Palustrine System. Open Peatlands Subsystem-- Rich shrub fen community

Rich shrub fen

Physical Setting: Rich shrub fens occupy most of the level ground immediately north and south of the Ice Pond (approximately centered at 41.460ºN, 73.612ºW (± 10 m) and 41.450ºN, 73.614ºW (± 10 m), respectively), forming two narrow triangles bordered by the Ice Pond, and the east and west branches of the Metro North Railroad. Together the two fens cover approximately 58,175 square meters.

Substrate and Hydrology: The fens are flooded to a depth of about one meter throughout the year. The bottom is composed of a thick layer of partially decomposed plant material (peat).

Biota: There is a nearly continuous canopy of mature trees and shrubs generally less than 3 m tall. The basal stems and roots of these species form floating hummocks about one meter in diameter and one meter high (half above and half below the water surface). Each hummock is dominated by one or more woody plant species, especially Acer rubrum L., Alnus serrulata (Aiton) Willd., Clethra alnifolia L., Rhododendron viscosa (L..) Torr., Vaccinium corymbosum L., Rosa palustris Marshall, Cephalanthus occidentalis L., Amelanchier sp., Rhamnus frangula L., Aronia arbutifolia (L.) Pers., Toxicodendron vernix (L.) Kuntze, and Chamaedaphne calyculata (L.) Moench. Decodon verticillatus (L.) Elliott is abundant in isolated openings where other woody vegetation is absent. One individual of Nemopanthus mucronatus (L.) Loes. occurs at the southern edge of the northern fen. Herbaceous species grow around the woody roots forming a mosaic of several species, including: Asclepias incarnata L., Boehmeria cylindrica (L.) Sw., Lysimachia terrestris (L.) Britton, Stearns and Poggenb., Moehringia lateriflora (L.) Fenzl., Bidens connata Muhl. ex Willd, Rorippa palustris (L.) Besser var. palustris, Pilea fontana (Lunell) Rydb., Pilea pumila (L.) A. Gray, Triadenum fraseri (Spach) Gleason, Verbena hastata L., Persicaria punctata (Elliott) Small and Campanula aparinoides Pursh; the fern: Thelypteris palustris (A. Gray) Schott and; the vines: Mikania scandens (L.) Willd. and Amphicarpaea bracteata (L.) Fernald.

Cultural: The only evidence of human intervention is the occasional discarded tire, bucket or appliance. The surrounding terrain is little altered except for the two railroad beds bordering the fens, but even before these were installed the area would likely have been unsuitable for structures, cultivation or pasturage.

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