Article II. — An Ecological Study of Prairie and Forest Inverte- 

 brates. By Charles C. Adams, Ph.D. 



Introductory 



In four generations a true wilderness has been transformed into 

 the present prosperous State of Illinois. This transformation has been 

 so complete that in many parts of the state nearly all of the plant and 

 animal life of the original prairie and forest has been completely ex- 

 terminated. Between the degree of change which has taken place in 

 any given area and the suitability of that area for agriculture there has 

 been an almost direct relation. Fortunately, however, for the preser- 

 vation of prairie and forest animals, the state is not homogeneous, 

 some areas being too hilly, rocky, or sandy for prosperous agriculture. 



The character and mode of transformation which has taken place 

 in the past is instructive in several particulars because it serves to 

 guide our anticipations as to the future of our fauna. The forested 

 southern part of the state (see frontispiece) was first invaded by trap- 

 pers and hunters, who began the extermination of the larger animals. 

 These invaders were in turn followed by others who, with the round 

 of the season, were hunters or farmers, and continued this exterminat- 

 ing process, particularly in the clearings, which began to replace the 

 forest. These pioneers, men of little wealth, possessed a combination 

 of mental and economic habits which was the result of life in a for- 

 ested country, and naturally they settled in those places most like their 

 former homes — within the forest or near the forest margin. From 

 these settlements they looked out upon the prairies as vast wastes to 

 be dreaded and avoided. As a result of this attitude toward the prai- 

 ries, it required some time, even a new generation, some economic 

 pressure, and a change of habits before the prairies were settled. Mean- 

 while the northern part of the state was yet a wilderness ; but through 

 the influence of the Great Lakes, as a route of communication with 

 the populous East, a rapid invasion of settlers set in from that direc- 

 tion. Though these settlers also came from a wooded country, they 

 were more wealthy, settled upon a very fertile soil which was favorably 

 located with regard to eastward communication, and they therefore 

 progressed more rapidly than the less favored, more isolated southern 

 invaders on the poorer soil ; consequently they spread from the forest 



