New York City volunteers planted 20,000 marsh seedlings on a dying salt marsh in 2003, but 80% of the site was healthy just two years later | World News

PC:  National Park Service

In 2003, a restoration effort at New York City’s Big Egg Marsh took a major step when National Park Service scientists and 100 volunteers planted 20,000 smooth cordgrass seedlings across an area that had been raised with clean sand. The work was part of an experiment to restore a salt marsh in Jamaica Bay, where marshes had been disappearing for decades. The seedlings faced early setbacks, including grazing by geese, tides and marine debris. The vegetation continued to spread. Just two years into the restoration, more than 80% of the experiment site was reported to be vegetated and healthy, offering an encouraging result for the damaged marsh.

20,000 seedlings planted on New York City’s dying salt marsh

Once the marsh had been raised, the restoration team needed to establish vegetation across the treated area. In October 2003, National Park Service scientists and 100 volunteers planted 20,000 seedlings of smooth cordgrass, known scientifically as Spartina alterniflora. The planting covered the part of Big Egg Marsh where the sand had been sprayed.Smooth cordgrass was particularly suited to the difficult conditions of a salt marsh because it can thrive in high-salinity environments. According to the National Park Service, the plant’s roots trap sediment, allowing it to build up into nutrient-rich peat. That peat creates a stronger foundation for further plant growth, meaning the vegetation could contribute to the longer-term development and stability covering the restored ground.

Scientists begin monitoring Big Egg Marsh

The planting was followed by systematic monitoring. Scientists established one-metre-by-one-metre plots across Big Egg Marsh and repeatedly returned to record elevation, plant numbers, soil characteristics and the animals present. This allowed researchers to track changes over time rather than judging the restoration from a single observation. Monitoring began in 2004 and continued several times a year through 2008.Geese ate some of the seedlings, while tides washed others away and marine debris such as logs, bottles, plastic bags and straw buried or suffocated some plants. Despite these losses, smooth cordgrass continued to grow, while new seedlings appeared naturally and saltmeadow cordgrass, or salt hay (Spartina patens), also began to establish.

80% of the experiment site becomes healthy

Two years into the restoration, the results showed a substantial change across the experiment area. The National Park Service reports that over 80% of its experimental site was vegetated and healthy. This meant that despite the early losses among planted seedlings, vegetation had successfully become established across most of the restoration site.Monitoring continued to provide information about what happened to the marsh over the longer term. In 2021, nearly two decades after restoration began in 2002, Dr George W. Frame returned to Big Egg Marsh to examine its condition. The restoration also helped pave the way for other projects in Jamaica Bay, with efforts across the bay eventually restoring more than 150 acres of marshland.