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Fluctuation in releases may be additive to extreme weather problems. For example, fluctuation in <br />releases and elevated water levels at Lewis and Clark Lake in 1989 resulted in bird mortality, but <br />mortality increased when cold, rainy weather followed. As discussed previously, birds are forced to <br />nest at lower elevations or closer to the water when habitat is limited by System operations. Such <br />operation does not allow much room for wave and wind action. Any increase in flows during nesting, <br />which brings water levels within a few inches of the nest, subjects the nest to increased pressure by <br />wave or wind action. Wave action was documented by Schwalbach (1988) for nest losses in 1986 <br />and 1987 on the Missouri River. <br />Sandbar erosion, due at least in part to dam operations (fluctuation extremes and intensity of releases), <br />also has caused the loss of habitat as well as nests on the Missouri River (Dirks and Higgins 1988, <br />Mayer and Dryer 1989). The high number of abandoned nests, numerous renesting attempts, and low <br />fledging success in 1986 was reflective of operational or high -water effects on nesting area suitability <br />and hence low productivity (Schwalbach 1988). Schwalbach (1988) found many sandbars were low <br />profile (less than 18 in [45.7 cm] above surface water) below Gavins Point Dam in 1986 and below <br />Fort Randall in 1986 and 1987 and, therefore, were subject to wave actions or small changes in water <br />levels. <br />Data collected to look at habitat suitability for terns and plovers on the Gavins Point and Fort Randall <br />reaches indicate that flooding, vegetative encroachment, and recreational activity all affect site selection <br />by the birds (Schwalbach 1988). In comparison with other areas, Schwalbach (1988) found Gavins <br />Point sandbar sites moderately stable (57 percent of the tern sites and 55 percent of the plover sites <br />were either new or abandoned) and Fort Randall sandbar sites highly unstable (78 percent of the tern <br />sites and 100 percent of the plover sites were either new or abandoned). <br />Pallid Sturgeon <br />MR and KR Operations and the operations and maintenance of the BSNP will continue to affect pallid <br />sturgeon by decreasing the quantity and quality of aquatic habitat in the Missouri River, thus, (1) <br />reducing larval and juvenile rearing habitat; (2) reducing the availability of seasonal refugia; (3) reducing <br />the forage base of pallid sturgeon by reducing nutrient cycling and habitat diversity in the Missouri <br />River; (4) reducing pallid sturgeon staging and spawning cues and (5) increasing hybridization with the <br />shovelnose sturgeon. cam &,� <br />Modified Hydrograph - Missouri River main stem dam operations currently reduce flows from April <br />to July for flood control, and increase flows from July to November for primarily navigation, <br />hydropower, flood control and water supply. Before impoundment behind reservoirs, two periods of <br />peak discharge occurred on much of the Missouri River (above St. Joseph, MO); one in April from <br />spring runoff and snowmelt on the Great Plains and a second higher peak in late May to early June from <br />mountain snowmelt. The spawning period for pallid sturgeon, which is believed to occur from late April <br />Effects - MR - Ps 217 <br />