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Expansive, positive changes to habitat diversity following the formation of a valley plug in a degraded desert river
  • Tansy T. Remiszewski,
  • Phaedra Budy,
  • William Macfarlane
Tansy T. Remiszewski
Utah State University SJ and Jessie E Quinney College of Natural Resources

Corresponding Author:[email protected]

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Phaedra Budy
Utah State University SJ and Jessie E Quinney College of Natural Resources
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William Macfarlane
Utah State University SJ and Jessie E Quinney College of Natural Resources
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Abstract

Widespread hydrologic alterations have simplified in-stream habitats in rivers globally, driving population declines and local extirpations of many native fishes. Here, we examine how rapid geomorphic change in a historically degraded desert river has influenced habitat diversification and ecosystem persistence. In 2010, a large reach of the degraded and simplified lower San Rafael River (SRR), Utah, was impacted by the formation of a valley plug and began to shift from a homogenous, single-thread channel to a complex, multi-threaded riverscape. We combined field measurements and drone-collected imagery to document habitat changes due to the valley plug. Our results demonstrate that in 2021, the valley plug reach was more diverse than any other stream reach along the SRR, containing 641% more diverse habitat (e.g., pools, riffles, backwaters) than what was measured in 2015. The plug reach also retained water for periods beyond what was expected during seasonal drying, with the total extent of inundation within the riverscape increasing by over 2,800%. Since the formation of the valley plug, riparian habitat has increased by 230% and channel networks have expanded to more than 50 distinct channels throughout the zone of influence. Our results provide evidence of successful self-restoration in a formerly highly degraded reach of desert river, and encourage new methods of desert river restoration. We aim to inform the use of large-scale, disruptive restoration actions like intentional channel occlusions, with the goal of mitigating the impacts of simplification and increasing habitat persistence in the face of exacerbated aridity in the desert Southwest.
26 Dec 2022Submitted to River Research and Applications
26 Dec 2022Submission Checks Completed
26 Dec 2022Assigned to Editor
05 Jan 2023Review(s) Completed, Editorial Evaluation Pending
05 Jan 2023Reviewer(s) Assigned
04 Jun 2023Editorial Decision: Revise Major
06 Aug 20231st Revision Received
08 Aug 2023Submission Checks Completed
08 Aug 2023Assigned to Editor
08 Aug 2023Review(s) Completed, Editorial Evaluation Pending
09 Aug 2023Reviewer(s) Assigned
04 Sep 2023Editorial Decision: Accept