English Top Ad

Conserving Canada’s Wetlands

Menu ↓ 

Learn about wetlands

What is a wetland?

A wetland is any area that holds water either temporarily or permanently. Some wetlands hold water year-round while others may only hold water for one or two months each spring.

Depending on where you live, wetlands may more commonly be known as sloughs, ponds and marshes. The Canadian Wetland Inventory identifies five types of wetlands:



Bogs are peat-covered wetlands (peatlands), in which the vegetation shows the effects of a high water table and a general lack of nutrients. The plant community is dominated by cushion-forming Sphagnum mosses (peat mosses), ericaceous shrubs and black spruce trees.



Fens are peatlands characterized by a high water table, but with very slow internal drainage by seepage. Similar to bogs, the surface water in fens is also generally nutrient poor. Dominant plants include black spruce, tamarack, sedges, grasses, and various mosses.


Marshes are wetlands that are periodically inundated by standing or slowly moving water and hence are rich in nutrients. Marshes are mainly wet, mineral-soil areas, but shallow, well-decomposed peat may be present. They are characterized by an emergent vegetation of reeds, rushes or sedges and the absence of woody vegetation.


Swamps are wetlands where standing or gently moving waters occur seasonally or persist for long periods, leaving the subsurface continuously waterlogged. The vegetation may consist of dense coniferous or deciduous forest, or tall shrub thickets.

Shallow / Open Water

Shallow / Open Water can represent wetlands, water bodies or portions of wetlands and water bodies, usually with water depths less than 2 metres during low water conditions. They can also include the transition stage between lakes and marshes.

These five wetland classes can be further recognized by their “form” based on surface, water, and underlying mineral soil characteristics. The class/form combinations can be further described by their “type” based on the vegetation communities associated with them. A more detailed description of the five wetland classes along with their forms and types can be found in: National Wetlands Working Group. 1997. The Canadian Wetland Classification System, 2nd Edition. Warner, B.G. and C.D.A. Rubec (eds.), Wetlands Research Centre, University of Waterloo, Waterloo, ON, Canada. 68 p.