As previously reported, the Missisquoi National Wildlife Refuge staff and Lake Champlain Fish and Wildlife Resources Office partnered with the Lake Champlain Basin Program to enlist the help of volunteers and government partners on July 27, 2006 to attack a newly-discovered water chestnut infestation on the refuge. Federal and State agencies, volunteers, conservation organizations, and others worked together to control a severe chestnut invasion in the refuge's main waterfowl sanctuary areas, Cranberry Pool and Big Marsh Slough. Thirty-four staff, volunteers and partners pulled 2700 water chestnut rosettes from the Big Marsh Slough.

Refuge staff, volunteers, and Vermont Department of Environmental Conservation personnel repeatedly visited these areas before and after July 27 to determine the extent of the infestation and to pull plants before the seeds became viable. Overall, 11,931 rosettes were removed in approximately 257 "puller-hours" (a puller-hour equating to one person in the marsh pulling water chestnut plants for one hour). Vermont Youth Conservation Corp, who spent three weeks on the refuge this year, were particularly helpful in this effort. With each succeeding trip to the marsh, fewer plants were located and pulled until it was determined that the infestation had been controlled for this year. No plants have been found outside the confines of the sanctuary areas, except one small cluster of plants in Long Marsh Channel. With the loan of the Montezuma National Wildlife Refuge air boat the search for more plants will continue. Staff from all agencies feel that a major ecological disaster has been averted.

While difficult to ascertain, it is believed that water chestnut plants were brought into the area by waterfowl. Cranberry Pool in particular has no boat access, making the possibility of transportation by boat highly unlikely. Big Marsh Slough is accessible by shallow draft vessel from Lake Champlain but again, a boat would be an unlikely source of introduction. More likely, waterfowl transported mature seeds from the large infestation on the South River, south of Montreal, Quebec, Canada which is less than 50 miles distant as the crow flies. It is interesting to note that the Big Marsh Slough area was surveyed for water chestnut by air boat in August 2005 but no plants were observed.

Refuge staff and partners are planning to return to these sites for residual control work next summer and will remain vigilant to infestation in other areas.