Presentation Abstract
The increasing number of dams approaching the end of their useful lives compels a need for knowledge about how to conduct riparian restoration associated with dam removal. One of the most difficult challenges following dam removal is restoring native vegetation to drained reservoir beds, which can be impeded by ungulate browsing. Woody plant growth can be slow in dry nutrient-poor reservoir sediment, and browsing can impede forest establishment further. We evaluated the potential for large woody debris (LWD) to limit ungulate browsing on riparian trees and shrubs following dam removal in the Elwha ecosystem. We studied LWD mitigation of browsing in the largest former Elwha reservoir and a comparable valley upriver. We measured browse intensity in randomly located plots stratified by LWD extent, from no LWD to complete LWD enclosure. We compared effects of LWD on browse pressure using analysis of variance. LWD reduced browse intensity three-fold in both study areas, but only in plots fully surrounded by LWD. Protection from browse was greatest for plant species preferred by ungulates. These results suggest an effective strategy for restoring forests at dam removal sites and other riparian restoration projects. LWD can protect plants from browsing, but only when it entirely surrounds plants. Planting within LWD clusters or placing LWD clusters in restoration sites can facilitate establishment of forest islands, potentially advancing restoration progress by decades.
Session Title
Track: Shorelines, Estuaries & Rivers – Posters
Conference Track
Shorelines, Estuaries & Rivers
Conference Name
Salish Sea Ecosystem Conference (2020 : Online)
Document Type
Event
SSEC Identifier
2020_abstractID_3416
Start Date
21-4-2020 9:00 AM
End Date
22-4-2020 4:45 PM
Genre/Form
posters
Subjects – Topical (LCSH)
Dam retirement--Washington (State)--Elwha River; Coarse woody debris--Washington (State)--Elwha River; Riparian forests--Effect of browsing on--Washington (State)--Elwha River; Ungulates--Food--Washington (State)--Elwha River
Geographic Coverage
Salish Sea (B.C. and Wash.); Elwha River (Wash.)
Rights
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.
Type
Text
Language
English
Format
application/PDF
Included in
Fresh Water Studies Commons, Marine Biology Commons, Natural Resources and Conservation Commons, Terrestrial and Aquatic Ecology Commons
Large woody debris protects woody plants from browsing in restoration following Elwha dam removal.
The increasing number of dams approaching the end of their useful lives compels a need for knowledge about how to conduct riparian restoration associated with dam removal. One of the most difficult challenges following dam removal is restoring native vegetation to drained reservoir beds, which can be impeded by ungulate browsing. Woody plant growth can be slow in dry nutrient-poor reservoir sediment, and browsing can impede forest establishment further. We evaluated the potential for large woody debris (LWD) to limit ungulate browsing on riparian trees and shrubs following dam removal in the Elwha ecosystem. We studied LWD mitigation of browsing in the largest former Elwha reservoir and a comparable valley upriver. We measured browse intensity in randomly located plots stratified by LWD extent, from no LWD to complete LWD enclosure. We compared effects of LWD on browse pressure using analysis of variance. LWD reduced browse intensity three-fold in both study areas, but only in plots fully surrounded by LWD. Protection from browse was greatest for plant species preferred by ungulates. These results suggest an effective strategy for restoring forests at dam removal sites and other riparian restoration projects. LWD can protect plants from browsing, but only when it entirely surrounds plants. Planting within LWD clusters or placing LWD clusters in restoration sites can facilitate establishment of forest islands, potentially advancing restoration progress by decades.
