Algific Soils and Landscapes in the Driftless Area, USA.

Algific slopes are natural, yet rare, microclimatic ecosystems found sparingly across the heavily forested, topographically dissected Driftless Area of the Midwest and in West Virginia. Algific slopes are defined as cold-air, north-facing colluvial slopes that exhibit remarkably lower ambient growing-season temperatures compared to non-algific slopes across the region. Their unique microclimatological properties are due to geologic features fundamental to algific slope formation. Essentially, cool moist air and warm moist air – through a complex system of sinkholes, geologic fissures, and interconnected vents – is circulated across ice trapped in the fractured geologic substrate, which causes cool moist air to be vented to these north-facing slopes during the warm months, thus effectively shaping local flora and fauna. As a result of this cold-air microsite phenomenon, algific slopes of the Driftless Area are home to several federally listed endangered plant and animal species, including, the only known population of Iowa Pleistocene snail (Discus macclintocki), considered to be a relic of the last Ice Age. In Iowa, anomalous balsam fir (Abies balsamea) stands are often used to identify algific areas. In a sense, because algific slopes retain a significantly cooler than normal microclimate during the summer months, these unique cold-air habitats can be thought in terms of global climate change, whereas local non-algific areas have been subjected to post-glacial warming/global change, Algific sites have resisted post-glacial warming and may ultimately serve as ecological controls in the context of global climate change. There has never been a pedological evaluation of these areas; scientific knowledge of algific slopes is generally limited to floral and faunal inventories at select locations. If the climate is significantly cooler on these slopes, it should be measureable with modern instrumentation, and the soil morphology should reflect those differences. This presentation will include an inventory of algific ecosystems in the Driftless Area, a characterization the microclimate of selected algific ecosystems, and the impact on soil morphology, classification, and vegetation as compared to selected non-algific reference areas.