260 APPLIED ECOLOGY 



including predators, as well as of game animals. Before white men 

 came to America the native plants and animals were getting along 

 together very nicely. There was a nice balance between the plants 

 and the animals that fed upon them, between hosts and parasites, 

 between predators and those preyed upon, which has been called the 

 balance of nature. It is known, however, that the balance of nature 

 is never a static thing but is always fluctuating. For each species of 

 animal there seem to be natural cycles involving maximum and 

 minimum numbers in any particular community. These cycles may 

 or may not coincide with climatic cycles. Their causes are not fully 

 understood and they offer a fertile field of investigation for the 

 wildlife conservationist. 



The purpose of wildlife conservation may differ in different biotic 

 communities. On farms the object may be to maintain a proper 

 cover and food supply to support normal numbers of the smaller 

 game animals. In larger communities, such as some of the national 

 forests, the object may be to produce maximum numbers of the 

 larger game animals primarily for the sport of hunting. In addition 

 to these and other purposes, it is necessary that some chunks of 

 wilderness areas be preserved in an unmodified condition in order 

 that the ecological relations of the plants and animals may be studied 

 in wholly natural habitats and that the millions of nature lovers of 

 the country may be able to enjoy unspoiled biotic communities. 

 Such areas are provided for in the national parks and monuments 

 where all species of native plants and animals are given full and 

 impartial protection. In all cases, however, success in the con- 

 servation of wildlife can come only if those charged with administer- 

 ing it have an adequate knowledge of the ecological relations of 



both plants and animals. 



REFERENCES 



Baker, O. E.: The Agriculture of the Great Plains Region, Ann. Assn. Am. 

 Geog., 13, 109-167, 1923. 



Bates, C. G. : The Forest Influence on Stream Flow Under Divergent Condi- 

 tions, Jour. For., 34, 961-969, 1936. 



BoERKER, R. H. : A Historical Study of Forest Ecology— Its Development in 

 the Field of Botany and Forestry, Forestry Quarterly, pp. 1-53, 1916. 



Some Fundamental Considerations in the Prosecution of Silvicultural 



Research, Jour. Forestry, 16, 792-806, 871-887, 1918. 



Bruner, W. E., and Weaver, J. E.: Size and Structure of Leaves of Cereals 

 in Relation to Climate: A Study in Crop Ecology, Univ. Studies, Univ. 

 Nebraska, 23, 163-200, 7 fig., 1923. 



Burgess, Paul S.: The Yield and Mineral Content of Crop Plants as Influ- 

 enced by Those Preceding, Rhode Island Agric. Exp. Sta. Bull, 198, 1-25, 

 1924. 



