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The rapid return of marine-derived nutrients to a freshwater food web following dam removal

October 2, 2015

Dam removal is increasingly being recognized as a viable river restoration action. Although the main beneficiaries of restored connectivity are often migratory fish populations, little is known regarding recovery of other parts of the freshwater food web, particularly terrestrial components. We measured stable isotopes in key components to the freshwater food web: salmon, freshwater macroinvertebrates and a river specialist bird, American dipper (Cinclus mexicanus), before and after removal of the Elwha Dam, WA, USA. Less than a year after dam removal, salmon returned to the system and released marine-derived nutrients (MDN). In that same year we documented an increase in stable-nitrogen and carbon isotope ratios in American dippers. These results indicate that MDN from anadromous fish, an important nutrient subsidy that crosses the aquatic–terrestrial boundary, can return rapidly to food webs after dams are removed which is an important component of ecosystem recovery.

Citation Information

Publication Year 2015
Title The rapid return of marine-derived nutrients to a freshwater food web following dam removal
DOI 10.1016/j.biocon.2015.09.009
Authors Christopher M Tonra, Kimberly A. Sager-Fradkin, Sarah A. Morley, Jeffrey J. Duda, Peter P. Marra
Publication Type Article
Publication Subtype Journal Article
Series Title Biological Conservation
Series Number
Index ID 70158598
Record Source USGS Publications Warehouse
USGS Organization Western Fisheries Research Center