causes, of questioning the applicability of a climax status to some 

 climax areas, especially if the investigator does not realize he is 

 dealing with a phasic cycle. The apparent lack of stability be- 

 tween individual phases may contribute to this opinion, especially 

 when a downgrade change is taking place and is prominent. 

 However, if the phasic cycle is analyzed as a whole in relation to 

 surrounding vegetation, the community will be found to fulfill 

 the criteria of the climax since the phasic cycle is operative within 

 the climax framework. If the upgrade phases, inclusive of the 

 most complex phase, are predominant in the area and give the 

 community its aspect, then the vegetation might be interpreted 

 as a successional stage. If, on the other hand, the downgrade 

 phases are predominant, the vegetation might be interpreted as 

 a retrogression stage. Either error is serious because it may lead 

 to the conclusion that a climax status is not applicable. 



The change from one cyclic phase to another phase is certainly 

 directional in detail, whether it is upgrade or downgrade, for 

 there is a change in the habitat, kinds of species, abundance, and 

 life-forms. However, considered as repetitive cycles, there is no 

 directional change. The cycle as a whole is within the limits of 

 the criteria of the steady-state, but a single phase may not meet 

 such criteria. A long-term study of the phasic cycle will reveal 

 that as a whole any over-all changes will take on the qualities of 

 a fluctuation change instead of the radical alterations which are 

 so prominent between two succeeding phases. The pattern of 

 microcommunities and populations is related to the pattern of 

 mesogradients and of microgradients of the habitat. It is just as 

 valid to consider phasic cycle changes and stages as inherent 

 processes and parts of the climax steady-state as it is to consider 

 the changes and stages following the death of an occasional tree 

 in the forest or the death of clumps of blue gramagrass {Bouteloua 

 gracilis) in a grassland climax as such. 



In the application of the climax concept, the alternation of 

 communities, or an intercommunity cyclic change, may present 

 more difficulty than microcommunity alternation or cyclic change 

 because of the apparent lack of stability of each phasic commu- 

 nity and of the cycle as a whole. The downgrade phase, especially, 



Habitat Pattermms, Chaztges, ax%«l Climax • 165 



