Vantage to Pomona FEIS Index 34 - Laserfiche WebLink

Home Browse Search

Vantage to Pomona Heights Chapter 3 230 kV Transmission Line Project FEIS Affected Environment PAGE 3-44 agricultural land use, and altered fire-regimes. Sagebrush/perennial grassland occurs throughout the entire Project study area. Annual grassland occurs in large patches along the western half of each of the Action Alternatives, and also southeast of the Vantage Substation. Agricultural areas predominately occur east of the Columbia River and south of the Saddle Mountains (Route Segment 3a), along Badger Pocket (Route Segments Manastash Ridge (MR) 1 and NNR-5), near the Pomona Heights Substation (Route Segments 1a/NNR-1 and NNR-2), and south of JBLM-YTC (Route Segments 1c and 2c). Perennial grassland occurs in small patches throughout, but predominates along the southern Alternatives A-H (Route Segments 1b, 1c, 2b, and 3b). 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. For more information on water resources in the Project study area, refer to Section 3.14 - Water Resources and the Water Resources and Wetlands Map in Appendix A. Shrub-Steppe In the Project study area, shrub-steppe habitat consists primarily of sagebrush-steppe with big sagebrush (Artemisia tridentata) and stiff sagebrush (Artemisia rigida). Stiff sagebrush typically occurs on rocky shallow soils with Sandberg bluegrass (Poa sandbergii; JBLM YTC 2002). Sagebrush-steppe 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 of the Project study area (665.4 acres). Other shrub-steppe habitat types include rabbitbrush (Chrysothamnus viscidiflorus and Ericameria nauseosa)/annual grassland (469.8 acres; 0.3%) and bitterbrush (Purshia tridentata)/perennial grassland (5.2 acres; <0.1%) Shrub-steppe habitats are used by a diverse group of wildlife species. Some of these are sagebrush obligates (restricted to sagebrush habitats during the breeding season or year-round) or sagebrush dependent species (near-obligates; occurring in both sagebrush and grassland habitats). Sagebrush obligates include the sage sparrow (Artemisiospiza nevadensis), Brewer’s sparrow (Spizella breweri), sage thrasher (Oreoscoptes montanus), Sage-Grouse, sagebrush vole (Lemmiscus curtatus), sagebrush lizard (Sceloporus graciosus), and pronghorn (Antilocapra americana; Paige and Ritter 1999). As these species breed only in shrub-steppe habitats, disturbance or conversion of shrub-steppe to agricultural and other human land uses or to annual grasslands directly affects their distribution. Shrub-steppe habitats typically provide unobstructed views over large areas, creating ideal hunting conditions for some raptors. Raptors that breed and/or forage in shrub-steppe habitats include prairie falcon (Falco mexicanus), ferruginous hawk (Buteo regalis), Swainson’s hawk (Buteo swainsoni), and golden eagle (Aquila chrysaetos; Dobkin and Sauder 2004; Dobler et al. 1996). Wildlife species commonly found in shrub- steppe habitat are presented in Table 3.3-1. Annual and Perennial Grasslands Annual grasslands in the Project study area are typically dominated by annual grasses such as cheatgrass (Bromus tectorum). Annual grasslands cover approximately 20 percent of the Project study area (36,799 acres). Most native shrub-steppe birds either do not use cheatgrass or their use occurs at lower densities where it is the predominant ground cover (Shaw et al. 1999). However, cheatgrass monocultures produce an open landscape that is used by wildlife species including the long-billed curlew (Numenius americanus) and burrowing owl (Athene cunicularia; Rich et al. 2005).