Type 8 Wetlands: Bogs

wetland types
Written By Azalea Hallin-Graber

One of North America’s most distinctive kinds of wetlands, bogs are filled with spongy peat, acidic water, and a thick layer of sphagnum moss. They prevent downstream flooding by absorbing precipitation and provide habitat to animal species that are threatened by human encroachment. 

Understanding Bogs

Bogs exclusively receive water from rainfall and are distinguished by their spongy peat deposits and thick layer of sphagnum moss that grows on the bog floor. There are two ways that bogs form: from sphagnum moss growing over a lake or pond, slowly filling it (known as terrestrialization), or from sphagnum moss blanketing over dry land, preventing water from leaving the surface (known as paludification). Acidic peat deposits build up over time in both types of bog formation. This results in plant and animal communities that adapt to low nutrient levels, waterlogged conditions, and acidic waters. Bogs have a powerful and fragile ecosystem that can be destroyed in a matter of days and require hundreds to thousands of years to form naturally. 

Northern bogs exist in lower temperatures with short growing seasons in areas that have plenty of precipitation and high humidity, causing excessive moisture accumulation. These bogs form in old glacials lakes and have a lot of open water surrounded by floating vegetation, or vegetation that has covered the lake. Sphagnum peat creates very acidic water, resulting in a very unique ecosystem. 

Characteristics Specific to Bogs

Soil Profile: Soil is typically waterlogged with moss covering. They are distinguished by their wet, spongy, and peaty soils.

Vegetation: Plants include health shrubs, sphagnum moss, sedge, leatherleaf, labrador-tea, cranberries, and cottongrass, as well as scattered and often stunted black spruce and tamarack.

Fauna: Bogs host very unique conditions that are home to the greater sandhill crane, the sora rail, moose, deer, lynx, and the great gray owl. 

Functions & Benefits

Bogs prevent downstream flooding by absorbing precipitation and are found mostly in the Great Lakes regions as well as in the southeast. There has historically been a large decline of bogs, as they were drained for cropland and mined for their peat. Peat acts as a carbon store and sustains wildlife habitat, carbon storage, water filtration, flood prevention, as well as grazing land and recreational areas.

Flood Mitigation & Erosion Control: Due to their high concentration of sphagnum moss, bogs prevent downstream flooding. Sphagnum moss can absorb up to 20 times its weight in water. 

Water Quality & Infiltration: Sphagnum can be up to 70 percent of the water held in bogs, which creates a large density of water storage and becomes very acidic from sphagnum. 

Habitat & Species Diversity: As noted earlier, bogs provide a very unique habitat for animals threatened by human encroachment. 

Economic & Recreational Value: Because of the amount of peat in bogs, they serve a huge role in carbon storage which takes an important role in the economy of our climate. They are also a wonderful source of ecological diversity and interest for people to enjoy.

Mitigation Partners, Inc. Founders Dax Dickson & Tory Christensen

Azalea Hallin-Graber
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