Under Alternative A, Big Cedar Ridge area is an ACEC with management objectives designed to protect and maintain paleontological resources and provide hands-on educational experiences for visitors and groups.
Under Alternative A, restrictions on mineral development would result in adverse impacts to the use of these resources in the ACEC. The low potential for most mineral resources in the ACEC minimizes the adverse impacts of these restrictions on mineral development. Restrictions on mineral development would benefit the paleontological value of concern in the ACEC.
The ACEC is withdrawn from appropriation under the mining laws and the fossil concentration area (260 acres) is closed to mineral materials disposal. Withdrawing the ACEC would result in adverse impacts to locatable mineral development in the ACEC by prohibiting development of these minerals. However, the likelihood of adverse impacts is limited because the low potential in the ACEC for bentonite and gypsum (the only locatable minerals currently extracted in commercial quantities in the Planning Area) and sand and gravel. Withdrawing the Big Cedar Ridge ACEC would benefit paleontological resources by reducing the potential for destruction or degradation of these resources.
Alternative A manages the ACEC as open to mineral leasing with an NSO restriction and a prohibition of surface disturbance from geothermal exploration and development. Allowing mineral leasing with an NSO restriction may result in adverse impacts to mineral leasing in the ACEC by requiring directional drilling or other development techniques that may limit economically feasible recovery of these resources. NSO restrictions would benefit the values in the ACEC by reducing the potential for destruction or degradation of paleontological resources. However, the low development potential for oil and gas and the historically limited interest in such development in this area may minimize impacts to and from oil and gas development.
Managing the ACEC an ROW exclusion area, closing it to the use of heavy equipment, and limiting motorized vehicle use to existing roads and trails would result in adverse impacts to these resource uses in the ACEC. Restrictions on these resource uses would benefit paleontological resources in the ACEC by preventing direct disturbance to these resources and by limiting the potential for indirect impacts from theft and vandalism, which increases with accessibility.
Management that allows the collection of fossils and provides educational research opportunities (including working with museums), while also protecting the resource, would result in beneficial impacts by protecting and promoting the paleontological values of the area. Allowing the use of hand tools in the ACEC to collect plant fossils for research and casual use in the fossil concentration areas, and only allowing mechanized collection on a case-by-case basis pending approval, would further increase benefits to paleontological values associated with research and would limit the use of heavy equipment or other excavation methods that could destroy or degrade resources.
Site-specific surveys for cultural and historic resources for casual use collection of plant fossils are not required. Because only casual use collection and use of hand tools are allowed for collection of fossils, these activities would not be likely to result in the destruction of cultural or historic resources if they are discovered.
Providing a focus area for recreational collection would benefit recreation in the Planning Area by allowing opportunities for legal recreational collection of common fossils. Recreational collection may result in long-term adverse impacts to paleontological resources in the ACEC because these resources would be lost to scientific and educational public uses.
The management of and impacts from designating the Big Cedar Ridge ACEC under Alternative B are the same as under Alternative A.
Under Alternative C, the BLM would not manage the Big Cedar Ridge area as an ACEC, but would manage it in accordance with multiple use principles consistent with other resource objectives and standard guidelines related to surface-disturbing activities would apply.
Under Alternative C, the area is open to locatable mineral entry, open to mineral leasing (with moderate constraints on 214 acres and standard stipulations on the remainder), and open to mineral materials disposal. Management of this area under Alternative C would be the least restrictive to mineral development, and may result in the greatest adverse impact to the paleontological values of concern.
Under Alternative C, the BLM would manage the Big Cedar Ridge area primarily as an ROW avoidance/mitigation area (223 acres), and would manage the remaining area as open to ROW authorizations. ROWs are allowed under this alternative, which would result in an increased potential for damage to known paleontological resources compared to the other alternatives.
Motorized vehicle use is limited to existing roads and trails under this alternative, and impacts from travel management would be the same as under Alternative A.
Applicable laws and regulations and the management described in Section 4.5.2 Paleontological Resources control the collection of fossils under Alternative C. These decisions include protective management, such as surveying and monitoring requirements in PFYC 5 formations, but generally would provide less protection for the paleontological values of concern than the other alternatives.
The management of and impacts from designating the Big Cedar Ridge ACEC under Alternative D are the same as under Alternative A.
Under alternatives A, B, and D, the BLM would manage the Red Gulch Dinosaur Tracksite area as an ACEC (1,798 acres); the BLM would not manage the area as an ACEC under Alternative C. Paleontological resources (in the form of trace fossils of early Jurassic age) are the values of concern in the Red Gulch Dinosaur Tracksite ACEC. Threats to the values of concern in this area include surface disturbance from mineral and ROW development, and theft and vandalism.