URI Scientists examine the success of
restored salt marshes
Narragansett, RI -- March 4, 2002 -- The restoration of salt marshes is a common way to rectify past environmental damage caused by dikes, roadways, and other man-made structures that restrict water flow and alter the delicate ecosystem. But how successful is the attempt to restore salt marshes?
URI Graduate School of Oceanography (GSO) researcher Mary-Jane James-Pirri, along with GSO alumnus Kenneth Raposa of the Narragansett Bay National Estuarine Research Reserve and John G. Catena of the National Marine Fisheries Service, compared the diets of salt marsh predators in restored and undisturbed marshes to help determine the success or failure of a restoration project. The results of the study, funded by the National Marine Fisheries Service Restoration Center, were published in a recent issue of Estuarine, Coastal, and Shelf Science.
James-Pirri studied the mummichog (Fundulus heteroclitus) , an abundant resident and an important component in the food structure of salt marshes, functioning both as a predator and as prey. Mummichogs are predators that forage in the intertidal areas of salt marshes, feeding on worms, small crustaceans, insects, and snails. Acting also as prey for larger fish and crustaceans, mummichogs are an ideal species to use to quantify responses to restoration.
The scientific team conducted its study at Sachuest Point salt marsh in Middletown, R.I. (a trail shown above). Two-thirds of the salt marsh had been tidally restricted by a road and causeway constructed across the main tidal creek in the 1950s. This restriction reduced tidal flow into the southern region of the marsh, impounding fresh water, and changed the existing salt marsh into a brackish system. The salt marsh restoration began in 1998, resulting in an increase in tidal flow, desirable vegetation, and species density.
After collecting 465 fish from 91 stations, James-Pirri compared the diet and growth parameters of mummichogs from undisturbed and restored marshes to determine if the restored marsh provided similar food resources as the site that had not been damaged. The researchers found that lengths, weights, gut fullness, and diet composition of mummichogs were similar within habitats between restoring and undisturbed salt marshes. This indicates that a restoring marsh is providing similar energy resources and functioning as an unrestricted marsh.
"Results from this study show that restored wetlands can respond quickly to tidal restoration," said James-Pirri. "Furthermore, evidence from diet composition indicates that restored wetlands are able to provide food resources for fish, suggesting that the community structure of salt marshes may become established within one year after restoration."
The URI Graduate School of Oceanography is one of the country's largest marine science education programs, and one of the world's foremost marine research institutions. Founded in 1961 in Narragansett, RI, GSO serves a community of scientists who are researching the causes of and solutions to such problems as acid rain, global warming, air and water pollution, oil spills, overfishing, and coastal erosion. GSO is home to the Coastal Institute, the Coastal Resources Center, the Pell Marine Sciences Library, the URI Research Vessel Endeavor, Rhode Island Sea Grant, and the National Sea Grant Library.
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