Leaf litter decomposition and detrital communities following the removal of two large dams on the Elwha River (Washington, USA)

Frontiers in Ecology and Evolution

Ecology and Evolution

Rebecca Mahan¹  Jacqueline Van Der Hout²  Carri J. LeRoy²  Sorrel Hartford²  Brandy K. Kamakawiwo’ole²  Ali Bailey²  Cameron Pennell²  Alex A. Zinck²  Caitlyn Oswell²  Paris J. Lamoureux²  Mary Silva²  Sarah A. Morley³  Justin Stapleton⁴  Roger Peters⁵  Melissa M. Foley⁶  Jeffrey J. Duda⁷  Rachelle C. Johnson⁷ 

[1] Clallam County Department of Community Development, Port Angeles, WA, United States;Tribal Environmental Quality Program, Lower Elwha Klallam Tribe, Port Angeles, WA, United States;Environmental Studies Program, The Evergreen State College, Olympia, WA, United States;Fish Ecology Division, National Marine Fisheries Service, National Oceanic and Atmospheric Association, Seattle, WA, United States;Tribal Environmental Quality Program, Lower Elwha Klallam Tribe, Port Angeles, WA, United States;U.S. Fish and Wildlife Service, Western Washington Fish and Wildlife Conservation Office, Lacey, WA, United States;U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA, United States;Resilient Landscapes Program, San Francisco Estuary Institute, Richmond, CA, United States;U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA, United States;

关键词: dam removal;    leaf litter decomposition;    aquatic–terrestrial interaction;    macroinvertebrate communities;    fungal communities;    aquatic decomposition;    ecological restoration;   

DOI  :  10.3389/fevo.2023.1231689

 received in 2023-05-30, accepted in 2023-10-03,  发布年份 2023

来源: Frontiers

【 摘 要 】

Large-scale dam removals provide opportunities to restore river function in the long-term and are massive disturbances to riverine ecosystems in the short-term. The removal of two dams on the Elwha River (WA, USA) between 2011 and 2014 was the largest dam removal project to be completed by that time and has since resulted in major changes to channel dynamics, river substrates, in-stream communities, and the size and shape of the river delta. To assess ecosystem function across the restored Elwha watershed, we compared leaf litter decomposition at twenty sites: 1) four tributary sites not influenced by restoration activities; 2) four river sites downstream of the upper dam (Glines Canyon Dam); 3) four river sites within the footprint of the former Aldwell Reservoir upstream of the lower dam (Elwha Dam); 4) four river sites downstream of the lower dam; and 5) four lentic sites in the newly developing Elwha delta. Three major findings emerged: 1) decomposition rates differed among sections of the Elwha watershed, with slowest decomposition rates at the delta sites and fastest decomposition rates just downstream of the upper dam; 2) aquatic macroinvertebrate communities establishing in leaf litterbags differed significantly among sections of the Elwha watershed; and 3) aquatic fungal communities growing on leaf litter differed significantly among sections. Aquatic macroinvertebrate and fungal diversity were sensitive to differences in canopy cover, water chemistry, and river bottom sediments across sites, with a stronger relationship to elevation for aquatic macroinvertebrates. As the Elwha River undergoes recovery following the massive sediment flows associated with dam removal, we expect to see changes in leaf litter processing dynamics and shifts in litter-dependent decomposer communities (both fungal and invertebrate) involved in this key ecosystem process.

【 授权许可】

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Copyright © 2023 LeRoy, Morley, Duda, Zinck, Lamoureux, Pennell, Bailey, Oswell, Silva, Kamakawiwo’ole, Hartford, Van Der Hout, Peters, Mahan, Stapleton, Johnson and Foley