Common (Translated Scientific) Name: Leatherleaf / Few-seed Sedge / Peatmoss species Poor Fen

Colloquial Name: Laurentian Leatherleaf Poor Fen

Hierarchy Level:  Association

Type Concept: This dwarf-shrub poor fen community is found in the northern Great Lakes region and across much of central Canada. Sites are found on peatlands with low exposure to mineral-rich groundwater, including basin fens, shores above the level of seasonal flooding, and margins of larger peatlands. Stands have a saturated hydrology with a fibric Sphagnum spp. peat soil and a pH usually <4.5. Vegetation is dominated by an open dwarf-shrub/scrub conifer layer with very scattered trees (<10% cover). Microtopography is high to intermediate hummocks with hollows or a flat lawn of Sphagnum spp. Ericaceous dwarf-shrubs are dominant, including Chamaedaphne calyculata, Kalmia polifolia, and Ledum groenlandicum, and the creeping dwarf-shrubs Andromeda polifolia and Vaccinium oxycoccos. Betula pumila has low cover but is fairly constant. Scrub conifers include Larix laricina and Picea mariana. They also occur as scattered trees (>3 m). The herb layer is species-poor, containing Carex oligosperma, Carex limosa, Equisetum fluviatile, Menyanthes trifoliata, Sarracenia purpurea, and Scheuchzeria palustris. The moss layer forms a continuous hummocky mat dominated by Sphagnum angustifolium, Sphagnum fuscum, and Sphagnum magellanicum. Diagnostic features include the dominance of a dwarf-shrub ericaceous layer, absence of a tree layer (<10%), species-poor herbaceous layer, and a low abundance of minerotrophic indicators, such as Betula pumila, Carex aquatilis and Carex stricta.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: It is difficult to distinguish this leatherleaf poor fen from leatherleaf bogs in the field, but conceptually this type has somewhat more minerotrophic influence and a corresponding set of minerotrophic indicators. When minerotrophic indicators are absent or "very low", the type is placed in ~Chamaedaphne calyculata - Ledum groenlandicum - Kalmia polifolia Bog (CEGL005278)$$ (Harris et al. 1996). Stands with sparse black spruce-tamarack layer (<10% tree cover) are part of this type. Stands with 10-25% black spruce and tamarack cover are placed in black spruce/leatherleaf semi-treed bog, ~Picea mariana / Chamaedaphne calyculata / Sphagnum spp. Open Bog Woodland (CEGL005218)$$. This type also overlaps closely with a "scrubby poor fen type" ~Larix laricina / Chamaedaphne calyculata / Carex lasiocarpa Acidic Peatland (CEGL005226)$$. There are intermediates between this poor fen and sedge meadows, such as when Sphagnum spp. and Chamaedaphne calyculata have invaded a Carex rostrata meadow and the Carex rostrata is hanging on because it still has deep rooting in the underlying minerotrophic peat or mineral soil (N. Aaseng pers. comm. 2000).

Similar NVC Types: No Data Available

note: No Data Available