Methods and assumptions used in this impact analysis include the following:
The BLM, in cooperation with state and other federal wildlife agencies, is responsible for managing habitat (e.g., quality, suitability, usability), whereas state and federal wildlife management agencies (e.g., WGFD, USFWS) have primary authority for overseeing management of wildlife populations. Therefore, this analysis primarily relies on vegetation changes and loss of habitat use due to disruptive activities to estimate impacts to wildlife habitats.
For each alternative, changes to vegetation types, either in quantity, quality, or increased fragmentation, are compared to baseline conditions. Adverse and beneficial impacts to vegetation types (i.e., wildlife habitats) are assumed to have a corresponding adverse or beneficial impact on wildlife species.
Disturbance impacts to wildlife are evaluated by comparison to current management practices in the Planning Area; increased protection in time or space are beneficial, whereas reduced protection result in adverse impacts.
Disturbance during sensitive periods adversely affects wildlife.
Habitat fragmentation adversely affects wildlife.
Prescribed fire, where historical fire regimes occurred, is a tool used to manage vegetative communities and can result in short-term adverse impacts with long-term beneficial impacts to wildlife, certain wildlife habitats, and in some cases to forage productivity and availability.
Forest management actions replicating natural historical disturbance regimes and managing wildlife habitats instead of, or in addition to, managing forest products are anticipated to benefit wildlife habitats.
Management actions aimed at benefiting specific wildlife species can have adverse or beneficial impacts to other wildlife species.
Alternatives with a larger number of acres of wetlands developed or protected will exhibit a greater benefit to waterfowl and other riparian/wetland wildlife species when compared to alternatives with smaller acreage of wetlands developed or protected.
Alternatives providing more protection of water sources beneficial to wildlife are anticipated to have the greatest benefit to wildlife.
Surface disturbance generally causes adverse impacts to wildlife habitats. Lesser amounts of surface disturbance in wildlife habitats have a corresponding lesser adverse impact to wildlife compared to more surface disturbance. The extent of adverse impacts due to surface disturbance depends on the precipitation zone.
Prohibiting surface disturbance or occupancy is more restrictive and provides more protection for wildlife than avoiding surface disturbance or occupancy.
The more surface disturbance that occurs on steep slopes or on highly erosive soils, the greater the potential for adverse impacts to wildlife habitats. Adverse impacts from surface disturbance also increase in areas that receive less precipitation.
The higher the road density and the frequency of use in the Planning Area, the greater the potential to degrade adjacent wildlife habitat quality in the Planning Area.
The more area used by OHVs and the higher the density of motorized vehicle use, the greater adverse impacts are anticipated to wildlife habitats.
The BLM utilizes the best available information, management and conservation plans, and other research and related directives, as appropriate, to guide wildlife habitat management on BLM-administered lands.
Natural variability in wildlife health, population levels, and habitat conditions would continue. Periods of mild or severe weather as well as outbreaks of wildlife disease or insects/diseases that impact habitat (e.g., bark beetle, blister rust, mistletoe, and bleeding rust) may impact wildlife population levels.
Wildlife habitats being protected are generally in desired natural condition and those being managed are being managed toward a more desirable condition.
Habitat vegetation that trends away from natural vegetation condition (due to increase in invasive species), similarly trends away from natural wildlife species composition.