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CLA Macrophyte Report Finds Healthy Amounts of Threatened Plant Species in Lake

 

Racine-Johnson Aquatic Ecologists gathered plants from the bottom of Chautauqua Lake as part of its 2019 report on the presence and abundance of aquatic plants in the lake. Photo submitted by Racine-Johnson Aquatic Ecologists

Anannual report commissioned by the Chautauqua Lake Association found 22 species of aquatic plants in Chautauqua Lake, including amounts of Hill’s pondweed — a threatened species, as designated by New York’s Department of Environmental Conservation.

This species count puts the lake on par with past years. A median number of 24 species has been found in the lake since 2002.

“The lake is dynamic,” said Doug Conroe, CLA’s executive director. “In many respects, it’s constant over the years. The plant colonies haven’t changed a lot in terms of what species are there, but the density changes; the locations change.”

CLA has commissioned a survey of the aquatic plants, or macrophytes, in Chautauqua Lake every spring and fall since 2002. Bob Johnson has conducted the survey each year, first in conjunction with Cornell University, where he worked until 2008, and now through his Ithaca-based firm, Racine-Johnson Aquatic Ecologists.

CLA is particularly interested in the state of the lake’s aquatic plants because it is in charge of weed harvesting in the lake’s recreation areas.

“If you’re going to be managing the macrophytes, it’s imperative you know the truth and the facts about what’s there and in what density,” Conroe said.

He said the report’s findings do not affect the harvesters’ day-to-day operations, but they do highlight areas where plant populations are more sensitive.

This year’s survey was conducted from May 15 to 30. Researchers dragged double-sided rakes along the bottom of the lake in 366 locations, focusing on areas near Mayville and Burtis Bay, where the lake is more shallow and the presence of plants is more of a concern.

The researchers then separated the plants gathered from each rake toss, by species, in trays. The plant abundance in each test location was measured.

Johnson said the report is typically released in the fall after his firm has had the chance to survey the macrophytes in the spring and fall each year. This year, the first part of the report was published soon after it was conducted in the spring to provide important information about aquatic plants to lake stakeholders.

“We decided to publish the report early because of all the controversy about what’s growing in the lake,” Johnson said. “There appears to be a lot of misinformation out there about what people are observing.”

For example, he said his reports going back to 2002 show that the presence of plants in the lake has remained “extremely stable,” although some insist the weeds get worse each year.

With an average of 24 different aquatic plant species year to year, Chautauqua Lake has a rich diversity of species, Conroe said.

“That creates a richness of ecology that has a lot of good side effects,” he said.

The two most prevalent native plant species in the lake are coontail and Elodea, which have made up 15% and 14%, respectively, of all of the native species.

The survey found the threatened species, Hill’s pondweed, in both lake basins in greater numbers than it has been in the past. The species was most concentrated in the southern end of the lake’s South Basin.

Among the 22 species found, only two were invasive and nonnative: Eurasian watermilfoil and curly-leaf pondweed.

While these invasives are a source of concern, the presence of five different species of insects, including the weevil, help keep invasive plants at bay, Johnson said.

Racine-Johnson Aquatic Ecologists gathered plants from the bottom of Chautauqua Lake as part of its 2019 report on the presence and abundance of aquatic plants in the lake. Photo submitted by Racine-Johnson Aquatic Ecologists

“In Chautauqua Lake, even though you have a lot of Eurasian watermilfoil in the lake, it doesn’t come to the surface and flower and have problems with matting,” he said.

In recent years, Johnson said he can only remember matting — when plants grow together in large swaths that block sunlight to the water below  — being a problem in 2002 and 2006.

While large numbers of plants near the shore can be a nuisance to people enjoying the lake, the presence of macrophytes is crucial for a healthy ecosystem.

They improve water quality and clarity, provide a home for fish and stabilize the lake bottom, which would be stirred up by waves if it weren’t for the roots of plants holding lake sediment in place.

When lake sediment is disturbed, it can make the water appear more cloudy, in addition to releasing the algae-feeding nutrients of phosphorus and nitrogen into the surrounding water.

“(Macrophytes are) important to uptake nutrients that the algae would otherwise uptake and become an algal problem,” Conroe said.

CLA manages areas of the lake near docks and the shore where plants have grown out of control and affect peoples’ ability to boat, fish and swim.

“What we’re doing is, we’re essentially looking for nuisance conditions and harvesting to mitigate those conditions,” Conroe said. “We’re not doing it in undeveloped areas. We’re not doing it out further in the lake where the plant bed serves other purposes for ecology.”

Due to budget cuts, the CLA can only deploy four of its eight weed-harvesting boats this  season, and can only hire 27 workers this year, down from 42 last year, according to a June 24 press release from the association.

CLA’s 2019 operating budget is $640,000. Last year, it was $730,000. The state of New York contributed $150,000 last year, which was administered by the state DEC, but is not contributing any money this year. The villages of Bemus Point and Celoron, and the towns of Chautauqua and Ellery also did not contribute funding to the CLA this year.

Luckily, the report found that the macrophyte population is slightly less dense this year. And that, Conroe said, is a good thing for everybody.

Tags : Chautauqua Lake Associationenvironment
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The author Julia Preszler

Julia Preszler covers the environmental beat for the Daily. She is a journalism student at Northeastern University in Boston. Julia has previously interned at The Boston Globe and two community newspapers in her home state of Connecticut. In her free time, she enjoys hiking, photography and watching stand-up comedy. This is her first season at Chautauqua.

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