FIELD STUDY 47 



Every one soon tires of any subject unless new 

 features are constantly being discovered. 



In the description of the associations in any given 

 habitat, the problem is much simplified if one has a 

 clear idea of dominance, knows how to recognize 

 it, and understands some of its main implications. 

 The dominant forms are the most common and power- 

 ful individuals in the association. They may or 

 may not be the most conspicuous, from a super- 

 ficial view. Conspicuousness may depend upon 

 size, but dominance refers to large absolute numbers 

 and to influence exerted. We may profitably com- 

 pare an association of animals in a given habitat to a 

 play upon the stage. The environment corresponds 

 to the stage. The dominant members of the asso- 

 ciation correspond to the leading characters, the 

 secondary species, always present, to the essential 

 but subordinate characters. The individual animals 

 adjust themselves to one another, especially to the 

 dominant forms, and to the environment, as the 

 personalities in the play adjust themselves to the 

 dominant characters, to one another, and to the en- 

 vironment. In both groups some individuals are 

 dominant, some used and useful, some are tolerated, 

 others pick up the crumbs, still others are predatory 

 or parasitic, and all must be mutually adjusted to 

 one another and to the environment. 



The number of dominant species within an asso- 

 ciation is relatively limited, a fact which holds for 

 both plants and animals. A knowledge of per- 

 haps 200 or 300 species of animals (and 150 plants) 



