Northwest Fisheries Science Center

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Document Type: Chapter or Section
Center: NWFSC
Document ID: 4319
Type of Book: Technical
Section or Chapter Title: Biological effects of shoreline armoring in Puget Sound:  past studies and future directions for science
Book Title: Puget Sound shorelines and the impacts of armoring:  proceedings of a state of the science workshop, May 2009
Author: Casey A. Rice
Editor: Hugh Shipman, Megan N. Dethier, Guy Gelfenbaum, Kurt L. Fresh, R. S. Dinacola (Eds.)
Publication Year: 2011
Publisher: U.S. Geological Survey Scientific Investigations Report No. 2010-5254
Pages: 155-160
Keywords: shoreline armoring

Human alteration of Puget Sound shorelines is extensive, yet its biological consequences are largely unknown, in part because research and monitoring of the Puget Sound ecosystem  (1) has usually not included anthropogenic disturbances such as shoreline armoring as explicit factors in sampling design and data analysis,  (2) tends to not make direct measures of biological condition a top priority,  and (3) has rarely sampled across the full range of natural physical and biological conditions within the system.  Several recent site– and local–scale field studies have documented differences between modified and more natural beaches in terms of several biological attributes (for example, spatial extent and patch size of eelgrass; supratidal invertebrate abundance and assemblage composition; embryo condition of intertidally spawning fish; and taxonomic composition, size, behavior and diet in fish assemblages).  Many of these results are equivocal, and no large–scale biological field studies have resolved the uncertainty.  However, combination and reanalysis of bird survey and shoreline–attribute monitoring data from all of greater Puget Sound illustrate the value of landscape–scale studies focusing explicitly on biological responses to human influence across a range of natural ecological gradients (for example, season, year, oceanographic sub–basin, shoreform).  Changes in the taxonomic composition of marine bird and waterfowl assemblages were related to urban land cover gradients along Puget Sound shorelines throughout greater Puget Sound, although specific effects of armoring itself were not detected.  Together these studies demonstrate that armoring of Puget Sound shorelines affects abiotic attributes (for example, physical structure and microclimate), can adversely affect the biota at local scales, and suggest the potential for Sound–wide changes in biology as a result of shoreline armoring.  But the cumulative, population, and ecosystem–level effects of armoring remain understudied and unknown.  Expanded, systematic field studies that characterize biological attributes across a range of armoring, other anthropogenic disturbances, and natural ecological conditions (for example, geomorphology, exposure, landscape position) are necessary to improve our understanding and management of the biological effects of shoreline armoring in Puget Sound.  Only one such study is planned for central Puget Sound, but others increasingly are being proposed.   

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Theme: Recovery and rebuilding of marine and coastal species
Foci: Describe the relationships between human activities and species recovery, rebuilding and sustainability.