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EXECUTIVE SUMMARY <br />The Central Nebraska Public Power and Irrigation District and the Nebraska Public <br />Power District purchased approximately 2,700 ha of property along the central Platte <br />River in two parcels, Jeffrey Island and Cottonwood Ranch. The purchase of this <br />property was required as part of their FERC license to operate hydroelectric power plants <br />on the North Platte, South Platte, and central Platte River systems. Biological monitoring <br />to develop a baseline, and subsequent monitoring to evaluate the effects of planned <br />restoration activities is also required. This report presents the results of a baseline <br />vegetation survey conducted at the Jeffrey Island and Cottonwood Ranch properties in <br />2001. The survey was designed to collect vegetation data that is representative of the <br />properties as a whole. <br />Eight land cover types occurred on Jeffrey Island and Cottonwood Ranch. Three were <br />non - vegetated, including Open Water, Open Water Canal, and Wetted Channel. <br />Agricultural fields included those areas that were actively cultivated in monoculture <br />crops at the time of the survey. The remaining cover types were vegetated and are <br />described herein. <br />Exposed Sand Beach / Bar: Exposed sand beach/bar included areas such as inactive <br />channels, islands, point bars, and areas adjacent to active channels with exposed sandy <br />soils and relatively low vegetative cover. This cover type occurred more frequently at <br />Jeffrey Island (found on 24 transects) than at Cottonwood Ranch (found on 1 transect). <br />Vegetative cover averaged 58 percent at Jeffery Island and averaged 78 percent at <br />Cottonwood Ranch. Plant species found in these areas are adapted to the dry, sandy soils, <br />and are often weedy pioneer species. Common species found in this cover type included <br />western sagewort (Artemesia campestris), common sunflower (Helianthus annus), yellow <br />sweetclover (Melilotus officinalis), common ragweed (Ambrosia artemisiifolia), and <br />grasses such as downy brome (Bromus tectorum) and sand dropseed (Sporobolus <br />cryptandrus). Occasional depressions or low spots in this cover type with standing water <br />or groundwater near the soil surface supported emergent wetland species. <br />Emergent Wetland: Emergent wetlands were found on saturated and inundated soils <br />where water depths did not exceed one meter. At Jeffrey Island and Cottonwood Ranch, <br />emergent wetlands were found in swales, drainages, and along riverbanks, pond margins, <br />and ditches. At Cottonwood Ranch, emergent wetlands were also found in some inactive <br />river channels that cut through the forest. Emergent wetlands occurred on 17 of 35 <br />transects at Jeffrey Island and on 12 of 13 transects at Cottonwood Ranch. Vegetative <br />cover in emergent wetlands averaged 74 percent at Jeffrey Island and averaged 84 <br />percent at Cottonwood Ranch. Common species found in the emergent wetlands included <br />cattail (Typha latifolia), which was often found in dense, monotypic stands, various <br />bulrushes (Scirpus spp.) and sedges (Carex spp.), reed grasses such as common reed <br />(Phragmites australis) and reed canarygrass (Phalaris arundinaceae), and northern fog - <br />fruit (Lippia lanceolata). Dense patches of sandbar willow were found at some emergent <br />wetland sites, but most were dominated by herbaceous species. <br />