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RARE NATURAL COMMUNITY DISCOVERED IN THE HONEOYE LAKE WATERSHED
Submitted by
Bruce Gilman, Professor Emeritus and Finger Lakes Herbarium Curator
Finger Lakes Community College
Canandaigua, New York 14424
Although recently retired from FLCC, I continue to study and learn about the natural communities of our wondrous Finger Lakes region. This fall I visited one such area in the Honeoye Lake watershed. This site had always intrigued me because of the unusual presence of northern white cedar, a tree of alkaline soils, growing in an otherwise acidic landscape.
It was quite a surprise to find what else was growing there, but I’m getting ahead of my story.
Natural communities in New York State have been ecologically classified and described by the New York Natural Heritage Program (www.nynhp.org). Communities are organized first into one of seven systems, with each system further divided into subsystems. The Honeoye discovery falls into the palustrine system, then the open peatland subsystem. It is specifically named a rich sloping fen. So it is an unusual type of natural wetland community. The Heritage Program also ranks each natural community type for its rarity. A rich sloping fen, based on the information available to the Heritage Program, is ranked S1S2, meaning there are less than 20 documented occurrences across New York State, making it especially unique and vulnerable.
So what characterizes a rich sloping fen? They are small natural communities that occur in shallow depressions on gentle slopes composed of calcareous glacial deposits. Rich sloping fens are minerotrophic wetlands fed by small springs. So far, the Honeoye Valley has one known location with this unique set of conditions. The high hills surrounding the Honeoye Valley serve as aquifer recharge areas, creating just the right conditions for artesian springs along the valley floor. Groundwater upwelling through calcareous glacial deposits becomes mineral rich and has a high pH. The water is cold and constantly flowing through the fen in tiny rivulets. Rich sloping fens are usually surrounded by upland forests and transition downslope into shrub swamps and shallow emergent marshes. Biodiversity is very high, with scattered trees and shrubs, and a nearly continuous layer of herbaceous plants and mosses.
Shrubs of the Honeoye rich sloping fen include arrowwood, red osier dogwood, mountain holly, gray dogwood, alder-leaf buckthorn and several species of willow. Virgin’s bower is the characteristic vine. Herbaceous plants include field horsetail, marsh fern, cinnamon fern, spotted Joe Pye weed, spreading goldenrod, various sedges (especially Carex flava and C. hystericina), purple-stem aster, cat-tails, purple avens, tall meadowrue, mannagrass, water-horehound, tall coneflower, golden ragwort and the insectivorous sundew. The sundews, named because their glandular hairs glisten like dew in the sun, are tiny plants that grow on mossy hummocks in the Honeoye rich sloping fen. The hairs are stalked glands that produce digestive juices. These juices increase in production once insect prey has been captured on the sticky leaf. Research in England estimated that six million insects were caught annually in a two acre fen!