568 



THE COMMUNITY 



blackish brown with moist depressions, (4) 

 brown with distinctly drying crust, (5) Hght 

 brown with very thick crust, (6) Light 

 brown chip, and dry throughout. 



Such a cattle dropping is one of the 

 habitat niches of the grassland floor, and 



weight, dry chip. In many instances, sea- 

 sonal succession (p. 530) complicates the 

 serai picture, depending upon the length of 

 time such serai processes require. In Figure 

 207 the seasonal changes are in close cor- 

 relation with the serai stages of cattle drop- 



-EVAPORATIOM. DAILY 

 B-SOJL MOISTURE, JULY 



SOIL TEMP, SURFACE 



'ULTRAVIOLET 



Fig. 205. Each serai stage in the forest-on-sand sere of northern Indiana has a characteristic 



factor complex. (After Strohecker. ) 



may be termed a biotope, habitat, habitat 

 niche, a microhabitat (Mohr, 1943), bio- 

 coenose, or community without in any way 

 doing violence to the realities of the situa- 

 tion. This microcosm is an integral part of 

 the relatively independent prairie com- 

 munity, it obviously cannot exist without 

 the presence of cattle (or their equiva- 

 lents), and passes through a minor succes- 

 sion endine in the formation of a light- 



pings as a consequence of the relative 

 brevity of the serai process. 



Cattle droppings (p. 472), in their last 

 serai stage, eventually lose their identity 

 and become a homogeneous part of the 

 pasture community. Mohr (1943) has given 

 ihe name microsere for such a serai se- 

 quence, and considers that the several 

 definable stages are microseral stages. 



This is one of many available examples 



