Groundwater declines are linked to changes in Great Plains stream fish assemblages

Proceedings of the National Academy of Sciences of the United States of America
By: , and 

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Abstract

Groundwater pumping for agriculture is a major driver causing declines of global freshwater ecosystems, yet the ecological consequences for stream fish assemblages are rarely quantified. We combined retrospective (1950–2010) and prospective (2011–2060) modeling approaches within a multiscale framework to predict change in Great Plains stream fish assemblages associated with groundwater pumping from the United States High Plains Aquifer. We modeled the relationship between the length of stream receiving water from the High Plains Aquifer and the occurrence of fishes characteristic of small and large streams in the western Great Plains at a regional scale and for six subwatersheds nested within the region. Water development at the regional scale was associated with construction of 154 barriers that fragment stream habitats, increased depth to groundwater and loss of 558 km of stream, and transformation of fish assemblage structure from dominance by large-stream to small-stream fishes. Scaling down to subwatersheds revealed consistent transformations in fish assemblage structure among western subwatersheds with increasing depths to groundwater. Although transformations occurred in the absence of barriers, barriers along mainstem rivers isolate depauperate western fish assemblages from relatively intact eastern fish assemblages. Projections to 2060 indicate loss of an additional 286 km of stream across the region, as well as continued replacement of large-stream fishes by small-stream fishes where groundwater pumping has increased depth to groundwater. Our work illustrates the shrinking of streams and homogenization of Great Plains stream fish assemblages related to groundwater pumping, and we predict similar transformations worldwide where local and regional aquifer depletions occur.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Groundwater declines are linked to changes in Great Plains stream fish assemblages
Series title Proceedings of the National Academy of Sciences of the United States of America
DOI 10.1073/pnas.1618936114
Volume 114
Issue 28
Year Published 2017
Language English
Publisher National Academy of Sciences of the United States of America
Contributing office(s) Coop Res Unit Seattle
Description 6 p.
First page 7373
Last page 7378
Country United States
State Colorado, Kansas, Nebraska
Other Geospatial Great Plains