Ruth Indrick lectures July 10 on marsh restoration at the Bath Freight Shed. Laura Sitterly / The Times Record

The project director for the Kennebec Estuary Land Trust told those at a community gathering on July 10 that rising sea levels are threatening vulnerable species.

“Sea level rise may drown marshes if protection methods aren’t taken quickly,” Ruth Indrick told those meeting at the Bath Freight Shed. “That’s where conservation comes into play.”

KELT has observed lush stretches of cordgrass disappearing each year, slowly diminishing Maine’s salt marshes.

The intertidal zone is crucial for nursing fish species, filtering pollutants and shielding the coast from flooding. It’s also home to the saltmarsh sparrow, a species the Maine Department of Inland Fisheries and Wildlife recently listed as endangered, according to a press release from the department in November 2023.

Thesaltmarsh sparrow may be the first bird to go extinct due to rising sea levels. Indrick said the turning point will be between 2030 and 2060, so the time to act is now.

Why do salt marshes matter?

Indrick emphasized that acre for acre, the mosquito-infested marshes are among the most valuable ecosystems on the planet. 

Ruth Indrick meanders through the KELT preserve en route to install water level sensors. Kennebec Estuary Land Trust photo

Not only do they benefit people — research has shown that if waves pass over a marsh during a storm before hitting a seaside property, damages decrease up to 30% — they also provide a wealth of ecosystem services. 

Indrick said sphagnum moss, typical on salt marsh peatlands, is profound at carbon capture. The plant buries carbon in its roots, trumping woodland sequestration in its success. 

“Tidal marshes are a vital habitat for many species,” Indrick said. “Creatures, from birds to mammals to fish rely on these channels. Marshes support inland fisheries — housing mummichogs and striped bass — and aquaculture, too. They slowly add nutrients to coastal waters, fueling the phytoplankton that is foundational to the Gulf of Maine’s food system.” 

Encroaching extinction

Among other coastal critters, the saltmarsh sparrow breeds in marshes, nesting between the highest spring tides. Since the late 1990s, the population has declined 9% each year, threatened by a fraction of an inch of annual sea level rise caused by climate change. 

Indrick predicted the species could reach a threshold as high spring tides become more frequent, facing extinction in the next six years. 

Midcoast ornithologists are working to ensure that the saltmarsh sparrow is listed as endangered not just in Maine but nationally as well. 

Purportedly, Reid State Park and Popham Beach are home to dwindling populations, including the Nelson’s sparrow. Indrick said the sparrow’s distinct bird call — like a steam whistle on a train — adds an air of charm to the seascape. 

Susan Adamowicz, an estuarine ecosystem scientist at the Rachel Carson National Wildlife Refuge, specializes in the preservation of northeast marsh acreage.

“By 2030, we may hit a minimum that would be difficult to restore,” Adamowicz said. “By 2050, we could experience their extinction. We’re faced with a dual situation — the saltmarsh sparrow, in dire need of advocacy, and rising sea levels, narrowing our opportunity to make significant advances.”

Moving forward

Indrick leads an array of local marsh restoration projects across Georgetown, Arrowsic, Westport Island, Woolwich and Phippsburg. 

While most Kennebec Estuary Land Trust projects handle salt marshes, some, like those in Woolwich, function as brackish tidal wetlands, home to unique flora and fauna. 

“Looking at how the water moves and the way plants are distributed reveals past stories,” Indrick said. “It tells us which were used for agriculture and what methods the land endured. Three of our current projects address problems caused by terrace agriculture that once used embankments [large berms] to keep the water out.” 

Since subsidence structures weren’t maintained, they have become counterintuitive — trapping water on the surface of the marsh, causing them to sink and degrade. Restoration means creating a natural channel for water to ebb and flow once again throughout the marsh system.

Ruth Indrick sets up water level sensors in a brackish tidal marsh. Kennebec Estuary Land Trust photo

The Kennebec Estuary Land Trust isn’t tackling restoration alone; the organization has partnered with state and local governments to achieve joint goals, such as road safety. 

All of Indrick’s projects flooded during the January storms. Her restoration works to strengthen the health of the marsh and enhance climate resilience, tending to nearby road infrastructure so that both can sustain future sea level rise and storms. 

While municipal goals aim to improve road safety, prevent flooding, and decrease long-term road maintenance costs, the Land Trust’s role is to help incorporate considerations about tidal marsh habitat and fish movement into the design. 

“Salt marshes exist between the high and low tide lines,” Indrick said. “They go down about three-quarters of the way to the tide because they need water to survive. But too much inundation causes vegetation to drown. If that’s the case, marshes will migrate, but they need somewhere to go.” 

Natural and human-made barriers, such as rocky cliffs, roads, seawalls and berms, impede wetland migration. When one of these barriers is located along the inland edge, the vegetation cannot shift inland, causing it to narrow over time and eventually disappear under the rising sea.

According to Indrick, conserving upland areas is the best thing to do. She pointed to Little River Preserve as an example; as sea level rises, marshes have the potential to expand into new areas if given a buffer of conserved land. 

Adamowicz noted that future planning can’t rely solely on marsh migration. It must also include adaption resilience, she said, referring to her “Keep it HOTT” methodology: halt subsidence (fix the site’s hydrology), optimize accretion (gain platform elevation), tune for wildlife (restore habitat for tidal-dependent species) and tend to the marsh (support long-term activity). 

Groups across the state are leading similar marsh resilience projects, from Downeast, Maine Coast Heritage Trust, to southern Maine, Wells Estuarine Research Reserve. Others are trying new ideas, like the state’s coastal Coastwise program at the Department of Marine Resources. It offers guidance for replacing tidal road structures in a way that respects people and marshes. 

“If we don’t tend to our marshes now, we’ll lose significant acreage,” Indrick said. “What we’ve lost, we can’t get back, but what we preserve now, we can maintain.”