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Effects on Habitats According to Fish and Wildlife Service aerial surveys, spring crane utilization of the Platte correlates well to these points of flow diversion and return. For example, on April 7, 1977, 8,184 cranes were counted from Chapman west to CNPP&ID's Johnson Return whil e only one crane was observed from upstream of the diversion return west to Brady. (Note: This was an index count and was not designed to count the majority of the cranes. At the time of the count, roughly 250,000 cranes were in the area; but most had left the river at the time of the flight (FiSh and ~Jildlife Service, 1977)). BaSically, flow depletions have transformed the Brady-Lexington reach of the Platte River from a wide, shallow, un vegetated channel with excellent visibility to a narrow, timber-choked channel with poor ' vis ibil ity (Fish and Wil dli fe Servi ce, 1976). Such degradation renders the river habitat useless for cranes (FiSh and Wildlife Service, 1977). This habitat deterioration may be readily verified by a comparison of 1938 and 1969 aerial photos of the Platte River. Fish and Wildl He personnel in the Grand Island office have arranged 19 such comparison transects, each 2 miles wide. The transects were selected on a stratified-random basis and represent about a 23 percent sample (Fish and Wildlife Service, 1977). \, 'e_ , As mentioned previously, the encroachment of woody vegetation is inhibited by scour during high flows, and by ice jam washouts and ice- induced scouring. The relative importance of the usual peak flows during April-June versus those occurring during the December-'f4arch ice-affe'cted period in prOviding scour is not known (Geolbgical Survey, 1975). . , '..' " However, according to the Fish and Wildlife Service (1976), severe flow depletions, such as those which have occurred betvleen Brady and Lexington, negate the river's natural capacity to prevent tree encroachment. And thi s, coupl ed with the concurrent constri ction of the wetted stream perimeter and loss of shallow sandbar habitat, eliminates sandhill crane use. Sandhills will completely shun habitat which does not offer good visibility and shallow, open sandbars (Fish and Wildlife Service, 1977). Historically, wet meadows adjacent to the Platte River have been lost to crop production, sand and gravel mining, golf courses, businessE!sL___, "and highways (Fish and Wildlife Service, 1977). Any of these activities pennanently eliminates the value of this habitat type to cranes. This continuing reduction in quantity of wet meadow habitat is a threat to the viability of the sandhill crane populations. The cranes depend on the wet meadow habitat for sources of animal protein. Animal protein is an essential part of the cranes' diet, supplementing the vegetable fiber supplied by crop residues. " 30 I