Southern Wisconsin Invasive Cattail and Phragmites Treatments
By Jason Fleener, Wetland Habitat Specialist, Wisconsin DNR
This article originally appeared in Wisconsin Waterfowl Association’s October, 2021 Newsletter edition.
This will be the first in a series of Waterfowl Stamp project highlights. This series is intended to connect waterfowl hunters with habitat projects funded by State Waterfowl (Duck) Stamp dollars across Wisconsin. A recent fee increase in the stamp from $7 to $12 will result in increased funding and project work that is being carried out by DNR, WWA and other conservation partners. All funded projects are intended to maintain, restore or enhance habitat for waterfowl. Several of these habitat projects can be observed from the field when you are out in the marsh.
The first project highlight is a multi-property collaborative to treat invasive cattail and phragmites (aka common reed grass) across state wildlife areas. During August 2021, over 380 acres were aerially treated with an imazapyr-based herbicide across five state wildlife areas in southern Wisconsin; Horicon (Dodge County), Prince’s Point (Jefferson County), Mud Lake (Columbia County), Paradise Marsh (Columbia County) and Theresa (Dodge and Washington Counties). A minimum of 50 acres was treated on each property. All spraying conducted was done in accordance with EPA regulations, product label instructions, and is properly permitted within DNR.
The low bid for these properties went to T&T Endeavors, a drone contracting company based in Wisconsin. The use of drones for herbicide application is relatively novel technology for the agriculture industry and for conservation. While herbicide treatments on cattails and phragmites from a drone cannot be done as quickly as a helicopter, a drone offers a more precise application on targeted areas with minimal disturbance during operations.
An eight-blade drone, is programmed with GIS data to treat targeted patches of plants from a 2.5-gallon tank of herbicide and surfactant (photo by Angie Rusch, DNR).
Approximately $50K of Waterfowl Stamp funds paid for this contract work. DNR and conservation partners will attempt to offer the Waterfowl Stamp funds spent on these projects as match to earn federal grants to further waterfowl habitat conservation work in the region.
Several marshes in nutrient-rich southern Wisconsin commonly experience an inundation of narrow-leaved and/or hybrid cattails, which outcompete other emergent and aquatic plant species that are more desirable to ducks. Once a majority of a marsh is covered with cattail, action is often taken by wildlife managers to control some of the cattail so that more open water pockets are created with a hemi-marsh goal in mind (an even mosaic of emergent plants and open water). After a year or two following spraying, open water conditions will form, which sets the stage for growth of desired aquatic vegetation, increased duck use, and better areas for hunter use and access.
Herbicide Treatment on invasive cattails in action on the Theresa Wildlife Area, Dodge County (photo by Angie Rusch, DNR).
The goal for treating invasive phragmites, on the other hand, is to eradicate as many stands or clones as possible. The negative impacts of invasive phragmites on waterfowl and other water birds are perhaps more profound than invasive cattail. The goal of DNR and other cooperating invasive species partners is to stop or slow the westward expansion of invasive phragmites across the state. Hunters can do their part to prevent the spread by avoiding the use of phragmites as concealment material on portable blinds and boats. Wisconsin is also home to a native species of phragmites, which is typically shorter, less dense and less aggressive in colonization. DNR is diligent to spray only the exotic, invasive sub-species of phragmites (Phragmites australis australis).
To effectively control invasive cattails and phragmites long-term, a toolbox of management tools is often strategically implemented in addition to herbicide treatment (e.g. proper water level management on flowages, prescribed burning and mowing). Many times all of these tools cannot be feasibly implemented on a given site, but the more that are implemented with proper timing and sequencing will yield better long-term management success.