Study Provides Valuable Data on Eelgrass Restoration

By ecoRI News staff

For more than 80 years, eelgrass populations in southern New England and New York have been in serious decline, but insight from a new, cutting-edge scientific study led by one of the world’s most renowned eelgrass researchers could help reverse the decline.

Eelgrass meadows in the coastal waters of southern New England and New York provide critical habitat for recreationally and commercially important fish and invertebrate species such as flounder and bay scallops. Properly conserving eelgrass, by applying sound research and management principles, will create benefits for commercial and recreational fishing interests and provide a blueprint for improving water quality.

The new study, led by Frederick Short, Ph.D., a research professor in the University of New Hampshire’s Department of Natural Resources and the Environment, and sponsored by The Nature Conservancy, highlights the critical need for increased management to reduce nitrogen loading into coastal waters. Nitrogen pollution and warming ocean temperatures are considered the biggest threats to eelgrass health.

The research also:

Highlights the need to place additional focus on preserving the region’s most resilient eelgrass populations, including populations in Narragansett Bay, Great South Bay in New York and Great Bay in New Hampshire, that are providing the ecosystem benefits we depend on and have high potential to be used to assist restoration in bays where eelgrass meadows have been lost.

Provides valuable information about the distinct genetic characteristics of regional eelgrass populations and about how eelgrass spreads — information that could make restoration efforts much more effective.

The research, which is the first phase of a larger eelgrass research and restoration effort, was funded via a Federal appropriation through the National Oceanic and Atmospheric Administration (NOAA).

“Rhode Island is a recognized leader in eelgrass restoration thanks to the efforts of groups like Save The Bay and NOAA’s community-based restoration programs,” said John Torgan, director of ocean and coastal conservation for The Nature Conservancy in Rhode Island. “This study shows that, in order to be successful in the long-term, we must act now to address water quality problems, better understand the role of genetics, and take strong steps to protect the remaining eelgrass beds in Rhode Island waters.”

Since 1931, regional eelgrass populations have suffered losses of up to 90 percent due to myriad factors, including pollution, disease, brown tides, impacts from multiple uses of the waterways and other causes not yet understood, according to The Nature Conservancy.

Nitrogen pollution is considered the most severe threat. It comes from sewage treatment plant wastewater discharges, polluted groundwater and runoff from stormwater containing fertilizers and pet waste. Atmospheric nitrogen from burning fossil fuels is another significant source of nutrient pollution, according to the nationwide organization.

The new research centered on laboratory analysis of plants from 10 locations around the region, from Cape Cod to Long Island. The results showed that some eelgrass populations are more resilient to multiple sources of stress than others. In particular, plants from Narragansett Bay, Great South Bay in New York and Great Bay in New Hampshire are better adapted to survive under increased nitrogen and ocean temperature conditions.

Restoration efforts could be significantly improved by focusing on use of these populations as donors to restoration locations elsewhere.