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A web of walkways and boardwalks guide me (and my leashed dog) on a recent visit to Belle Isle Marsh — a natural oasis that stretches more than 300 acres across East Boston, Winthrop, and Revere. It’s the largest remaining salt marsh in Boston.
Hues of blue and vibrant green extend for miles as sky meets sea meets scrub-shrub wetland. A shadowy view of Boston’s skyline sits on the horizon. I heard about this salt marsh during my ongoing search for more scenic, green spaces near the water. I’ve been living in a busy neighborhood in Back Bay, and visits to these wide open landscapes helps me relax.
The marsh is home to more than 270 species of birds, some listed by the state as endangered, including the saltmarsh sparrow, which is found in salt marshes along the Atlantic coast. In addition to providing habitat to vulnerable species, Belle Isle Marsh also acts as a natural buffer during storms, preventing flooding in nearby communities. Salt marshes also sequester carbon emissions, which felt ironic, I thought on my visit, as I heard the rumblings of a plane pass overhead. Belle Isle Marsh helps naturally offset the emissions from exhaust produced next door at Logan Airport — parts of which were once salt marsh, too.
In the 1960s, a group of East Boston residents stopped Belle Isle Marsh from being absorbed into another one of Massport’s Logan Airport expansion plans. That grassroots group is now a nonprofit known as the Friends of Belle Isle Marsh, and their mission has stayed the same: “To make sure the marsh remains a marsh, the marsh remains a habitat for all the plants that depend on it, and it remains an open space that people can access,” says Kannan Thiruvengadam, the president of Friends of Belle Isle Marsh. They celebrated their 40th anniversary last year.
“There’s a renewed interest in marshes because of all of the values they have,” Thiruvengadam tells me. “The defense mechanism that they have against climate change. Because they are strong storm buffers, as well as sinks for carbon. They’re beautiful, open spaces that people enjoy, especially in parts of the city where otherwise open space can be scarce. And they are, of course, migration stopping points for birds.”
The Department of Conservation and Recreation (DCR) now manages the marsh. In addition to maintaining it, the state agency is weighing intervention efforts that would restore and protect its fragile habitats.
“Like any coastal marsh anywhere right now, we’re certainly seeing changes in the habitat,” Sean Riley, Steward Research Biologist at the DCR, tells me. “The walls of the estuary are starting to degrade. We’re seeing transitional habitats change. The high marsh is starting to convert to low marsh.”
The high marsh supports the saltmarsh sparrow, which nests right on the marsh’s surface. “They’re a very fast-breeding species,” Riley says. “They used to nest in this narrow window. Now that window has changed with the season. Tidal cycles are different, and we’re getting more and more king tides and increased tidal inundation at these high marsh habitats.”
Saltmarsh sparrow nest bowls can take “a little bit of tidal inundation,” Riley says. “The eggs and the chicks can actually float a little bit. But repeated tides and flooding essentially drowns the birds and the nest pools and the nest bowls. They’re not a species that can, say, just move up into a tree or a meadow or something like that. It’s a very niche species — one of those species that can’t adapt this quickly to changing times. So, because they exclusively nest in high marsh, we’re trying to prolong and protect high marsh habitat, and the plant communities that are in high marsh habitat, as much as we can.”
We just want the marsh to remain, and we want the people who depend on the marsh, who live around the marsh, to learn about the marsh and its benefits, and know that our own wellbeing is interlinked with the wellbeing of the marsh,
– Kannan Thiruvengadam, President of the Friends of Belle Isle Marsh
In Massachusetts, there is strict permitting for wetland restoration projects, so the DCR is still in the early stages of figuring out what interventions might look like at Belle Isle Marsh. They’re eyeing other saltmarsh restoration projects that have been done in the state, such as the Great Marsh, where 1,274 acres of the marsh in Newbury, Essex, and Ipswich underwent an innovative nature-based “ditch remediation.”
“We have all our modeling, and we’re looking at what we can do next as sort of the most low-impact restoration interventions that we can do there,” Riley says. “There’s no clear cut permitting process for coastal wetlands yet. It might be years, but we’re moving toward these steps as quickly as we can in a way that makes sense.”
I pick a bench facing one of the tidal pools at Belle Isle Marsh and take in the sounds of singing birds and rustling beachgrass. I think about how this marsh wasn’t always this quiet haven away from urban life. The site was used as a dumping ground for dredged materials in the 1930s, and was an outdoor movie theater from the 1950s to the 1970s. The DCR acquired the land and opened it to the public in 1986. With help from partnering organizations like the Friends of Belle Isle Marsh and the Mystic River Watershed Association, the DCR continues upkeep and hosts educational, volunteer, and bird-watching events there.
“We just want the marsh to remain, and we want the people who depend on the marsh, who live around the marsh, to learn about the marsh and its benefits, and know that our own wellbeing is interlinked with the wellbeing of the marsh,” Kannan Thiruvengadam says.
I ask him about the nearby Suffolk Downs real estate project under construction, which hosts the music venue the Stage at Suffolk Downs. I could hear the venue’s tunes faintly in the distance during my visit to the marsh. I wondered if the Friends of Belle Isle opposed this neighboring mixed-use development, which was designed to include 10,000 units of housing connecting East Boston and Revere. More than 900 of the units are supposed to be for affordable housing, and the others will be for senior, workforce, family, and young-professional housing, according to the project developer HYM Investment website.
“If we want to really protect the marsh, we have to protect the locations where it is likely to migrate to,” Thiruvengadam says. “And if you give up those spaces, then you subject the marsh to what’s called ‘coastal pinch.’ The seas are rising on one side and the buildings are rising on the other, and the space that the marsh is in will become less and less, and it will just eventually disappear.”
While the project does integrate sustainable design practices (see our story about Designing Public Spaces With Nature in Mind), Thiruvengadam told me that yes, some of the Friends of Belle Isle Marsh did have concerns about the development “and what that precludes in terms of what we need in the future.” (Construction on some of the Suffolk Downs housing units was indefinitely paused in July due to the high cost of interest rates and materials, according to the Boston Globe.)
Conservation experts are looking at other interventions to protect Belle Isle Marsh, such as using SMARTeams, also known as Salt Marsh Adaptation and Resiliency Teams — people who evaluate salt marshes and address restoration on a larger scale. SMARTeams offer technical support and education and training by working with organizations such as the Natural Resources Conservation Service, Mass Audubon, and NOAA.
“It’s a group of people who come in and figure out what’s feasible at this point in time, so we’re excited about that,” Thiruvengadam says.
The cities of East Boston, Winthrop, and Revere are also working together to come up with conservation solutions at Belle Isle, using Municipal Vulnerability Preparedness (MVP) program funding, which is a state grant offered to communities to tackle climate resilience projects. The marsh is listed as an Area of Critical Environmental Concern and a Mass Audubon-designated Important Bird and Biodiversity Area.
Sean Riley at the DCR brings it all back to the saltmarsh sparrow, who might be the real stars of this story.
“This is a bird that’s really on the brink of extinction,” Riley says, adding that they’ve had a 12% annual population decline, and about an 80% decline since the 1990s.
“It’s interesting at Belle Isle — we have one of the most comprehensive datasets for saltmarsh sparrows,” Riley says. “We’ve done three years of banding there. So when we’re doing passive surveys, which has been the standard for a long time, you go out with an audio lure and see how many birds would pop up. We would get between five and eight birds, usually. So we figured that was right around the population. We’ve banded almost 100 birds at the site. So this is a species which is very hard to detect and do a population assessment just by sort of bird monitoring protocols and surveys,” Riley says. “So it’s both alarming and concerning.”
What’s encouraging, however, “is our high marsh habitat at Belle Isle is very small. We have 100 birds in this small section of marsh. You don’t need 10,000 acres to maintain that population, so that’s very encouraging,” Riley says. “And there are some groundbreaking datasets that we figured out that said you need to preserve these populations in these small microhabitats.”
There’s a federal focus on the saltmarsh sparrow now, thanks in part to the DCR’s research at Belle Isle.
“They should have already been federally listed, but the U.S. Fish and Wildlife Service I think has them on the docket this year,” Riley says. “There’s already a lot of federal funds being freed up to do restorations and look at really saving saltmarsh sparrows in Massachusetts. We’re not very far off from these birds. So it’s something to be taken very seriously, and it’s something that warrants a lot of our protection in these areas.”
I don’t think I saw any saltmarsh sparrows at Belle Isle, but I did see a snowy egret fly by and an osprey nest in the distance. The Friends of Belle Isle Marsh maintain a 24 hour osprey webcam that I found myself constantly checking over the summer before the chicks fledged. Kannan Thiruvengadam says it’s one of the most-enjoyed features on their website. He reminds me that one of the best ways to support the marsh, aside from making a donation or volunteering, is by simply visiting.
“I think the more people who visit the marsh, the better,” Thiruvengadam says.
Belle Isle Marsh has an entrance across the street from the MBTA’s Suffolk County station. To learn more about what’s happening there, visit friendsofbelleislemarsh.com.
Read next: Secrets of the Salt Marshes by Sam Moore
