Parks and Paths

Shelburne frogbit harvest: calling all paddlers

by Peg Rosenau

The invasive species frogbit threatens to choke the LaPlatte River and McCabe’s brook. The leaves are about the size of a quarter; much smaller than those of common lillypads.

Just south of us in Charlotte, an impressive effort has been underway to greatly reduce the amount of the invasive plant frogbit, a floating aquatic plant that is choking up rivers and marshes around Lake Champlain. For the past several years, the Lewis Creek Association and its conservation partners have been successfully controlling the population by removing and composting many tons of this plant from Town Farm Bay. Last season, a survey in Shelburne showed that frogbit has also gained a foothold in the LaPlatte River and McCabe’s Brook, and the race is on to prevent an all-out takeover of the open water surface in these areas by this nefarious weed.

Frogbit was first discovered in Lake Champlain in 1993, and it is thought that it likely was brought in on boat trailers from an infested lake in New York or Ontario. Native to Europe, frogbit is a floating plant with small, heart-shaped, leathery leaves and a single three-petaled white flower. The roots do not attach to the substrate, so it drifts freely from place to place, congregating in river mouths and calmer bay and marsh areas. If left unchecked, the plant reproduces rapidly and the roots intertwine and form huge dense mats that can block waterways, choke out native vegetation, and negatively impact recreation opportunities like fishing and kayaking.

A partnership of conservation groups including Lewis Creek, Shelburne Natural Resources & Conservation Committee, Shelburne Bay Boat Club, the Nature Conservancy, and the LaPlatte Watershed Partnership have been gearing up all winter to establish plans for a frogbit removal volunteer group with a base at the Shelburne Bay Boat Club at the mouth of the LaPlatte River. To be effective, the removal project must be performed before the plant sends up flowers and begins to produce turions – small reproductive buds that break off the plant and sink to the bottom to overwinter. As each plant can produce 100 or more turions, early, intensive removal efforts are necessary to keep growth suppressed to manageable levels. The crucial removal time is generally over the eight weeks between June 1 and August 1. The plants float and can be scooped off the surface with hand rakes or nets from a canoe or kayak. Full baskets are unloaded onto the shore and left to dry out. Drying destroys the plant completely- no special disposal is necessary to avoid re-population of the waterway from the harvested material.

Eliminating the plant completely from waterways is probably unrealistic, and the goal of the program is to keep the frogbit population at a level that does not impact native flora and fauna, water quality or recreation opportunities. The 2012 plan is only the start of what will need to be an on-going monitoring and removal program. Volunteer frogbit pickers and waterway monitors will be essential to the success of this effort, as will financial support from organizations that support the maintenance of a healthy Lake Champlain.

Organizers plan to run twice-weekly removal parties throughout June and July, with a variety of days and hours available to accommodate different work schedules. Lewis Creek Association will provide canoes, kayaks, life vests, hand rakes and buckets, as well as training in identification and removal technique. Volunteers who have their own canoes and kayaks (areas can be too shallow or marshy for motor boats) are also encouraged to join the effort, as are scouts, neighborhoods, and other groups who recreate in Lake Champlain. Families are also welcome though this activity is probably best for older children who can handle a boat and have the stamina to be on the water for several hours. By all accounts, frogbit picking is a fun, community-building activity with a high degree of satisfaction as results are immediate. Participants also get to see some incredible wildlife and enjoy some time in a beautiful natural area while helping preserve the lake that they love. If you or your group would like to be included on the e-mail list that will provide up to date information on days and times of removal parties, please contact Shelburne project coordinator Judy Raven at 985-2247 or ravenvt@msn.com.

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