Tuesday, August 3, 2010 - 8:40 AM

COS 21-3: Controlling invasive reed: Comparing herbicide effectiveness and impacts on marsh benthic communities

Joseph R. Holomuzki, Ohio State University, Robert S. Whyte, California University of Pennsylvania, and David M. Klarer, Ohio Department of Natural Resources.

Background/Question/Methods

Controlling Phragmites australis, the common reed, is a priority of many North American wetland managers because reed spread can potentially adversely affect plant diversity and wildlife habitat. Glyphosate and imazapyr herbicides (e.g., AquaNeat® and Habitat®, respectively) are commonly used to control reed, but it is unclear which is most cost-effective. We compared herbicide effectiveness and examined benthic community structure post-application in 20 x 20 m plots of reed that were either: hand-sprayed with AquaNeat® (30% solution), sprayed with Habitat® (5% solution), or left unsprayed (controls) (n = 5 plots/treatment). 

Results/Conclusions

Emergent plant diversity (Shannon-Weaver H’) was significantly higher in both sprayed treatments than in controls 1-year post-spraying. However, plant H’, emergent plant density, and % Phragmites cover were similar between both herbicide treatments.  Macroinvertebrate H’ and assemblage, and juvenile fish captures, were similar among all treatments. Even after 2 years post-spraying, both herbicides had similar effects on plant community recovery and reed control. We estimate AquaNeat® provides 3X more product/dollar than Habitat® at these commonly used dilutions.