Natural Community Systems -- Photo Guide

Rich sloping fen system

[note: this system was previously named calcareous sloping fen system]

rich sloping fen system in Monroe
rich sloping fen system in Monroe (photo by Ben Kimball)


Description:  Rich, calcareous fens are dominated by a unique assemblage of low sedges and other graminoids over a carpet of “brown” mosses and several uncommon to rare peat mosses.  Scattered willow and dogwood shrubs are often present.  These peatlands are among the most botanically diverse in New Hampshire and contain many calciphilic plant species in addition to more common wetland species.  There are often numerous orchids and other unique herbs interspersed among the graminoids and shrubs, which are also absent in oligotrophic to moderately minerotrophic peatland systems such as medium and poor level fen/bogs and kettle hole bogs.  Many of these species are rare, and restricted to these systems. 

These systems are restricted to areas that have considerable year-round seepage through base-rich or carbonate-bearing bedrock types.  Minerotrophic seepage is the primary water source in these systems and there are often rivulets or small open pools.  These systems are small in size and occur in a variety of settings in New Hampshire including both groundwater influenced and “disturbed” areas, such as old pastures.  Common settings for this system include headwater positions, open gaps in calcareous seepage swamps (e.g. northern white cedar swamps), step terraces of rivers or streams, and side slopes of hills.  They also occur in small basins, kettles, or catchments with seepage influence and along margins of streams flowing through marshes or swamps in areas with calcareous bedrock.  Certain expressions of these systems often occur where disturbance maintains vegetation in an early successional state, such as beaver meadows and grazed pastures or hay fields.

Soils typically are comprised of shallow to moderate depths of well-decomposed peat.  Peat depth varies with landscape setting; deeper peat accumulation occurs in basins and gentle slopes relative to steeper slopes or periodically disturbed areas such as terraces along major rivers or old pastures.  While some examples are nearly level, most have gentle to prominent slopes.

Diagnostic natural communities:

      • Calcareous sedge - moss fen (S2)

Landscape settings: headwater positions, openings in northern white cedar swamps, steep terraces of rivers or streams, hill side slopes; also in small basins or catchments, stream margins, and old pastures

Soils: well decomposed shallow to moderately deep peat; strongly minerotrophic; pH ranges from 6.7 to 8.2 (average 7.2); soligenous

Spatial pattern: small patch (mostly <5 acres); irregular zonation or uniform

Physiognomy: graminoid - moss carpets, sedge - medium height shrub

Distribution: north and northwest of the White Mountains and northern Connecticut River valley

Characteristic species:
Calcareous sedge – moss fen:
Trees and shrubs
      Cornus sericea (red osier dogwood) 
      Pentaphylloides floribunda (shrubby cinquefoil)
      Thuja occidentalis (northern white cedar)

      Carex interior (inland sedge)
      Carex  flava (yellow sedge)
      Carex hystericina (porcupine sedge)
      Carex aurea (golden-fruited sedge)
      Carex castanea (chestnut sedge)
      Trichophorum cespitosum (northern cotton club rush)
      Senecio schweinitzianus (New England groundsel, Robbins’ ragwort)
      Lobelia kalmii (Kalm's lobelia)
      Parnassia glauca (grass-of-parnassus)
      Petasites frigidus var. palmatus (sweet coltsfoot)
      Cypripedium reginae (showy lady's slipper)

      Aulocomnium palustre (moss)
      Philonotus fontana (moss)
      Sphagnum warnstorfii (peat moss)
      Tomenthypnum nitens (moss)
      Bryum pseudotriquetrum (moss)
      Campyllium stellatum (moss)
      Pellia epiphylla (liverwort)

Associated natural community systems: 
This system is most often associated with northern white cedar minerotrophic swamp systems, and occasionally emergent marsh - shrub swamp or spruce - fir forest/swamp systems.

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