Local and landscape level variables influencing migratory bird abundance, diversity, behavior, and community structure in Rainwater Basin wetlands

• Main Author: Brennan, Elisabeth K.
• Other Authors: Wilde, Gene R., McIntyre, Nancy E., Strauss, Richard E., Vrtiska, Mark, Smith, Loren M.
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2006
• Subjects: Species richness; Conservation; Landscape; Migration; Playas; Wetland birds; Rainwater basin; Canada; Anas acuta; Branta canadensis
• Online Access: http://hdl.handle.net/2346/985

The Rainwater Basin (RWB) region in south-central Nebraska, which currently contains approximately 400 wetlands, is one of the most threatened and least studied wetland complexes in the Great Plains. Early soil surveys indicate the RWB originally included more than 4,000 natural wetland basins, totaling approximately 38,000 ha; however, conversion of wetlands to agricultural fields has resulted in the destruction of over 90% of the wetlands and 88% of the original wetland area. Even in their reduced, degraded condition, RWB wetlands provide essential stopover and staging areas to migratory wetland birds in the Central Flyway. Consequently, the RWB region has been identified as containing waterfowl habitat of major concern by the North American Waterfowl Management Plan. Five to 7 million waterfowl pass through the RWB region every spring, including virtually all of the 600,000 mid-continental white-fronted geese (Anser albifrons), 500,000 Canada geese (Branta canadensis), 50% of the mid-continental mallard (Anas platyrhynchos) population, and 30% of the continental northern pintail (Anas acuta) population. Staging areas and migratory stopovers often function as geographic bottlenecks; entire populations within a flyway can be affected by the quality and quantity of available wetland habitat at stopover sites. This common dependence among migratory birds on staging sites has major implications for wetland conservation and restoration. In an effort to guide wetland stopover site restoration and conservation efforts, there has been an increased effort to determine what factors influence wetland habitat quality for migrating shorebirds and waterfowl. Although previous studies have shown that local and landscape-level factors influence abundance, diversity, and behavior of breeding birds on wetlands, few studies have assessed the impact of these factors on wetland birds during migration. Moreover, examination of wetland bird habitat use, behavior, and community structure provides the opportunity to test hypotheses ...