Threats to Wildlife and the Platte River

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WILDLIM p. 21 inherently limited in their ability to determine the specific needs of this endangered species (and other species of concern). Danger lies in the fact that, in the case of the Whooping Crane, the physical parameters of their roosting habitat requirements set forth by the Fish and Wildlife Service as part of the Platte River Management Joint Study (see chapter IV) are preliminary.8 While computer modelling can be an effective analytical tool, the results are only as good as the information fed into the program. Yet, computer models have become a popular means of trying to resolve development conflicts. While analytical techniques are continually being refined and new (perhaps critical) data on the Whooping Crane are being gathered, Audubon suggests that a margin for error be included in recommendations for wildlife (see chapter III) until more definitive conclusions can be drawn about species' needs. If no margin for error is included in agency assessments of the habitat needs for survival and recovery of Whooping Cranes, development on the river may be allowed to increase beyond the true (yet unknown) critical point and the habitat could be lost forever. Bald Eagles The endangered Bald Eagle symbolizes our country more perfectly in the late twentieth century than the founding fathers could have imagined: bold, beautiful, and diminished by a deteriorating environment. Bald Eagles nest in Wyoming and Colorado, but not in Nebraska at present. Nonetheless, the Nebraska portion of the Platte is an important wintering ground for Bald. Eagles, and their population in the state has increased dramatically in the past 30 years. In 1983, Nebraska ranked 13th out of 46 states in number of wintering eagles (NGPC 1985a, p 30). Approximately 150 -250 eagles spend the winter on the Platte between North Platte and Kearney (Currier et al. 1985, p 30). As much as 30 percent of the statewide population may winter in the 36 -mile stretch between Lexington and Kearney (NGPC 1985a, p 33). The needs of Bald Eagles are somewhat different than those of cranes, and eagles rely on the Platte River at a different time of year. Winter often is the most stressful period of the annual cycle for species that spend it in cold climates. Thus, even if summer breeding productivity is high, annual survival can be very low if good wintering habitat is not available. 8 The Ziewitz model, used by the Platte River Trust and based on FWS/PRMJS- determined cri- teria, evaluates only short-term consequences of discharge ( Ziewitz 1987, p 6), and does not address the essential long -term aspects of channel morphology, sediment movement, vegetative encroachment, and wetland maintenance. See table 2D for a comparison of flow evaluations.