Prairie Pothole

Description:

Prairie potholes are depressional wetlands (primarily freshwater marshes) found in the northeastern section of Montana.  This formerly glaciated landscape is pockmarked with an immense number of potholes, which fill with snowmelt and rain in the spring. Some prairie pothole marshes are temporary, while others may be essentially permanent. Here a pattern of rough concentric circles develops. Submerged and floating aquatic plants take over the deeper water in the middle of the pothole while less flood tolerant wetland plants grow closer to shore. 1

Function and Value:

The prairie pothole region, because of its numerous shallow lakes and marshes, rich soils, and warm summers is described as being one of the most important wetland regions in the world. The area is home to more than 50 percent of North American migratory waterfowl, with many species dependent on the potholes for breeding and feeding. In addition prairie potholes also absorb surges of rain, snow melt, and flood waters thereby reducing the risk and severity of down stream flooding.

Photos of Prairie Potholes:

Prairie potholes dotting an agricultural landscape in Alan Hills, North-Central Saskatchewan
Photo by: Jim Ringelman
"Prairie potholes dotting an agricultural
landscape in Alan Hills, North-Central
Saskatchewan."

Prairie potholes near Comertown in the Northeastern corner of Montana
Photo by Mike Rabenburg
"Prairie potholes near Comertown in the
Northeastern corner of Montana, April 1999."

Prairie pothole in Northern Blaine County, MT
Photo By: Karen Newlon
"Prairie pothole in Northern Blaine County, Montana
showing the characteristic vegetative ring zones."

Distribution Map of Prairie Potholes:
Distribution Map of Prairie Potholes

Potential Stressors:

Agricultural:

The contrast between native pothole regions and the agricultural landscape that has replaced the majority of it
Photo by: Unknown
"The contrast between native pothole regions and
the agricultural landscape that has replaced the
majority of it."

Pothole wetland surrounded by agricultural fields
Photo by: Ducks Unlimited, Inc.
"Pothole wetland surrounded by agricultural fields"

Grazing:

The effects of cattle grazing on pothole wetlands
Photo by : Bryce Maxell
"The effects of cattle grazing on pothole wetlands."

Cattle hummocking in a wetland where livestock were allowed to graze and water
Photo by: Bryce Maxell
"Cattle hummocking in a wetland where livestock
were allowed to graze and water."

Nutrient Enrichment:

Algal growth as a result of nutrient enrichment from agricultural runoff in a pothole wetland
Photo by: Unknown
"Algal growth as a result of nutrient enrichment
from agricultural runoff in a pothole wetland."

Invasive Species:

Smooth Brome invasion of a prairie pothole in Comertown Prairie, Sheridan County, MT
Photo By: Natalie Byars
"Smooth Brome invasion of a prairie pothole in
Comertown Prairie, Sheridan County, Montana."

Ditching and Draining:

An example of an wetland that has been drained via piping
Photo by: Larry Urban
"An example of an wetland that has been drained
via piping."

Converting Wetlands to Open Water:

Prairie pothole excavated for use as a stock pond
Photo By: Natalie Byars
"Prairie pothole excavated for use as a stock pond."

Reference:

 

1 EPA Prairie Potholes