OutdoorNebraska

50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 GUIDE TO NEBRASKA'S WETLANDS called the Lower North Platte River (LaGrange 2005), but was changed to Platte Confl uence to conform with the Nebraska Natural Legacy Project (Schneider et al. 2011). This wetland complex consists of riverine and palustrine wetlands lying within the historically active fl oodplain and channel of the river. Temporarily and seasonally fl ooded vegetated wetlands comprise an estimated 80% of all wetlands in the Platte Confl uence. There are also extensive wetlands all along the North Platte River upstream of Sutherland. Many of these wetlands are included within the Western Alkaline Wetland complex. Loss and Threats Sidle et al. (1989) reported the active river channel width between North Platte and Lake McConaughy has declined 85% since 1860. Wet meadow acreage losses along the North Platte River were estimated to be 23-33% since 1938, though many of the farmable meadows already were converted and under gravity irrigation prior to 1938 (Sidle et al. 1989). Additionally, an increase of scrub-shrub and forested wetland types has occurred at the expense of riverine and emergent wetlands as a response to decreased instream fl ows and increased sediment storage in upstream reservoirs. This wetland complex was given a Priority 2 ranking in the Nebraska Wetlands Priority Plan (Gersib 1991)because of extensive past losses. Agricultural conversion, groundwater depletions, and sand and gravel mining operations pose the greatest short-term threats to wet meadows adjacent to the North Platte River. Residential and commercial developments commonly encroach on wet meadows after drainage, fi lling, or the mining of sand and gravel. Groundwater depletions and degradation of the riverbed will continue to affect the remaining wet meadows in the long-term. Impoundments and the diversion of river water and sediment are the main factors that have caused and will continue to cause the shift from a wide, shallow, open channel to a narrow, deep one bordered by uplands or scrub-shrub/ forested wetlands. Benefi ts During the spring, about 220,000 migrating sandhill cranes spend up to six weeks feeding and resting in the Platte Confl uence complex and along the North Platte River upstream of Lake McConaughy to Oshkosh and the lower ends of adjacent tributaries such as Blue Creek and Birdwood Creek (Caven et al. 2020, Varner et al. 2020). Sandhill cranes roost in the river and wet meadows at night and forage in wet meadows, grassland, and cropland during the day. Endangered whooping cranes occasionally use this stretch of river during both spring and fall migrations. Migrating and wintering waterfowl use the river and associated wet meadows (Varner et al. 2020). The entire North Platte River is the most important area in the state for wintering Canada geese and is one of the most important for wintering mallards (Matt Garrick, Nebraska Game and Parks, pers. comm.). The Platte Confl uence and its associated aquifer provide municipal and irrigation water supplies (Missouri River Basin Commission 1976). During high-fl ow periods, the river recharges the underlying aquifer. Because the Platte River system, including the Platte Confl uence, is highly regulated by a series of upstream reservoirs and diversions for irrigation and power district canals, the groundwater discharge and recharge functions of the river and associated wetlands have been signifi cantly altered from natural conditions (Missouri River Basin Commission 1976). Although upstream reservoirs on the North Platte River provide considerable fl ood protection, the continued loss of wetlands and channel capacity increases the future chances of fl ood damage. Waterfowl hunting and fi shing occur in the Platte Confl uence (Anderson et al. 1989). A survey by the University of Nebraska indicated that Nebraskans have a keen interest in a variety of recreational activities available in this complex and support further efforts to provide these recreational opportunities (Bureau of Sociological Research 1988). Conservation Success Stories Over the past 15 years, dense stands of invasive trees, including Russian olive, have been removed from the North River Wildlife Management Area, and grazing and fi re management strategies have been implemented. At the nearby Muskrat Run Wildlife Management Area, similar improvements were initiated. These actions have opened up the The North Platte River provides important habitat for Canada geese during the winter months. JULIE GEISER, NEBRASKALAND

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