Also known as the Paleozoic Plateau, the Driftless Region encompasses portions of northeast Iowa, southeast Minnesota, northwest Illinois, and three counties of southern Wisconsin. This region of the Midwest is unique — and of great interest to naturalists and geologists — because it was not inundated by the last round of glaciers some 10,000 years ago. And it wasn't until very recently, in 1989, that naturalists discovered an entire community of ancient creatures still going about their business in Iowa.
Iowa Pleistocene
Land Snail |
Fossil records throughout the Midwest showed that a small land snail was once widespread across the region. This tiny creature was chalked up as one more casualty of the glaciers until 1955, when a living specimen, a true living fossil, was discovered in Iowa. Unchanged since the Pleistocene Era, naturalists named it the Iowa Pleistocene Land Snail.
Nearly 30 more years would pass before entire colonies of these snails, along with several other species of prehistoric land snails, were discovered thriving in small, secluded areas of Iowa's Driftless Region in the 1980s. Scattered across this region are unique natural communities built around underground caverns and crevices known as “sinkholes.” Groundwater below keeps the rocky slopes around the sinkholes very cold in summer, and warm enough in winter to produce clouds of steam on a cold day. Small creeks and springs often occur at the openings. In these unique environments, plants native to alpine and tundra areas thrive. Canada yew and birch trees grow, along with lovely orchids, ferns, mosses, and other plants normally seen hundreds or thousands of miles north.
The snails are tiny, about the size of a pencil eraser, with shells colored a greenish-brown. Along with the Iowa Pleistocene Land Snail are eight other species of ancient land snail, including the Minnesota Pleistocene Amber Snail. They inhabit the leaf litter on the ground, with a lifespan of about seven years or so. They hibernate in winter, and lay their eggs on logs or decomposing bark in spring.
In 1989, the Driftless Area National Wildlife Refuge was established to protect the unique microhabitat that supports these odd little creatures, along with several threatened or endangered wildflowers; the beautiful Northern Monkshood is one such wildflower thriving here. At just 530 acres, Driftless NWR is one of the country's smallest refuges, encompassing scattered parcels of land in three Iowa counties. Visitation to this refuge is very limited, and possible only by making special arrangements in advance with refuge staff.
Driftless Area National Wildlife Refuge
(319) 873-3423
Fax: (319) 873-3803
The Refuge is located on scattered tracts in northeastern Iowa. The total area of the refuge is 618 acres.
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