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Eelgrass study highlights importance of preservation

June 29, 2012

Researchers at The Nature Conservancy and Save The Bay are currently consulting a new study, conducted by Dr. Frederick Short of UNH, on eelgrass populations and their resiliency in Narragansett Bay and other coastal zones, such as Point Judith Pond.

NARRAGANSETT—Coastal zones throughout Narragansett Bay and along Rhode Island’s southern coast boast a rich tapestry of plants and animals living together, sharing the successes and challenges of the underwater environment. Habitats for species such as scallops and groundfish rely upon protection from eelgrass, and a new study from the University of New Hampshire aims at augmenting the knowledge base of eelgrass restoration, already developed by organizations such as The Nature Conservancy and Save The Bay.

UNH professor Dr. Frederick Short has recently completed a report on the status and survivability of eelgrass meadows in the coastal waters of Narragansett Bay and southern Rhode Island. The study, sponsored by The Nature Conservancy (TNC), identifies the main challenges to eelgrass ecosystems, and provides a guide for future research which will, in turn, be crucial in developing better commercial fishing opportunities and improve water quality.

“Eelgrass populations in Rhode Island waters have declined significantly from historic levels, but there is evidence that some wild eelgrass populations have been bouncing back and efforts to restore it have been moderately successful,” said John Torgan, Director of Ocean and Coastal Conservation at TNC.  “The study looks at the genetics of surviving wild, natural patches of eelgrass to see if they are particularly adapted to challenges in Rhode Island waters.”

“The study did find that there may be some truth to the genetic argument,” he added.

According to TNC, from 1931 to today, eelgrass populations have declined up to 90 percent, a result of pollution and subsequent algal blooms from residential waste and storm water run-off. The environmental impacts from the Bay’s many users are still being measured, and Torgan stated that Short’s research can only enhance efforts throughout the region to understand and restore eelgrass habitats.

“It is clear that pollution is still a big problem, especially nutrient pollution, which causes algae blooms and warmer waters that hurt eelgrass,” said Torgan. “Eelgrass is a critically important habitat for scallops, winter flounder, and a wide range of plant and animal species, and it needs clean water to live.”

“We need to continue efforts to clean up Narragansett Bay and the ponds, and we need to focus on bringing back eelgrass,” he added.

Save The Bay’s Eelgrass Restoration Program, led by Director of Restoration Wenley Ferguson, has already incorporated previous studies conducted by Short.  The continuously updated methodologies and results associated with eelgrass restoration improves their own body of work significantly, which currently focuses on eelgrass populations in central portions of Narragansett Bay, namely around Prudence Island and Greenwich Cove.

“We’ve been doing eelgrass restoration since 2001, and we developed a site suitability model with [Short’s] guidance for Narragansett Bay, looking at whatever data we had for water quality, historic distribution of eelgrass, et cetera,” said Ferguson. “We looked at existing data and identified potential eelgrass restoration sites, sharing that information with a group of scientists who identified 19 different sites throughout Narragansett Bay to test transplants.”

Through Save The Bay’s Eelgrass Restoration Program, Ferguson is more able to identify where eelgrass populations are successful in the Bay environment, as well as where they find it more difficult to survive.   

“In the Narrow River and Wickford Harbor areas, for example, there could be restoration opportunities in the inner coves, but nitrogen pollution from cesspools and septic systems impacts water quality as well,” said Ferguson. “In June, waters may look good but go back in August, and one finds large algal blooms and not enough light penetrating into the water column to get to the plant.”

"That is why eelgrass itself is a great indicator of good water quality because it needs clear water to grow,” she added.

Save The Bay also participates with scientists from the University of Rhode Island in an eelgrass mapping program, identifying current eelgrass meadows and future places for opportunity.

“Our eelgrass mapping efforts are state wide, using aerial images,” said Ferguson. “Mike Bradley from URI will do the mapping, reviewing and updating maps that we helped coordinate in 2006, and we did another effort in 1996. We are trying to use this as a tool to see what our regional eelgrass populations are doing and their overall health.”

“Hopefully, this mapping effort will help identify sites and whether there are new beds forming and transplants expanding,” she added. “We hope we can really compare this data.”

Both Torgan and Ferguson stress the need to continue eelgrass restoration efforts, noting the progress the state has made over the past 20 years in preserving the vital aquatic habitat.

“I think that the bigger conclusion of the study is that if you want to have healthy eelgrass, we need to reduce pollution and manage ponds better,” said Torgan. “We need to continue to support restoration efforts. That work is important and we have to do a better job."

“We need to continue to study and understand what makes eelgrass beds successful, and that can hold clues into the future of larger scale restoration,” he added.


Southern Rhode Island Newspapers
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