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<br />Effects on Habitats <br /> <br />According to Fish and Wildlife Se~viceaerial surveys, spring crane <br />utilization of the Platte correlates well to these points of flow <br />diversion and return. For example, on April 7, 1977, 8,184 cranes. <br />were counted from Chapman west toCNPP&ID's Johnson Return while only <br />one crane was observed from upstream of the diver-sion return west to <br />Brady. (Note: This was an index count and was not designed to count <br />the majority of the cranes. At the time of the count, roughly 250,000 <br />cranes were in the area, but most had left the river at the time of <br />the flight (Fish and Wildlife Service, 1977)). <br /> <br />Basically, flow depletions have transformed the Brady-Lexington reach <br />of the Platte River from a wide, shallow, unvegetated channel with <br />exc;ellent visibility to. a narrow, timber.,.cho,ked<;hQnnelwith poor . <br />visibility (Fish and Wildlife Service, 1976). Such degradation renders <br />the river habitat useless for cranes (Fish and Wildlife Service, 1977). <br />This habitat deterioration may be readily verified by a comparison of <br />1938 and 1969 aerial photos of the Platte River. . Fish and Wildlife <br />personnel in the Grand Island office have arranged 19 such comparison <br />transects, each 2 miles wide. The transects were selected on a <br />stratified-random basis and represent about a 23'percent sample (Fish <br />and tlildlife Service, 1977). - <br /> <br /> <br />As mentioned previously, the encroachment of woody vegetation is <br />inhibited .by scour during high .flows, and by ice jam washouts and ice- <br />induced scouring. The relative importance of the usual peak flows <br />during April-June versus those occurring during the December-March <br />i ce-a ffe.cted periOd in pravi di ng scour is not known (Geo logi ca 1 Survey, <br />1975). . . <br /> <br />However, according to the Fish and Wildlife Service (1976), severe <br />flow depl etions, such as those Which have' occurred between Brady .and <br />LeXington, negate the river's natural capacity to prevent tree <br />encroachment. And this, cOt.lpl ed with the concurrent constriction of <br />the wetted stream perimeter and loss of shallow sandbar habitat, <br />eliminates sandhill crane use. Sandhills will completely shun habitat <br />which does not offer good visibility and shallow, open sandbars (Fish <br />and Wildlife Service, 1977). <br /> <br />Historically, wet meadows adjacent to the Platte River have been lost <br />to crop production, sand and gravel mining, golf courses, businesses, <br />-H-and highways (FiSh and Wildlife Service, 1977). Any of these activlHeS-- <br />permanently eliminates the value of this habitat type to cranes.. This <br />continuing reduction in quantity of wet meadow habitat is a threat to <br />the viability of the sandhill crane populations. The cranes depend <br />on the wet meadow habitat for sources of animal protein. Animal protein <br />is an essential part of the cranes' diet, supplementing the vegetable <br />fiber supplied by crop residues. . .. <br /> <br />30 <br /> <br /> <br />.,,' . <br />.' .' <br /> <br />" .' <br /> <br /> <br /> <br />" ~ ' <br />