geochemical values associated with these rock layers, which are exposed in only a few areas worldwide. The area contains mammalian and botanical fossil resources, and its geologic information relates to global warming and paleoclimate change. This stratigraphic boundary represents a transition from the Paleocene Epoch to the Eocene Epoch (the Fort Union/Willwood formations) and produces fossils and geochemical data used in the study of a major Carbon Isotope Excursion recorded during a period of global warming (the Paleocene-Eocene Thermal Maximum). The area also contains scenic and colorful badlands and eroded features.
Management challenges for this area include soil instability, erosion potential, and fossil occurrence that make it vulnerable to surface disturbance and the loss of its identified resource values. At present, the BLM manages the area as VRM Class IV, with motorized vehicle use limited to existing roads and trails.
The proposed McCullough Peaks Paleontological Area ACEC (6,994 acres) is adjacent to the McCullough Peaks WSA (which forms the proposed ACEC’s northeastern boundary), east of Cody, Wyoming, in Park County. The ACEC is proposed to protect the area’s stratigraphic contact zone and the paleontological and geochemical values associated with these rock layers, which are exposed in only a few areas worldwide. The area contains mammalian and botanical fossil resources and its geologic information relates to global warming and paleoclimate change. This stratigraphic boundary represents a transition from the Paleocene Epoch to the Eocene Epoch (the Fort Union/Willwood formations) and produces fossils and geochemical data used in the study of a major Carbon Isotope Excursion recorded during a period of global warming (the Paleocene-Eocene Thermal Maximum). The area also contains scenic and colorful badlands and eroded features.
Management challenges for this area include soil instability, erosion potential, and fossil occurrence that make it vulnerable to surface disturbance and the loss of its identified resource values. At present, the BLM manages the area as VRM Classes II and III, with motorized vehicle use limited to designated roads and trails.
The proposed Rainbow Canyon ACEC (1,443 acres) is at the foot of the western Big Horn Mountains in Big Horn County, near the northeastern corner of the Planning Area. The proposed ACEC contains scenic and geologic resources, and paleontological resources that include dinosaurian and paleobotanical fossils. The area is dominated by outcrops of the Cretaceous Cloverly Formation, which is known for early Cretaceous dinosaur fossils. These important scientific resources are found throughout large portions of the area. The geology of the area is weathered and eroded, creating a colorful landscape.
Management challenges for this area include soil instability, erosion potential, and fossil occurrence that make it vulnerable to surface disturbance and the loss of its identified resource values. At present, the BLM manages this area as VRM Class III, with motorized vehicle use limited to designated roads and trails.
The proposed Rattlesnake Mountain ACEC (19,119 acres) is approximately 5 miles northwest of Cody and immediately north of the Buffalo Bill Reservoir. The area is proposed to protect wildlife habitat and desired plant communities, including special status plant species. The proposed ACEC contains winter, transition, and parturition ranges for elk, mule deer, and moose. The winter ranges in this area are the eastern-most terminuses of some of the longest intact migration routes in the lower 48 states. The area also contains grizzly bear and gray wolf habitat, and potential Canada lynx habitat. Bird habitat in the area includes greater sage-grouse brood-rearing and migratory bird nesting areas. The North Fork of the Shoshone River provides cold water fisheries habitat. The area is used for hunting and other recreational activities. Important vegetation types and sensitive plant species in the area include mixed conifer and aspen stands and riparian willow, sagebrush, and mountain shrub communities. The unusual aspect of the vegetation habitat in this area is the volcanic, Precambrian, and limestone soils (associated with the Laramide Orogeny), which provide habitat for rare and BLM sensitive plant species.
At present, the BLM manages the area as VRM Class II. This area includes 18,662 acres limited to designated roads and trails and 457 acres limited to existing roads and trails for motorized vehicle use.
The proposed Sheep Mountain ACEC (25,153 acres or 14,201 acres depending on the management alternative) is immediately west of Buffalo Bill Reservoir in the northwestern quadrant of the Planning Area. The area is proposed to protect important wildlife habitat and desired plant communities. The area contains big game winter, transition, and parturition ranges, and migration corridors that link USFS land and Yellowstone National Park with available habitat for wintering and raising young. The area also contains grizzly bear and gray wolf habitat, potential Canada lynx habitat, and greater sage-grouse brood-rearing and migratory bird nesting habitat. Drainages in the area provide cold water fisheries habitat. The area is used for hunting and other recreational activities and contains visual alignments associated with the equinox and solstice.
Important vegetation types and sensitive plant species in the area include mixed conifer and aspen stands, riparian willow, sagebrush, and mountain shrub communities. The unusual aspect of the vegetation habitat in this area is the volcanic and limestone soils (associated with the Heart Mountain Detachment), which provide habitat for rare and BLM sensitive plant species.
At present, the BLM manages this area as VRM Class II. The area contains 22,926 acres limited to designated roads and trails and 2,227 acres limited to existing roads and trails for motorized vehicle use.