Phragmites is a relentless plant threatening the environment of Newport.
It fills almost all of the fresh and brackish water marshes in Newport County. Growing up to 12 feet tall and lush with corn-like acorns, its lazy beauty is such a dominant presence in wetlands that few people know it is not a native plant. Likely to have overflowed with the hold of the colonial era, this ubiquitous plant with the odd name is phragmites (FRAG-mi-teez), from the Greek word for “fence.” It has spread across North America, giving environmentalists crises, so much so that learning to live with it has replaced all hope of eradication.
“From 1980 to 2010, a herbicide was used”, explains Dr Laura Meyerson from the University of Rhode Island, who has studied Phragmites for 25 years. “It can work, but it takes years of repetition. And despite what the manufacturers say, the components of glyphosate remain in the ecosystem. People burned phrags when the reeds die off in the fall, but the ashes only fertilize the growth of the following year.
Locally, it’s everywhere. It plugs the brackish marsh under the Norman ornithological reserve‘s Hanging Rock and fills bodies of fresh water like Almy Pond, where it thrives on the neighborhood fertilizer runoff. This made some of the East Bay marshes impassable, even for deer. It looks like wheat on steroids, looking like the stubble that housed the professor, Mary Ann and the others on Gilligan Island, and it can wipe out almost any other plant, including its native, less conquering North American cousin, the Common Reed.
Phragmites also puts environmentalists in a bind. Native swamp life would undoubtedly be better off without it, but it is here to stay, and biologists strive to minimize its drawbacks while still realizing its benefits. It’s a tough walk, which won’t be perfect, but done well, it could prepare local marshes for climate change while leaving room for native flora and fauna.
Phragmites likes three things: wetlands, high nutrient loads and disturbed soils.
All of this makes the New England coast a happy home: a place first hacked by settler pickaxes and now 21st century backhoes, while being inundated with runoff from lawn, farm waste and dirt. sewer overflow. Phragmites do not have many weaknesses, but salt, despite the plant’s high tolerance, is one. It can typically tolerate up to 22% salinity, and in places where human activity has reduced that number, conservationists are working to restore it.
“Our goal is to reduce the size and vigor of the phrag,” says Wenley Ferguson, biologist Save the bay. “It’s in our landscape now, but we can handle it. Gooseneck Cove is a good example. we shot [out] a dam and carried out other work to restore the tidal flow. Phragmites is still there, but it’s less now, and what’s there is stunted.
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She notes similar work done at the Sachuest Marsh behind Third Beach, where the United States Fish and Wildlife Service removed a culvert to increase tidal flow. This toppled the Phragmites, if not wiped out. Such efforts allow less suffocating plants such as cordgrass (Spartina) to restore. In Jamestown’s Round Marsh, Save The Bay channeled near the Red Maple Marsh in the Conanicut Island Sanctuary. “It lowered the water table to drain runoff from the roads,” says Ferguson. “It also increased the salinity and significantly limited the spread of Phragmites. It will take maintenance over the years to stick with it, but you really only see it on the sidelines now. ”
This is critical. Like most non-native species, Phragmites are an ecological wrench. One thing that makes it so suffocating for wetlands is its growth strategy. Although her high seed heads allow her to spread in the wind from one wetland to another, once established, she relies on the growth of rhizomes and the ability of any broken stems to send roots into peat. and start from scratch. (Rhizome growth is the spreading of roots where the plants then rise next to each other, creating a dense clonal “forest”.)
The effects of Phragmites on birds vary
Monocultures of all kinds blunt biodiversity. With life being the nimble force that it is, however, Phragmites alone do not produce the Zombie Apocalypse. While URI ornithologist Dr Charles Clarkson acknowledges the overall detrimental effects of Phragmites on bird life, he says it’s nuanced.
“Phragmites is a double-edged sword. As densities increase, we still see some species diversity, but the overall number of birds is decreasing. Where it’s thickest is when the specialists fall or disappear – these are species that co-evolved with the native swamp and didn’t adapt: birds like the Wren marshes, salt marsh sparrows and the rail family.
Less demanding species, however, fare better. These include warblers like warblers and yellow warblers, as well as red-shouldered robins, the males of which adorn all wetlands in the county with their scarlet epaulettes.
The waders are also mixed, some doing well even when the conquest of the Phragmites is over.
“Birds that practice crypsia – which use camouflage both to hunt and escape predation – seem to agree with phrag,” says Clarkson. “Black-crowned night herons are one of them, and some Great Lakes studies show that American bitterns are actually increasing. ”
Once again, however, the news looks worse than good.
What is the impact of Phragmites on the ecosystem?
“Phragmites change the hydrology of a swamp,” explains Clarkson. “This affects the flow and habitat of baitfish, degrading conditions for birds like great blue herons or the egret family.”
URI’s Dr. Meyerson studied the effects of Phragmites on Death Shock, the otherwise hardy baitfish that obscure Rhode Island’s salt marshes. Marshes are marine nurseries and strongly influence life at sea, including for sport fish such as scup, stripers and bluefish.
“Where phragmites dominate, dead shockers are smaller, slower to grow and less fruitful,” she says. “They prefer native algae and can’t find what they need in dense stands of phrags. It’s the popcorn of the sea, and it affects the entire food chain.
Swamps, however, face other challenges, which some environmentalists reluctantly say phragmites can help with, starting with storing nutrients. The phosphorus and nitrogen runoff that helps Phragmites is a plague on wetlands in the form of algal blooms. Phragmites lock these elements into stems and roots, and can do the same with legacy industrial pollutants like cadmium and lead.
“Those, of course, don’t break down,” Meyerson notes. “But Phrag is at least temporarily confining them.”
Due to its biomass, Phragmites also store a large amount of carbon. With CO2 being one of the main drivers of climate change, this is a huge asset, although Meyerson is still concerned.
“As the phrag breaks down, it releases methane, a more potent greenhouse gas. Yes, the carbon storage is great, but it can be a wash. ”
Between the multiple challenges of climate change and development, Newport County’s salt marshes are struggling. The phragmites’ extensive root systems help retain peat in swamps. As rising seas force swamps inland, these root networks should help future swamps migrate to higher lands.
Ferguson and Meyerson both see the potential benefits. Noting that Rhode Island’s salt marshes are increasing 1.8mm per year due to decaying plant matter, while sea level is rising 5.2mm per year, Ferguson says the marshes are not keeping pace with everything. simply not. She and Meyerson, however, find that the Phragmites keep pace.
“Will it save our swamps?” Meyerson asks. “To me that’s not really the answer, but it’s an interesting question.”
The Phragmites undoubtedly harms biodiversity, but its tenacity compels conservationists to seek benefits while managing this vice. Rising sea level is too wild a wildcard to know what this final toll will say, but as Meyerson observes, it’s an interesting question.