All alternatives could result in proliferation of noxious and invasive weeds into areas considered weed-free, and there may be an increase in noxious and invasive weeds where they already exist. In general, surface-disturbing activities (e.g., mineral development, road construction) would adversely impact invasive species and pest management under all alternatives. Reclamation of these areas reduces the chance of invasive species establishment. Vegetation treatments would beneficially impact the management of invasive species under all alternatives. Treatments may cause short-term impacts to vegetation by decreasing vegetation production and increasing establishment of early successional species. Long-term impacts could include increased production and diversity of vegetation communities, thereby controlling the spread of invasive species.
ROW authorizations would contribute to the spread of invasive species under all alternatives. The road network is a major conduit for the initial spread of invasive species, although the availability to access areas also results in the opportunity to find and treat new infestations. ROWs concentrated in a corridor tend to localize or confine disturbance to a smaller area and reduce disturbance in areas identified as sensitive, which would minimize potential impacts from invasive species spread.
Indirect, adverse, short- and long-term impacts from transportation of materials, people, and vehicles occur throughout the Planning Area at recreation sites, trailheads, trails, and transportation routes. Invasive species are established in some of these areas and their seeds are spread to other areas by vehicles, people, livestock, and wildlife. Due to the permanent nature of most recreation sites, trails, and transportation routes, most associated adverse impacts under all alternatives are anticipated to be long-term.
Fire and fuels management is likely to impact invasive species and pest management. By destroying or damaging invasive plants and seeds, beneficial impacts can be realized based on the timing and location of fire. Conversely, adverse impacts from suppression activities that disturb soil and from fires that remove native vegetation and expose soil result in conditions that provide a seedbed for weed establishment, such as cheatgrass. Most weeds can out-compete native species and typically respond rapidly after fire. The likelihood of weed expansion after a wildland fire increases in areas where weeds occur or are nearby. Firefighters and their equipment may also introduce or spread weeds. Impacts of fire management are not just limited to terrestrial invasive species; the use of water for fire suppression and rehabilitation activities can also contribute to the spread of aquatic invasive species, which are anticipated to become a greater management challenge in the Planning Area. Under all alternatives, fire-fighting equipment must be cleaned in areas with high-risk aquatic invasive species to prevent the spread of these species. The adverse impacts from fire management may be direct or indirect because the impact(s) may or may not occur immediately.
Because all alternatives would be managed according to the Standards for Healthy Rangelands and Guidelines for Livestock Grazing Management for the Public Lands Administered by the BLM in the State of Wyoming (Appendix N), the types of adverse impacts from livestock grazing and wild horse use to vegetation and soil are expected to be similar among alternatives. The number and distribution of native ungulates and current allowable management levels of wild horses also are anticipated to be similar among alternatives, because the number of AUMs does not change by alternative. The impacts of livestock, wild horse, and native ungulate grazing on the management of invasive species from all alternatives are anticipated to result in a mix of beneficial and adverse impacts.
Livestock and wild horse grazing, depending on its timing and intensity, can cause variable impacts to invasive species. Short- and long-term adverse impacts associated with livestock, wild horse, and native ungulate grazing are anticipated primarily where these species concentrate (e.g., water sources, trails, favored forage) and include transport of weed seeds and disturbance of soil, creating environments for the spread of invasive species. As the vegetation of riparian/wetland areas is fragile and these areas are vulnerable to wildlife, wild horse, and livestock concentrations, so too are they vulnerable to the spread of invasive species. High densities of native ungulates can reduce or eliminate shrub seed production and impair recruitment of young shrubs (Kay 1995). In addition, as vegetation stubble height is reduced, there can be a shift in cattle preference and damage to vegetation (Hall and Bryant 1995). These impacts would be expected to result in adverse impacts by increasing the establishment of invasive species.
Livestock grazing management in accordance with guidelines associated with the Standards for Healthy Rangelands and Guidelines for Livestock Grazing Management for the Public Lands Administered by the BLM in the State of Wyoming (Appendix N) may result in beneficial impacts by improving rangeland health and decreasing the potential for the spread and establishment of invasive species. Studies have shown that proper livestock grazing management can increase a plant community’s resistance to cheatgrass invasion after a disturbance such as wildland fire and effectively control other invasive species (Hall and Bryant 1995, Stohlgren et al. 1999, Davies et al. 2009). In addition, livestock grazing in sagebrush communities can increase plant species richness and diversity (Manier and Hobbs 2007), decreasing vulnerability to invasive species spread. The impacts described by these studies are expected to remain site-specific in the Planning Area under all alternatives.
Proactive management actions common to all alternatives that may control the spread of invasive species include watershed stabilization, the use of certified noxious weed-free vegetation products, developing and maintaining an invasive species and pest management plan, and subjecting surface-disturbing activities to the Wyoming BLM Mitigation Guidelines for Surface-Disturbing and Disruptive Activities (Appendix H) and the BLM Reclamation Policy (BLM 2009l). The BLM also continues to collaborate with cooperating agencies and interested stakeholders in educating public lands users about the control of invasive species, funding development and implementation of integrated pest management, and reducing and preventing the expansion of cheatgrass. Other management actions common to all alternatives can adversely impact the control of invasive species, such as restricting aerial pesticide application when its use conflicts with other resource management objectives.
The surface disturbance projected for Alternative A would contribute to the spread of invasive species, in both the short and long term. Short-term impacts would occur during the 5 years following disturbance while the soil is bare of vegetation and reclamation activities strive to stabilize the soil and revegetate the area. Long-term impacts would last longer than 5 years due to reclamation efforts not completely effective in preventing weed establishment.
Surface-disturbing activities from all actions listed in Appendix T provide opportunities for the establishment and spread of invasive species. It is anticipated that BLM actions under Alternative A would impact 136,415 acres over the short term and 15,710 acres over the long term in the Planning Area (Table 4-1). The impacts from invasive species spread due to surface disturbance under Alternative A are anticipated to be proportional with the intensity of reasonable foreseeable actions shown in Appendix T.
Under Alternative A, the BLM determines the rate of erosion and the degree of soil stability during rangeland health evaluations. The BLM requires the reestablishment of vegetative cover in disturbed areas within 5 years of initial seeding and routine seeding on a priority basis in disturbed areas, but does not require reclamation plans. Based on reclamation measures, Alternative A would have the highest opportunity for the spread of invasive species in disturbed areas. Under Alternative A, activities to control invasive species would disturb the surface of approximately 2,000 acres (Appendix T) that would be reclaimed in the long term. Surface disturbance to control weeds is likely to occur in areas already infested, and therefore is not likely to contribute to the spread of invasive species.
Under Alternative A, mineral development would result in 25,390 acres of short-term and 12,969 acres of long-term surface disturbance (Appendix T). Most of the Planning Area would remain open to mineral extraction. Most of the impacts would be temporary during the life of the operation with most areas of disturbance reclaimed following closure of operations. Typically, a large portion of a mineral material site is disturbed leaving the area prone to the spread of invasive species.
Forest and woodland treatments and forest products would result in 30,000 acres of short-term surface disturbance under Alternative A, but that same acreage would be reclaimed (Appendix T). Alternative A allows for clear-cutting, which may cause adverse impacts by generating changes to the microclimate and destabilizing soil, thus facilitating the spread of weeds where seed sources are present. Harvesting timber on commercial forestland in a manner to protect watershed and riparian/wetland habitat values would minimize potential impacts from invasive species, which are more likely to spread to degraded habitats. Alternative A allows salvage of dead stands on a case-by-case basis but does not use the full range of silviculture treatments to manage endemic insect and disease outbreaks.
Utility corridors and linear ROWs in the Planning Area, including pipelines and powerlines, would result in 3,287 acres of short-term disturbance; however, impacts associated with these activities would be reclaimed and mitigated to the extent practicable through standard operating procedures, resulting in minimal long-term disturbance (Appendix T). Motorized vehicle use to maintain these corridors has the potential to cause adverse impacts by contributing to the spread of weeds. The road network is a major conduit for the initial spread of invasive species, although the availability to access areas also results in the opportunity to find and treat new infestations. Alternative A results in 1,966 acres of short-term and 983 acres of long-term surface disturbance from road construction. The risk of adverse impacts due to the spread of invasive species is expected to increase proportionally with the long-term surface disturbance from new road construction.
Under Alternative A, the creation of new roads and trails for recreational purposes would result in 1,233 acres of short-term and 835 acres of long-term surface disturbance. Adverse impacts would result from the spread of invasive species into potentially undisturbed areas in the Planning Area, and may be correlated with the amount of surface disturbance (Appendix T). Alternative A closes 59,192 acres to motorized vehicle use, resulting in beneficial impacts by slowing the potential spread of invasive species transported by motor vehicles. Restricting motorized vehicle use (e.g., limiting motorized vehicle use to designated roads and trails in areas with fragile soils) would reduce the threat of invasive species establishment and spread.
The degree of recreational site development under Alternative A may result in adverse and beneficial impacts. The BLM projects recreational site development to result in approximately 350 acres of long-term surface disturbance, which may leave these areas more vulnerable to invasive species spread. However, when recreational developments confine dispersed recreation to areas with higher use (e.g., vehicle barriers), beneficial impacts may result by reducing surface disturbance and the potential for introduction of invasive species to undisturbed areas. In addition, detection and treatment of new noxious weed infestations are more likely at centrally developed locations than over larger areas with more dispersed recreational activity. At developed sites, educational and prevention materials can be displayed and interpreted to the public resulting in the potential for lower risk of new infestations over time. However, when developments are likely to generate more visitors (e.g., trail or access route improvements) then they are likely to cause adverse impacts, as recreationists spread the seeds and material of weeds. In general, recreation management actions under Alternative A call for more development, if demand warrants, of facilities to augment and enhance visitor use and enjoyment including fire rings, sanitary facilities, parking areas, road improvements and vehicle barriers, the impacts of which are likely to be site specific.
Alternative A prohibits the placement of salt, mineral, or forage supplements within ¼ mile of water, wetlands, riparian, or other areas with sensitive vegetation, such as reclaimed or reforested areas. This restriction would provide beneficial impacts by preventing livestock and native ungulate concentration, therefore reducing the potential to spread invasive species in these areas.
Under Alternative A, the BLM evaluates “I” category livestock grazing allotments and AMPs to determine if they are meeting the Wyoming Standards for Healthy Rangelands, resulting in the least amount of monitoring among the alternatives. Based on the lack of a required 72-hour holding period for livestock (see ‘Proactive Management’ below) and less monitoring of grazing allotments, livestock grazing under Alternative A is anticipated to have short- and long-term adverse impacts.
In general, special designations under Alternative A (ACECs and WSAs) place restrictions on surface-disturbing activities (e.g., mineral development, ROW development, and fire suppression) that may facilitate the spread of weeds. These restrictions would result in beneficial impacts to the management of invasive species. Current management designates nine ACECs under Alternative A.
Resource management actions would result in adverse and beneficial impacts to invasive species and pest management. Managing to maintain or enhance native vegetation would result in indirect beneficial impacts by controlling the spread of weeds. Other resource programs may also result in adverse impacts to managing invasive species, primarily by limiting their control (e.g., restricting the application of pesticides) to avoid conflicts with other resource management objectives.
Management actions specific to Alternative A allow the aerial application of pesticides on a case-by-case basis, the most efficient means of controlling invasive species at the landscape scale, thereby beneficially affecting invasive species and pest management.
Alternative A utilizes fire to restore fire adapted ecosystems and reduce hazardous fuels. Vegetation response following planned ignitions and mechanical and chemical treatment varies depending on a set of factors such as fire conditions, timing, and pre- and post-treatment weather conditions. Impacts to the spread of invasive species from fire and fuels management under Alternative A are likely to be site and species specific. No specific management actions that address the use of fire to control weed species exist under Alternative A. Based on projected surface disturbance (Appendix T), fire and fuels management under Alternative A may result in adverse impacts in areas where fire facilitates the spread of invasive species, such as cheatgrass, and beneficial impacts where it restores native fire-adapted vegetation.
Under Alternative A, vegetation management involves implementing DPC objectives for watershed protection, forestland management, and livestock grazing on 600,000 acres. Widespread vegetation management may result in beneficial impacts by controlling and monitoring the spread of invasive species in these managed areas. Vegetation not meeting DPC has the highest risk of having lost or losing key ecosystem components that make these areas more vulnerable to invasive species establishment. Managing riparian/wetland areas toward achieving PFC would result in beneficial impacts by controlling the spread of invasive species in these areas.
Proactive management actions specific to the invasive species and pest management program would focus on aerial pesticide restrictions and livestock flushing. Allowing the aerial application of pesticides on a case-by-case basis would result in the greatest beneficial impact to the management of invasive species by placing the fewest restrictions on aerial pesticide application.
The transport of invasive species seeds and material by livestock and native ungulates occurs when they attach to the animals’ coats and feet or are ingested. One method to control the spread of invasive species ingested by livestock is to hold the animals in one area before they are allowed to move to other areas. A holding period of 72 hours allows the animals to flush the ingested weed material from their systems so they would not transport the ingested material to uninfested areas. Alternative A requires livestock flushing on a case-by-case basis, but does not require a holding period before moving livestock onto or within public lands. Proactive management actions under Alternative A are expected to help control the spread of invasive species.
The projected long-term disturbance acreage for Alternative B is approximately 30 percent less than Alternative A, 74 percent less than Alternative C, and 41 percent less than Alternative D. Compared to the other alternatives, Alternative B has the strictest requirements (e.g., 50 percent pre-disturbance of vegetative cover within three growing seasons, 80 percent cover within 5 years of initial seeding, topsoil salvage, and development of a reclamation plan before surface disturbance) regarding the reclamation of disturbed areas. These measures would result in beneficial impacts decreasing the likelihood of invasive species establishment and spread. Although the extent of treatments for invasive species and pests would be less under this alternative—indicated by the projected surface disturbance from invasive species and pest management (Appendix T)—the less overall surface disturbance and proactive reclamation requirements under Alternative B may result in the least adverse impact due to the least potential for the spread of invasive species.
Under Alternative B, mineral development would result in 17,327 acres of short-term surface disturbance and 6,217 acres of long-term surface disturbance, likely having the least adverse impact to invasive species management, compared to the other alternatives (Appendix T). The types of impacts from mineral development under Alternative B would be similar to those under Alternative A.
Forest and woodland treatments and recovery of forest products are projected to result in 20,000 acres of short-term surface disturbance under Alternative B (Appendix T); however, all of this acreage would be reclaimed. Alternative B prohibits clear-cutting, which is likely to result in beneficial impacts by maintaining microclimatic and soil conditions so there is less opportunity for the establishment of invasive species. Timber harvest is only allowed in areas where natural processes are unable to accomplish forest health goals, likely resulting in less use of motorized machinery that can disturb soils and carry invasive species seeds. Under Alternative B, these practices would have the most beneficial impact by slowing the spread of invasive plant species, compared to the other alternatives. However, managing endemic insect and disease outbreaks only as necessary for human health and safety and prohibiting precommercial thinning would adversely affect pest management by limiting bark beetle control efforts.
Utility corridors and linear ROWs in the Planning Area, including pipelines and powerlines, would involve 2,425 acres of short-term and 1 acre of long-term surface disturbance (Appendix T), which would result in impacts similar to Alternative A, but to a lesser degree. Alternative B would involve 1,229 acres of short-term and 614 acres of long-term surface disturbance due to road construction, the least of all alternatives. The risk of adverse impacts from the spread of invasive species is expected to increase proportionally with long-term surface disturbance from new road construction.
Under Alternative B, the creation of new roads and trails for recreational purposes would result in 2,776 acres of short-term and 1,068 acres of long-term surface disturbance, the second least of the alternatives (Appendix T). The resulting impact would be the potential spread of invasive species into new areas where disturbance occurs. Alternative B closes the largest area to motorized vehicle use and limits motorized vehicle use to designated roads and trails in the largest area, compared to the other alternatives. Restricting motorized vehicle access would reduce the area to which vehicles may spread invasive species; however, restricting vehicle access would also make detection and subsequent treatment of new or expanding weed areas more difficult. Prohibiting off-road motorized vehicle use for big game retrieval and dispersed campsite access in areas with limited travel designations would result in beneficial impacts by controlling the spread of invasive species from motorized travel the most, compared to the other alternatives. For known weed infestations selected for treatment, the BLM may authorize motorized vehicle use for performing treatment activities, where appropriate. Adverse impacts from motorized vehicle use would be the least under Alternative B.
In areas developed for recreational use outside of SRMAs, further development to enhance recreation and visitor services would generally be the least extensive under Alternative B. However, recreational development in SRMAs and RMZs would be greatest under Alternative B. Developments would include new trails and trailheads, access route improvements, and new motorized touring loops that may increase public access and the potential for invasive species spread but may also consolidate recreational activity to facilitate potential detection and treatment. Due to more intensive management of SRMAs and RMZs to maintain the desired recreation setting and, therefore, the more active control of invasive species, recreational use under Alternative B would result in fewer adverse impacts to invasive species and pest management than under Alternative A.
Alternative B prohibits the placement of salt, mineral, or forage supplements within ½ mile of water, wetlands, riparian, or other areas with sensitive vegetation such as reclaimed or reforested areas. This alternative provides the largest buffer and would, therefore, provide the greatest beneficial impacts by controlling the spread of invasive species by livestock and native ungulates in these vulnerable areas.
Under Alternative B, the BLM closes large areas—including crucial winter range for elk and greater sage-grouse Key Habitat Areas—to livestock grazing, allowing existing uses pending site-specific analysis. Closing areas to livestock grazing would limit the transport of invasive species and reduce the overall consumption of native vegetation, improving plant vigor, and resulting in more effective native plant competition over possible invasive species introduction. However, prohibiting livestock grazing may preclude its use as a tool to control invasive species in certain areas (Stohlgren et al. 1999 and DiTomaso 2000). The opportunity for risk of introduction of noxious weed seeds by wildlife or birds would still remain under this alternative.
The BLM monitors those allotments not meeting rangeland health standards due to livestock grazing under Alternative B. This management action may require an increase in rangeland monitoring, compared to other alternatives, which would provide beneficial impacts by monitoring the spread of invasive species to better serve control and treatment efforts.
In general, special designations (e.g., ACECs and WSAs) under Alternative B place the most restrictions on surface-disturbing activities (e.g., mineral development, ROW development, and fire suppression) that facilitate the spread of invasive species. In addition to the nine ACECs designated under Alternative A, four existing ACECs would be expanded, and eight new ACECs designated. Although seasonal stipulations on invasive, nonnative pest species control in the Chapman Bench, Clarks Fork Canyon, Rattlesnake Mountain, and Sheep Mountain ACECs may adversely impact invasive species management by restricting control methods or timing, ACEC designations under this alternative would place restrictions on actions most likely to contribute to the spread of invasive species, resulting in the greatest beneficial impacts to invasive species control, compared to the other alternatives. Two back country byways would be designated and developed under Alternative B. If these designations and facility developments increase use from motorized vehicles, then adverse impacts may result from increased potential to spread invasive species along these byways.
Alternative B would utilize fire to restore fire adapted ecosystems and reduce hazardous fuels. Vegetation response following planned ignitions and mechanical and chemical treatment typically varies depending on a set of factors such as fire conditions, timing, and pre- and post-treatment weather conditions. Alternative B uses mechanical, chemical, or biological treatments in the wildland urban interface to protect structures and private property from fire. Mechanical treatments may cause adverse impacts by increasing the potential of invasive species spread, because the surface disturbance associated with these treatments would occur in habitat that may already be degraded. In other situations, such as in areas affected by cheatgrass, burning has a greater adverse effect on weed spread than some mechanical treatments may have (Keeley 2006). Although fire and fuels management under Alternative B may result in the least short-term surface disturbance overall (Appendix T) and therefore the least adverse impact by spreading invasive species, it would also result in the least long-term beneficial impact from restoring native fire-adapted vegetation.
Under Alternative B, vegetation management would be less extensive than alternatives A, C, or D. Though the BLM would manage toward achieving 75 percent of Historical Climax Plant Community and to maintain native plant communities on contiguous blocks of BLM-administered land—resulting in beneficial impacts by limiting new areas susceptible to invasive species spread due to improved habitat integrity—the greater reliance on natural processes for vegetation treatment under this alternative would result in the smallest beneficial impact. Alternative B also prohibits the aerial application of pesticides within 1 mile of special status plant species populations, which may result in adverse impacts by limiting widespread pesticide use to control invasive species spread. As managing riparian/wetland areas toward DPC is assumed to exceed the requirements of managing toward PFC, Alternative B may result in greater beneficial impacts than Alternative A by controlling the spread of invasive species in these areas.
The BLM prohibits the aerial application of pesticides within ½ mile of riparian/wetland areas and aquatic habitats under Alternative B. Although this restriction may adversely affect the control of invasive species, exceptions can be made to manage riparian weed species when the beneficial impacts of invasive species control are greater than the risks to aquatic habitat from pesticides applied in conformance to label requirements.
Allowing the authorized officer, on a case-by-case basis, to hold livestock that may have ingested invasive species material or seeds for a period of 72 hours would reduce the potential of livestock to transport invasive species material or seeds under Alternative B. This allows the animals to flush the ingested invasive species material from their systems before moving on to or within public lands. It is anticipated that this action, more than actions under other alternatives, may reduce the adverse, indirect impacts associated with the spread of invasive species from livestock.
Alternative C is projected to result in the greatest acreage of short-term surface disturbance. The projected long-term disturbance acreage for Alternative C is approximately 164 percent more than Alternative A, 282 percent more than Alternative B, and 125 percent more than Alternative D. Alternative C has less stringent reclamation requirements (e.g., 30 percent desired vegetative cover within three growing seasons, and no subsequent requirement) than alternatives B and D, but potentially more stringent requirements than Alternative A by requiring reclamation plans on a case-by-case basis. Additionally, seeding of areas not meeting resource objectives using approved seed mixes containing both native and nonnative species may allow for the selection of species most capable of competing with invasive species and, therefore, reduce the chances of invasive species establishment in these areas relative to Alternative A. Alternative C is likely to result in the most short- and long-term adverse impacts by providing the most opportunity for invasive species spread in disturbed areas. Although the extent of treatments for invasive species and pests would be twice that of alternatives A and D and 40 times more than Alternative B—indicated by the projected surface disturbance from invasive species and pest management (Appendix T)—the greater overall surface disturbance and limited requirements for revegetation under Alternative C may have the greatest adverse impacts to invasive species and pest management.
Under Alternative C, mineral development would result in 25,771 acres of short-term and 13,120 acres of long-term surface disturbance (Appendix T). Thus, Alternative C would result in similar adverse impacts to those under Alternative A, but to a greater degree. Most of the Planning Area would remain open to mineral extraction, with the least acreage closed compared to the other alternatives. Most of the impacts would be temporary during the life of the operation with most areas of disturbance reclaimed following closure of operations.
Forest and woodland treatments and recovery of forest products would result in 40,000 acres of short-term surface disturbance under Alternative C, but no long-term surface disturbance due to complete reclamation of these sites (Appendix T). Alternative C would allow larger clear-cuts than Alternative A and the continued use of spur roads to complete other resource goals or for new recreational purposes would increase the potential spread of invasive species from vehicle use in these areas. Commercial forestland would be open to timber harvesting, resulting in the greatest adverse impacts for potential invasive plant species spread from motorized machinery and soil disturbance, compared to the other alternatives. However, managing endemic insect and disease with the full range of silviculture techniques and treatment methods and allowing precommercial thinning and salvage operations would beneficially impact pest management such as bark beetle control.
Utility corridors and linear ROWs in the Planning Area, including pipelines and powerlines, would involve 3,460 acres of short-term and 1 acre of long-term surface disturbance (Appendix T), which would result in impacts similar to Alternative A, but to a greater degree. Alternative C would involve 4,638 acres of short-term and 2,319 acres of long-term surface disturbance from road construction, the most of all alternatives (Appendix T). The risk of adverse impacts due to the spread of invasive species is expected to increase proportionally with long-term surface disturbance from new road construction.
Under Alternative C, the creation of new roads and trails for recreational purposes would result in 12,907 acres of short-term and 12,735 acres of long-term surface disturbance, the most of all the alternatives (Appendix T). The resulting impact would be the potential spread of invasive species into new areas where disturbance occurs. Alternative C limits motorized vehicle use to designated roads and trails in less acreage than alternatives B and D—though more acreage than Alternative A—closes the least acreage to motorized vehicle use, and allows off-road motorized vehicle use for big game retrieval and dispersed campsite access in areas with limited travel designations, which would result in the greatest potential adverse impacts from the spread of invasive species, compared to the other alternatives. Conversely, less restrictive travel management under this alternative would allow the greatest access to detect new and treat existing invasive species infestations, which may result in a beneficial impact to the control of these species.
In areas developed for recreational use, impacts from recreational development under Alternative C would be similar to those under Alternative A, but to a greater degree. The potential visitor increase to recreational areas may be greater than Alternative B, but if the BLM upgrades or develops facilities in response to demand, the consolidation of recreational activity may result in beneficial impacts to invasive species and pest management as described under Alternative A. Alternative C manages the least areas as SRMAs, and therefore would pursue the least intensive management to maintain the desired recreation setting, resulting in the least beneficial impact to invasive species control.
Alternative C allows the placement of salt, mineral, or forage supplements in wetlands, riparian, or other areas with sensitive vegetation such as reclaimed or reforested areas to maximize livestock use. The potential concentrated livestock use and associated soil disturbance and invasive species spread would be the greatest under Alternative C, compared to the other alternatives.
Under Alternative C, the BLM excludes livestock grazing from the same areas as Alternative A but manages livestock grazing to optimize commodity production while meeting rangeland health standards, not to provide for the enhancement of other resource values. The potential adverse impacts by allowing livestock grazing in areas where it is likely to contribute to, rather than help control, the spread of invasive species would be greatest under this alternative. Alternative C, by prioritizing monitoring on “I” category allotments and those allotments not meeting rangeland health standards due to current livestock grazing, would result in more monitoring to aid invasive species detection and treatment than Alternative A.
In general, special designations (e.g., ACECs and WSAs) under Alternative C would place the least restrictions on surface-disturbing activities (e.g., mineral development, ROW development, and fire suppression) that facilitate the spread of invasive species. Furthermore, only the Spanish Point Karst and Brown/Howe Dinosaur Area ACECs would be designated under this alternative, providing the fewest beneficial impacts from special designations from limiting surface disturbance to control the spread of invasive species, compared to the other alternatives.
Alternative C would utilize fire to restore fire adapted ecosystems and reduce hazardous fuels. Vegetation response following planned ignitions and mechanical and chemical treatment varies depending on a set of factors such as fire conditions, timing, and pre- and post-treatment weather conditions. Mechanical, chemical, or biological treatments would be used across the landscape as needed to restore vegetative diversity and reduce the risk of unnatural fire. Although fire management actions result in the greatest amount of surface disturbance in the short term, by restoring vegetative diversity the risk of invasive species establishment would decrease, resulting in beneficial impacts in the long term. Under Alternative C, the BLM would seek to restore vegetation diversity while decreasing the risk of unnatural fire. Fire management under this alternative is likely to result in the greatest long-term beneficial impact, compared to the other alternatives.
Under Alternative C, the BLM manages grasslands and shrublands toward meeting the Wyoming Standards for Healthy Rangelands (Appendix N) in the greatest acreage, compared to the other alternatives. However, the BLM does not manage to maintain native species on contiguous blocks of BLM-administered land. Managing all riparian/wetland areas to meet or make progress toward PFC while prioritizing areas functioning at-risk with a downward trend or in nonfunctioning condition would focus management on those areas most vulnerable to invasive species spread and may result in a greater beneficial impact than riparian/wetland management under Alternative A. Due to the larger extent of vegetation management, Alternative C may result in more beneficial impacts to control the spread of invasive species than alternatives A, B, and D.
Prohibiting the aerial application of pesticides within ½ mile of special status plant species would result in a greater potential adverse impact than Alternative A, but less than Alternative B, by limiting widespread pesticide use to control invasive species.
The BLM prohibits aerial application of pesticides within 100 feet of riparian/wetland areas and aquatic habitats under Alternative C. Although this restriction would adversely affect the control of invasive species, exceptions could be made to manage riparian weed species, when the beneficial impacts of invasive species control are greater than the risks from pesticides to aquatic habitat when applied in conformance with the label. Proactive management under Alternative C includes expansion of integrated pest management for identified infestations, a beneficial impact, but a reduction in livestock management measures (i.e., livestock flushing) that may prevent new infestations, an adverse impact.
The projected long-term disturbance acreage for Alternative D is approximately 17 percent more than Alternative A, 69 percent more than Alternative B, and 57 percent less than Alternative C. Overall, Alternative D has more stringent reclamation requirements than alternatives A and C, but less than Alternative B. The BLM allows nonnative species for seeding, which would result in similar beneficial impacts to those under Alternative C. Alternative D is likely to result in more short-term adverse impacts than Alternative A, but less long-term adverse impacts by employing reclamation practices that reduce the opportunity for invasive species spread in disturbed areas. The extent of treatments for invasive species and pests under Alternative D is similar to that under Alternative A.
Under Alternative D, mineral development would result in 24,896 acres of short-term and 12,596 acres of long-term surface disturbance (Appendix T). Mineral development under Alternative D would result in similar adverse impacts to those under Alternative A, but to a lesser degree.
Forest and woodland treatments and recovery of forest products would result in impacts similar to Alternative A, but to a greater degree from allowing clear cuts up to 100 acres. However, managing endemic insects and disease with the full range of silviculture techniques and treatment methods and allowing precommercial thinning and salvage operations would create beneficial impacts similar to Alternative C.
Under Alternative D, utility corridors, new road construction, and linear ROWs, including pipelines and powerlines, would result in impacts similar to Alternative A. However, managing more area as ROW avoidance/mitigation or exclusion areas under this alternative may consolidate ROW development and, therefore, limit the dispersal of invasive species.
Under Alternative D, the creation of new roads and trails for recreational purposes would involve 5,820 acres of short-term and 1,879 acres of long-term surface disturbance, the second most of the alternatives (Appendix T). The resulting impact would be the potential spread of invasive species into new disturbed areas. Alternative D closes the second largest acreage to motorized vehicle use and limits motorized vehicle use to designated roads and trails in the second largest acreage compared to other alternatives. Alternative D also limits off-road vehicle travel for big game retrieval and dispersed campsite access to within 300 feet of established roads. Under Alternative D, beneficial and adverse impacts to invasive species management would be greater than under alternatives A and C, but less than under Alternative B.
Recreational development under Alternative D in areas outside SRMAs would result in impacts similar to Alternative C. Recreation management actions in SRMAs would result in impacts similar to those under Alternative B, but to a lesser extent because SRMAs encompass less acreage under Alternative D.
Livestock grazing management under Alternative D would result in impacts similar to Alternative A. Allotment monitoring would cause beneficial impacts similar to Alternative C, but to a greater degree. Prioritizing monitoring on allotments that do not meet rangeland health standards due to all livestock grazing, not just current, may increase monitoring in more areas vulnerable to invasive species spread.
Special designations under Alternative D would result in impacts similar to Alternative A, but to a greater degree. In addition to the nine ACECs designated under Alternative A, Alternative D designates four new ACECs and two new management areas that emphasize resource protection, placing more restrictions on resource uses and activities likely to contribute to the spread of invasive species. Although seasonal stipulations on controlling invasive, nonnative pest species in the Chapman Bench Management Area and the Clarks Fork Canyon and Sheep Mountain ACECs may adversely affect invasive species management by restricting control methods or timing, ACEC designations under Alternative D would create more beneficial impacts than under alternatives A and C by limiting the spread of invasive species.
Fire and fuels management practices under Alternative D would result in impacts to invasive species and pest management similar to Alternative A in both extent and intensity. Similar to Alternative B, Alternative D places more emphasis on using fire as a resource management tool, which may beneficially impact invasive species management if the BLM uses fire more frequently in areas where it helps to control the spread of invasive species.
Vegetation management under Alternative D would create beneficial impacts similar to Alternative B, but to a lesser degree and extent. Based on the amount of projected surface disturbance (Appendix T), Alternative D would actively manage a similar amount of vegetation as Alternative A. However, managing grasslands and shrublands toward achieving 65 percent or more of Historical Climax Plant Community and maintaining contiguous blocks of native plant communities would create more beneficial impacts, similar to Alternative B but to a greater extent. Management of riparian/wetland vegetation would create beneficial impacts similar to Alternative C, but to a greater degree because Alternative D manages certain areas to obtain DFC, which requires more intensive management than PFC.
Avoiding aerial applications of herbicides within ½ mile of BLM special status plant species would result in similar adverse impacts to invasive species management as those under Alternative C, but to a lesser degree.
Proactive management actions to control the spread of invasive species under Alternative D would create impacts similar to Alternative A.
Certain types of management that restricts surface-disturbing activities and other resource uses would, generally, provide habitat protection for fish, wildlife, special status species, and wild horses. Table 4–9 below provides an overview of these selected protective management actions by important habitat types where they would occur for each alternative. This table is intended to provide a comparative overview comparison of the alternatives. Further discussion of the effects of these and other management actions for each fish and wildlife habitat types is provided in the proceeding sections. Impacts to special status species appear in sections 4.4.7 through 4.4.9, and impacts to wild horses appear in Section 4.4.10.
Table 4.9. Summary of Protective Management by Alternative for Selected Fish, Wildlife, Special Status Species, and Wild Horse Habitat
| Alternative | Big Game Crucial Winter Range (acres) | Big Game Parturition Habitat (acres) | Fish-bearing Streams (miles) | Greater Sage-grouse Key Habitat Areas (acres) | Herd Management Areas (acres) | |
|---|---|---|---|---|---|---|
| Locatable Minerals - Closed | A | 24,755 | 5,828 | 64 | 9,552 | 0 |
| B | 120,623 | 45,921 | 80 | 80,687 | 0 | |
| C | 10,402 | 920 | 11 | 4,173 | 0 | |
| D | 16,921 | 2,935 | 32 | 8,714 | 0 | |
| Oil and Gas Constraints - Closed | A | 45,855 | 2,495 | 35 | 37,933 | 27,763 |
| B | 817,576 | 73,646 | 122 | 1,226,064 | 248,560 | |
| C | 41,165 | 551 | 16 | 35,435 | 27,763 | |
| D | 109,768 | 72,019 | 47 | 74,481 | 27,640 | |
| Oil and Gas Constraints - Major | A | 679,240 | 71,264 | 122 | 534,236 | 22,698 |
| B | 487,758 | 6,815 | 52 | 0 | 40,647 | |
| C | 82,360 | 4,617 | 103 | 46,564 | 10,772 | |
| D | 46,387 | 5,435 | 26 | 21,789 | 4,367 | |
| Oil and Gas Constraints - Moderate | A | 580,238 | 6,702 | 16 | 512,190 | 103,074 |
| B | 0 | 0 | 2 | 0 | 3 | |
| C | 683,976 | 60,671 | 44 | 809,855 | 87,092 | |
| D | 1,622,938 | 89,373 | 93 | 1,423,567 | 148,356 | |
| ROW - Exclusion | A | 36,161 | 712 | 60 | 20,729 | 7,240 |
| B | 109,839 | 18,359 | 60 | 132,248 | 7,168 | |
| C | 1,007 | 0 | 2 | 0 | 0 | |
| D | 9,961 | 0 | 5 | 264 | 0 | |
| Lands with Wilderness Characteristics1 | A | N/A | N/A | N/A | N/A | N/A |
| B | 246,064 | 37,900 | 59 | 200,959 | 78,032 | |
| C | N/A | N/A | N/A | N/A | N/A | |
| D | 39,311 | 22,772 | 13 | 4,414 | 0 | |
| Livestock Grazing - Closed | A | 1,479 | 41 | 3 | 312 | 22 |
| B | 1,298,07 | 65,608 | 140 | 1,231,095 | 155,690 | |
| C | 1,479 | 41 | 3 | 312 | 22 | |
| D | 1,479 | 41 | 3 | 312 | 22 | |
| ACEC | A | 32,433 | 12,612 | 29 | 20,461 | 0 |
| B | 144,012 | 64,929 | 43 | 94,399 | 0 | |
| C | 11,241 | 392 | 8 | 5,268 | 0 | |
| D | 51,138 | 26,242 | 31 | 23,144 | 0 | |
| WSR | A | 20,745 | 3,807 | 51 | 7,446 | 0 |
| B | 20,745 | 3,807 | 51 | 7,446 | 0 | |
| C | N/A | N/A | N/A | N/A | N/A | |
| D | N/A | N/A | N/A | N/A | N/A | |
| WSA | A | 38,378 | 338 | 16 | 35,673 | 28,392 |
| B | 38,378 | 338 | 16 | 35,673 | 38,268 | |
| C | 38,378 | 338 | 16 | 35,673 | 28,392 | |
| D | 38,378 | 338 | 16 | 35,673 | 38,268 |
1Includes only lands designated as Wild Lands.
| ACEC | Areas of Critical Environmental Concern | WSA | Wilderness Study Area |
| N/A | not applicable | WSR | Wild and Scenic River |
| ROW | rights-of-way |