Archived: Eelgrass beds in Puget Sound
Seagrasses are an important bio-indicator of ecosystemhealth – both globally and within Puget Sound. Long-term trends in distributioncan signal localized and/or regional changes in ecological conditions (e.g.,water quality and sediment transport) within the nearshore environment.Although native eelgrass has declined from historic levels, it remains widelydistributed within Puget Sound. Eelgrass provides many critical ecosystemservices. Crustaceans, such as Dungeness crabs, utilize eelgrass beds forhabitat and nursery areas. Fish, such as juvenile salmon, use eelgrass beds asmigratory corridors as they pass through Puget Sound. Some forage fish species,including Pacific herring, lay their eggs on eelgrass, and many marine birdsfeed extensively in eelgrass beds. Eelgrass beds also help stabilize nearshoresediments, thereby preventing erosion. Other ecosystem services includenutrient cycling, and capturing and storing carbon (sequestration).
The Puget Sound Partnership set an eelgrass recovery targetof a 20% increase in soundwide eelgrass area by 2020 compared to a 2000-2008baseline. In support of this long-term target, eelgrass area should increase byapproximately 10% in 2016 (23,730 ha). Our best estimates indicate thateelgrass has increased approximately 8.3% (3-year average 2012-2014) comparedto the baseline. The 2014 annual estimate appears to have met the 2016 target,but this value is subject to some uncertainty, due to year to year variability inour estimates. An alternative method of analyzing trends is looking atindividual locations within Puget Sound. Recent results at individual sitessuggest improvements in eelgrass condition. Between 2010 and 2014, moreindividual sites showed increases (17) than declines (2). Long term patterns atindividual sites (2003-2014), show an equal number of increasing (22) anddeclining (25) sites.
We developed a comprehensive eelgrass recovery strategy: DNR and the Puget Sound Partnership convened a workgroup composed of state and federal natural resource agencies, tribes, nongovernmental organizations, and industry representatives to develop a comprehensive eelgrass recovery strategy for Puget Sound. The workgroup met five times between April and September 2014 to review environmental stressors and identify actions to advance recovery. A final strategy was published in 2015, and is available for download from the Department of Natural Resources website.
Avoiding and minimizing impacts to eelgrass on state-owned aquatic lands: DNR is applying site-specific stewardship measures to ensure that uses of state-owned aquatic lands avoid and minimize impacts to eelgrass habitat. Stewardship measures include applying avoidance buffers to activities in the nearshore and requiring grating for over water structures to minimize shading of aquatic vegetation.
Conducting eelgrass transplant projects: DNR’s Nearshore Habitat Program in collaboration with the Pacific Northwest National Laboratory has developed a site suitability model for eelgrass transplant projects. This model is designed to improve transplant success by identifying areas of Puget Sound with the environmental conditions necessary to support eelgrass growth and expansion. Thirty test transplants have been completed so far. Up to 15 acres of more intensive transplants are scheduled through 2016. Over time, natural expansion – through vegetative growth and sexual reproduction – can colonize much larger areas than the original transplant footprint.
Citizens can support eelgrass recovery efforts through:
a) Avoiding in-water construction, dredging, and vessel anchoring within eelgrass habitats
b) Ensuring mooring buoys utilize embedded anchors and mid-lines floats
c) Utilizing soft shoreline stabilization techniques as an alternative to traditional bulkheads
d) Protecting and restoring coastal vegetation buffers to reduce runoff into nearshore habitats
e) Ensuring on-site septic systems are properly functioning through regular inspections
f) Constructing environmentally-friendly landscape designs to promote on-site infiltration and inflow of stormwater
g) Avoiding discharge of chemicals, fertilizers, and other pollutants into storm drains