Climate-driven dynamics of lakes and wetlands in the Rainwater Basin, Nebraska and its ecological implications

Lakes and wetlands of the Midwest of the United States serve as an important stopover point for millions of migrating birds making their way along the Central Flyway (Poor 1999). The Rainwater Basin (RWB), located in south-central Nebraska, corresponds to the narrowest part of the Central Flyway through which an estimated 9.8 million waterfowl pass through each spring (Bishop & Vrtiska 2008b). Due to intensive agriculture, lakes and wetlands in the area have suffered greatly (Price & Brand 1984, Bishop & Vrtiska 2008a). However, the total extent of the damage and its impact on the migrating waterfowl are relatively unknown. Preliminary work shows the RWB contains thousands of shallow lakes and wetlands that cover slightly more than 10,000 square kilometers (Utrup & Davis 2007). Surface-water basins are sealed by a low-permeability layer of wind-blown silt loam (Tiner 2003). Thus, the water balance is dominated by snow melt and rain accumulation (Dappen et al. 2001). The goal of this research is to investigate the hydrologic responses of the water bodies in the RWB as a function of climate variability and to elucidate their associations with migratory birds. Climatic data were obtained from the National Climatic Data Center to determine the long-term variability in climate with respect to residual moisture. Satellite (i.e., LANDSAT TM) images were obtained and processed for 14 years between 1986 and 2010 and habitat networks were created to represent theoretical paths traveled by waterfowl during their stopover in the RWB. The results of this study showed dramatic variations in water-body numbers and areas in the RWB in the past few decades, and such variations in water bodies could be attributed to the fluctuation of residual moisture. This study also found that variability in the populations of migratory birds (in both individual and species counts) correlate with the water-body areas and numbers, which could provide useful implications for the habitat conservation of the RWB.A five-year embargo was granted for this item.Academic Major: Earth Science