Study on the habitat evolution after dam removal in a habitat-alternative tributary of large hydropower station

Journal of Environmental Management, Journal Year: 2024, Volume and Issue: 360, P. 121155 - 121155

Published: May 17, 2024

Language: Английский

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Challenges of implementing a multi-agency monitoring and adaptive management strategy for federally threatened Chinook salmon and steelhead trout during and after dam removal in the Elwha River

Frontiers in Environmental Science, Journal Year: 2024, Volume and Issue: 12

Published: July 19, 2024

Adaptive management, a process of planning, implementing, and evaluating management strategies, is often recommended for monitoring ecological systems. However, few examples successful implementation retrospective case studies exist. We provide study adaptively managing hatchery-assisted protection recovery Chinook salmon ( Oncorhynchus tshawytscha ) winter steelhead trout O. mykiss during after the removal two large mainstem dams in Elwha River, WA. summarize key aspects adaptive plan over last decade highlight successes, challenges, complications plan’s implementation. The Monitoring Management Guidelines included trigger-based system moving through four phases that preservation, recolonization, local adaptation, viable natural population, each with differing levels hatchery production as actions. component has been very successful, providing critical data to guide actions otherwise may not have occurred and, opportunistically, provided other native species River. Implementing mixed results was at times hindered by divergent goals among project partners, inflexibility Endangered Species Act regulatory requirements implemented this project, conflicting information guidance documents. learned some metrics triggers were ill-defined or too difficult measure field. In cases, performance indicators and/or successfully modified incorporate what learned; however, we unable revise values due opinions partners. ability reach consensus on revised appeared be influenced trajectory involved. strategy resulted substantial collaboration learning, which but imperfect. Sufficient long-term funding necessary implement well-designed program could benefit from including defined leadership position shepherd facilitate multi-stakeholder program. Additionally, incorporating into legally binding conditions under feasible, requires pre-planning close coordination agencies.

Language: Английский

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Acoustic‐tagged American Shad utilize historic habitat following dam removal in northern Delaware

Marine and Coastal Fisheries, Journal Year: 2024, Volume and Issue: 16(6)

Published: Dec. 1, 2024

Abstract Objective The anadromous American Shad Alosa sapidissima , a once commercially important species in the mid‐Atlantic region, experienced population declines due to overfishing, poor water quality, and impediments accessing freshwater spawning habitat. Efforts at regional national scale substantially addressed former two obstacles facilitate growth, but dam modifications or removal are still ongoing. In 2019, state of Delaware removed first barrier fish passage on Brandywine River (a tributary River), Dam 1. Methods A total 24 were surgically tagged with acoustic transmitters from 2021 2022 above recently 1 tracked estuary coastal waters Atlantic Ocean. Result length available habitat increased by 1.3 km, 75.0% used historic grounds following removal. Nine individuals exhibited long‐term residency May June, demonstrating importance this newly adults. Additionally, one returned between years, displaying interannual site fidelity iteroparity. We also observed exploratory behavior three additional that exited within same year. Conclusion Overall, we document successful collaborative network via receiver array maintenance answer questions regarding migration use

Language: Английский

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Projecting fish community responses to dam removal – Data-limited modeling

Ecological Indicators, Journal Year: 2023, Volume and Issue: 154, P. 110805 - 110805

Published: Aug. 15, 2023

Modeling fish community responses to dam removal is an emerging field of study as removals become more common, but uncertainties concerning recovery time and stability remain. In Europe, EU-wide biodiversity strategy plans restore around 25,000 km rivers free-flowing status, which emphasizes the importance being able predict after removal. We developed a multi-species size spectrum model for in Mörrum River Sweden identify possible outcomes was removed 2020. Electrofishing monitoring before used calibrate model. projected multiple scenarios into future explore patterns stability, individual species responses, while varying parameters related mortality, base resource rate change, maximum recruitment change. created 30 hypothetical using abrupt change perspective (parameters are step-based) gradual smooth). both perspectives, mortality decreasing reduced biomass delayed compared pre-dam conditions. Our results demonstrate that from scenario not necessarily benefit all species. where practices or failures cause high events sustained impacts on trophic level resources, pre-removal may take decades, be unstable twice time-period. shows models can applied potential outcomes, particularly risk avoidance perspective. A such approach relatively low data requirements needed perform projections (e.g., present species, growth rates, relative abundance). Implementing this other river systems, at reach scale, help restoration management assess tradeoffs associated with different habitat approaches prior committing plan.

Language: Английский

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Large wood supports Elwha revegetation by reducing ungulate browsing

Frontiers in Ecology and Evolution, Journal Year: 2023, Volume and Issue: 11

Published: Aug. 30, 2023

Introduction The increasing number of dams approaching obsolescence drives a need for knowledge about riparian restoration associated with dam removal. Restoring woody vegetation on exposed reservoir beds following removal is essential to stabilizing sediment, reconnecting riverine and terrestrial systems, providing future sources shade, nutrients, wood. Revegetation after many rivers can be challenging due rapidly drying low sediment nutrient content, heavy ungulate browse pressure. in Elwha River restoration, the largest date, used large debris (LWD) mitigate moisture limitation but browsing has constrained plant growth coarse deposits. We evaluated potential LWD reduce Methods studied mitigation former comparable valley upriver natural floodplain. measured intensity randomly located plots stratified by four levels extent, from no complete enclosure. Results reduced four-fold reservoir, only fully surrounded LWD. Partial enclosure provided little reduction. obtained similar results valley, where was somewhat lower except within wood clusters. Wood-mediated reduction slightly greater than valley. Protection greatest species preferred ungulates. Discussion These suggest forest expedited surrounding young trees logs. Planting clusters or placing sites facilitate establishment islands strategic locations. support dispersal seeds marine derived reconnect established river, potentially advance decades.

Language: Английский

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