Methods and assumptions used in this impact analysis include the following:
Roadways, trails, ROWs, and corridors are major routes that can spread invasive species through transport on motor vehicles and off-road motorized vehicle uses. Invasive species also can spread through watercourses, wind, and by wildlife and livestock movement.
The amount of new surface disturbance associated with an alternative is a good index of potential impact by invasive species. The larger the acreage of surface disturbance, the greater the potential adverse impact by invasive species.
Success of reclamation measures prescribed as a condition of development is unknown and could either overestimate or underestimate the potential impact from weeds.
Enforcement of restrictions related to recreation and off-road motorized vehicle use and dispersed travel can be assumed only if adequate funding and personnel are available to do the job.
Instruction Memorandum (IM) 2006-073 (BLM 2006b) establishes policy and guidance for use of certified weed-free seed and mulch to prevent the establishment of new invasive species population in restoration projects on public lands.
Partners Against Weeds – An Action Plan for the BLM (BLM 1996), establishes a strategy to prevent weeds through cooperation with all partners. It outlines goals and specific actions to help prevent and control the spread of weeds. This action plan, along with any future updates and guidance, would be followed to control and prevent weed problems.
Seeds from some weeds can remain dormant and viable in the soil for periods that exceed the 5–year division between short- and long-term impacts. Therefore, favorable site conditions may serve to reintroduce invasive species to reclaimed sites without additional surface disturbance.
The area evaluated for potential impacts includes the Planning Area and Big Horn, Hot Springs, Park, and Washakie County weed-control districts.
The acreage of long-term disturbance (Appendix T) includes facilities that cannot be reclaimed and that, in most cases, would not provide long-term habitats for invasive species. For example, well pads, communication sites, powerlines, roads, wind-energy facilities, and other infrastructure would replace existing native vegetation with pervious or impervious surfaces for a period exceeding 5 years.
Integrated Pest Management includes chemical, mechanical, biological, and cultural techniques.
The introduction of aquatic invasive invertebrates, vertebrates, microorganisms, and pathogens can threaten the stability of ecosystems, create serious human health consequences, and cause substantial economic burdens. Large majorities of native and nonnative species do not pose a threat to natural or human systems. However, if any of these species were to become a concern, the WFO and CYFO would cooperate and coordinate with appropriate government agencies, private industry, and other interested parties involved in public education efforts and control, management, and research of invasive species.