Vantage to Pomona FEIS Index 34 - Laserfiche WebLink

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Vantage to Pomona Heights Chapter 3 230 kV Transmission Line Project FEIS Affected Environment PAGE 3-7 Rabbitbrush/Annual Grassland Rabbitbrush (Chrysothamnus viscidiflorus and Ericameria nauseosa) typically occurs where prior disturbance has removed sagebrush. Within the Project study area, rabbitbrush occurs with an understory of annual grasses, such as cheatgrass. Rabbitbrush/annual grasslands occur on approximately 469.8 acres (0.3 percent) within the Project study area. Riparian/Wetland Very few wetlands and riparian areas occur within the Project study area. The majority of riparian areas within the Project study area are seasonally moist uplands. These drier riparian areas are typically vegetated with upland shrubs, including sagebrush. The largest riparian and wetland areas consist of a band of riparian vegetation occurring along Lower Crab Creek and a quaking aspen (Populus tremuloides) grove associated with an area that is seasonally moist (Route Segment 3c). Much of the Lower Crab Creek riparian area is bordered by pastureland and disturbed, often grazed, shrub-steppe habitats. Within the Project study area, the vegetation bordering Lower Crab Creek consists of dense thickets of peachleaf willow (Salix amygdaloides), narrowleaf willow (Salix exigua), Russian olive (Elaeagnus angustifolia), and black cottonwood (Populus balsamifera ssp. trichocarpa) trees. The understory in this area is variable, including native species, such as soft-stem bulrush (Schoenoplectus tabernaemontani) and broad-leaf cattail (Typha latifolia), as well as a host of non-native species such as diffuse knapweed (Centaurea diffusa) and common reed (Phragmites australis). A small wetland is present in the JBLM YTC Cantonment Area (Route Segment NNR-2). Vegetation at this wetland included narrowleaf willow, purple loosestrife (Lythrum salicaria), water speedwell (Veronica anagalis- aquatica), mountain rush (Juncus arcticus ssp. littoralis), common rush (Juncus effusus), slenderbeak sedge (Carex athrostachya), water horsetail (Equisetum fluviatile), and hardstem bulrush (Schoenoplectus acutus var. acutus). For more information on water resources in the Project study area, refer to Section 3.14 - Water Resources. Sagebrush/Perennial Grassland and Sagebrush/Annual Grassland Within the Project study area, sagebrush shrublands consist of big sagebrush (Artemisia tridentata) and stiff sagebrush (Artemisia rigida). Stiff sagebrush typically occurs on rocky shallow soils with primarily Sandberg’s bluegrass (JBLM YTC 2002). Sagebrush shrublands with a perennial grass understory is the most common vegetation cover type within the Project study area, covering 48.7 percent (87,696.5 acres) of the Project study area. Sagebrush shrublands with an annual grass understory comprise 0.4 percent (665.4 acres) of the Project study area. 3.2.2.2 Noxious Weeds and Invasive Plant Species Many exotic plant species are found within the Project study area, but only a portion of these are designated as noxious weeds. Noxious weeds are non-native species that spread quickly, are difficult to control and cause ecological and economical damage. The Washington State Department of Agriculture maintains a list of noxious weeds to be controlled in Washington. Class A noxious weeds have limited distribution in the state and state law requires their eradication. Class B noxious weeds are either absent or have limited distribution throughout the state. The goal for Class B noxious weeds is to contain the infestations to their current locations and prevent their spread to new areas. Class C noxious weeds are already widespread in the state; counties can choose to either enforce their control or can focus on educating residents about controlling these noxious weeds. In addition to the state designated noxious weed list, each County and District Noxious Weed Control Board can develop and enforce a list of weeds that are considered noxious in their county or district (Washington State Noxious Weed Control Board [WSNWCB] 2015). Within the right-of-way (ROW) for each of the Project route segments, a Project-specific survey was completed. Qualified botanists conducted a complete, floristic pedestrian survey to target noxious weed species on accessible federal and Washington State Department of Transportation (WSDOT) lands.