What are Types of Wetlands?

I have a Bachelor of Science degree in Fisheries and Wildlife Sciences, so I’ve taken a few classes about ecosystems and the animals that can be found in them.

We had a lab station in the middle of a deciduous forest, and took field trips to a nearby bog to go exploring.

I loved learning about different ecosystems and their importance for the structure of the community as a whole. 

Wetlands are biomes where the area of land is either covered in water or densely saturated. The water comes from natural springs, lakes and rivers, or seawater. Specific species of plants and animals are adapted to live in wet environments and wetlands can occur in varying climate zones. 

In this article we will define each type of wetland biome and explain how they differ from one another.

We will talk about their individual characteristics and what types of plants and animals can be found in each as well as their ecological benefit.

We will discuss where they can be found in the world and what type of water can be seen in each ecosystem. 

Marshes Are Wetlands

Marshes are characteristic of flat, grassy expanses near rivers, bays, and coasts. They have saturated and water-logged soil that retains the majority of the water that supplies them continuously. They are largely treeless with herbaceous plant species 

A freshwater marsh I love to visit to look for frogs
(Photo by Daniella, Master Herpetologist)

Marshes exist all over the world, and a large portion occurs in the Southeast United States, the most well-known example being the Everglades of Florida.

They can provide suitable habitat for a variety of small animal species, frogs, turtles, and wading birds. 

Saltwater Marsh 

Saltwater marshes occur at the shores where oceans meet land.

Their position can help slow land erosion and reduce harm from hurricanes by being a buffer zone and reduce saltwater intrusion into inland wetlands.

They feed off the ocean tides and from river deltas depositing into the ocean. 

Aerial Photograph of salt water marshes on the Eastern Shore of Virginia

These grassy areas are home to more salt-tolerant species, aquatic and wading birds, crustaceans, fish, reptile, salt tolerant frogs.

The saltwater marshes in Northern Australia are dominated by algae that provides cover for amphibians. These marshes are also frequented by saltwater crocodiles. 

Freshwater Marsh 

Freshwater marshes occur inland around lakes and streams. They are characteristic of fertile soil in a temperate climate and were developed by water filling holes left from glaciers.

The water is typically muddy and slow-moving and at the top of the region’s water table. 

A freshwater marsh I regularly to visit to look for frogs during Spring and Summer
(Photo by Daniella, Master Herpetologist)

Freshwater marshes are rich in biodiversity and an important stop for migratory birds.

In North America, an example of a region where freshwater marshes can be found is in the American Midwest and central Canada.

Botswana has the largest freshwater march in the world where a river empties into a delta in a desert. 

Swamps Are Wetlands

A swamp is an area permanently filled with water and dominated by tree species. They can be named for the main tree species that they hold, such as a cypress swamp, and can be permanently flooded areas or former ponds overtaken by trees.

Taxodium distichum (Bald Cypress Trees) in a Swamp in the American South.

Swamps can be found on every continent besides Antarctica and are transitional areas in a variety of climate regions. 

Saltwater Swamp 

Saltwater swamps form on coastlines where water-tolerant trees, such as mangroves, anchor to the sand and sediment on the coast to grow together as a habitat.

Much of the water in saltwater swamps is actually brackish, a mixture of fresh and saltwater. These water conditions make them good homes for a variety of species. 

Green Mangrove Forest Along a Saltwater Swamp

Saltwater swamps are actually nest and spawn sites for marine, aquatic, and bird species. They almost act as nurseries where young species can live and mature. Droppings from these visiting species mix with the root decay of the mangrove trees and fertilize the swamp. 

Freshwater Swamp 

Freshwater swamps prefer heat and humidity and occur inland from coasts. They are found where the land is flat, water table is high, and run off is slow. These areas also house water-tolerant plant species that attract a variety of animal species. Depending on the area of the world, freshwater swamps attract large mammals to feast on its lush vegetation.

Freshwater Swamp in The Deep Southern USA

The humidity and stillness of the water found in inland swamps makes good habitat for insects and amphibian species, and tropical locations like the Congo sees dozens of frog species. Algae typically grows over the surface of the water, creating cover for amphibians and snakes. 

Bogs Are Wetlands

Bogs are generally found in colder climates, including the arctic but may also be found in warmer climates. They are lakes filled with plant matter and vegetation. Old plant debris on the bottom of the lake becomes a substance called peat.

In college I once had a professor that took us on a field trip to a local bog in upstate New York. It was wet and spongy and a little difficult to walk through!

Photo of a typical bog landscape

There was a lot of vegetation, including pitcher plants, and I even picked up a snake that was skimming through the water. 

Since bogs are composed of decaying plant matter, they are slow to develop.

Vegetation slowly creeps from the lake’s edges inwards. The water is oxygen-poor and nutrient rich, making the soil acidic. 

Fens Are Peat-Based Wetlands

Fens are similar to bogs as they form peat at their base, however, fens are less acidic and support a rich biodiversity of animal and plant species. They are fed by abundant precipitation, steady underground water sources, and high humidity.

Fens are mainly associated with cooler climates and occur most in the northeastern United States and Canada.

They are springy underfoot and rich in calcium and magnesium. The groundwater that feeds them is mineral-rich. 

Fen I visited in the Frontenac National Park, Quebec
(Photo by Daniella, Master Herpetologist)

Fens can be classified based on the location they are found and the plant species that make them up.

Prairie fens are found in savanna regions, patterned fens have alternating peat ridge depressions, poor fens have low water flow and mineral content, northern fens have bedrock covered in glacial debris. 

This article was written by Melissa M. who holds a Bachelors of Science in Fisheries and Wildlife Sciences, and a Master Herpetologist certificate. The article was edited and published by Daniella, Master Herpetologist in the author profile below.

Sources

Environmental Protection Agency. (n.d.). EPA. Retrieved from https://www.epa.gov/wetlands/classification-and-types-wetlands##Fens 

Wetland Management. (n.d.). Bogs and Fens. Private Land Partnerships Working Together For Wildlife. 

Wetland. National Ge