Sixth summer of program combating invasive species

Aquatic invasive plant species have long threatened the health and populations of native plants in the Lewis Creek watershed. By forming dense mats of vegetation, aquatic invasive plant species impede the activities of recreational boaters, swimmers and anglers, while degrading ecosystems and wildlife habitats.

Aquatic and riparian environments are fragile and sensitive to change. The health of these places is essential to the health of surrounding plants and animals. Terrestrial invasive plants also create hazards by altering erosion patterns, out-competing native species and impacting water quality. Management of all invasive species can be difficult because they are easily spread via seeds, roots, fragments, animals and humans.

Bristol Pond and Monkton Pond, popular destinations for anglers, recreational boaters and wildlife enthusiasts, both contain aquatic invasive plant species. As of 2024, there were three known aquatic invasive species in Bristol Pond: European frogbit, Eurasian watermilfoil and brittle naiad. There are four aquatic invasive species in Monkton Pond: Eurasian watermilfoil, curly-leaf pondweed, banded mystery snail and Chinese mystery snail.

If left unmanaged, the aquatic invasive plant species in these ponds will spread throughout the rest of the watershed and the state. To prevent further spread, Lewis Creek Association, a local non-profit watershed group, will be launching their sixth summer of the boat launch steward program at Bristol and Monkton ponds beginning in June.

The boat launch steward program was created to teach the public about aquatic invasive plant species within the Lewis Creek watershed. At Bristol and Monkton Ponds, the boat launch stewards greet boaters as they arrive and offer to inspect their boats for aquatic invasive species, while also collecting data on where the boat has been and how many aquatic organisms they encounter. They tell boat owners about how to prevent the spread of aquatic invasive plant species, which includes cleaning, draining and drying your boat, and other equipment that has been in the water, before moving to another body of water. This could include swimsuits and life jackets, which can carry microscopic organisms like the fishhook waterflea, which was recently found in Lake Champlain.

In addition to staffing the ponds on the weekends, the stewards also work on manually removing Japanese knotweed at two sites along Lewis Creek in North Ferrisburgh and Starksboro. Japanese knotweed is a particularly tough plant to remove; it spreads primarily by its roots or rhizomes, which can break off during a flood then resprout and form a new colony downstream.

Knotweed in the Lewis Creek watershed is patchy and has not yet spread prevalently across streambanks (unlike in many other Vermont watersheds where it covers nearly every square foot available). The Lewis Creek Association is excited to demonstrate a non-chemical removal method at these two sites, where stewards will lead weekly removal efforts and occasionally display these methods to the public.

Everyone is invited to help. Lewis Creek Association is partnering with Mike Bald of Got Weeds? to guide this work and demonstrate effective methods for knotweed removal without herbicides.

You can also get involved in a project to help understand the distribution of knotweed in the watershed using iNaturalist. With this app, you can photograph and identify invasive or native plants and post your findings so other users can corroborate the plants’ identity. This creates a map that can be used to understand where Japanese knotweed is found in the watershed.

If you’re interested in learning more, sign up at or email Kate or call 802-488-5203.

Since 2020, Lewis Creek Association’s boat launch stewards have been the first line of defense against invasive species within the Lewis Creek watershed. At Bristol and Monkton Ponds, stewards have interacted with over 2,250 boats and intercepted 493 boats that had aquatic plants on them. They informed many more members of the community about the threat and spread of aquatic invasive plant species at these ponds.

Next time you are out at Bristol or Monkton ponds, say hi to Lewis Creek Association’s boat launch stewards. They will gladly discuss any topics regarding aquatic invasive plant species and show you how to help prevent their spread.

Volunteer to remove

The Lewis Creek Association has been working closely with the Vermont Department of Environmental Conservation and the Lake Champlain Basin Program since 2009 to monitor and remove European frogbit, water chestnut, yellow iris and flowering rush in Town Farm Bay in Charlotte and the LaPlatte River Natural Area in Shelburne. These two areas are very diverse ecologically, and many people recreate there, making control of non-native invasive species critical.

Frogbit removal efforts in Town Farm Bay began in 2009, when approximately 50 percent of the wetland there was covered in frogbit. Since 2011 in Town Farm Bay and 2012 in the LaPlatte River Natural Area, volunteers have helped rake frogbit off the surface of the water each summer to maintain a small population, which has resulted in the annual coverage to decline to less than 5 percent.

Though frogbit will never be eradicated in either location, maintaining this low population allows native plants and animals to thrive. Through the end or 2024, the association and volunteers have removed 31.7 tons (63,356 pounds) of frogbit from Town Farm Bay and 8.5 tons (16,960 pounds) of frogbit from the LaPlatte River Natural Area.

The frogbit removal volunteer program runs in June and July at both locations. The Lewis Creek Association provides all the equipment, and you provide a few hours of your time to weed on the water. These trips are great fun; all you have to do is show up and be able to paddle in a canoe or kayak, raking plants off the water surface and putting them into a bucket or laundry basket on your boat.

If you’re interested in an enjoyable paddle, while making a difference in the health of your local wetland, contact Sara Lovitz or 802-488-5295.Even better, get a group of friends and sign up together to make a difference.