The vast majority of theses in this collection are open access and freely available. There are a small number of theses that have access restricted to the WWU campus. For off-campus access to a thesis labeled "Campus Only Access," please log in here with your WWU universal ID, or talk to your librarian about requesting the restricted thesis through interlibrary loan.
Date Permissions Signed
Date of Award
Department or Program Affiliation
Huxley College of Environmental Sciences
Master of Science (MS)
Matthews, Robin A., 1952-
Helfield, James M.
This thesis investigated the managed revegetation outcomes of the exposed Lake Mills reservoir bed was investigated following the Glines Canyon dam removal on the Elwha River located in the Pacific Northwest, United States. During the following four years of restoration, one seeded species, riverbank lupine (Lupinus rivularis), quickly established on the coarse textured terraces that also had low organic matter (OM) and low soil nitrogen (N) levels. Nitrogen-fixing lupines may facilitate plant recruitment and conifer establishment, while demonstrating a relationship with ectomycorrhizal (ECM) communities which perform essential forest ecosystem functions. The purpose of this study was to investigate lupine’s influence on forest recovery, measured under three levels of abundance: sparse, medium, and dense. Each plot was assessed for nitrogen bioavailability, tree growth, plant community structure, soil N and OM development, and ECM abundance. My study demonstrates that lupine abundance has a positive relationship with restoration conifer growth and foliar N concentrations. In addition, lupine abundance corresponds with the surrounding plant species richness and diversity. Finally, lupine abundance has an inverse relationship with conifer root ECM colonization, thereby demonstrating that certain ecological conditions driven by the presence of lupine may dictate the symbiotic strategies between trees and fungi. Though the data illustrate lupine’s ability to influence N uptake in neighboring conifers, I did not see differences in soil N or differences in soil OM during this early phase of succession. I provide supportive evidence of lupine’s ability to aid in forest restoration in highly disturbed novel landscapes following dam removal is demonstrated. These data will be synthesized into best management practices for similar revegetation projects where dam removal, coupled with seeding and planting, restores forests that are linked to the greater riverine ecosystems.
lupine, forest restoration, Elwha River, Lake Mills, ectomycorrhizae
Western Washington University
Subject – LCSH
Dam retirement--Washington (State)--Upper Elwha Dam; Riverbank lupine--Washington (State)--Elwha River; Grassland restoration--Washington (State)--Elwha River; Forest restoration--Washington (State)--Elwha River; Ectomycorrhizas
Upper Elwha Dam (Wash.); Elwha River (Wash.)
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.
Kardouni, James, "Forest restoration of the exposed Lake Mills bed: assessing vegetation, ectomycorrhizae, and nitrogen relative to riverbank lupine (Lupinus rivularis)" (2020). WWU Graduate School Collection. 945.