The Brown/Howe Dinosaur Area ACEC is on 5,517 acres of BLM-administered land north of Shell, Wyoming. The area was designated to protect paleontological resources, mostly notably dinosaur fossils from the suborder Theropoda and Sauropoda, that have been recovered there. The tracks of flesh-eating dinosaurs have been found associated with the fossils of plant-eating dinosaurs in this area, as have soft-tissue fossils. Since the 1930s, the Brown Howe Quarries, which are on nearby private land, have produced hundreds of dinosaur bones. The fossil-bearing sediments likely continue onto portions of adjacent BLM-administered lands in the ACEC. The Big Al Quarry in the Morrison Formation, on BLM-administered land just north of the Brown Howe Quarries, was the site of the discovery of a nearly complete Allosaurus (“Big Al”) skeleton that has subsequently been the subject of several scientific studies and a recent television program. Additional quarrying is ongoing in this area for dinosaur fossils such sauropods, pterausaurs, and nonsauropod plant eaters.
The proposed expansion of the Brown/Howe Dinosaur Area ACEC flanks the existing ACEC to the southeast and the northwest and would expand the area by 15,246 acres. As with the existing ACEC, the proposed expansion area contains paleontological resources, primarily from dinosaurs and marine reptiles. This expansion area also includes vertebrate fossils and scientifically important paleobotanical, palynological (pollen), mammalian fossil, and dinosaur eggshell site resources.
Management challenges for this area include soil instability, erosion potential, and fossil occurrence that make it vulnerable to surface disturbance. At present, the BLM manages the proposed expansion area as VRM Class II, III, or IV, with approximately 15,173 acres limited to designated roads and trails and 73 acres limited to existing roads and trails for motorized vehicle use.
The Carter Mountain ACEC consists of approximately 10,867 acres of BLM-administered lands on the east slope of the Absaroka Mountains. The BLM manages the area to protect areas of alpine tundra and fragile soils, much of which remains in pristine condition. Some disturbance has occurred in the past, and this juxtaposition of disturbed and undisturbed alpine tundra allows an opportunity to study the effects of disturbance on alpine soils, vegetation, and wildlife. The ACEC also contains scenic areas and provides crucial winter range for elk and mule deer. Recreational opportunities in the ACEC include hunting opportunities pursued by local and extra local visitors.
The proposed expansion of the Carter Mountain ACEC surrounds the area of the existing ACEC and would expand the area by 5,706 acres. Like the existing ACEC, the proposed expansion is a scenic area that contains intact alpine tundra and other habitats, fragile soils, and crucial winter ranges for big game. The proposed expansion also contains important habitat for wildlife transition, parturition, and summer ranges. Elk, deer, and bighorn sheep use the area as they migrate from Yellowstone National Park and the upper reaches of the Shoshone National Forest. In addition, the proposed expansion area supports grizzly bears and grey wolves, and has potential Canada lynx habitat; all three species are current or former listed species (see Section 3.4.9 Special Status Species - Wildlife). Three perennial streams in the area support riparian habitat and a pure strain of Yellowstone cutthroat trout (a BLM sensitive species; see Section 3.4.8 Special Status Species - Fish); additional streams in the area might have suitable habitat. Portions of the expansion area contain several special status raptor species and a number of rare and special status species plants.
The Five Springs Falls ACEC consists of 163 acres of BLM-administered public lands on the west slope of the Big Horn Mountains east of Lovell, Wyoming. The BLM objective for managing the ACEC is to protect existing populations of four near-endemic rare and sensitive plant species in the Five Springs Falls area. This ACEC also contains the Five Springs Falls Campground, which attracts local and Yellowstone National Park visitors. Waterfalls in the steep rocky canyon that makes up the ACEC are public recreational and scenic attractions.
The proposed expansion of the Five Springs Falls ACEC is south and west of the existing ACEC and would expand the area by 1,646 acres. The area of the proposed expansion is dominated by outcrops of highly folded, faulted, and forested limestones and Paleozoic age dolomites. The area is unstable due to steep topography. Downslope movements of soil and rock are common, and landslide deposits and rock-fall (slump) have been documented in the area. This natural phenomenon can pose a risk to public safety. The area also has unstable soil, erosion potential, and fossil occurrence that make it vulnerable to continued surface disturbance and loss of paleontological resources. At present, the BLM manages this area as VRM Classes II and III, with motorized vehicle use limited to designated roads and trails.
The Little Mountain ACEC consists of approximately 21,475 acres of BLM-administered land on the west slope of the Big Horn Mountains northeast of Lovell, Wyoming. BLM objectives for managing the ACEC are to protect and manage important caves and cave-related paleontological resources, cultural resources, and the maintenance of scenic values. The Little Mountain ACEC contains several caves used by the public for recreational, educational, and research purposes. This ACEC provides hunting opportunities. The area also contains AML hazards due to previous uranium mining activities (refer to Section 3.8.3 Health and Safety).
The proposed expansion of the Little Mountain ACEC includes areas east and south of the existing ACEC and would expand the area by 47,569 acres. This expansion area is proposed due to identified wildlife, special status species, recreation, vegetation, and scenic values. The proposed expansion area includes big game winter, transition, and parturition ranges; migration corridors; and a bighorn sheep population (see Section 3.4.6 Wildlife). A number of BLM sensitive animal species and regionally endemic plant species can be found in the area. Potential Canada lynx habitats and greater sage-grouse brood-rearing, nesting, and winter range can also be found in this area. Desired plant communities in the proposed expansion area include a portion of the only curl-leaf mountain mahogany population in Wyoming. Recreational use (including hunting, fishing, wildlife viewing, and visitation to the nearby medicine wheel archeological site) is heavy. Scenic resources in the area include deep canyons (including Devil’s Canyon and Cottonwood Canyon) and high plateaus that contain paleontological resources.
At present, the BLM manages the area as VRM Classes II and III, with motorized vehicle use limited to designated roads and trails.
The Upper Owl Creek ACEC includes 13,057 acres of BLM-administered public lands in the upper foothills of the Absaroka Mountains surrounding the Owl Creek, Rock Creek, Klicker Creek, Slab Creek, and Vass Creek drainages. BLM management objectives for the area are to protect overlapping and important big game habitats and migration corridors, fisheries habitat, shallow soils, alpine vegetation and rare plants, cultural resources and Native American traditional values, primitive recreational opportunities, and scenic quality. The ACEC contains wildlife resources and special status species (including neotropical migrant birds, wolves, grizzly bears, moose, and wolverines), cultural resources, and primitive recreational opportunities such as hiking, camping, fishing, and horseback riding. Desired plant communities include endemic plants species growing in “moonscapes” where rocky, sparsely-vegetated soils support low-growing, cushion plant communities, and forested areas that include old-growth tree stands. This ACEC also provides hunting opportunities.
The proposed expansion of the Upper Owl Creek ACEC includes areas east and south of the existing ACEC and would expand the area by 19,720 acres. BLM management objectives and resource values for this area are similar to those in the area of the existing Upper Owl Creek ACEC. At present, the BLM manages the area as VRM Classes II and III, with 18,080 acres limited to designated roads and trails and 1,640 acres limited to existing roads and trails for motorized vehicle use.