12 NATURE AND RELATIONS OF BIO-ECOLOGY 



tigation of the deciduous forest worked by Weese, and for comparison 

 made studies of biotic communities of the pine-hemlock climax in 

 Maine, as well as those of the upper slopes of IMount Ktaadn, taking 

 the mammals and birds also into account. Smith (1928) utilized the 

 same forest, together with its developmental (serai) stages, while the 

 same author (Smith-Davidson, 1930, 1931) endeavored to evaluate 

 the influence of the various animal species, basing this principally 

 upon their abundance and the division into layers and seasonal groups. 

 Some attention was given to differences between the two years of 

 study, as well as to the characteristics of the climax animals. Blake 

 (1931) has instituted a comparison between the results obtained by 

 himself, Weese, and Smith, finding a good general agreement among 

 them, inasmuch as 36 species were important numerically or otherwise 

 in at least two of the lists. 



Shackleford (1929); Bird (1930). Shackleford made a study of 

 prairie similar to that of Bird but much farther south; she compared 

 the animal communities of the high and low prairies, treating the sea- 

 sonal aspects in detail. Bird investigated the biotic community of 

 the aspen parkland of western Manitoba in a comprehensive manner. 

 The animals have been dealt with in quantitative fashion, embracing 

 the determination of the food coactions and the evaluation of many 

 of the constituent species. 



Shelf ord and Olson (1935). The authors showed the close relation 

 of the coniferous forest animals to the plant constituents and evalu- 

 ated the mammals, birds, and a few invertebrates on the basis of size, 

 abundance, and movements through the climax and serai stages. This 

 study followed the senior author's (1932) suggestion that mammals 

 are usually the outstanding influents in communities of this type. 



Phillips (1930-1935). Phillips has made comprehensive applica- 

 tions of the concept of the biome in two regions in Africa, where biotic 

 communities possess an exceptional wealth of animal forms and still 

 retain much of their primeval character. This was first utilized in 

 the study of the Knysna forests of the Cape region, with especial 

 attention to the coactions of plants and animals in the community 

 proper and to their responses under experimental screens. Even more 

 extensive and important investigations were made on the East 

 African plateau in Tanganyika, where the biotic communities remain 

 essentially primitive. The general relations taken into account com- 

 prised grazing and browsing, fruit coactions, and soil reactions. The 

 biotic projects were focused upon the ecology of the tsetse fly (Glos- 

 sina), constituting altogether the most significant program of research 

 in this vast field. His several projects have led him to the conclusion 

 that the most logical working concept is that of the biotic community. 

 To him the view that the community is a complex organism has defi- 

 nite practical value. 



Recently, he has given a review of quantitative methods as applied 

 to the animals of the biome, with extensions derived from the re- 

 searches on the tsetse fly (1930), and he has further considered the 

 concept of the biotic community in a series of three critical papers 

 (1934-35). 



