Habitat
This very small snail makes its home on cool rocky slopes, near the coldwater streams, cliffs, valleys, and sinkholes that make up the Driftless Area National Wildlife Refuge in Iowa.
Known from fossil records to have existed 400,000 years ago, it is one of many glacial relict species that found refuge in the region of northeast Iowa, northwest Illinois, southeast Minnesota, and southwest Wisconsin called the driftless area. The rugged seemingly driftless area was so called because of the inability of early geologists to find evidence of glacial drift. Much of the area was indeed covered by glaciers about 500,000 years ago.
The Iowa Pleistocene snail found its current home with desirable temperature, moisture, and food resources about 10,000 years ago as ice age conditions moderated. Certain slopes, usually north facing, have loose rock that allows ice-cooled air to exit from underground cracks and fissures. Upland sinkholes contribute to the air flow regime and are an important component of a unique system called an algific talus slope, meaning cold producing rocky slope. Even when outside air temperature is 90 °F (32 °C), ground temperatures on these slopes can be close to freezing. This air flow provides a climate similar to what was prevalent in glacial eras. Freezing winter temperatures are moderated on the slopes giving a year round range of about -10 to 10 °C (14 to 50 °F).
The Iowa Pleistocene snail was thought to be extinct, until it was discovered in 1955 by a scientist working in northeast Iowa. It was listed as endangered in 1978.
Read more about this topic: Discus Macclintocki
Famous quotes containing the word habitat:
“Neither moral relations nor the moral law can swing in vacuo. Their only habitat can be a mind which feels them; and no world composed of merely physical facts can possibly be a world to which ethical propositions apply.”
—William James (1842–1910)
“Nature is the mother and the habitat of man, even if sometimes a stepmother and an unfriendly home.”
—John Dewey (1859–1952)