What is a marsh?
Marshes are wetlands periodically inundated by standing or slowly moving water and creating nutrient-rich soil.
Ecological benefits
- Most biologically diverse
- Marshes moderate flooding and minimize soil erosion
- Filter and trap nutrients and neutralize a number of contaminants
- Vital habitat for many wildlife such as waterfowl, moose, beaver and muskrat
Type of Marshes
- Emergent marshes: dominated by flood-tolerant cattail and rushes; located between deeper open water and meadow marshes
- Meadow marshes: dominated by sedges and grasses; less flood tolerant and occupy shallow water areas
Vegetation
- Cattail, bulrush and sedges occupy more than 25% of the area interspersed with open water
- Floating vegetation (e.g. pondweeds and milfoil) occupies open water
Hydrology
- Water levels fluctuate seasonally and can periodically dry out
- Water sources include precipitation, run-off, groundwater and streams
Soil
- Mineral-based soils with shallow organic deposits (<40cm)
- Nutrient-rich soils resulting from periodic drying out and exposure to oxygen
Types of wetlands
Canada’s wetlands can be broadly categorized into two types: organic and mineral.
Organic wetlands
Otherwise known as peatlands, these wetlands have an abundance of peat accumulation on which organic soils (excluding Folisols) are developed. These types of wetlands can include swamps, marshes, or shallow open-water wetlands.
Bogs
Bogs are peatlands that have deep deposits of poorly decomposed organic material (referred to as peat). They are elevated above the surrounding terrain and receive water and most nutrients from precipitation.
Fens
Fens are peatlands with deep organic deposits and are influenced by slow, lateral water movement. Often referred to as “muskeg,” fens are the most extensive wetlands in the western boreal forest.
Mineral wetlands
Mineral wetlands are found in locations where there is an excess of water on the surface and where there is little or no organic matter or peat due to geomorphic, hydrologic, biotic, edaphic (soil-related), or climatic causes. These wetlands are distinguished by gleysolic soils or peaty phases of these soils.
Marshes
Marshes are wetlands periodically inundated by standing or slowly moving water and creating nutrient-rich soil.
Swamps
Most commonly recognized as shoreline areas of streams, lakes and floodplains, swamps are either treed or shrubby.
Shallow open-water wetlands
Shallow open-water wetlands have water depths of less than two metres, yet are too deep for emergent marsh vegetation to establish.