Vol. XXIII. July, I9 i2. No. 2. 



BIOLOGICAL BULLETIN 



ECOLOGICAL SUCCESSION. 



IV. VEGETATION AND THE CONTROL OF 

 LAND ANIMAL COMMUNITIES. 



VICTOR E. SHELFORD. 



PAGE. 

 I. Introduction 5Q 



II. Localities of Study 61 



III. Presentation of Data 65 



IV. Discussion of Data 72 



V. Causes of Succession or The Control of Animal Communities 73 



I. Materials for Abode and Food 73 



2- Soil 73 



3. Atmosphere 75 



(a) Temperature '. 76 



(6) Light 76 



(c) Combinations or Complexes of Factors 76 



(d) Evaporation in Forest Animal Habitats 79 



4. Influence of Physiography and Vegetation upon Animal Habitats. 82 



5. Stratifications of Condition 83 



6. Apparent Anomalous Distribution 84 



7. Agreement of Plant and Animal Communities 87 



VI. General Discussion 88 



VII. Summary 93 



VIII. Acknowledgments and Bibliography 94 



I. INTRODUCTION. 



In the preceding papers of this series, we have discussed the 

 succession of animals in two types of aquatic habitats with 

 particular reference to fish. While the data presented are 

 only a minor part of those at hand they have served to illus- 

 trate some of the principles of succession in aquatic habitats. 

 Discussion of other aquatic situations would enable us to point 

 out many more important facts but we must now pass to land 

 habitats. To illustrate principles here we might discuss the 

 development of either forest or prairie animal communities 



59 



