Invasive plants found in lake
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By Tom Mitchell Herald Staff - Published: September 22, 2006
Property owners on Lake St. Catherine are watching out for water chestnuts after a diver this summer found a small infestation of the exotic invasive plants on Lily Pond at the north end of the lake.
The diver, Chris Sheldon, pulled up a number of the nuisance plants in early August, after a contractor found them while conducting a plant survey by airboat. The contractor had been hired to treat the pond with an herbicide to control Eurasian water milfoil.
"I picked a lot of it from shore," Sheldon said. The plants were growing next to someone's dock in a swampy area on the east side of the pond.
Sheldon estimated he removed more than 50 of the plants from an area measuring 15 feet by 15 feet. Representatives from the Department of Environmental Conservation found another patch of about 46 rosettes two weeks later, said DEC Environmental Scientist Tim Hunt.
The plants were found in a bay on the northeast east side of the pond along a path measuring about 100 feet by 40 feet.
This is the first time water chestnut plants have been found in Lake St. Catherine, according to Jim Canders, president of the Lake St. Catherine Association. He said the association is distributing folding cards to lake residents with information about the exotic plants.
The idea is to raise awareness of what water chestnuts look like and that could pose a problem if they were to get a foothold in the lake. Like water milfoil, water chestnuts can fill in a water body and choke out native plants.
Canders said he agreed with the state that the seeds that started this bunch of plant may have been brought in attached to a waterfowl.
If chestnut plants or seeds were carried by a boat, Canders said, it would have been found in another part of the lake.
Sheldon, the diver, said since water chestnut was not spotted during a plant survey last year, it may have been there less than a year. Hunt said he assumed infestations could have been there a year or two.
Once a water chestnut seed germinates, it can make a stem that will branch out and support five to 10 floating rosettes, Hunt said.
Normally, a water chestnut will produce one to five rosettes, but in places where it has the space it can produce as many as 10 rosettes on one stem, Hunt said.
Each rosette can carry an average of about 10 seeds.
After treating the lake with Sonar two years ago, Lily Pond and Little Lake were treated with another herbicide called Renovate.
In a proactive effort to keep Eurasian water milfoil from reinfesting the lake, the association has paid an inspector to screen boats coming into the lake to make sure they are not carrying it or other exotic invasive species, Canders said.
"Most of the boats have been clean … "he said. adding that boaters were getting accustomed to the idea that the lake group was checking them to try to make sure the lake did not get infested with milfoil.
Since the two small infestations of water chestnuts were found, no additional plants of that type have been found in the main lake, said Jeff Crandall, a trustee with the Lake St. Catherine Association.
"We take very seriously the need to stay on top of any nuisance plants that reemerge in Lake St. Catherine," Crandall said.
The plants can spread like other invasives, he said. "We have no reason to believe it is a problem in Lake St. Catherine," Crandall said. "But we want to make sure it doesn't get a foothold."
A smaller infestation was found on Lake Bomoseen about 10 years ago. Those plants were pulled and none were found in Lake Bomoseen during a search in August.
Even though the state has an aggressive chestnut harvesting program on Lake Champlain, the plants have been expanding there, Hunt said.
Some new infestations were found in wetlands this summer in the vicinity of Missisquoi Bay, he said.
After only seven rosettes were found by the mouth of Missisquoi River in a wetland inside the refuge last year, many more were found this year starting early in the summer. There's an artificial berm in the area that holds in water for duck and goose habitat, Hunt said.
A bird watcher was in there counting black tern seabirds, when his son noticed the chestnut plant growing and various ended up finding and pulling 10,000 to 12,000 plants altogether.
In a first infestation in wetlands within Missisquoi Refuge, the state handpulled about 3,500 plants, Hunt said. "We just kept finding more and more…"
The water chestnut were in Cranberry Pool, a 400-plus acre wetland Highgate and Big Marsh Slough, another similarly big wetland within the Missisquoi Refuge in the same town.
The volunteer Youth Conservation Corp. working in canoes and pulled out about 3,000 plants, Hunt said.
The large infestation likely resulted from the dropping of seeds carried in by waterfowl, he said.
Contact Tom Mitchell at tom.mitchell@rutland herald.com
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