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US Fish & Wildlife Service FieldNotes

Conservation Biology in the Midwest Driftless Area

Region 3, February 15, 2012
Biologists survey land snails on an algific slopes.  The workers have to watch the placement of each step on the slope and look very carefully to avoid disturbing these highly sensitive habitats.  The plant cover has taken thousands of years to develop and mature.
Biologists survey land snails on an algific slopes. The workers have to watch the placement of each step on the slope and look very carefully to avoid disturbing these highly sensitive habitats. The plant cover has taken thousands of years to develop and mature. - Photo Credit: n/a

The Driftless Area is an expanse of land found where the corners of Iowa, Illinois, Wisconsin and Minnesota meet. “Drift” refers to the rocks, stones and dirt that flowed from or were left by retreating glaciers. In contrast to surrounding areas, the surface geology of the Driftless Area has little to no glacial drift. The result is a surface geology much different from surrounding areas that often supports unique assemblages of plants and animals. One geologic feature and associated ecosystem of the Driftless Area, the algific talus slope, was the focus of a recent workshop at the Rock Island Ecological Services Field Office.

Although the mechanics remain somewhat of a mystery, algific slopes are limestone bluff and slopes that produce cold air during summer, creating climate conditions much cooler than surrounding areas. Usually forested, these cooler pockets support plant and animal communities different from surrounding woodlands. One species found on these slopes is found nowhere else in the world, the state and federally endangered Iowa Pleistocene snail. Common during the Pleistocene Epoch, it was thought to be extinct until an Iowa naturalist collected a live specimen. The Iowa Pleistocene snail is referred to as a climate or glacial relict as it was once widespread during the last Ice Age (i.e., Pleistocene Epoch) and is now limited to the cold air slopes in the Driftless Area. Another climate relict found on algific slopes is the state and federally threatened Northern monkshood. In the Midwest, this tall flowering plant only occurs in the Driftless Area, but is also found in cold climate habitats of northeastern United States.

There are other plants found on Driftless Area algific slopes that are found nowhere else in the Midwest but do occur in cold climate habitats much farther away. For instance, a shrub of Canada’s boreal forests, the Canada yew also grows on Driftless Area algific slopes. Populations like the Canada yew, separated from the main population on isolated patches, are considered disjunct populations. There are many climate relict species and disjunct populations living on the Driftless Area algific slopes.

A coalition of biologists and geologists gathered for a workshop co-hosted by the Driftless Area National Wildlife Refuge and the Rock Island, Illinois, Ecological Services Field Office to discuss methods to monitor air temperatures and species populations on Driftless Area algific slopes. Outcomes of the workshop included lists of technical, budget and staff considerations for developing monitoring plans. A follow-up workshop is planned to create a conceptual site model to explain the nature of the continuous cold air circulation on the slopes, which is a rare phenomenon. The conceptual site model will be useful to assess whether the air circulation mechanisms are vulnerable to climate change.

Why monitor and study climate relict and disjunct species? We can learn about the mechanisms that cause extinction by studying climate relict species and disjunct populations. The Iowa Pleistocene snail, although a relict, has survived climate shifts during and after a number of glacial advances and retreats. Understanding how it responded to climate shifts in the past and how it responds now may give us insight into conservation strategies as our climate warms. Also, conserving these species helps sustain our Nation’s biodiversity. Ecosystems with high biological diversity are more resilient to modern day stressors. Functioning ecosystems provide many valuable ecological services and human uses for society.

The U.S. Fish and Wildlife Service manages the Driftless Area National Wildlife Refuge in northeast Iowa. The Driftless Area National Wildlife Refuge was established in 1989 to help protect algific talus slopes and conserve the federally listed species that depend on these habitats.The partnership is working on a web page to serve as a repository of conservation reports for the Driftless Area algific slope monitoring results, and information for the public, educators, and scientists. See the links below to learn more about the Driftless Area, Iowa Pleistocene snail, and cold climate plants.

Please contact Kim Mitchell at kim_mitchell@fws.gov for more information on the development of the new web site or if you have information to offer, contact driftless@fws.gov for more information on the Driftless Area National Wildlife Refuge, and Mike Coffey at michael_coffey@fws.gov for more information on the Driftless Area in general.

Contact Info: Mike Coffey, 309-793-5800 X515, michael_coffey@fws.gov