CHAPTER 7 

 CLIMAX AND SERE 



NATURE AND SIGNIFICANCE 



General Relations. Climax and sere have been the chief topics of 

 study in plant ecology but at the same time have received sufficient 

 attention in animal ecology to make their meaning clear. The present 

 treatment may well be limited to the expansion of the concepts as 

 demanded by bio-ecology. This involves the extension of the term to 

 the climatic plant-animal community and renders it synonymous with 

 the biotic formation (biome), as already indicated in Chapter 2. A 

 corollary of this is the inclusion of the biomes in the ocean, sluggish 

 rivers and larger lakes. As a consequence, it becomes necessary to 

 recognize hydroclimates in bodies of water (Huntsman, 1920; Was- 

 mund, 1934) and to establish comparisons between them and those on 

 land. 



Climax and Climate. Although the usual meaning of the word 

 climax is in harmony with its application to the adult or final stage 

 of community development or succession, its primary sense is more 

 significant of the concept involved here. It is derived from the same 

 root as climate, and hence this cognate relation is well adapted to 

 express the cause-and-effect bond between the two. As a consequence, 

 climax is peculiarly appropriate when it is desired to emphasize its 

 causal connection or ultimate nature, and biome when the idea of the 

 biotic community is uppermost. The basic principle that climaxes 

 constitute the most exact expression and hence the best indicators of 

 land climates appears susceptible of extension to the waters. The 

 nature of the aquatic climate is discussed in some detail in Chapter 9, 

 where the greater density of the essential medium, its circulation, 

 greater carrying power as compared with air, the floating organisms 

 and non-living suspended matter with their effect on light penetration, 

 etc., are considered. Wasmund (1934) has also discussed hydro- 

 climate and hydrometeorology in comparison with the corresponding 

 phenomena of the air. 



Life Forms. Though a biome may be composed of several different 

 life forms, its characteristic physiognomy is due mainly to a single 



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