Threats to Wildlife and the Platte River

Home Browse Search

p. 15 The crowding of cranes increases their vulnerability to major disturbances such as disease outbreaks, oil spills, 3 and pesticide runoff from adjacent agricultural lands. Any circumstance resulting in heavy mortality (e.g., an avian cholera outbreak) could deal a serious blow to the Sandhill population. "Loss of riparian habitat is of particular concern because crowding caused by habitat deterioration increases the potential for high crane - mortality from severe storms and disease" ( Krapu 1981). Sandhill Cranes' potential for recovery would be limited because of their slow reproductive rate. These cranes do not breed until their third yea? and normally raise one chick per summer (Boise 1979; Buller 1979 in Krapu et al. 1982). If the Platte becomes entirely unsuitable for cranes, it is doubtful that they could compensate by using other areas, and a large -scale population decline would probably result. This is because there is little alternate suitable habitat on the Great Plains, and nothing that compares in quality with the Platte valley. Indeed, "Loss of habitat elsewhere along the migration route probably has... contributed to increased use of the Nebraska staging areas... The present high densities of cranes using available roost sites... indicate a need for measures to limit further loss of channel habitat" ( Krapu et al. 1984, p 415). The Fish and Wildlife Service recently designated two critical stretches of the Platte as Resource Category 15: an 80 -mile stretch between Overton and Chapman on the Platte River in Nebraska for Sandhill Cranes and Greater White- fronted Geese, and a 20 -mile area on the North Platte between Sutherland and the town of North Platte for Sandhill Cranes (U.S. Dept. of Interior 1987). As habitat conditions deteriorate, cranes are becoming increasingly restricted and vulner- able. How tragic that these birds, which annually travel thousands of miles borne by their own muscle and inner urgings, have nowhere to run. The beauty and grace of cranes has long been an inspiration; a Buddhist poem says, "No provisions are given to the wild cranes, but the heavens and 3 Oil spills are a valid concern along the North Platte, considering Wyoming is a major oil pro- ducing state. In April 1980, an oil spill occurred on the North Platte near Glenrock. A pipeline ruptured, causing approximately 8,550 barrels (360,000 gal.) of oil to spill into the river. An oil slick extended for 106 km (66 miles) on the North Platte, affecting 1,900 animals of 66 different species. (M. Wilson, pers. comm. in Lingle 1987, p 333). 4 New data indicate that Sandhill Cranes do not breed until they are 5 -7 years old (Tacha 1988, written comm.). 5 Resource Category 1 habitat is a federal classification recognizing significant habitat -- unique and irreplaceable- -for nonendangered species (see chapter VII).