Sunday, March 13, 2016

Clearing Phragmites from Wetlands

Clean water in Lake St. Clair depends in significant part on healthy shoreline wetlands.

Mallard Ducklings - Mike Powell

Wetlands slow and filter storm runoff, provide shelter for fish, birds and other wildlife and incubate their young. But a vast array of native wetlands plant life is being choked out by invasive plants.

One in particular spreads rapidly, the ubiquitous tall reed with the feathery top that you see in wet places where there used to be cattails. It is phragmites (frag-MY-teez), an invasive plant from Europe.

Phragmites grows in thickets that now dominate many Great Lakes shorelines, as well as inland ponds, lake shores and ditches.

In addition to displacing other plants, dense stands of phragmites crowd out birds, mammals and amphibians. The plant also inhibits commercial and recreational uses.

Eighty percent of the phragmites plant is underground. It can reach heights of 15 feet or more. The roots can radiate 60 feet, reach a depth of six feet and expand outward at the rate of six feet per year. These giant weeds spread more rapidly by their roots and broken fragments than by seeds.

The U.S. Environmental Protection Agency committed nearly a million dollars to a 1200 acre (later expanded) phragmites eradication project undertaken by Ducks Unlimited, which provided matching funds, around northern Lake St. Clair from 2010 to 2013.

A Ducks Unlimited spokesman reported:

The spread of highly invasive Phragmites (Phragmites australis) is a recent and major factor in the degradation of Lake St. Clair’s coastal wetlands. The recent decrease in Great Lakes water levels has lead to the expansion of emergent vegetation in the littoral zone of Lake St. Clair; however, lower water levels have also facilitated the rapid expansion of Phragmites. In many areas of Lake St. Clair, Phragmites is expanding at a much faster rate than native emergent plants. With its strong capacity to spread by rhizomes, near-monotypic stands of invasive Phragmites have replaced high quality, complex communities of native plants, leading to loss of fish and wildlife habitat, biodiversity, and a native plant community resiliency. In addition to impacts on the area’s natural resources, the residents of Lake St. Clair have also observed ecological, economic and social impacts as a result of the Phragmites invasion.

Ducks Unlimited (DU) along with project partners approached this project through 3 primary components: 1) an integrated management effort to control Phragmites on both public and private coastal wetlands through aerial and ground herbicide treatments, followed by mowing, burning and spot herbicide treatments, 2) monitoring the response of native vegetation and avifauna to these enhancement efforts, and 3) implementation of a public education and outreach program to inform citizens about the impacts and effective management of Phragmites.

The work continues through successive phases.

No comments:

Post a Comment