Seasons of Wildlife
In the summer, air is drawn down through sinkholes, flows over frozen groundwater and is released through vents on the slopes. This air flow provides a climate similar to what was prevalent in glacial eras. Summer temperatures on the slopes range from just above freezing to 55 degrees. In winter, the air is drawn into the vents and the groundwater freezes again.
Because of the cool temperatures and moist conditions, unusual plants for this part of the country grow on the slopes. Typically growing in a colder more northern climate, yews, balsam fir, showy lady’s slipper and golden saxifrage can be found on the cool slopes. These cold microclimates allow the rare plants and animals to survive.
A tiny land snail, the Iowa Pleistocene snail, is smaller than a shirt button measuring about 5 millimeters (1/4 inch) in diameter. Considered a glacial relict species, it has survived only on these small areas where temperature, moisture and food are suitable. The snail seeks cool, rocky slopes near coldwater streams, cliffs, valleys and sinkholes.
Because of the fragile nature of the habitat and the small size of the total population, this snail was placed on the federal endangered species list. The primary recovery option for the tiny snail is permanent protection of remaining colonies. Thirty-six known colonies are currently in northeast Iowa with one population occurring in northwest Illinois.
The threatened northern monkshood, belonging to the buttercup family, grows on 114 algific (cold air) talus (loose rock) slopes and similar cool moist habitats in Iowa, Wisconsin, Ohio and New York. The majority of the sites are in Iowa. The purple hood-shaped flower, an adaptation for bumble bee pollination, was listed as threatened in 1978. Its options for recovery are similar to the snail.
Northern monkshood is noted for its very distinctive, blue hood-shaped flowers. The flowers are about 1 inch long, and a single stem may have many flowers. Stems range from about 1 to 4 feet in length. The leaves are broad with coarse, toothed lobes.
Northern monkshood is a perennial and reproduces from both seed and small tubers. The flowers bloom between June and September and are pollinated when bumblebees pry open the blossom to collect nectar and pollen.