boreal wetlands Fens Fen Complex Fens Treed Fen Fens are peatlands with deep organic (peat) deposits (>40 cm) and are influenced by slow, lateral water movement. Water sources have been in contact with nutrient-rich surface and/or groundwater making fens more productive and biologically diverse than bogs. Fens can be treed, shrubby or open. Often referred to as “muskeg,” fens are the most extensive wetlands in the western boreal forest. Shrubby Fen Ecological Benefits Types of Fens j Known as the “green rivers” of the j Treed fens: Sparsely vegetated and boreal, fens transport large volumes stunted (<10 m) tamarack, sometimes of water and nutrients across the land- mixed with black spruce, shrubs, sedges scape; help to regulate water flow and mosses j Help prevent downstream flooding by j Shrubby fens: sparse to medium density; absorbing precipitation and run-off short (<2 m) shrubs (e.g. bog birch and j Due to deep organic deposits, fens store willow) mixed with sedges and mosses large amounts of carbon and help to j Graminoid (open) fens: dominated with moderate climate change sedges, mosses and herbs (e.g. buckbean) j Provide important habitat for the often interspersed with open water threatened woodland caribou Graminoid Fen ducks.ca boreal wetlands Fens Patterned Fen complex with treed, shrubby and open graminoid components b tamarack g brown mosses b Identifying Characteristics c willow h meadow horsetail d sphagnum moss i bog cranberry e j Vegetation dwarf bog-rosemary bog birch 1) f water sedge 1) black spruce j Plant species reflect nutrient and c j moisture gradients f j The plant communities of nutrient-poor e h i fens more closely resemble those of bogs, d g while rich fens have more diverse and robust vegetation water table j Treed Fens: organic material – trees (<10 m) make up 25-60% of mineral soil surface area – dominated by tamarack although black spruce can occur Soil j Shrubby Fens: j Deep peat deposits (>40 cm) – shrubs (<2 m) dominate (>25%) with j Similar to bogs but with greater composition of sedge peat less than 25% tree cover j Decomposition is slow due to the wet, cool, anoxic (oxygen- Woodland Caribou – common species are bog birch, deprived) environment, resulting in the accumulation of willow and sweet gale deep organic deposits j Graminoid (open) fens: j Depending on water sources and nutrient availability, 0 – dominated by sedges, mosses and fens can be either nutrient rich or nutrient poor 20 buckbean acrotem j Two distinct layers (right): 40 – Acrotem: the living layer, top 30-50 cm Hydrology 60 – Catotelm: the lower, non-living layer j Complex hydrology with surface, sub- 80cm catotelm surface and groundwater interactions j High water table (at or slightly below the surface) with lateral water flow often Resources connecting wetland systems over vast j Ducks Unlimited Canada Natural Values Fact Sheet Series distances (ducks.ca/naturalvalues) j Field Guide to the Wetlands of the Boreal Plains Ecozone of Canada (ducks.ca/boreal-field-guide) j Ducks Unlimited Canada Western Boreal Program (borealforest.ca) ducks.ca.