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

Damremoval is increasingly being recognized as a viable river restoration action. Although themain beneficiaries of restored connectivity are often migratory fish populations, little is known regarding recovery of other parts of the freshwater foodweb, particularly terrestrial components.Wemeasured 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 systemand released marine-derived nutrients (MDN). In that same yearwe 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.