Draft Baseline Report - Least Turn and Piping Plover Section

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Background Population Ecology Least Tern Population Ecology The interior population of the least tern (Sterna antillarum) was listed as an endangered species on May 28, 1985 (50 FR 21792). The least tern in the interior of North America were historically distributed along the major rivers including the Arkansas, Colorado, Mississippi, Missouri, Platte, and Rio Grande (Boyd and Thompson 1985, Ducey 1985 in Wilson et al. 1993). Past surveys have shown that over 50% of the interior least tern population occurs in the Mississippi River between Osceola, Arkansas, and Cairo, Illinois; the Salt Plains National Wildlife Refuge in Oklahoma; and the Platte River in Nebraska (Shoemaker 1988 in Wilson et al. 1993). The historic and current distribution of least terns and piping plovers is shown in lirgure lto b u�oluced) Kirsch and Sidle (1999) compiled data from 1984 to 1995 of breeding interior least tern populations, and estimated population trends at 31 local areas in the Great Plains that had been surveyed three or more years within the 12 -year period. They found that five areas had significant positive population trends, two areas had significant negative trends, and no trends were detected at 24 of the local areas. The central Platte River was one of the local areas for which no trend was detected. Local breeding areas fluctuated substantially, year -to -year (Kirsch and Sidle 1999). Piping Plover Population Ecology The piping plover (Charadrius melodus) was listed as a threatened species on December 11, 1985 (50 FR 50733). The piping plover has been extirpated from Illinois, Indiana, Ohio, Pennsylvania, and New Hampshire (Russell 1983, Haig and Oring 1985 in Gaines 1988). The Great Plains population has continued to decline from an estimated 1,500 pairs in 1985 to less than 1,100 pairs in 1990 (Great Lakes and Northern Great Plains Piping Plover Recovery Team, Unpub. Data, in Root et al. 1992). Most Great Plains nesting areas that have been monitored for a minimum of 10 years have experienced a population decline of piping plovers, with an overall decrease of 13 percent between 1987 and 1991 (Haig and Plissner 1992). The 1996 International piping plover census reported a total of 3,332 birds, including 1,398 pairs, found at 340 sites in the Canadian Prairie and U.S. Great Plains rivers, reservoirs and other wetlands. This represented a 5.0% decline since the 1991 International census over the same region ( Plissner and Haig 1996). In Nebraska, the International piping plover census recorded a total of 398 piping plovers in 1991, and 366 piping plovers in 1996. This represented an 8% (32 adults) decline in Draft Baseline Report, July 2002 4 -3