About 20 experimental “rock socks” (biodegradable bags containing head-started pickerelweed, water willow, and water plantain plants) were recently placed in Ashville Bay as part of a pilot program to combat invasive starry stonewort in that location. Photo by Bethany O’Hagan

The phrase “fight fire with fire” is not just an idiom – it actually works in practice. For example, when combating forest fires, crews will carry out controlled burns in the path of an approaching inferno to remove any burnable materials from the area, thus depriving the blaze of fuel. Fire extinguishes fire!

When trying to remove ecologically harmful and/or economically costly invasive species from an area, the controlled use of fire is sometimes an appropriate tool as well. But unfortunately, that is not always the recommended, or most feasible, approach. And in the case of aquatic invasive plants that grow underwater, fire really doesn’t get you anywhere. However, in the spirit of this idiom, which refers to responding to a threat in the same manner as it presents itself, why not fight plants with plants?

In terrestrial settings, this is already a mainstay of invasive species management. It is one thing to remove a patch of Japanese knotweed or other invasive, but if that area is left unvegetated, then the most likely plants to move into that void will be highly successful colonizing species, such as invasives. When unwanted vegetation is removed and not immediately replaced with native species of plants, the problem will not go away. But desirable plants can be used to fight undesirable ones.

Anyone who has walked the Riverwalk in downtown Jamestown recently may have seen our staff and numerous hard-working volunteers planting almost 3,500 plugs of a variety of native wildflowers and grasses on the newly restored Chadakoin Riverbank below the train station. After removing invasive and diseased trees and all manner of invasive species, and after rebuilding the bank sections that were about to collapse into the river, we have now installed our first line of defense against the return of the invasives there. Sure, they will try to recolonize the area, but we will be waiting next spring to spot-treat and remove them as needed. And in the meantime, we will encourage the plants that we do want to grow there and have them fill in the empty habitat areas that were left after construction, until the desirable plants greatly outnumber the ones we want to get rid of.

Although this is not common practice yet, we have just started a small pilot project to see if a similar approach can help us combat unwanted aquatic invasives too, such as the dreaded Starry Stonewort. The Towns of Chautauqua and North Harmony have received funding to try and remove nuisance growth of this harmful invasive from Chautauqua Lake. Together with the Chautauqua Lake and Watershed Management Alliance and the Chautauqua Watershed Conservancy, we are exploring using Diver Assisted Suction Harvesting (DASH), as well as the use of Mobitracs at some point in 2025, to see how effectively these methods can remove the incredibly fast-growing Starry Stonewort. DASH has been used in other water bodies and on other aquatic invasive species, but it has never been done in Chautauqua Lake or at this scale. Earlier pilot removal efforts using Mobitracs in late 2023 showed promise when our staff surveyed the target area in Ashville Bay. However, even though early season results were encouraging, by the end of the 2024 growing season, Starry Stonewort had recolonized the areas from which we were able to remove it.

Back to my earlier point – assuming that we can be successful in removing Starry Stonewort from significant areas in Chautauqua Lake in 2025 (as we are fully intending on accomplishing!), a critical next step needs to be taken: revegetating the harvested areas with densely growing native aquatic plants before unwanted invasives move in. During our many lake surveys this past summer and fall, we have come across several instances where emergent pickerelweed or floating water lilies appeared to suppress the growth of nearby Starry Stonewort. Similarly, dense stands of eelgrass seem to form a barrier to its spread. In the last few weeks, our staff has installed about 20 experimental “rock socks” in the lake, which are biodegradable bags containing head-started pickerelweed, water willow, and water plantain plants. They are dormant right now but will hopefully grow out of their bags and into the areas where we’ve planted them come spring.

Funding permitting, we hope to do a full-fledged pilot project next year, experimenting with how we can best create an underwater nursery of sorts to propagate transplantable and fast-growing native aquatic plants that we can deploy in our fight against harmful invasives. Fighting fire with fire – even underwater!

Chautauqua Watershed Conservancy is a not-for-profit organization with the mission to preserve and enhance the quality, scenic beauty, and ecological health of the Chautauqua region’s lands and waters for our community. For more information, visit chautauquawatershed.org and follow us on Facebook and Instagram.