INTRODUCTORY. 11 



A few remarks concerning the character of the field work, upon which 

 the ecological reports have been based, will be of interest and also indicate 

 the general bearing of such work. The aim of the present expedition was 

 not directed primarily along the lines usually followed by natural history 

 surveys. The aim was to secure ecological facts and relations concerning 

 the' plants and animals of the regions visited. In order to accomplish this, 

 it was necessary not only to collect specimens but also to make observa- 

 tions concerning the relation of plants and animals to their environment. 

 Mr. Ruthven was therefore instructed to run lines of survey across the 

 region examined, in such a way as to include examples of all of the repre- 

 sentative habitats or environments. These habitats were then to be examined 

 in as much detail as time permitted. There is nothing unique in this method 

 of selecting special localities, but in the detailed study of these various 

 habitats special attention was given to the relations of the biota* to its environ- 

 ment. In this study attention was directed particularly to the forces and 

 conditions composing the environment, in order that the dominant forces 

 might be clearly recognized. This involved a careful analysis of the con- 

 ditions, as it is only by such means that the laws of change can be recognized, 

 and the dynamics of the habitat be understood. In this way, the habitat 

 can be studied from the standpoint of processes rather than from that of 

 the end result or effects of such forces, for it is very evident that if the habi- 

 tats are to be understood it must be by a study of their laws of change. 



Somewhat similar methods have been applied to special problems by a 

 few plant ecologists, notably Cowles and his students, from whom many 

 suggestions have been received, but such methods have not been applied 

 to the study of both the plants and animals, and their interrelations, for any 

 region. In the detailed application of this standpoint to the study of habitats, 

 with its method of description in terms of processes, this report (Ruthven's 

 section) is believed to be unique. That the ideal of interpretation, dynami- 

 cally considered, has not been realized in the present ecological studies, 

 will not be surprising to any one who understands the dynamic relations of 

 ideals, or to one who has ever tried to depart from the customary static 

 methods of working in order to think in terms of processes dynamically. 



As this method of thinking is not generally understood, it is occasionally 

 applied in such a crude and general sense that its bearing can not be grasped 

 when applied to special or concrete problems. There can be no question 

 as to the general validity of this method, but what is now needed is to know 

 how these processes are combined and related to produce particular environ- 

 mental conditions or situations. It seems a very simple matter to give 

 assent to the idea of the law of change, yet in its practical application this 

 simplicity often vanishes at once when it is seen that it involves the re- 

 lation of cause and effect. The organic environment is very complex and 

 the ecologist, like the geologist has very frequently to deal with a complex 

 of causes. But to be able even to refer a change to such a complex 

 is often a distinct advance, as this involves a recognition of a problem 

 requiring analysis, which is a further advance. 



That these difficulties are not confined to the ecologist alone, but are 

 obstacles which arise in any attempt as scientific interpretation, is worthy 

 of special notice. We are thus able to see why certain naturalists apparently 

 not recognizing or understanding the developmental processes which scien- 

 tific, ideas undergo, nor being acquainted with the tendencies of interpreta- 

 tion", dynamically considered, now making such rapid headway in ecological 



*Biota "the total of animal or plan* life of a given region or period." Stejneger. 



