Know Your Wetland Classes, Part 4: Marvelous Marshes

Did you know that there are 5 classes of wetland in Canada? Learn to recognize them and get acquainted with the wetlands near you. You can learn about all 5 classes of wetland in greater detail by reading the Canadian Wetland Classification System. This post is Part 4 of a 5 Part series entitled Know Your Wetland Classes.

The theme this week is marshes. You can find Part 1 of the series (Fens) here, Part 2 (Bogs) here, and Part 3 (Swamps) here. 

This freshwater marsh in Corner Brook, NL is frequently used by Ducks Unlimited 

for their Project Webfoot field trips. It is part of the Corner Brook Stream Trail 

and is a perfect spot for walking and birding.

What is a Marsh?

A marsh typically has surface water for most (if not all) of the year, and is dominated by grasses and other herbaceous plants around the edges and in the middle. The ratio of emergent plants to open water is usually about 50/50, and they are the most biologically productive wetland class in the world.  There are many sub-forms, but most are either fresh- or saltwater marshes. 

Naturally-occurring marshes are relatively rare in Newfoundland and Labrador (compared with bogs, which are far more common). 

Dragonfly nymphs such as this are popular occupants of marshes

Freshwater marsh

Freshwater marshes occur along rivers and lakes. Unlike bogs and fens, they contain little or no peat and are minerotrophic. Dominant plants include grasses, bulrushes, reeds, sedges, cattails and other herbaceous species. 

Freshwater marshes tend to be pH neutral and therefore can support many different species of birds, invertebrates and other animals. Common species include ducks, geese, swans, songbirds, beavers, frogs, and insects of all sorts.

Lundrigans Marsh: a Management Unit in St.Johns

Salt marsh

Because salt marshes typically develop on bays and estuaries they are frequently or continuously flooded by shallow salty water. For this reason, they are dominated by halophytic (salt tolerant) herbaceous plants.

Because of the brackish water, animals that choose to call salt marshes home must be accustomed to salty water. One might find crabs, mussels, worms, gulls, shorebirds, fish, and shrimp.
 

The Importance of Marshes

Marshes have a very important role in the ecosystem. They can store large quantities of water to prevent flooding, are excellent wildlife habitat, slow erosion along shorelines and buffer stormy seas. Most interestingly, the microbes and plants that inhabit marshes can actually use pollutants such as phosphorus and sulphur as a nutrient source, preventing dangerous chemical runoff from entering our drinking water, oceans, and estuaries. Because of this quality, many people now value marshes for their ability to remove pollutants from agricultural, residential and commercial wastewater.