Phragmites, the 12 feet tall perennial grass that aggressively colonizes and forms dense stands in freshwater wetlands can be eradicated using herbicides, but it takes years of repetition. The glyphosate components in the herbicide stay in the ecosystem which can lead to loss of biodiversity, making them more vulnerable to pollution and climate change. An alternative to eradication is burning, but the ash only fertilizes next year’s growth.
Phragmites obliterate nearly all other plant life, it changes a marsh’s hydrology that affects flow and habitat for baitfish and degrade conditions for birds along with altering water levels by trapping sediment.
Researchers know that phragmites doesn’t have many weaknesses, but salt is one of them and conservationists are restoring salinity to Rhode Island waterways by removing dams and restoring tidal flow. While the invasive plant is still there, it is stunted and numbers are reduced enough to allow less-suffocating plants to reestablish.
And after efforts to eradicate or reduce plant numbers, conservationists begrudgingly say phragmites may actually help save the marshes from climate change issues such as rising sea levels. These rising waters force the salt marshes inland, phragmites root networks retain peat in marshes and could help future marshes migrate to higher ground.
The phragmites are also excellent at capturing and storing nutrients. The plant locks elements such as phosphorus and nitrogen in its stalks and roots and also absorb industry legacy pollutants such as cadmium and lead. The biomass is also effective in storing carbon which is a chief driver of climate change.
So, do the benefits offset the harm?