Alternative A does not designate the area as an ACEC; the BLM manages the area in accordance with multiple use principles consistent with other resource objectives.
The area would be open to locatable mineral entry, open to mineral leasing (with primarily major constraints on 13,791 acres and moderate constraints on 4,528 acres), and open to mineral materials disposal. Mineral development would be most likely on the small areas with high-potential for gypsum (291 acres) and sand and gravel (928 acres); the potential for bentonite is low and the development potential for oil and gas is very low. Surface disturbance from mineral development is one of the threats and allowing this type of development, with minimal restrictions, would result in surface disturbance and increased potential for invasive species infestations. This type of development also would result in adverse impacts to special status species and wildlife winter and transition habitat due to increased fragmentation and increased potential for disturbance of wildlife during sensitive times of the year when these habitats are in use.
The Rattlesnake Mountain area is managed as open to ROW authorizations (9,179 acres) and as an ROW avoidance/mitigation area (9,940 acres). Areas open to ROW authorizations would be more likely to experience surface disturbance, an identified threat to the values of concern, and adverse impacts similar to those from mineral development. Areas with fewer restrictions would benefit ROW authorizations by increasing the potential for development in these areas. Interest in ROW authorizations in the form of wind-energy development are of concern in this area. Development of wind energy would result in adverse impacts to the values of concern due to large wind turbines, construction activities, and required infrastructure (e.g., roads, transmission lines, facilities).
Alternative A limits motorized vehicle use primarily to designated roads and trails (18,662 acres), with a much smaller area limited to existing roads and trails (457 acres). Managing the area as primarily limited to designated roads and trails would reduce fragmentation of habitat and reduce stress on wildlife during sensitive times of the year.
Standard guidelines related to surface disturbance would apply in the area. Although these standard guidelines may reduce the severity of impacts to the values of concern from surface disturbance, adverse impacts still would be likely if surface-disturbing activities are authorized.
Management for the Rattlesnake Mountain ACEC under Alternative B reduces adverse impacts to the values of concern in the area by prohibiting surface-disturbing activities. Surface disturbance prohibitions would result in beneficial impacts to special status species and wildlife winter and transition habitat because it would reduce fragmentation, the potential for invasive species infestation, and the disturbance of wildlife during sensitive times of the year when these habitats are in use. This management is more restrictive to surface-disturbing activities in the Rattlesnake Mountain area compared to the other alternatives.
Withdrawing the Rattlesnake Mountain ACEC from appropriation under the mining laws, managing the area as administratively unavailable to mineral leasing, and closing the area to mineral materials disposal and geophysical exploration would result in more adverse impacts to mineral development than Alternative A. Conversely, restricting mineral development would result in greater beneficial impacts to the values of concern than Alternative A. However, the low potential for most mineral resources in the area may minimize these impacts.
Alternative B is more restrictive than Alternative A regarding ROWs and motorized vehicle use. The Rattlesnake Mountain ACEC is an ROW exclusion area, a renewable energy exclusion area, and seasonally closed to motorized and mechanized vehicle use on part and limited to designated roads and trails on the remainder. Under Alternative B, more restrictive ROW and travel management would result in greater adverse impacts to ROW and wind-energy development in this area, and would adversely affect the ability of the public to access the area compared to Alternative A by limiting the times of year and routes available for travel. Conversely, limiting travel seasonally would allow additional protection for wildlife during sensitive times of the year, and beneficial impacts to these values of concern would be greater under Alternative B than Alternative A.
Allowing and seasonally stipulating vegetative/silviculture treatments, invasive/nonnative pest species control, fuels management, and maintenance of existing facilities in the Rattlesnake Mountain ACEC would protect wildlife and special status species during sensitive times of the year, while still allowing maintenance and treatments to occur.
Alternative C does not designate the area as an ACEC; the BLM manages the area in accordance with multiple use principles consistent with other resource objectives. Standard guidelines related to surface disturbance would apply, with impacts similar to those under Alternative A.
Management of and impacts associated with mineral development under Alternative C would be similar to Alternative A. The area is open to mineral leasing (with primarily moderate constraints on 18,439 acres).
The Rattlesnake Mountain area is managed as open to ROW authorizations (18,824 acres), with a smaller portion managed as an ROW avoidance/mitigation area (294 acres). The area open to ROW authorizations would greater than under Alternative A, and the extent of adverse impacts to the values of concern described under Alternative A would be greater than under Alternative C. This alternative would be the most beneficial to ROW and wind developments of any alternative by managing the area with the least restrictions on ROW and renewable energy development.
Motorized vehicle use is managed primarily as limited with seasonal stipulations (13,709 acres), with a smaller area limited to designated roads and trails (5,409 acres). Impacts to and from travel would be similar to those described under Alternative B.
Alternative D does not designate the area as an ACEC; the BLM manages the area in accordance with multiple use principles consistent with other resource objectives. Standard guidelines related to surface disturbance would still apply, with similar impacts as Alternative A.
Management of and impacts associated with mineral development under Alternative D would be similar to Alternative C. The area is available for locatable mineral entry, open to mineral leasing (with moderate constraints), and open to mineral materials disposal.
The Rattlesnake Mountain area is managed as an ROW avoidance/mitigation area. Management of ROW authorizations would be less restrictive (and more beneficial to the values of concern) than under Alternative B, and more restrictive (and less beneficial to the values of concern) than under alternatives A and C.
Alternative D limits motorized vehicle use to designated roads and trails, and impacts would be the same as under Alterative A.
Alternatives B (25,153 acres) and D (14,201 acres) would designate the Sheep Mountain area as an ACEC; alternatives A and C would not. The values of concern in the proposed Sheep Mountain ACEC are varied vegetation communities, sensitive plants, and big game wildlife habitat.