Fens are wetlands of conservation concern across temperate regions of the world. Understanding how abiotic factors such as light intensity and hydrology affect typical fen plants will help to direct management of these wetlands. The goal of this research was to investigate how light intensity, hydrology, and forest canopy gaps impact the globally rare and declining fen plant Trollius laxus (Ranunculaceae). Studies in the field and greenhouse suggested that T. laxus may be excluded from drier, more optimal areas of wetlands by plants that are better competitors for light.

Project Title: Population Ecology of the Rare Wetland Plant Trollius laxus (Ranunculaceae)

A matrix population model using six years of experimental data showed that, on average, T. laxus subpopulations in a forested fen responded to experimental canopy gaps with first increasing, then declining stem and flower production and population growth rates. The declines, which increased in severity with greater light transmittance, were likely caused by herbaceous layer competition and litter accumulation. The results also demonstrated that canopy gaps can have nonlinear and indirect effects on understory plant demography. We concluded that active management is likely to be needed to conserve the rare plants that are characteristic of North American fens. Managers will need to consider hydrology when predicting how rare plants will respond to the removal of competing vegetation in fens.

Location: Nelson Swamp Unique Area, New York, USA

Timeline: 2001 – 2009

Field participants:
Greg Owens (New York State Department of Environmental Conservation)
Tony Eallonardo, Jess Riddle, Sara Hasenstab, Lauren Goldmann, Jeff Stein, Betsy Berg, Collin Shephard, Margot Mercer, Valerie Darnley, and Chuck Schirmer (all of SUNY-ESF)
Connie Scanga, Carrie Scanga, and Chris Scanga

Principal Investigators:
Donald J. Leopold (SUNY-ESF)
Sara Scanga (SUNY-ESF; current affiliation is Utica College)

• US Environmental Protection Agency (EPA), under the Science to Achieve Results Graduate Fellowship Program
• Edna Bailey Sussman Foundation
• National Science Foundation/New England Wild Flower Society
• New England Botanical Club

Sara E. Scanga, Utica College, 1600 Burrstone Road, Utica, NY 13502,, (315) 792-3137