Watershed Actions Determine Lake Plant Growth, Part I

Chautauqua Lake is a biologically productive lake known for its outstanding muskellunge and bass fisheries. Its plants provide important habitat and are part of the food chain for a variety of fish and wildlife, including migratory waterfowl. However, some species of plants grow excessively and seriously impair the use of the lake for recreation and affect the use and value of adjacent properties. This lake is a shallow lake that has experienced excessive inputs of nutrients and sediments from human activities for well more than a century. Clearing and leveling the land for farming, farming activities, the construction of homes, roads, yards, parking lots, factories and businesses has and continues to cause the delivery of excess amounts of storm water, nutrients, sediments, salt and a range of other pollutants to Chautauqua Lake and other area lakes and streams.

The plant community of this lake is diverse. Forty-four species of plants and macro algae (algae resembling plants) have been documented in this lake over the last 80 years. Twenty-seven species were documented in sampling undertaken by Racine-Johnson Aquatic Ecologists in 2007. Most of those plants are native and beneficial to the lake’s fisheries, ecology and wildlife. The lake even provides habitat for a New York State Threatened Species identified as Hill’s pondweed (Potamogeton hillii). A few exotic (non-native) species and native species grow to the surface and interfere with navigation and recreation. In Chautauqua Lake, curly-leafed pondweed (Potamogeton crispus), an exotic species, grows rapidly in the spring and dies back by early July. Lack of ice and snow cover in winter, as experienced last winter, promotes its abundant growth. A few native pondweeds can also grow to nuisance densities in the first part of the recreational season, and they also die back by early July.

Eurasian watermilfoil (Myriophyllum spicatum), an aggressive, opportunistic Eurasian aquatic plant, has historically caused the most interference with lake use. Given conditions of annual depositions of nutrient laden silt, it out-competes native plants, forming dense beds that grow to the surface and impede swimming and navigation. In Europe, it is only a problem where excessive sedimentation gives it a competitive advantage over other plants. At Conesus Lake, where farm conservation practices such as streamside buffer strips and better manure management were successfully implemented, substantially reducing nutrients and topsoil running into the lake. Milfoil growth decreased. Chautauqua Lake annually experiences excessive deposition of sediments and nutrients from multiple sources, such as manure-laden pasture lands eroding into streams, animal feedlots draining to streams, eroding road ditches, lakefront lawns and construction sites, and excessive phosphorus and nitrogen from community wastewater treatment plants. This means that the bottom of the lake where milfoil grows gets recharged with nutrients and topsoil to keep the plants growing abundantly year after year.

It is not surprising that some of the most prevalent, recurring and troublesome beds of aquatic plants with large percentages of milfoil are near the Northern Chautauqua Lake Sewer District outfall in Mayville, in Ashville Bay near the mouth of Goose Creek, and along Lakewood and West Ellicott, where some of the most-nutrient laden and/or sediment laden waters are entering Chautauqua Lake.

In Part II next week, I will discuss what actions can be taken by the county, its municipalities, businesses, organizations and the public to control Chautauqua Lake’s plants.

The Chautauqua Watershed Conservancy is a private, not-for-profit, 501(c)3 organization with a mission to preserve and enhance the water quality, scenic beauty and ecological health of the lakes, streams and watersheds of the Chautauqua region. Its present focus is to conserve and enhance the natural shores and banks of Chautauqua County’s lakes and streams, which provide fish and wildlife habitat and pollution filtering functions. The Conservancy is funded primarily through membership donations, and its 2013 annual membership campaign is currently underway. Its next tour is at the Loomis Goose Creek Wetland Preserve on Saturday, Jan. 26 at 2 p.m.