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4.0 Study Area Description <br /> Site Description <br /> The project area consists of approximately 72.8 acres of lowland-riparian habitats and <br /> agricultural lands along the Colorado River corridor. A significant portion of the <br /> Property is flood-irrigated, and there is one major irrigation ditch system (Bernudy Ditch) <br /> serving other properties which flows through the parcel from east to west. The Property <br /> has historically been used as a ranch,both for grazing and hay production. There are a <br /> number of fences, 2-track access roads, extensive irrigation lateral ditches, old culverts <br /> and other farming implements and debris scattered throughout the parcel. Much of the <br /> property falls within the historical floodplain of the Colorado River and contains remnant <br /> cottonwood galleries and evidence of some old floodplain channels, mainly on the <br /> northern half of the parcel,though none currently show any evidence of recent <br /> inundation. <br /> Vegetation <br /> The Property contains a significant area of planted hayfields and pastures, mainly <br /> consisting of Orchardgrass(Dactylis glomerata), Smooth brome(Bromus inermis), <br /> redtop bentgrass (Agrostis stolonifera), Kentucky bluegrass (Poa pratensis), red fescue <br /> (Festuca rubra)and some alfalfa(Medicago sativa). Flood irrigation activities have also <br /> promoted hydrophytes to establish in the more low-lying areas, and these include Arctic <br /> rush (Juncus arcticus), Clustered field sedge(Carex praegracilis),tall scouring rush <br /> (Equisetum hyemale), inland saltgrass(Distichlis spicata)and beaked sedge (Carex <br /> utriculata). <br /> Upland areas consist of two distinct vegetation communities: mature cottonwood <br /> galleries or sagebrush/rabbitbrush shrublands. The cottonwood galleries generally occur <br /> along the riparian corridor near the river and along the old floodplain channels. These are <br /> dominated by an overstory of mature narrowleaf cottonwood(Populus angustifolia)and <br /> Fremont cottonwood(Populus fremontii)with a dense mid-story of invasive Russian <br /> olive(Elaeagnus angustifolia)and Siberian elm (Ulmus pumila). Many of the <br /> cottonwoods are dead-standing and the remainder are very mature, old trees nearing the <br /> end of their life cycle. The herbaceous understory is generally sparse consisting of <br /> intermediate wheatgrass (Thinopyrum intermedium), smooth brome (Bromus inermis), <br /> orchardgrass(Dactylis glomerata), globemallow(Sphaeralcea coccinea)and weedy <br /> forbs such as musk thistle(Carduus nutans),houndstongue (Cynoglossum officinale)and <br /> curlycup gumweed (Grindelia squarossa). <br /> The drier uplands are dominated by big sagebrush(Artemisia tridentata), rabbitbrush <br /> (Chrysothamnus nauseosus)and some Greasewood (Sarcobatus vermiculatus)with an <br /> understory of Basin wildrye (Elymus cinereus), Western wheatgrass (Agropyron smithii), <br /> Quackgrass(Elymus repens) and a variety of weedy species, including Kochia(Kochia <br /> scoparia), Russian knapweed(Acroptilon repens), Scotch thistle(Onopordum <br /> acanthium), cheatgrass (Bromus tectorum),Horseweed(Conyza canadensis) and Prickly <br /> lettuce (Lactuca serriola). The upland sites have an extensive infestation of Russian <br /> 4 <br />