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I I I I I I I I I I I I I I I I I I I OD2li82 noxious weed site conditions within the east campground/launch area are provided in Appendix C as NOX 1-504a and NOX 1-504b, Canada thistle also occurs at the campground/launch area on the west side of the Williams Fork Reservoir, but, at this location, it appears as a number of one-quarter to one-half-acre patches (NOX3-608, NOX3-609). Percent cover of Canada thistle at these west campgroundlboat launch sites is estimated at approximately 10 percent. The vegetation within these sites is grassy (predominantly smooth brome [Bromus inermis] and foxtail) with common weeds including curly dock, yellow sweet clover, pennycress, tumblemustard, a weedy forget-me-not (Myosotis sp,), and a few scattered musk thistles. Typical noxious weed site conditions within the west campground/launch area are shown in Photograph NOX3-609a in Appendix C. East of the boat launch itself, these areas appear to have been inundated until recently before the noxious weed survey was conducted, a condition that, as discussed further below, seems to favor invasion by Canada thistle (see Photograph NOX3-608 in Appendix C). As elsewhere, Canada thistle continues in a line of individuals scattered along a shoreline footpath extending north from the boat launch area (NOX2- 703, NOX2- 704), Here it occurs primarily among grasses and again at approximately 10 percent cover. The surrounding vegetation type is a sagebrush upland, As at the east campground/launch area, the presence of these weedy areas is due to the high level of pedestrian and vehicular use. Canada thistle also occurs under rather different conditions at a number of sites at the Williams Fork Reservoir. Large expanses along the south and west shores of the reservoir are areas of low relief typified by sagebrush uplands with a variable band of grasses (primarily smooth brome) extending downslope to the reservoir or, in some cases, grading into emergent wetlands along the shore. Photographs representing typical site conditions of this vegetation type are provided in Appendix C as NOX3-604 and NOX3- 607, Canada thistle occurs in patches throughout many of these meadows, where it clearly occupies somewhat moister sites of a subirrigated nature (NOX3-604 through NOX3-607, NOX3-610), At some locations, these moist sites appear to be the result of alluvial seepage from adjacent shallow hillsides, and at others they may be the result of seasonal inundation. Several populations appear as narrow lines of Canada thistle within the grass community, just below the edge of the sagebrush and just above the shoreline or the high water mark (NOX2-70 I, NOX2-702, NOX2-705) (see Photograph NOX2-702 in Appendix C. At NOX3-606, Canada thistle is scattered along the erosion line of the reservoir margin in thick rabbitbrush (Chrysothamnus nauseosus), Canada thistle also occurs in some very wet meadows supporting willows (Salix spp.) (NOXI-529, NOXI- 529, NOX3-613, NOX3-614). The latter habitat is shown in Photograph NOX3-613a of Appendix C. The occurrence of Canada thistle at these latter sites does not seem to be associated with site disturbance, Rather, the species appears to have invaded healthy vigorous range, pasture, or meadow communities in response to a favorable moisture regime, Note that the wetland status of Canada thistle in the Intermountain Region is "facultative upland" (F ACU), which means that the probability of its occurring in wetland situations may be Williams Fork ReservOIr Hydroelectric Project January 2004 Stelgers Corporation Noxious Weed SUlVey Report Page 6