Draft terrestrial resources biological assessment
Download 486.24 Kb.
|
- Navigate this page:
- 3.1 Existing Baseline Conditions within the Agate Desert Region
3.0 Environmental BaselineThis section presents an analysis of the effects of past and ongoing human and natural factors leading to the current status of the species addressed in this assessment and its habitat (including CH, where designated) within the action area. In addition to describing the action area in greater detail, this section discusses the larger ecological context in which the proposed actions will occur, consistent with USFWS’ guidance on evaluating project impacts to threatened and endangered species and the associated critical habitats that support them. As discussed in Section 2.5, a single action area was established that encompasses all Design Options for the Build Alternatives, as well as large portions of the existing OR 62 corridor. The action area totals approximately 5,004 acres. Not all resources within the project action area would be affected or impacted by the Build Alternatives; rather, the purpose of the action area is to provide a broader context for discussing the impacts on resources that may be expected to result from implementing the Build Alternative. In 2010, ODOT modified the project design to include East Vilas Road, due to anticipated increases in traffic loading due to completion of the Project. Approximately 1,500 feet of East Vilas Road (outside of the originally surveyed areas, extending west to nearly Table Rock Road) has not been directly surveyed for vegetation community types or the presence of vernal pools. Portions of the action area where the proposed JTA Options between Vilas Road and the alignment’s intersection with Highway 62 and Agate Road have not been directly surveyed due to land access issues. ODOT is proposing to conduct a botanical survey in this area in the near future for ESA listed plant species within VPCs. The principle terrestrial resources analyzed in this BA are California / Nevada vernal pool fairy shrimp, Pacific Region Cook’s lomatium, Pacific Region large-flowered woolly meadowfoam and Southern Oregon buttercup. An overview of the vegetative communities originally surveyed has been detailed in the Terrestrial Resources Technical Report (URS 2010a). A discussion of VPC habitat is presented below as it is both suitable and CH designated for the above listed species. These three species constitute the only ESA-listed species with documented suitable habitat within the project action area and the project footing. Field surveys and consultation with the FWS Regional Biologist was made to confirm this finding (pers. Communication Sam Friendman, FWS, March 2011). Consultation was also made to confirm the absence of Southern Oregon buttercup within the project footprint. Field surveys conducted by MB&G in 1999 identified a population of buttercup within the action area, however it is outside of the project footprint and reasonably isolated by roadways from indirect impacts due to project construction (MB&G 2008). 3.1 Existing Baseline Conditions within the Agate Desert RegionThe project action area is located in the Rogue River Valley extending from Medford northeast to the northern portion of White City, Oregon (Figure 1-1). The terrain is relatively flat, being formed primarily by erosional forces of the Rogue River and nearby tributaries. Elevations within the project study area range from 1,340 feet above mean sea level (MSL) in the vicinity of the Airport to 1,280 feet MSL along Whetstone Creek in the northern portion of the project study area. Slopes throughout the project study area are generally less than five percent (USGS, 1983a, 1983b, and 1983c). Principle soil types include Agate-Winlo complex, Coker clay, Cove clay, Medford silty clay loam, Phoenix clay and Padigan clay (Johnson 1992). Mean annual maximum temperature is 67.2ºF and mean annual minimum temperature is 41.1ºF. Mean annual precipitation is 18.9 inches. Weather often follows the pattern of hot, dry summers and cool, wet winters; precipitation falls mainly as rain (URS 2010a).. Several distinct vegetation communities were identified within the action area. These vegetation communities include developed urban areas, dry grasslands common to the Agate Desert Region, unique VPCs and the riparian borders of several actively flowing streams. In general terms, the developed areas within the action area provide the lowest quality habitat for wildlife given the extensive impervious surfaces and lack of vegetation and natural cover in these areas. The same may be said for grassland areas where annual mowing or grazing can limit cover. Certain areas of grassland not routinely disturbed provide fair habitat to species adapted to open fields and the absence of forest structure. While occupying a large portion of the action area, the grassland community does not provide the primary constituent elements (PCEs) for ESA listed species addressed in this assessment (refer to Section 4.0 for PCE information for each listed species under evaluation). Riparian communities provide relatively good habitat for wildlife and a diversity of habitats, however they do not provide the PCEs necessary for the species under analysis. The VPC is a unique and necessary habitat for several species, such as the vernal pool fairy shrimp, Cook’s lomatium and woolly meadowfoam. Due to the importance of providing PCEs for all three listed species within the action area, this is the habitat unit that will be examined in this assessment. VPCs within the Agate Desert support the federally threatened vernal pool fairy shrimp as well as two endangered plant species, Cook’s lomatium and large-flowered woolly meadowfoam. Although many of the vernal pools within and immediately adjacent to the project footprint have been invaded by exotic plants and degraded by road construction and industrial development, several high-quality pools remain. In 1997, the Oregon Biodiversity Information Center (ORBIC, formerly the Oregon Natural Heritage Information Center (ORNHIC)), conducted a study, funded by the DSL, that provided a preliminary mapping and assessment of the integrity of the topography and vegetation of the vernal pools. OBIC concluded that only 23 percent of the original vernal pool topography and hydrology in the Agate Desert remains intact where the vegetation is not severely altered. Residential, commercial, and industrial development, along with land leveling (primarily for agriculture), has altered nearly 60 percent of the historic range of the Agate Desert landform. The remainder of the habitat is either severely altered by historic and continuing land uses, or occurs along the fringes of the landform where vernal pools are weakly expressed (USFWS 2011). FIGURE 3-1: EXISTING CONDITIONS WITHIN THE ACTION AREA Within the project footprint, vernal pools are generally disturbed, degraded and are dominated by non-native plant species as soon as water in the pools evaporates in late spring. Farming practices, grazing, introduction of non-native plant species, development, and trash dumping have all impacted vernal pool quality in the project study area. Originally, vernal pool habitat covered approximately 21,000 acres in the Agate Desert-Rogue River Plains region. Of the remaining 8,032.4 acres of vernal pool topography (intact, weakly expressed, or altered or weak), 59.2 percent is in the "intact topography/hydrology and altered vegetation" class and another 15.7 percent is in the "intact topography/hydrology and severely altered vegetation" class. This means that a total of 6,019.8 acres (74.9 %) has intact topography and hydrology. Only 2,012.6 acres (25.6 %) of the remaining habitat has altered or weakly expressed topography and hydrology (USFWS 2011). Directory: HWY62 -> Terrestrial BA Terrestrial BA -> Draft Terrestrial Resources Biological Assessment oregon highway 62 corridor solutions project Download 486.24 Kb. Share with your friends:
|