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<br />construction has created many sandbars between the dikes and many nesting <br />colonies are located on these sandbars (Landin et al. 1985, Rumancik 1986, <br />1987, 1988, 1989; J. Smith 1985, 1986, 1987). The extent to which these <br />sandbars are attaching to the riverbank and reducing tern habitat is not <br />,known but according to Smith and Stucky (1988) the processes of dike field <br />terrestrialization are well underway at several least tern colony sites in <br />,the lower Mississippi River. <br /> <br />Reservoir storage of flows responsible for scouring sandbars has <br />resulted in the encroachment of vegetation along many rivers such as the <br />Platte River, Nebraska and greatly reduced channel width (Currier et al. <br />1985, O'Brien and Currier 1987, Eschner et al. 1981, Lyons and Randle <br />1988, Sidle et al. 1989, Stinnett et al. 1987). In addition, river main <br />stem reservoirs now trap much of the sediment load resulting in less <br />aggradation and more degradation of the river bed and subsequently less <br />formation of suitable sandbar nesting habitat. Riverine habitat along the <br />central Platte River may require extensive vegetation clearing and other <br />intensive management. In contrast, the lower Platte River (Columbus, <br />Nebraska to the Missouri River confluence) has not undergone as extensive <br />habitat changes as the central Platte. During 1987-1989, riverine sandbar <br />habitat hosted 72% of the nests on the lower Platte and only 12% of the <br />nests on the central Platte (Kirsch 1989, Lingle 1989). <br /> <br />".f <br /> <br />Human disturbance: Many rivers have become the focus of recreational <br />activities. Human presence reduces reproductive success (Mayer and Dryer <br />1988, Smith and Renken 1990). In mid-America, sandbars are fast becoming <br />the recreational counterpart of coastal beaches. Even sand and gravel <br />pits and other artificial nesting sites receive a high level of human <br />disturbance. <br /> <br />Conservation Efforts <br /> <br />During the past few years there has been a great increase in the number <br />of interior least tern surveys, research projects and public relations <br />endeavors to protect the birds on the part of both public and private <br />conservation organizations. Proposed federal listing qf the interior <br />least tern prompted much of the interest in the northern G'reat Plains and <br />elsewhere. Today. many state, federal and private organizations are <br />collaborating to census the birds, curtail human disturbance and conduct <br />research. <br /> <br />Under authority of Section 7 of the Endangered Species Act, the U. S. <br />Fish and Wildlife Service is consulting with the U. S. Army Corps of <br />Engineers on whether dam operations on the Missouri and Arkansas Rivers <br />jeopardize the continued existence of the interior least tern (U.S Fish <br />and Wildlife Service 1989, 1990). The outcome of these formal <br />consultations is crucial to the recovery of the interior least tern. <br />Areas of habitat along the Missouri River, for example, continue to <br />degrade due to physical controls on the river and present water management <br />schemes. Changes in the water release regime and physical manipulation of <br />habitat will be necessary. <br /> <br />23 <br />