This area contains geological formations known as “kettleholes.” Historically, these were formed when giant blocks of ice from glaciers fell off and melted, making large bowl- shaped indentations in the ground. These unique geological formations make this preserve one of the more popular in the state. It often is used by schoolchildren, college students and many other groups to learn about prairie life. This site also is particularly distinctive and educational because the threatened prairie bush clover is found here.
Why You Should Visit
The natural communities here include the unique "kettle" wetland, dry gravel prairie to mesic prairie on the ridgetops and slopes, and wet mesic prairie and sedge meadow in the floodplain. The diversity of high-quality habitats supports more than 360 vascular plants, 34 bryophytes (mosses and liverworts) and numerous lichens.
Southwest of Okoboji, in Dickinson County, Iowa (15 minutes west of Spirit Lake)
There are usually an abundance of ticks on the preserve, so take precautions to limit your exposure. The grassland community is mid-grass to tall grass prairie, with an excellent view of the Little Sioux River valley from the top of the kettlehole.
Why the Conservancy Selected This Site
Freda Haffner Preserve protects one of Iowa’s best and largest glacial kettleholes and highly diverse native prairie communities, as well as several rare or endangered plants, mammals, birds and butterflies. The preserve was purchased in 1972 by the Conservancy with a gift from Freda Haffner and was named in her honor. In 1976 it was dedicated as a biological and geological State Preserve.
What the Conservancy Has Done/Is Doing
More than 50 acres of prairie have been reconstructed on portions of the Preserve that had been cropped, using a diverse mix of prairie seed collected from the Preserve and Cayler Prairie (four miles to the north).