Presentation Abstract

Shoreline armoring removal is becoming a common restoration technique in the nearshore of the Salish Sea, yet we lack a comprehensive understanding of the ecological benefits obtained, and how such an understanding could be used to inform management recommendations and educate diverse audiences. To address this knowledge gap, we studied effects of shoreline armor removal at 10 sites, expanding the spatial framework of what was previously known by collaborating across academic (University of Washington), agency (Washington Department of Fish and Wildlife), and citizen science groups. Each site had three beach types of: (1) restored beaches with armoring removed 1-11 years ago, with a mean of four years, (2) armored beaches altered by bulkheads or riprap, and (3) un-armored reference beaches with more natural conditions. We sampled eight metrics of physical and biological conditions, focusing on supratidal and upper intertidal elevations most affected by armoring and targeted by restoration actions: beach wrack, wrack invertebrates, sediments, terrestrial insects, riparian vegetation and logs, beach profiles, forage fish habitat, and stable isotopes of beach-hopper amphipods to reveal ratios of marine and terrestrial food sources. These metrics spanned the functions of beach stability, ecological diversity, and food web support for juvenile salmon and birds. Results indicated that some beach metrics restore quickly, such as wrack accumulation, while others take longer, such as log accumulation. Sediment sizes at restored beaches approximated those of reference beaches, and were appropriate for forage fish spawning. In general, terrestrial-associated metrics were greater at reference beaches, although there was evidence that insect diversity and logs with plant growth increased when beaches were restored greater than four years. This implies that restored beach functions increase through time, providing improved support for forage fish, salmon, and birds.

Session Title

Forage Fish Status, Spawning Beach Restoration and Monitoring, and Community Engagement in the Salish Sea

Keywords

Armor, Restoration, Beach, Shoreline

Conference Track

SSE1: Habitat Restoration and Protection

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE1-208

Start Date

5-4-2018 2:15 PM

End Date

5-4-2018 2:30 PM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 5th, 2:15 PM Apr 5th, 2:30 PM

Shoreline armoring removal: assessment of restoration effectiveness in the Salish Sea

Shoreline armoring removal is becoming a common restoration technique in the nearshore of the Salish Sea, yet we lack a comprehensive understanding of the ecological benefits obtained, and how such an understanding could be used to inform management recommendations and educate diverse audiences. To address this knowledge gap, we studied effects of shoreline armor removal at 10 sites, expanding the spatial framework of what was previously known by collaborating across academic (University of Washington), agency (Washington Department of Fish and Wildlife), and citizen science groups. Each site had three beach types of: (1) restored beaches with armoring removed 1-11 years ago, with a mean of four years, (2) armored beaches altered by bulkheads or riprap, and (3) un-armored reference beaches with more natural conditions. We sampled eight metrics of physical and biological conditions, focusing on supratidal and upper intertidal elevations most affected by armoring and targeted by restoration actions: beach wrack, wrack invertebrates, sediments, terrestrial insects, riparian vegetation and logs, beach profiles, forage fish habitat, and stable isotopes of beach-hopper amphipods to reveal ratios of marine and terrestrial food sources. These metrics spanned the functions of beach stability, ecological diversity, and food web support for juvenile salmon and birds. Results indicated that some beach metrics restore quickly, such as wrack accumulation, while others take longer, such as log accumulation. Sediment sizes at restored beaches approximated those of reference beaches, and were appropriate for forage fish spawning. In general, terrestrial-associated metrics were greater at reference beaches, although there was evidence that insect diversity and logs with plant growth increased when beaches were restored greater than four years. This implies that restored beach functions increase through time, providing improved support for forage fish, salmon, and birds.