HISTORICAL DEVELOPMENT OF THE CONCEPT 13 



Beklemischev (1931). This investigator has discussed the applica- 

 tion of the concepts of bio-ecology to the animal members of the com- 

 munity, with emphasis upon the importance of cycles, succession, and 

 climax. He considers abundance, dominance, frequence, homogeneity, 

 and constancy in relation to animals, defining dominance in terms of 

 comparative abundance, by contrast to the concept employed in the 

 present treatise (cf. p. 234). He distinguishes periodic from non- 

 periodic changes, recognizing daily, annual, and pluriennial cycles, 

 corresponding more or less exactly to diurnation, aspection, annuation, 

 etc. The progressive nature of succession is recognized and the signifi- 

 cance of stabilization perceived for animals as well as plants. Finally, 

 he accepts the view of developmental ecology, namely, that the climax 

 as a living complex includes all its several developmental stages 

 (seres) as essential to its development. Probably no other Conti- 

 nental ecologist has manifested such a clear perception of the funda- 

 mental relations of the biotic community. 



In a second paper, Beklemischev, Briukhanova and Shipitzina 

 (1931) have summarized the results of studies on the marshes about 

 Magnitogorsk in the Urals, on the basis of the coactions of the organ- 

 isms in the development from water to land (hydrosere) . 



The Biotic Formation in Water 



For a number of reasons, it is more difficult to trace the applica- 

 tion of the biotic concept in water than on land. The uncertainty 

 attaching to ]Mobius's use of the term biocenose continues through 

 much of the work of the limnologists, though by some it is definitely 

 limited to the animal community alone (Petersen, 1913; Gajl, 1927). 

 The general dominance of animals in certain types of fresh water and 

 in the sea, coupled with the minuteness of the phytoplankton, furnishes 

 a ready explanation of this. On the other hand, the biotic nature of 

 the plankton and its greater definiteness as a layer often carry the 

 inference of a biotic community when this was not intended. INIore- 

 over, the extensive study of food coactions in the sea especially 

 has in some cases given the impression of biotic unity when no com- 

 munities were recognized or named. 



The definite limits of the lake in particular have accorded it an 

 obvious unity, both in terms of habitat and community, rarely to be 

 found in any other area. To a certain extent this has long been 

 recognized, but it was perhaps first clearly expressed by Forbes, in 

 referring to the lake as a microcosm. This view has been emphasized 

 by the limnologists, especially Thienemann, Reswoy and AVerestchagin, 

 who consider the lake as a whole to be an organic entity or organism. 

 With tliem this concept seems to have been a more or less independent 

 development, and it suffers from a lack of acquaintance with the 

 similar concept in vegetation, i.e., the complex organism, which antici- 

 pated it by twenty years. In passing, it may be pointed out that to 

 include the habitat in the community obliterates the essential dis- 

 tinctions between the living and non-living, and carries synthesis to 

 the extreme where its very purpose is defeated. 



