Proposed Abstract Title

Long-term monitoring on multiple spatial scales: status and trends of eelgrass (Zostera marina) in greater Puget Sound

Type of Presentation

Oral

Session Title

The Role of Eelgrass Ecosystems in the Salish Sea

Location

2016SSEC

Description

Seagrasses provide important ecosystem services, and are sensitive to a wide range of environmental stressors, making them effective indicators of habitat condition. The WA Department of Natural Resources monitors seagrass (predominantly Zostera marina) area and depth distribution in greater Puget Sound, through the Submerged Vegetation Monitoring Program (SVMP). This long-term monitoring program, which started in 2000, uses underwater videography to estimate the areal extent of native seagrass beds at multiple spatial and temporal scales. Changes in soundwide native seagrass area are assessed in the framework of a long-term target (20% increase in soundwide seagrass area by 2020), while local patterns in seagrass distribution are examined on a shorter timeframe.

Results indicate that there are approximately 22,000 ha of native seagrass in greater Puget Sound, and that seagrass tends to be more widespread in the northern part of the Sound. Soundwide native seagrass area has been relatively stable over the last 15 years. Most sites sampled showed little change over time, but in some areas sites with long-term declines in native seagrass area outnumbered sites with increases. These declines are either the result of localized anthropogenic activities or broader climatic influences, and need to be further investigated to identify specific drivers. There are signs that seagrass conditions improved in recent years: several sites that were previously declining have stabilized between 2010 and 2014. At the Skokomish and the Nisqually River deltas, notable increases in eelgrass area were observed following removal of dikes and other restoration activities. A better understanding of the distribution of native seagrass beds and the mechanisms behind the observed changes could be used to hone conservation strategies and improve designs of future restoration projects.

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Long-term monitoring on multiple spatial scales: status and trends of eelgrass (Zostera marina) in greater Puget Sound

2016SSEC

Seagrasses provide important ecosystem services, and are sensitive to a wide range of environmental stressors, making them effective indicators of habitat condition. The WA Department of Natural Resources monitors seagrass (predominantly Zostera marina) area and depth distribution in greater Puget Sound, through the Submerged Vegetation Monitoring Program (SVMP). This long-term monitoring program, which started in 2000, uses underwater videography to estimate the areal extent of native seagrass beds at multiple spatial and temporal scales. Changes in soundwide native seagrass area are assessed in the framework of a long-term target (20% increase in soundwide seagrass area by 2020), while local patterns in seagrass distribution are examined on a shorter timeframe.

Results indicate that there are approximately 22,000 ha of native seagrass in greater Puget Sound, and that seagrass tends to be more widespread in the northern part of the Sound. Soundwide native seagrass area has been relatively stable over the last 15 years. Most sites sampled showed little change over time, but in some areas sites with long-term declines in native seagrass area outnumbered sites with increases. These declines are either the result of localized anthropogenic activities or broader climatic influences, and need to be further investigated to identify specific drivers. There are signs that seagrass conditions improved in recent years: several sites that were previously declining have stabilized between 2010 and 2014. At the Skokomish and the Nisqually River deltas, notable increases in eelgrass area were observed following removal of dikes and other restoration activities. A better understanding of the distribution of native seagrass beds and the mechanisms behind the observed changes could be used to hone conservation strategies and improve designs of future restoration projects.