Eurasian Watermilfoil – Dealing with the Threat
The FLCA is very excited to announce that the Ontario Trillium Foundation, an agency of the government of Ontario, approved our application for a grant to help us with our efforts to control the spread of Eurasian Watermilfoil (EWM) in Farlain Lake over the next three years! Over the past five years, we have worked hard to develop strategies to control the infestation of this very aggressive aquatic plant based on extensive research, consultation, networking and experience. The grant will help provide us with the resources we need to purchase equipment, supplies and services needed to manage the EWM and protect the future of our lake. It’s hoped that our learning and experience will also help other communities dealing with the EWM.
What is the Eurasian Water Milfoil (EWM)?
EWM is an extremely aggressive non-native invasive water plant that forms thick underwater stands of tangled stems and vast mats of vegetation on the water’s surface, especially in shallow lakes like Farlain Lake. It was discovered in Farlain Lake in 2012 during a FLCA aquatic plant study of the lake. It had not been observed by Ontario government organizations studying water quality or the fisheries of the lake prior to that. The pioneer colony (original infestation) was limited to a small isolated area less than one acre in size on the southwest shoreline of the lake.
EWM is considered one of the most widely distributed aquatic invasive species with records of EWM confirmed in 47 continental USA states as well as the provinces of British Columbia, Ontario, and Quebec. Various organizations have been combatting EWM for years. For example, Lake George in New York State’s Adirondack Park has been managing EWM for 32 years. The Okanagan Basin Water Board in British Columbia has been combatting EWM for the past 40 years. Control budgets vary depending on the severity of the problem and the size of the water body. For example, the Christina Lake, British Columbia, EWM control program is $213,000 annually. To manage EWM and improve the lake’s water quality in Puslinch Lake Ontario, through dredging the annual operating cost is approximately $150,000.
EWM will grow from plant fragments created from physical breakage by boaters, anglers, and other disturbances (e.g. forceful wave action, aquatic animals, fish, waterfowl, etc.) during the summer months. In late fall during the end of its growth period EWM becomes brittle and naturally break apart. Plant fragments are the primary means of EWM reproduction; they float on the surface and are dispersed by wind and wave actions to other areas where they sink and colonize into new plants. In optimum water temperatures (15°C – 35°C) EWM plants can grow 30 cm per week.
Why is EWM a Problem?
EWM is an extremely aggressive invasive aquatic plant that forms thick underwater stands of tangled stems and dense floating mats of vegetation.Some of the problems associated with EWM include:
Recreational activities such as boating, fishing, and swimming are impeded by dense growth at or near the surface.
Shoreline property values can be de-valued. EWM choked bodies of water can depress real estate values up to 20%.
The lake’s ecosystem will be altered. EWM will displace important native plants thus harming fish and wildlife habitat. Dense floating vegetation becomes breeding habitat for mosquitoes.
Stagnant oxygen-depleted conditions are often found in association with dense beds of EWM. Sudden nutrient release caused by late-season die-back of extensive plant beds may cause nuisance algae blooms.
Costs to manage EWM growth are borne by either local citizens, lake management organizations, and/or local governments.
What is the FLCA Doing to Manage the EWM?
The FLCA implemented a EWM Control Program in 2014 under the leadership of the EWM Steering Committee working with the FLCA Board, and with the support of many volunteers from the community. We also appreciate the ongoing support we receive from the Severn Sound Environmental Association (SSEA) and the Township of Tiny. There are no recent research studies in EWM in either the USA or Canada on effective control methods. The FLCA needs to rely on proven safe control methods to manage the growth of the plant on the lake. Initially focusing on hand harvesting using professional divers, additional methods have been added on a trial basis. Based on our learning and additional research each year, additional strategies have been added. Hand harvesting was augmented in 2017 using a DASH (diver assisted suction harvesting) system to expedite the removal of the plant from the water for collection and dispersal. Reward, a government approved herbicide, was applied to a limited targeted area in the pioneer colony and one other area by licensed applicators in 2018. Benthic or “bottom mats” were applied to a limited area of cut EWM on a trial basis.
For details on the 2018 control effort, please download the PDF Managing the Eurasian Watermilfoil on Farlain Lake here. These control efforts come at a cost both financially and in volunteer resources. The FLCA is fortunate to have a very dedicated group of volunteers on the Committee, helping with fund-raising, the physical labour during harvesting and ongoing research. A major fund-raising campaign was launched in 2017 and continues. We have sincerely appreciated financial support from Tiny Township and community sponsors as well. In May of 2018 an application was made to the Ontario Trillium Foundation (OTF) for a grant to fund control efforts for the next three years and we are thrilled that the grant was approved!
Please scroll down for information on the 2019 EWM Control Project.
We are dealing with a critical issue affecting the long term health of Farlain Lake’s ecosystem, lake usage, and property values.
There are five key challenges to managing EWM in Farlain Lake…
Up until now, the burden of raising funds to support our control efforts have fallen to the community. Between 2017 and 2018, over $46k was raised through donations, special activities, silent auction, sponsorship and support from the Township of Tiny. The OTF grant will provide the financial resources needed over the next three years. However, this threat is not going to go away and funding will be required for the long term. The balance of community funds available following the work done in 2018 will be used to start a “war chest” to allow us to continue managing the EWM beyond the three years of the grant.
Only a small core group of volunteers undertake the majority of the EWM control program work throughout the year. This group of dedicated volunteers represents 1% of the lake community’s population. Those who volunteer also have personal and family commitments, limited free time whether they are fully employed, partially employed, or retired. There are community residents who have health and mobility issues but are able to volunteer where they can. The reality of the volunteer situation is that volunteer fatigue will become a reality as the same volunteers are called upon time and time again to undertake the necessary fundraising and EWM control work. Ongoing effort to engage the rest of the community and beyond is needed in order to avoid volunteer burnout.
EWM Control Options
Our options of proven control methods are limited. There are no viable biological control methods. Unlike the United States where the primary control method is the application of various types of aquatic herbicides, the only herbicide approved by Health Canada to manage invasive aquatic plants is a contact herbicide (brand name Reward) that only slows the plant’s growth rather than kill the plant. Mechanical harvesting and chemical herbicides only provide short-term control and have negative impacts on native vegetation. As we continue to try alternative strategies, research and evaluation are necessary to determine the most effective approach for Farlain Lake and to be able to share the results with other affected communities.
Control efforts will be affected by uncontrolled and unpredictable natural circumstances (e.g. weather patterns, water level fluctuations, variations in water temperature, etc.).
It is vitally important for lake community members, their guests and visitors to the lake be aware of the threat EWM poses to the lake’s values we all share. The FLCA has erected an information kiosk with the support of the Township at the boat launch area on Andrew Drive, it has created publications and displays, and the Association has distributed information door-to-door around the lake community as well as mailing information directly to property owners’ home addresses. The FLCA has written articles for FOTTSA’s Tiny Cottager newsletter which is distributed to each property owner online and via mail. FLCA members receive ongoing EWM related information through the FLCA website, newsletters, and E-blasts. Each FLCA Annual General Meeting features an update on the EWM issue. Yet too many of our lake community residents are oblivious to the EWM threat and the fact that their recreational activities (e.g. boating, angling, etc.) contribute to the spread of EWM within the lake.
2019 EWM Control Project
Our team of volunteers, who regularly monitor our lake for the EWM, discovered new mature beds in September of last year. This marked a significant setback to our EWM management efforts. Since the fall of 2018 the EWM Steering Committee, in concert with members of the FLCA Board of Directors, developed a three year (2019-2021) EWM Integrated Management Plan based on our research and experience to date. The plan is consistent with our application for a grant from the Ontario Trillium Foundation (OTF) and we are thrilled that the approval of the application will allow us to move forward with our plan.
FLCA Members may download a copy of the Eurasian Watermilfoil Integrated Management Plan and further details on the management project by clicking here and entering the password. If you can’t remember the password please contact us at firstname.lastname@example.org.
All necessary permits/permission have been obtained from Department of Fisheries and Oceans Canada (DFO), Ontario Ministry of Natural Resources and Forestry (MNRF), and the Ontario Ministry of the Environment, Conservation, and Parks (MECP).
Our 2019 strategy consists of the following:
- Weed Watcher Recruitment and Training
- Mapping the Infestations
- Preparation of Equipment and Materials
- Application of the Herbicide
- Recruitment of Volunteers for Harvesting
- Application of Bottom Barrier Mats and Harvesting
Weed Watcher Recruitment and Training
In partnership with the SSEA, a shoreline workshop on June 29 will train volunteers in aquatic plant surveying/mapping/monitoring. A Weed Watcher Training Manual has been developed to provide a basis for educating our volunteers in the identification of not only the EWM but other aquatic plants. OTF funds have been used to purchase surveying/mapping/monitoring equipment (e.g. hand held GPS units, range finders, depth finders, underwater cameras, sampling rakes, marker buoys, etc.) required for the surveying/mapping/monitoring of the EWM. Volunteer Weed Watchers will be trained in the use of the equipment at the workshop.
Mapping the Infestations
The key to effective management of EWM in Farlain Lake is to locate EWM plants and prioritize control efforts. As we lack sufficient funding to undertake control efforts on a weekly basis throughout the summer months, our management efforts must be based on realistic, cost effective, and ecologically sound control efforts. Our strategy is to reduce the size of dense mature EWM infestations and to remove new small EWM plant infestations in high risk areas.
Mapping is a critical step in not only identifying where the infestations exist, but in our ongoing evaluation and reporting of the outcome of our control efforts. FLCA volunteers will be conducting extensive surveys of the lake to search for EWM plants. Working from the FLCA pontoon boats and other watercraft, the FLCA will locate EWM infestations, mark them with floating buoys, and map them for management priority setting. The SSEA has prepared a set of study sector maps requested by the FLCA. The maps will denote GIS images, bathymetry lake contour data, and study sector research grids. The mapping will be repeated at the end of the season as part of the evaluation of our efforts.
Preparation of Equipment and Materials
Funding provided by the Ontario Trillium Foundation have enabled the FLCA to purchase and equip a second pontoon boat to be used as a support vessel for our DASH (Diver Assisted Suction Harvesting) pontoon boat. Welcome Trillium I and Trillium II! The second pontoon boat will also be equipped for use in mapping/monitoring aquatic plants, and community outreach and education. Modifications to both boats, procurement of materials such as containment curtains for harvesting, sand bags, safety equipment, etc. are all part of the preparation.
In addition, contract are completed for the various services needed such as the professional divers and licensed applicators for the herbicide.
Application of the Herbicide
Application of the aquatic herbicide Reward will take place by licensed applicators between mid and end of July in order to avoid fisheries spawning and incubation. Application is very targeted only to specific infested areas and due to the fact that the herbicide is heavier than water, it does not spread. It also does not kill the plant but simply temporarily suppresses the growth. It is absorbed by targeted plants in just minutes with no toxicity to fish or wildlife. There is no need to restrict swimming. Notice will be sent out to members once a specific date is confirmed.
Recruitment of Volunteers
Harvesting and Application of Bottom Barriers
Harvesting and the laying down of benthic mats will take place over two weekends – Friday August 16-Sunday August 18 and Friday August 23-Sunday August 25. Base camp is located at the Sweenie Farm on the southwest of the lake. Harvesting utilizes FLCA’s DASH system, volunteers, and contracted commercial divers to remove the plant from targeted infested areas based on the mapping. In other areas, plants are cut and then covered with bottom barriers held down with sand bags. Barriers and bags will decompose over time.
An important step is the evaluation of all the strategies employed over the summer. This will consist of additional surveying following the August harvesting and feedback from participants through a focus group. The results will be provided to the FLCA members, SSEA, Township and included in a formal report to be submitted to the Ontario Trillium Foundation in December 2019 to ensure the continuation of funding for the second of the three years of the grant.
The FLCA is happy to share our experience and further details with other communities in Ontario who may be dealing with this very aggressive aquatic plant. Simply contact us through our email at email@example.com