Lessons from the Lake: Making Sense of the Science

by Becky Nystrom

This article was first published at chautauquawatershed.org.

Photo by Jane Conroe.

If only Chautauqua Lake, an ecological and economic treasure in our midst, could speak. How might we better understand and steward its complex ecosystems upon which so much aquatic life depends, while thoughtfully addressing the ongoing challenges of excessive plant growth, harmful algal blooms, and newly introduced invasive species? The lessons from the lake are knowingly complex and deserve our attention.

We know our lake is an old lake, rich in plant diversity and an abundance of living things. We know its “underwater gardens” are the spawning and nursery beds for bass, muskellunge, bluegill, and sunfish, and the basis for our famous warm water fishery. Nymphs of mayflies, damselflies, and dragonflies crawl among the leaf blades, feasting on tinier insects, while larvae of moths, caddisfly, and weevils forage upon tender buds and feathery foliage. Little things are eaten by bigger things, and all are woven together in an amazing web of interdependency, complexity, and connection. Beyond their importance to the food web, rooted plants release oxygen, stabilize the sediments, and reduce resuspension of silt and nutrients, all significantly improving water quality.

We know the photic zone, where light penetrates the water column, is home not only to obvious lake plants, but also to innumerable tiny green dancers, floaters, and clingers known as phytoplankton, or “algae.” Interestingly, “blue-green algae” aren’t really algae at all, but rather a form of aquatic bacteria known as “cyanobacteria.” In plant-dominated lakes such as Chautauqua, most algae and cyanobacteria are normal residents serving as microscopic oxygenators and food-producers of open waters. 

And yet…increased nutrient loading from urbanization of the watershed, erosion, loss of natural shorelines and buffered streambanks, poor lawn-care practices, and warming waters have led to weed-clogged waterways, unhappy humans, and conflicting ideas on solutions. Overgrowths of algae form unsightly and smelly surface scums. More insidiously, harmful algal blooms occur with greater frequency, some producing liver and nervous system toxins dangerous to humans, pets and aquatic creatures alike.

For decades, the Chautauqua Watershed Conservancy has strived to conserve and heal our watersheds to enhance the quality of our local waters over the long term. Our work encourages landowners, municipalities, and others to employ lake-friendly landscaping practices, construct erosion control systems, and install vegetated stream buffers, swales, and rain gardens to intercept pollutants before they flow downstream. We have protected over 1,000 acres of wooded wetlands, streambanks, shorelands, and other natural areas which absorb and filter rainfall and stormwater, reducing downstream nutrient loading and sedimentation which otherwise fuel excessive weed and algae growth in our waterways. 

Recent attempts to eradicate the long-naturalized Eurasian watermilfoil and curly-leaf pondweeds via herbicides in Chautauqua Lake have brought clashing viewpoints and confusing messaging. Alarming evidence of harm to our lake’s south basin ecology has caused deep concern and dismay over the apparent collateral damage from the narrowly-informed “quick-fix” chemical approach. Can’t we do better? What lessons may be learned?

Comprehensive scientific research by Robert L. Johnson of Racine-Johnson Aquatic Biologists (2019 Status of Chautauqua Lake’s Aquatic Macrophyte Community Determined by a Lake Summer/Early Fall Survey and Estimates of the Associated Invertebrate Community) warns that the ecological balance of the lake’s lower south basin may now be at risk. We should listen to the science. We hope that the Region 9 State Department of Environmental Conservation (DEC) will listen. 

Mr. Johnson is a highly respected scientist who has studied the aquatic plants of Chautauqua Lake, and the tiny insects that consume them, for eighteen consecutive years. His Racine-Johnson Point Intercept-Rake Drag plant sampling method is recognized as the industry standard. His methodology has been endorsed by the NYS DEC and has provided the invaluable long-term data that has guided plant management decisions by the Chautauqua Lake Association (CLA) since 2002. The entirety of his reports and all conclusions are solely the work of Racine-Johnson. He is an award-winning member, former director and past president of the Northeast Aquatic Plant Management Society and is widely recognized for his professional contributions towards improved understanding of the ecology of non-native species Eurasian watermilfoil (Myriophyllum spicatum) and Hydrilla.  He has served for many years as an independent third-party scientific herbicide-monitoring consultant for the DEC and other lake associations throughout New York.

 Compared to his May 2019 survey and previous years of sampling in the southeast end of Chautauqua Lake, Johnson’s 2019 mid-September survey revealed only barren sediment and unprecedented absence of nearly all aquatic plants. His report warned that these areas were in critical decline likely linked to the 2,4-D and endothall herbicides applied to the 388 south basin acres in May. Reports by seasoned fishermen using marine sonar concurred that nearly all traditional south basin weed lines were lost and replaced with thick algal blooms persisting into late fall. 

An earlier and very limited, third-party monitoring report by Princeton-Hydro, contracted by the Chautauqua Lake and Watershed Management Alliance, failed to identify the more widespread, longer-term outcomes documented by Johnson. Its researchers, however, did note that “total biomass…decreased markedly at the treatment sites,” and documented evidence of “potential herbicide drift and resultant reduction in non-target plant biomass” approximately 7-14 days after treatment. Because both herbicides used are known to damage plants many weeks or months after being introduced into the water column, Princeton-Hydro’s one-month study could not possibly capture those longer-term consequences revealed by the Racine-Johnson work. 

And while the Princeton-Hydro report did not address algae, the Fall 2019 Racine-Johnson report expressed concern that cyanobacteria and HABs were visually extensive and worsened as one proceeded south, consistent with herbicide application areas. It warned that the wholesale loss of rooted aquatic plants from the littoral zone could push the shallow south basin of Chautauqua Lake from a stable macrophyte-dominated state toward a turbid and undesirable algal-dominated one, with loss of our critical warm water fishery and increased risk of algal scums, cyanobacteria, and toxic HABs.

So much is at stake. There are enough lessons here to justify significant changes in future management decisions for Chautauqua Lake. Let’s listen to the science.

Rebecca Nystrom is a local naturalist and retired JCC Professor of Biology who holds Bachelor’s and Master’s degrees in biology from the University of Buffalo and SUNY Fredonia, respectively. She is a founding director of the Chautauqua Watershed Conservancy, member of the Chautauqua Lake and Watershed Management Alliance Scientific Review and Advisory Committee, and member of the Macrophyte Management Strategy Technical Review Committee.

Threatened Plant Species Prevalent in Chautauqua Lake

Tray of various aquatic plants.
Aquatic plants collected in Chautauqua Lake. Photo by Racine-Johnson Aquatic Ecologists.

Report find 22 aquatic plant species, one threatened and concentrated in South Basin

LAKEWOOD, NY June 19, 2019 – A late-spring third-party survey found 22 species of aquatic plants in Chautauqua Lake, one of which is a threatened species under state regulations that is concentrated in the lake’s South Basin.

Racine-Johnson Aquatic Ecologists of Ithaca, NY, prepared the report, Late Spring 2019 Presence and Abundance of Aquatic Plants in Chautauqua Lakefor the Chautauqua Lake Association. It found that Potamogeton hilli, commonly called Hill’s pondweed, exists throughout the lake.

New York State classifies Hill’s pondweed as a threatened species and found it prevalent in both lake basins, though scientists catalogued the greatest concentration lake-wide in the southern end of the South Basin. The CLA presented the 114-page report’s findings to the state Department of Environmental Conservation this week.

“The importance of having a robust healthy macrophyte [aquatic plant] community in the littoral zone [the area where plants grow] of Chautauqua Lake is essential to the overall health of the lake,” the report stated. “A decrease in macrophyte species diversity, richness and abundance has the potential to lead to a decline of the world-class, warm-water fishery dependent upon thehabitat that aquatic plants provide.”

The report profiled plant species in the lake since record keeping started in 1937, observing that the mean frequency during that time is 24 species.

Racine-Johnson, and its predecessor Cornell Ponds, performed annual lake-plant monitoring under contract to the Chautauqua Lake Association since 2002. Racine-Johnson executes scientific plant studies on lakes throughout New York and beyond. The firm is also well known for its work in understanding the role that herbivores serve in controlling the invasive Eurasian watermilfoil, one of two invasive species the report found in the lake.

Sampling Team collects and sorts aquatic plants.

“Eurasian watermilfoil is well established and widespread in the lake; however, a suite of invertebrate herbivores attacks the plant at various times of the year, significantly limiting growth of this non-native,” according to the report.

“The extremely large populations of insect herbivores in Chautauqua Lake, documented yearly since 2002 by Cornell University and Racine-Johnson Aquatic Ecologists, provide the lowest- cost, most-effective control possible of excessive growth of Eurasian watermilfoil,” the report continued.

“Therefore, conservation of these essential biological control agents is paramount in maintaininga healthy Chautauqua Lake.”

Excessive macrophyte growth remains as an ongoing concern . . .as it has for at least the last 100 years.

Late Spring 2019 Presence and Abundance of Aquatic Plants in Chautauqua La

“Excessive macrophyte growth remains as an ongoing concern for stakeholders of Chautauqua Lake, as it has for at least the last 100 years,” the report noted. “The lake is eutrophic [very nutrient rich] and shallow eutrophic lakes generally fall into a macrophyte [aquatic plant] or algae-dominated waterbody. Today, an algae-dominated lake would likely have large numbers of harmful algae or cyanobacteria.”

“The lake requires a macrophyte-dominated littoral zone that competes against an overabundance of cyanobacteria [HAB] to remain a healthy ecosystem with good water clarity and an excellent warm-water fishery.”

The report explained how the aquatic plants take up nutrients and block wave action that would cause nutrients to be more prevalent throughout the water column, which in turn results in growth of troublesome blue-green or cyanobacteria HAB blooms.

In describing the publicly perceived excessive plant growth, the report noted that the “area withmedium and dense growth of macrophytes is actually very small in relation to the total surface area of Chautauqua Lake.” It further noted that “a large percentage of the littoral area has only atrace occurrence of plant growth.”

The report also addressed the role that the invasive Curly-leaf pondweed serves in Chautauqua Lake.

“The plant provides important early season habitat for fish and invertebrates, while slowing or preventing excessive early growth of Eurasian watermilfoilelodea and coontail. Curly-leaf’searly growth outcompetes or displaces other species in the competition for space, food, or other resources, reducing early growth of Eurasian watermilfoil and native species, thereby saving management monies.”

The plant begins to die in late spring and disappears in early summer.

“Chautauqua Lake’s macrophyte community is species diverse and overwhelmingly dominated by desirable plant species,” the report concludes.

The complete report can be viewed on the lake association’s reports tab of its website:www.chautauqualakeassociation.org.

New York State awards CLA $100,000 to thwart new invasive plant species

The report’s release comes shortly after the announcement that New York State awarded the CLA $100,000 to thwart new invasive plant species through the Watercraft Steward Program of boat-launch inspections.

The program allows the CLA to provide watercraft stewards on boat launches on Chautauqua Lake, Cassadaga Lake and Lake Erie. In 2018, the CLA’s watercraft stewards interacted with 10,326 boaters, inspecting 5,685 boats of all sizes, shapes and propulsion methods.

The DEC prohibits boats and equipment from entering or leaving DEC launch sites without first being drained and cleaned.

“This is a smart, effective program that focuses on prevention and proactivity,” said Douglas Conroe, executive director of the Chautauqua Lake Association. “We’re grateful for the funding because this program has already proven its preventative value.”

The grant is for three years. In 2019 and 2020, the CLA will combine it with $39,900 from a Chautauqua County Occupancy Tax-funded grant in 2019 and a $15,000 Lake Erie Watershed Protection Alliance grant. Total program for the CLA is $194,800

This most recent funding, however, is unrelated to revenue shortfalls from New York and local municipalities that means the CLA can only hire 27 workers instead of 42, as in 2018, to harvest and clean the lake this summer.

The CLA’s lake services operating budget for 2019 is $640,000, down from $730,000 last summer. New York contributed $150,000 last year, but nothing toward the 2019 operating budget. The villages of Bemus Point and Celoron, and the towns of Chautauqua and Ellery, also contributed nothing this summer.

More about the Chautauqua Lake Association

The Chautauqua Lake Association traces its beginnings to 1946 and its actual formation in 1953. The current focus is to perform environmentally sound plant-control practices, undertake scientific monitoring and relevant research, service the shoreline in promotion of maintaining healthy conditions, and promote educational efforts to enhance public understanding of lake association methods and lake needs. MORE