13 



with clay and straw wherever the danger of blowing is greatest. 

 These methods are merely an amplification and a hastening of the 

 natural process of stabilization. 



REI<ATI0N OP ANIMALS TO PLANTS 



The writer's training had led him to the hypothesis that animals 

 and plants in a given terrestrial environment are very intimately re- 

 lated; that plant and animal associations are coextensive and to a 

 large extent interdependent, the animals being entirely dependent upon 

 the plants, speaking broadly, and the plants being partly dependent 

 upon the animals. If this be true, the boundaries of an animal as- 

 sociation are those of the plant association ; in fact both may be spoken 

 of as a single biotic association, composed of plant and animal as- 

 semblages. Once this relation were established, certain of the prob- 

 lems of animal ecology would be greatly simplified ; for although the 

 animal assemblage is at first very obscure, the plant assemblage is evi- 

 dent, giving the characteristic appearance to the area. This physiog- 

 nomy, lent by the plants, would thus serve as an index to the animals 

 of the association, as regards ecological type, distribution, etc. Then, 

 too, many of the methods of plant ecology, now an organized science, 

 might be used in studying the animals of the association. 



This study of the animals of the sand prairie was made with this 

 hypothesis in mind, and the evidence, though very incomplete, is in 

 accord with the theory.* It has seemed justifiable to treat the plant 

 and animal associations together. The associations have already 

 been named by the botanist, usually with reference to the dominant 

 feature, be it physical or vegetational. By the "bunch-grass associa- 

 tion" or the "black oak association," wherever the terms occur in 

 the following pages, is not meant the plants alone, but the entire 

 association of plants and animals. 



Annotated List of Animal SPECiESf 



In this section it has seemed desirable to bring together, as 

 far as possible, such ecological data — on habits, food, life-history, as- 

 sociated forms, etc. — as are significant for each species reported, and 

 accordingly many published sources of information have been freely 

 drawn upon to supplement the observations in the field. Specific ref- 



*An anah'sis of these relations between plants and animals, based on ma- 

 terial of this study, has been prepared, and is to be published separately. 



t'The plants of the sand prairie of the Illinois River valley are included in 

 Gleason's annotated list of plant-species ('10:145-170). 



