Proposed Abstract Title

Eelgrass (Zostera marina L.) decline at Dumas Bay, WA (USA): patterns and possible causes

Type of Presentation

Poster

Session Title

The Role of Eelgrass Ecosystems in the Salish Sea

Location

2016SSEC

Description

Long-term monitoring at Dumas Bay (located in Federal Way, Washington) has shown a significant decrease in eelgrass area and distribution. Since sampling began in 2000, as part of the Washington State Department of Natural Resources Submerged Vegetation Monitoring Program, eelgrass area has decreased from approximately 2.3 ha to 0.3 ha in 2014 and is now only found in the western-most portion of the bay. This study explores possible factors that have contributed to this decline, such as increased environmental stressors or interspecific competition. Using 15 years of video imagery, we compare changes in presence/absence and percent cover of nuisance algae (Ulva spp.) and eelgrass. Timeline data for several parameters, which influence water clarity and quality (i.e. streamflow, precipitation, light and temperature), were compiled to analyze the relationship between eelgrass extent and nearshore environmental drivers. Eelgrass provides a wide range of ecological services and is an indicator of habitat condition. Given the importance of eelgrass to the Puget Sound ecosystem, it is critical to identify and understand factors that cause eelgrass decline and whether changing environmental conditions have impacted the abundance and distribution of eelgrass at Dumas Bay.

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Eelgrass (Zostera marina L.) decline at Dumas Bay, WA (USA): patterns and possible causes

2016SSEC

Long-term monitoring at Dumas Bay (located in Federal Way, Washington) has shown a significant decrease in eelgrass area and distribution. Since sampling began in 2000, as part of the Washington State Department of Natural Resources Submerged Vegetation Monitoring Program, eelgrass area has decreased from approximately 2.3 ha to 0.3 ha in 2014 and is now only found in the western-most portion of the bay. This study explores possible factors that have contributed to this decline, such as increased environmental stressors or interspecific competition. Using 15 years of video imagery, we compare changes in presence/absence and percent cover of nuisance algae (Ulva spp.) and eelgrass. Timeline data for several parameters, which influence water clarity and quality (i.e. streamflow, precipitation, light and temperature), were compiled to analyze the relationship between eelgrass extent and nearshore environmental drivers. Eelgrass provides a wide range of ecological services and is an indicator of habitat condition. Given the importance of eelgrass to the Puget Sound ecosystem, it is critical to identify and understand factors that cause eelgrass decline and whether changing environmental conditions have impacted the abundance and distribution of eelgrass at Dumas Bay.