What is a wetland? — Ducks Unlimited Canada Skip to main content

What is a wetland?

Wetlands are a natural defence system for drought, floods and climate change.

Impact Area

Canada’s wetlands are diverse. They take the form of marshes, bogs, fens, swamps and open water. They appear on the prairies, in the boreal forest, along coastlines and even in the tundra. Every type helps to keep our communities healthy and safe.

Wetlands are defined as land that is saturated with water long enough to promote wetland or aquatic processes as indicated by poorly drained soils, vegetation and other biological activity adapted to a wet environment. (National Wetlands Working Group 1997).

Wetland ecosystems provide ample food sources for a range of plants, insects, microbes, waterfowl and wildlife.

Wetland plants absorb carbon dioxide as they grow, and when they die, that carbon doesn’t get released back into the atmosphere. © DUC

They protect us from flooding, drought and climate change. They protect wildlife by providing hundreds of species with safe places to eat, sleep and raise young. They give us natural places to play, learn and explore. They also clean the water we enjoy at beaches, lakes and rivers.

Types of wetlands

Canada’s wetlands can be broadly categorized into two types: organic and mineral.

Organic wetlands

Organic wetlands, bogs and fens, are known as peatlands or sometimes called muskeg. Vegetation characteristics include dwarf shrubs or stunted trees.  These wetlands have an abundance of peat accumulation on which organic soils (excluding Folisols) are developed. These types of wetlands can sometimes include swamps and marshes.



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 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 are wetlands periodically inundated by standing or slowly moving water and creating nutrient-rich soil.



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

Shallow open-water wetlands have water depths of less than two metres, yet are too deep for emergent marsh vegetation to establish.

How wetlands work

Wetlands act like sponges, soaking up rain and melted snow, and can slowly release water during drier seasons.

They are a natural filter, slowing the flow of water, where aquatic vegetation and bacteria can break down contaminants, and store nitrogen instead of releasing it into the atmosphere as carbon dioxide.

Wetlands are often highly connected aquatic systems moving water and nutrients over long distances, making them vulnerable to developments that block their natural flow.

How wetlands work? Wetlands act like sponges, soaking up rain and melted snow, and can slowly release water during drier seasons.

What we do

We are building on the momentum of our successes—working with our supporters to protect and restore Canada’s wetlands.

Estimates put 25 per cent of the world’s remaining marshes, bogs, swamps and other cattail-lined, carbon-rich water bodies inside Canada’s borders. Our understanding of wetlands is growing, but they continue to be lost. In southern areas of Canada, up to 70 per cent of our wetlands have already been destroyed or degraded and up to 95 per cent in densely populated areas. As they continue to disappear, so too do the many benefits they provide.

Putting wetlands on the map: Since 1979, DUC has used aerial photography and satellite imagery to map and inventory millions of acres of wetlands across Canada. In 2002, we started advocating for a national wetland inventory and monitoring system and, with the support of 150-plus conservation partners, have built a database — the Canadian Wetland Inventory.

Learn more about the Canadian Wetland Inventory

Ducks Unlimited Canada Research scientist Pascal Badiou.

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