Great Lakes Restoration Initiative (GLRI)


Innovative Phragmites Control Strategies

Template #67


Background/Problem

Phragmites, an invasive wetland plant, inhibits natural coastal functions such as nursery areas for critical fish and wildlife habitat and it blocks valuable lake views. Phragmites and other highly invasive plants continue to spread across the landscape and reduce the quality of habitat for wetland plants and animals, decrease the aesthetic value of property, and increase the likelihood of damaging fires. Current management approaches (e.g., spraying, burning, cutting) are resource-intensive and difficult to maintain over the long term. A recent study in which land managers were surveyed on the operation and effectiveness of their Phragmites programs found that an estimated $4.6 million is spent on mechanical and chemical Phragmites control on over 200,000 acres annually with no statistical relationship between resources invested and management success. This indicates a need for new, more effective techniques to combat this aggressive invader and underscores the importance of research to promote new strategies. This GLRI Project tests new strategies to reduce the invasive properties of Phragmites and minimize its competitive advantage. This project continues to work within the Integrated Pest Management (IPM) framework and make steady progress toward more sustainable strategies that landowners and resource managers could potentially use to control Phragmites and other invasive plants.


Description of Work

We are engaged in USGS-led field research to examine the growth response of non-native Phragmites to fungicide application aimed at controlling fungal microbes. We have formed a Collaborative of scientists that is coordinating research efforts to explore fungal mutualisms (i.e., both plant and microbe benefit from each other) in Phragmites and other invasive species. The intent is to pool our independent knowledge and attempt to develop a new strategy for managing Phragmites by targeting its fungal associates. We are partnering with researchers at Wayne State University to develop a strategy for silencing plant genes that code for traits that enhance invasions by Phragmites.


Relevance/Benefits

The progress made on this project is encouraging, because this type of control could be customized for other invasive species. A goal of this research is to create a completely species- and trait-specific treatment framework that could be applied to a suite of invasive species and provide another tool for resource managers. That means that land managers may be able to treat rapidly expanding or well established stands of an invasive species without having detrimental effects on other, non-target plant or animal species. The effects of gene silencing are transient, in that they cannot spread within the plant or be transferred to offspring. There is a great deal of excitement about this research in the management community and the topic remains one of the most visited pages on the Great Lakes Phragmites Collaborative webpage (http://greatlakesphragmites.net/). These results and the overall direction of this project directly support the broader Integrated Pest Management (IPM) approach being developed for Phragmites and many other invasive plants. There are many opportunities to work with the existing partners (e.g., SEMCOG, USFWS, TNC, GLC, DU) to build on this work, integrate with IPM efforts, and target our field trials in AOCs or other high priority sites.


Key Findings

Preliminary results of a small study conducted in summer 2012 by Dr. Rusty Rodriguez (Symbiogenics), Dr. Regina Redman (University of Washington), and Dr. Kurt Kowalski (USGS – Great Lakes Science Center) indicated that treatment of fungal endophytes (i.e., microbes found in all parts of plants) with the general use fungicide can decrease the number of new Phragmites stems growing compared to control plots. This initial study was conducted at a very small scale and did not allow for treatment of juvenile plants, but the results were promising. That study provided the underpinnings for a more comprehensive field study in 2013 that is designed to provide proof of concept that controlling endophytes can decrease the growth of Phragmites. This study will elucidate whether fungicide application affects the biomass production (above and belowground), stem density, and percent cover of Phragmites. It will also examine the effects of the treatments on native plant species diversity. This effort will produce the first comprehensive results that document how fungal associates can affect growth of the invasive Phragmites and provide a foundation for additional experiments on the path toward new control tools.

The USGS has partnered with Dr. Edward Golenberg at Wayne State University to examine the potential use of gene silencing in Phragmites management. Gene silencing is a process whereby the genetic message necessary to code for particular proteins is blocked (silenced), thus blocking the development of specific traits. For instance, if researchers target and silence the genetic code essential for photosynthesis, a plant will not be able to harness the sun’s energy and growth will be stunted. The project team continues to make incremental progress toward the application of this technology as a form of Phragmites management. Researchers at Wayne State have identified a suitable transmission vector for monocot species and completed several ‘proof of concept’ studies silencing the photosynthetic ability of plants similar to Phragmites. These successes and analysis of the Phragmites will allow expanded lab testing of gene silencing techniques in Phragmites.


Products

Braun, H. and K. P. Kowalski. Participated in the Great Lakes Phragmites Collaborative. Webinar, July 19, 2012 (http://greatlakesphragmites.net/webinars-presentations)

Presentation: Kowalski, K. P. Phragmites management: progress on multiple fronts. Lake Saint Clair/Saint Clair River Partnership Meeting. SEMCOG, Macomb, MI, June 27, 2012

Kowalski, K. P. Phragmites control: progress with multiple components. Presentation to EPA GLNPO and other partners during tour of the Huron-Erie corridor, August 28, 2012

Presentation: Kowalski, K. P. Phragmites control: progress with multiple components. Michigan Aquatic Invasive Species Council, Houghton Lake, MI, October 25, 2012


Contacts

Kurt P. Kowalski, kkowalski@usgs.gov
Great Lakes Science Center (GLSC)
734-214-9308

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