Great Plains Natural Science Society


The Prairie Naturalist

Date of this Version


Document Type



The Prairie Naturalist 45: 106–108. December 2013


Published by the Great Plains Natural Science Society, 2013. United States government work. Public domain material.


Salt concentrations in lakes are dynamic. In the western United States, water diversions have caused significant declines in lake levels resulting in increased salinity, placing many aquatic species at risk (Galat and Robinson 1983, Beutel et al. 2001). Severe droughts can have similar effects on salt concentrations and aquatic communities (Swanson et al. 2003). Conversely, large inputs of water can dilute salt concentrations and contribute to community shifts (Euliss et al. 2004).

Chase Lake is a large, shallow, alkaline lake in east-central North Dakota most famously known for supporting one of the largest breeding colonies of the American white pelican (Pelecanus erythrorhynchos) in North America (Sovada et al. 2005). Chase Lake was designated as a National Wildlife Refuge in 1908 to protect the American white pelican breeding colony, and in 2003 it was identified as a Globally Important Bird Area by the American Bird Conservancy. The physiographic region around Chase Lake has experienced a prolonged period of above-normal precipitation that began in 1993 (Winter and Rosenberry 1998). The resulting increase in water levels and associated dilution of salt concentrations in the closed basin of Chase Lake has led to a reshaping of the lake’s aquatic community.