Invasive plant control may affect lake health


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Posted: 5/8/2009


Some scientists researching invasive water plants look at the direct effects of these plants and others assess different control methods.

Mississippi State University graduate student Erica Schlickeisen wanted to know about the indirect and sometimes unanticipated effects invasive plants have on water quality and microbial activity.

"Invasive plant infestations create problems because they can take over a lake and spread to other undisturbed water systems," she said. "We need to know how these plants alter the processes within a lake system to keep from making a problem worse or causing additional problems."

Schlickeisen is working on a doctoral degree with an emphasis in aquatic ecology in the MSU Department of Wildlife and Fisheries. Her study is being funded through the Biological Resources Invasive Species Program of the U.S. Geological Survey in collaboration with the MSU Geosystems Research Institute.

Schlickeisen conducted her experiments at MSU’s mesocosm facility on the South Farm. The facility has a series of tanks, each with a holding capacity of 1,800 gallons of water. She created 24 different ecosystem settings with freshwater nuisance plants in these tanks. The settings were grouped according to treatment method: herbicides, biological control, mechanical removal and no manipulation.

"The MSU facility for establishing mesocosms was essential to this research because the tanks are large enough to represent natural processes occurring in lakes and small enough to manipulate and replicate for greater experimental rigor," she said. "It would not have been possible to plant invasive species in 24 real-life ponds as it would have been irresponsible to release them into the natural systems."

Schlickeisen measured water quality and microbial composition on a weekly and monthly basis. She found water quality and microbial activity varied with the techniques used.

"Even small, indirect changes in a lake ecosystem may affect the food supply and living conditions for fish and plants," Schlickeisen said. "My initial results suggest that managers may need to monitor water quality following treatments to ensure that acceptable conditions persist in the water after treatments for invasive species."

Wildlife and Fisheries