Aerial view of Savanna Army Depot.
In 1908, renowned botanist Henry Allan Gleason studied the vegetation of the inland sand deposits of Illinois. Gleason published the results of this work in the October 1910 Bulletin of the Illinois State Laboratory of Natural History (now the Illinois Natural History Survey). The article contains detailed descriptions and photographs of the plant communities characteristic of Illinois' prairies and oak forests on sandy soil. He spent a major portion of the summer of 1908 in the Hanover area in western Jo Daviess county, which at the time still had "extensive areas of [forest and prairie] ... in their original condition, or but slightly modified by grazing."
Ten years after Gleason's study, the U.S. Army purchased 6,500 acres of floodplain forest and 6,500 acres of the upland sand area that Gleason studied near Hanover. The Army's use of this land, known as the Savanna Army Depot, spared it from the plow and most development. However, although about 5,000 acres of uplands are still dominated by native vegetation, the landscape has changed considerably since Gleason studied it. A grid of roads and railroads crisscrosses the upland area, giving access to 132 warehouses and 437 earth-covered, concrete bunkers used to store ordnance. Nearly 80 years of fire suppression and heavy grazing have led to woody encroachment in the prairies, development of a thick understory in the savannas, and establishment of invasive plants such as spotted knapweed and garlic mustard. Despite this disturbed state, the depot is the largest contiguous remnant of sand prairie/savanna in Illinois, and it harbors more than 30 state threatened and endangered species.
Aerial view of Savanna Army Depot.
Next spring, the depot will close and the U.S. Fish and Wildlife Service (USFWS) will begin managing 9,500 of its 13,000 acres as the Lost Mound Wildlife Area. The upland portion of the USFWS land, approximately 3,000 acres, will be jointly managed by USFWS and the Illinois Department of Natural Resources. Two INHS scientists at the site are planning and will carry out research and restoration of the native ecosystems that Gleason studied.
Three main research projects are planned for the near future at Lost Mound. The main research will focus on approximately 500 acres of the prairie and will take advantage of the Army's grid of roads to conduct a statistically sound experiment investigating various components of prairie restoration and management, including the timing of prescribed fire, seed addition, and ground-disturbing activities. The reaction of prairie vegetation and the invasive species to these manipulations will be monitored in order to understand what controls the diversity of prairie plant communities. In addition, the effects of the management techniques on the ecology of selected grassland and shrubland birds will be studied. Of particular interest are the Grasshopper Sparrow (Ammodramus savannarum) and the Eastern and Western Meadowlarks (Sturnella magna and neglecta).
Another research topic will focus on species interactions with invasive species. The roles of birds and mammals as seed dispersers, seed predators, and herbivores of invasive plant species will be examined to complement the work on techniques to control invasive species. The third research topic will focus on blowouts--areas of bare sand created by wind erosion. Understanding how often these patches are created and how quickly plants fill them in will provide information on how to maintain habitat for species, such as the state-endangered false heather (Hudsonia tomentosa), that depend on open sand for survival.
Although restoration is still in its infancy at the Lost Mound Prairie, the potential for its impact is twofold. First, restoration at the site will return a small portion of Illinois' once vast prairie to its past grandeur, providing a refuge for plants and animals in dire need of protected habitat and a place for people to experience the prairie on a larger scale than just about anywhere else in Illinois. Second, and just as important, research at the site will provide information that will help answer questions about how to restore and maintain prairies and savannas in Illinois and throughout the Midwest.
Amy Symstad and Dan Wenny, Center for Biodiversity
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