A fen is defined as a type of peatland with nutrient-rich waters and is found primarily along the edges of lakes and rivers or the perimeters of bogs. The water contains dissolved minerals from the surrounding soils, and water levels fluctuate seasonally. The vegetation consists predominantly of sedges, grasses, rushes and mosses, with some shrubs and, at times a sparse tree layer. A fen is differentiated from a marsh by its peat layer, nutrient load and lower pH.

Primary production in fens is carried out mainly by sedges and grasses (in bogs, it is mosses); much of the organic material accumulates on the site as peat.

Fens are not common in Nova Scotia, but are still an important feature of the landscape. They are nutrient-rich wetlands with abundant wildlife, and contain several rare plant species of the coastal-plain flora (in southwestern Nova Scotia). If periodic flooding stops, a forest habitat is eventually established. Other changes to water flow cause fens to transition to bogs.

This Document Includes:

Formation
Physical Aspects
Ecosystem
Types of Fens

Flat Fen
Sloped Fen
Atlantic Ribbed Fen

Successional Sequence
Plants

Carex oligosperma subassociation
First Blue-joint Grass subassociation
Second Blue-joint Grass subassociation
Sweet Gale-Blue Flag subassociation

Animals
Special Features
Distribution

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Additional Keywords:
Carex oligosperma, Myrica gale, Sphagnum, Bog Goldenrod, Bog laurel, Mountain Fly-honeysuckle, Meadow Sweet, Aster radula, Meadow-rue, Marsh Cinquefoil, Meadowsweet, Blue Flag, Northern Manna Grass, Carex paupercula, Joe-Pye Weed, deerflies, horseflies, mosquitos, butterflies, moths, Crambidae, Leucania, Succineidae, Zonitoides nitidus, Deroceras laeve, Virginia Rail, Yellow Warbler, Swamp Sparrow, swallows, flycatchers, Cinerous Shrew, Water Shrew, Star-nosed mole, Muskrat

Associated Topics:

T4.2 Post-glacial Colonization by Plants
T8.1 Freshwater Hydrology
T8.2 Freshwater Environments
T9.1-T9.3 Soils
T10.2 Successional Trends in Vegetation
T10.4 Plant Communities in Nova Scotia
T10.5 Seed-bearing plants
T10.6 Trees
T10.8 Bryophytes (Mosses, Liverworts and Hornworts)
T11.5 Freshwater Wetland Birds and Waterfowl
T11.15 Amphibians and Reptiles
T11.16 Land and Freshwater Invertebrates

Associated Habitats:

H3.3 Bottom Lotic (Rivers and Streams)
H3.4 Bottom Lentic (Lakes and Ponds)
H3.5 Water's Edge Lotic (Rivers and Streams)
H3.6 Water's Edge Lentic (Lakes and Ponds)
H4.1 Bog
H2.3 Swamp
H4.4 Freshwater Marsh (Inland)