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Protecting coastal resources – for the people and wildlife that depend on them – has to be a priority when you’re a state with 400 miles of coastline and one of the highest ratios of coastline-to-land in the country.
In Rhode Island, one such effort involves restoring coastal marshes.
“Having a marsh is good because it can slow down waves that would be heading toward homes,” says Jen White, a USFWS biologist in Rhode Island. “If we lose the marsh, that will all turn into open water basically and you won’t have any protection.”
White is looking out at the Narrow River estuary, where FWS and partners are working on a marsh restoration technique called “thin-layer deposition,” which has been used widely in Gulf Coast states but is just recently gaining traction in the Northeast. Last year the partners used the technique on 11 acres at Sachuest Point NWR, and now are working on 30 acres along the Narrow River at Chafee NWR.
The objective is to dredge sediment from the estuary and spray it onto the marsh, raising the elevation of the marsh enough to allow it to keep better pace with sea-level rise.
“What we’ve seen here is a switch from high-marsh grasses to low-marsh grasses, so we’re losing the high-marsh habitat in this area,” says White. “By adding material we’re hoping to bring it back to high-marsh elevation and that will hopefully allow it to last into the future.”
The partners are aiming to add six inches of elevation to the marsh, which should allow the high-marsh grass to grow through. They will also re-plant the area with about 35,000 plugs of marsh grasses in the spring.
To achieve this delicate balance of elevation, the dredging and spraying machines are equipped with computer sensors that precisely monitor the process.
“The sand will be contoured so there will be hills and valleys — the hills will be where the high marsh will grow and where water will be able to drain off the marsh so we’re not creating any impounded water anywhere,” explains White.
Marshes are widely considered valuable assets for coastal protection – they buffer wave energy and absorb water. But they also harbor an amazing diversity of species. One important creature that depends on them is the saltmarsh sparrow (Ammodramus caudacutus).
“Saltmarsh sparrows breed in the high-marsh elevation grasses, so that’s informed the restoration planning we’re doing. Willets (Tringa semipalmata) also breed at that elevation,” says White. “Sea-level rise is going to be a big issue for the saltmarsh sparrow. As sea-level rise increases, these birds will have fewer and fewer breeding opportunities. By raising the marsh we hope to provide salt marsh nesting species habitat into the future.”
White notes that researchers (Field et al. 2016) estimate the sparrow may go extinct as early as 2035, with populations having dropped sharply since the 1990s according to the Saltmarsh Habitat & Avian Research Program (SHARP), a group of academic, government and nonprofit researchers along the East Coast.
“Sea-level rise is really the main issue for marshes, whether you’re talking about the habitat they provide for the saltmarsh sparrow or their ability to protect coastal communities from inundation.”
This is the fifth in a series of photo slideshows highlighting the people who have been working to defend their coastal ecosystems against storms in the wake of Hurricane Sandy. In previous weeks we have looked at Matt Whitbeck and Miles Simmons, combating climate change in the Chesapeake Bay, Julie Devers, assessing fish barriers and culverts in Maryland, Kevin Holcomb and Amy Ferguson building living shorelines at Chincoteague National Wildlife Refuge, and Eric Schrading and Katie Conrad building living shoreline oyster reefs at Gandy’s Beach in New Jersey.