Study of eelgrass shows populations steady across Puget Sound

Eelgrass provides critical habitat for many Puget Sound species. Photo courtesy of NOAA and the Seattle Times

Eelgrass provides critical habitat for many Puget Sound species. Photo courtesy of NOAA and the Seattle Times.

Although eelgrass populations have declined in some parts of Puget Sound, overall numbers for the aquatic plant have remained steady ecosystem-wide, according to an analysis of 41 years of data from the Washington Department of Fish and Wildlife.

The study, published in the Journal of Ecology, was co-authored by Puget Sound Institute lead ecosystem ecologist Tessa Francis and was aided by a team of University of Washington student assistants who sorted through more than 160,000 notebook entries to parse out survey findings.

The data comes from long-time surveys of Pacific Herring, which also included the detailed observations of eelgrass abundance. (We first wrote about this treasure trove of hand-written notebooks in a PSI blog focusing on its implication for herring studies.) The paper was co-authored by a team of scientists from NOAA, PSI, Earth Resource Technology, The Nature Conservancy, WDFW and the University of Washington School of Environmental and Forest Sciences.

The researchers say the findings give some hope that eelgrass meadows may be more resilient than expected to pressures such as climate change, but they caution that sharp declines in some areas are a source of concern.

“The fact that eelgrass has been stable over the last 40 years tells you that things are probably not getting worse, but it doesn’t mean that things are good,” study co-author Phil Levin, of the University of Washington and The Nature Conservancy told the Seattle Times today.

PSI’s Francis was also quoted in the Seattle Times story and called the findings “promising in terms of recovery, because it’s a lot easier to think of what we might do on a local scale, than to think of what we might do on a grand, ecosystem scale.”

Eelgrass is an aquatic flowering plant that provides important habitat for young salmon, herring, Dungeness crabs and many other species. You can read about efforts to restore eelgrass beds in Puget Sound in our magazine series Salish Sea Currents.

Read more about the new eelgrass paper in The Seattle Times and UW Today.

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