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.
