Spring 99 More About

...PRAIRIE POTHOLES:
Wetlands with a way cool past
from Ducks Unlimited's Puddler magazine Summer 1999

This is a picture of a prairie pothole. It doesn't seem like much of a wetland-it looks more like a big, shallow puddle with some weeds growing around it. But this is a special kind of wetland. In fact, it's downright amazing.
You might have heard the word "pothole" used to describe shallow holes in the road. Prairie potholes are shallow holes carved out of the land. They're not very big-some are barely bigger than a backyard. But they're very important. More than half of North America's duck population flocks to them each summer to nest and raise families. And, prairie potholes have an amazing history. You can think of them as "footprints" left behind by melting glaciers about 12,000 years ago!

AN ICY BEGINNING
North America looked different 12,000 years ago than it does today. In fact, much of this continent was covered by thick sheets of ice called glaciers. These glaciers spread from the Arctic down through Canada, and as far south as Illinois and Missouri.
Actually, much of the earth was covered in ice at this time. The Great Ice age, which began 2 million years ago, was just coming to an end. Where glaciers covered the land, temperatures were very cold. Few plants grew, just some tough cold-weather grasses.
Animals (and humans) did walk the glaciers. And lands that were glacier-free still had seasons, though summers were cooler and winters were very cold. As the glaciers had slowly flowed southward, so did most kinds of animals. Those that couldn't move or couldn't survive the cold died out.
This is where our prairie pothole story begins. As temperatures began to rise, the glaciers slowly began to melt. They shrank back northward. As chunks of ice left buried in the ground eventually melted, prairie potholes formed.

As temperatures began to rise, the glaciers slowly began to melt. They began retreating back northward.

ICE AGE LIFE
At the time prairie potholes formed, some strange creatures were on the scene in North America. There were cold-weather animals like the mammoth, which stood 17 feet tall, and the saber-toothed cat with fangs one foot long. There were camels, spotted hyenas, antelope, bison, squirrels, horses, and other furry animals which looked much like those living today. There also were giant vultures, beavers, wolves and ground sloths. As warm temperatures took over, and new plants began to grow, many of these animals died out. They couldn't take the heat, perhaps, or maybe their foods disappeared.

STILL AMAZING THROUGH THE YEARS
By 8,000 years ago, the glaciers had retreated to where they are today in North America. (You can still stand on glaciers in places in Canada, Montana and Alaska.) Millions of prairie pothole wetlands dotted the midwestern states of North and South Dakota, Montana and Iowa. They were filled with water, as well as fish, waterfowl and other modern day wetland animals.
Today, many of these potholes have been planted as farm fields, because soil in the region is so rich. Still, thousands are left to fill with water each summer and host nesting waterfowl.