Hill Prairies of Illinois* - 



ROBERT A. EVERS 



OX the sunny, windswept, upper 

 slopes of some of the bluffs along 

 the major Illinois streams are tree- 

 less areas distinctive enough to attract 

 the attention of observing travelers. These 

 areas are grassy strips or grassy openings 

 on the otherwise forested slopes of the 

 bluffs, frontispiece. Most of them have 

 been little disturbed by man or domesti- 

 cated animals. Those that are covered 

 with prairie plants are prairies. 



Prairies are grasslands. To many per- 

 sons, prairies are flat grasslands. How- 

 ever, it is not topography but vegetation 

 that distinguishes prairies and other plant 

 communities. Forests occur on flat land 

 or on slopes. So do prairies. Grasslands, 

 or prairies, on pronounced slopes are hill 

 prairies. 



The term hill prairies was first used in 

 1943 by a University of Illinois botanist. 

 Dr. Arthur G. Vestal, in his ecology 

 classes and seminars to characterize prai- 

 ries that occur on loess bluffs, on mounds, 

 on steep, rocky slopes, on steep slopes of 

 glacial drift, or on any other steep slopes. 

 With few e.xceptions, the hill prairies of 

 Illinois are not hill-top prairies; most of 

 them occupy only the upper west- and 

 southwest-facing slopes of elevations. 



Most of the once extensive flatland 

 prairies have disappeared from the Illinois 

 landscape. There yet remain a few 

 patches of these prairies on the till plains, 

 but they have been very much disturbed 

 by man or domesticated animals. The 

 prairies of the bottomlands, the type stud- 

 ied by Turner (1934a, 1934^), now occur 

 only in small scattered patches, usually in 

 field borders or borders of roadside ditches 

 in the Mississippi and Illinois river val- 

 leys. There are still sizable areas of sand 

 prairies of the tvpe studied bv Gleason 

 (1910), 'Gates (1912), Vestal (1913), 



•This article Is based upon a thesis submitted by the 

 writer to the Graduate College, University of Illinois. 

 Urbana, in partial fulfillment of the requirements for the 

 tlegree of Doctor of Philosophy in Botany. 



and others, but the extent of these prairies 

 is rapidly decreasing as a result of the ac- 

 tivities of man in converting them to fields 

 of watermelons or cantaloupes, or to an- 

 other type of grassland, the cornfield. 



There remain on the Illinois landscape 

 numerous tracts of hill prairie and, as 

 these prairie slopes were never plowed, 

 they are now the least disturbed type of 

 prairie in the state. Although rather com- 

 plete studies of till plain, bottomland, and 

 sand prairies of Illinois ha\e been pub- 

 lished, until this time no comparable study 

 has been done for the hill prairies of this 

 state. 



Several studies have been published 

 on the hill prairies of other states. The 

 study by Bush (1895) on the mound 

 flora of Atchison County, Missouri, and 

 the work of Steyermark (1940) on suc- 

 cession in Ozark glades of the same 

 state concerned, in part, prairie on pro- 

 nounced slopes. Studies of Pammel 

 (1896, 1899, 1902) and Shimek (1910a, 

 1910/-, 1911, 1924) described the vegeta- 

 tion and enumerated the species of the 

 loess bluff prairies in western Iowa or of 

 the prairie openings or grassy meadows on 

 the Iowa bluffs of the Mississippi River. 

 Reports of Hanson (1922), of Costello 

 (1931), and of Hopkins (1951) described 

 prairies on loess bluffs along the Missouri 

 River in Nebraska or prairies on loess 

 hills in central Nebraska. A paper by 

 Marks (1942) characterized what he 

 termed the "goat prairies" of AVisconsin 

 as prairies located on slopes "so steep that 

 only the nimble goat could graze them." 

 Sites described in these papers were prai- 

 ries on steep slopes, or hill prairies. 



Perhaps the earliest reference in the lit- 

 erature to Illinois grasslands on the upper 

 slopes of bluffs is found in reports on the 

 geology of Greene County and of Scott 

 County by Worthen (1868). In these re- 

 ports, Worthen described loess-capped 

 blufEs with grass-covered knobs. These 



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