New plant takes root in S. Jersey marshes

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Rowan professor Michael Grove studies the impact a plant new to the area has on fiddler crabs.

By JOEL LANDAU
jlandau@thedailyjournal.com

A Rowan University professor is studying the potential impact a new plant in area salt marshes might have on the ecosystem, particularly on fiddler crabs.

Michael Grove, an environmental science professor at Rowan University, is investigating the spread of phragmites austrailis in the salt marshes in South Jersey.

The plant has always been in North America, "but in the last 50 years it has spread out in places it never has before," Grove said.

Phragmites, which grows close together and can be as high as 12 feet, is replacing the common spartina plant, Grove said. The professor, along with his research partner Barbara McCraith, dean of the College of Arts and Sciences at College Misericordia in Dallas, Pa., and undergraduate students are examining the plant's impact on the fiddler crab.

"The real question is how the move from spartina to phragmites affects the way fiddler crabs are working," he said.

The crabs are important, because they burrow into the mud to hide from predators and mate, Grove said. The burrows are about a foot and a half deep, and the digging constantly turns the mud over and brings oxygen into the ground, releasing more nutrients to plants, which helps them grow, Grove said.

"Crabs heavily influence how much production we see in the marsh," he said. "The less crabs, the less number of plants and animals."

Grove said he's still compiling data, but so far he has found spartina, located in areas along creeks, attracts more crabs with larger burrows. Small spartina, found in higher elevations, produces fewer crabs with smaller burrows than phragmites. Short spartina is much more common, Grove said.

Grove and McCraith hope to publish a paper on the issue by next summer.

Traditionally invasive species tend to disrupt natural ecosystems, but "it's always difficult to put a good and bad on things," Grove said. "We're just looking at what it is."

Phragmites spread quickly for a variety of reasons, Grove said.

Their long thin leaves blow in the wind easily and the seeds on the top fly off, he said. The plant's roots spread underground, which is why the plant grows so close together and why other plants don't grow next to it, Grove said, adding it's why it's also hard to get rid of.

Not many animals eat phragmites, Grove added.

"It's why they are so successful as an invader," he said.

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