Frag expands as plant nag


Invasive: A reed that has been around for years is increasingly crowding out species, but it has some benefits, too.

April 02, 2004|By Tom Horton | Tom Horton,SUN STAFF

For years I've been confused about Phragmites australis, the tall, plumed reed growing densely in patches, and occasionally vast stands, throughout the bay region.

Known as water reed, reed grass or frag, it's frequently reviled as an invasive species, spreading throughout native Chesapeake wetlands.

At the same time, it's clear that phragmites (frag-MY-tees) has been around a while. It's in peat deposits on the Delmarva Peninsula dating back thousands of years; natives in the Southwest historically have used it for everything from arrow shafts to prayer sticks.

But during the past 30 to 40 years, frag has begun to expand its territory in our region, colonizing thousands of acres from Baltimore harbor to the Blackwater National Wildlife Refuge on the Eastern Shore.

It used to grow as part of mixed communities of other wetlands plants but increasingly occurs in dense stands that crowd out everything else.

With a tenacious root system that can extend horizontally up to 6 feet in one year, the giant reed (up to 12 feet tall) is highly resistant to cutting, burning or any known means of control.

It also spreads rapidly. A small fragment of root, carried by tides or currents, is enough to establish another colony.

But why has something that's been around forever suddenly run amok?

Part of the reason, confirmed recently by a University of Maryland scientist, is that we're dealing with two different phragmites, virtually indistinguishable except through DNA analysis.

Kristin Saltonstall, a post-doctoral student at Maryland's Horn Point laboratory on the Choptank River near Cambridge, found unique genetic mutations that let her sort native phragmites from other lineages of the reed.

One of the world's most widespread plants, phragmites occurs naturally on every continent - even Antarctica in palmier times, based on fragments found in ice cores there.

Sure enough, Saltonstall found that we have a European strain of frag in our midst. The Atlantic seaboard has mostly lost its native frag to the more aggressive European variety, she found.

The two exceptions are in parts of Maine and around the Chesapeake, where substantial areas of native reed exist. (We have plenty of the European strain, too.)

This raises the ironic possibility that the frag we've come to despise might be a threatened species in some areas.

I still wondered why the European frag has become a problem only in recent decades. It was most likely brought here two centuries or more ago.

Saltonstall says frag's expansion probably followed the expansion of roads, with their hospitable roadside ditches. In addition, ditching marshes, in misguided attempts to control mosquitoes, created disturbed soils - which frag loves to colonize - and altered salinity patterns to favor the reed.

Another boon to frag's expansion - and even the native variety appears to be expanding - has been the increase in dredging. Show me a spoil disposal area and I'll show you phragmites.

There's no sure way to tell by eye whether frag is native or European, but native reed can have a shinier stalk, with black spots, and more purple in the stalk and base of leaves. In winter, leaf sheathes remain on European frag stalks while the native sheds or holds them loosely.

A most ominous suspect in boosting native and non-native frag is the nutrient pollution devastating bay waters - too much nitrogen and phosphorus, coming from sewage, farm and urban runoff, and dirty air.

Saltonstall has fertilized native and European frag with both of these nutrients. Both grew faster, but the European invader grew much, much faster.

Although its value for wildlife is marginal, phragmites has its good points, Saltonstall and other bay scientists point out.

It keeps sediment out of the bay by stabilizing poor-quality soils such as dredge spoil, where no other plants would grow.

It takes up significant quantities of polluting nutrients and toxic metals that otherwise would run into waterways. And, unlike many plants that shed toxins when they drop leaves, frag retains them in its extensive root system.

In Europe, phragmites is highly valued and in decline. There it is used for everything from livestock fodder to making paper to thatch for high-quality roofing. One sparrow in Europe nests only in frag.

Suspects in its decline there range from pollution to predation by insects. No insect predators exist here, and introducing another exotic species to control frag would carry risks, Saltonstall says.

We may be overlooking a good thing in frag, says roof thatcher Colin McGhee of Charlottesville, Va.

"I ride around Baltimore and other waterfronts, and I see all that good frag and I just laugh - thousands of acres of good reed going to waste," McGhee says.

He recently finished thatching roofs for the set of a movie about the Alamo and is putting a reed roof on a $2 million home in Indiana. "And I am having to go all the way to Hungary and the Ukraine" to get frag, he says.

For a time, McGhee paid out-of-work crabbers to cut and bundle frag on Kent Island. "It's good reed around here, worth about $4 a bundle, and you can get up to 400 bundles off an acre," he says.

The problem, he says, is that there is "no reliable supply here. I used to cut it myself, but I can't do it and thatch, too. I've given up."

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