Benthic Invertebrates and Periphyton in the Elwha River Basin: Current Conditions and Predicted Response to Dam Removal

摘要: The impending removal of two dams on the Elwha River in Washington State offers a unique opportunity to study ecosystem restoration at watershed scale. We examine how periphyton and benthic invertebrate assemblages vary across regulated unregulated sections different habitat types, establish baseline data for tracking future changes following dam removal. collected multiple years physical habitat, water chemistry, periphyton, invertebrates from 52 sites reference section Quinault River, neighboring basin. found that substrate river was coarser less heterogeneous size than sections, summer temperature specific conductivity higher. Periphyton biomass also consistently higher sections. Benthic assemblage structure above both distinct between below dams, due large part dominance mayfly taxa compared relative abundance midges non-insect downstream sites. Following removal, we anticipate diversity will temporarily decrease as result sediment released behind reservoirs. Over long-term, increased floodplain heterogeneity recolonization by anadromous fish alter via increases niche inputs marine-derived nutrients. extended timeline predicted recovery complexities forecasting ecological response highlights need more long-term assessments practices.