Trying to fine tune a salt marsh


From Robert Whitcomb’s “Digital Diary,’’ in

WBUR, one of the two major NPR stations in Boston (the other is WGBH), ran a nice story July 2 about efforts to improve New England’s largest salt marsh, in Massachusetts’s northeast corner, in the Parker River National Wildlife Refuge. Over the years, farmers, to encourage the growing of salt-marsh hay for livestock, and other local residents seeking to control the mosquito population, had ditches dug to drain what was seen as excess water from the marsh. But, says WBUR reporter Miriam Wasser, that did some damage to some creatures and the marsh’s general health and so some of its drainage ditches were blocked.

But wait! Maybe they went overboard. So, as wildlife biologist Nancy Pau told Ms. Wasser:

"Our concern about too much draining has shifted, and the concern now is that the marsh is getting too much flooding," she says. “It’s important for the marsh to get flooded, but also for the water to come back off. Anything that interrupts either of those two processes can negatively impact the marsh," which is a buffer against sea-level rise. Among the negative effects of bad water flow are the spread of algae, which can kill other life. So now some of those ditch plugs are being removed, letting water behind them to go to the Plum Island River. It’s a tricky balancing act.

As the tide rises and falls, marsh grass traps sentiment, which builds up the peat out of which the grass grows. This most dramatically helps protect the coast from storm surges in hurricanes and nor’easters.

Scientists continue to learn more about wetlands biology and geology, and how to adjust “marsh management’’ to maximize these wetlands’ biological health and their role as buffers against sea-level rise and coastal erosion. When I was a boy living very close to salt marshes most of us mostly saw them as homes for birds and the source of strong, rather unpleasant smells. But biologists know a lot more now of just how important coastal wetlands are to wildlife, including the shellfish and finfish we eat. The writer and marine biologist Rachel Carson, author of The Edge of the Sea, The Sea Around Us and the world-historical Silent Spring, would presumably be pleased by the progress. She focused her work for many years on the New England coast. But we need to know a lot more about how these ecological systems work.

In any event, wetlands overseers along the whole New England coast might learn some things from the restoration efforts at the beautiful Parker River Wildlife Refuge

To see Ms. Wasser’s story, please hit this link.