The ecosystem of the prairie grasslands, including buffalo wallows and playas are far more complex than explorers, who once called the area the Great American desert, thought. They are crucial to the health and well-being of humans as well as animals, reptiles and plants.
A common behavior of the American bison, dust-bathing or wallowing results in a circular soil depression that still persist today, apparently caused by intensive soil compaction over many years, including in Barton County, although according to a study by University of Notre Dame, not all depressions were caused by bison.
Clay forms an impermeable floor in a buffalo wallow. The wallows fill with water during wet years and range in size from one to ten meters in diameter.
Playas are a much larger wetland and are significant in recharging the Ogallala Aquifer, which is where water for irrigation as well as drinking water in the Central Plains comes from. Most of them are round and come and go, according to wet/dry cycles. Spanish Conquistadors named the pools of water Playas, which is the Spanish word for beach.
Playas do exist in other parts of the world, but they are nowhere as dense as in southern high plains, ranging in size from one acre to 100 acres. They were not caused by bison. Clay also forms an impermeable floor in a playa as well. Water seeps from the playas to recharge the aquifer.
Cheyenne Bottoms is different from both.
“Cheyenne Bottoms is a permanent marsh,” said Curtis Wolf, biologist at the Kansas Wetlands Education Center. “The best theories of how Cheyenne Bottoms was formed involve a “land sink”, possibly due to the dissolution of underground salt deposits. Wind erosion has helped scour out the basin, but erosion itself probably did not form the basin.”
Many playas are considered critically threatened, with more than 70 percent of these wetlands now altered. There are estimates of 60,000 to 75,000 playas across the Great Plains.
Not only do they recharge the aquifer, they also provide habitat for hundreds of thousands of waterfowl and shorebirds that generally migrate through the area each fall and each spring. Frogs and toads use the water sources as well.
The Ogallala Aquifer has been depleted of more than 150 feet primarily in areas of Texas, but also in Oklahoma and western Kansas. In central Kansas, which is a part of the High Plains Aquifer that includes the Ogallala there has been no significant change of water depth or a change in 10 to 25 feet. It is estimated that 85 percent of the water recharge is from playas.
Cultivation has altered playas and has decreased the there value as wildlife habitat. Financial incentives through various programs are offered to farmers to keep the playas intact, which should include a grass buffer area.
Information for this article came from the U.S. Department of the Interior, Playas Lakes Joint Venture, The University of Notre Dame, American Institute of Biological Services, and the Kansas Wetlands Education Center.