Northwest Fisheries Science Center

Display All Information

Document Type: Journal Article
Center: NWFSC
Document ID: 4584
Title: Impacts of terrestrial and shoreline stressors on eelgrass in Puget Sound: an expert elicitation
Author: Amanda Pearl Rehr, G. D. Williams, N. Tolimieri, P. S. Levin
Publication Year: 2014
Journal: Coastal Management
Volume: 42
Pages: 246-262
Keywords: eelgrass, Zostera marina, expert elicitation, recovery target, probabilistic model,
Abstract:

We used expert elicitation to examine potential responses of eelgrass to several restoration strategies in Puget Sound. Restoration strategies included shoreline armor removal and modification, overwater structure removal and modification, and efforts to improve water clarity via reductions in anthropogenic nutrient and sediment loadings. Expert responses indicated a general belief that reducing stressors would increase eelgrass cover; however responses were non-linear and varied greatly among stressors. Our analyses revealed that removal of overwater structures, nutrient loading and shoreline armoring will have significantly larger effects on eelgrass recovery than would removal of sediment loading, with removal of overwater structures having the largest effect.  We then used a probabilistic model to estimate what actions, singularly or in combination, could yield a large increase in eelgrass cover.  Reducing single stressors could, in theory, result in recovery of eelgrass in Puget Sound; however, the magnitude of actions required would be so great that it is likely not practical.  In contrast, we identified combinations of smaller reductions of stressors that could achieve significant eelgrass recovery.   For example, a 40% reduction in overwater structures, combined with 20% reductions in shoreline armor, and nutrient and sediment loadings, was predicted to be one of the more feasible combinations of actions for meeting the target. The importance of eelgrass to Puget requires prompt input of scientific advice, and this work fills an important knowledge gap in the face of rapidly approaching legislative deadlines.  While coded expert opinion of the sort we use here is a weak substitute for data, our work provides clear scientific guidance that can be used while empirical data are gathered.

Theme: Sustaining Marine Ecosystem and Human Health
Foci: Develop methods, technologies, and data integration tools to predict ocean-related public health risks into health early warning and ocean observing systems
Develop methods, technologies, and data integration tools to predict ocean-related public health risks into health early warning and ocean observing systems