CLASSIFICATION SYSTEMS FOR 



HABITAT AND ECOSYSTEMS 



Robert G. Bailey 



During the 1930s, the federal land management agencies began to inventory and 

 study a broad range of individual natural resources and plan for their development.' 

 By the late 1950s, it was apparent that looking at individual resources by themselves 

 was too limited. One thing that was lacking was a uniform and integrated 

 classification system. At the same time, land managers became more acutely aware of 

 the integrated nature of the landscape and its resources. It was also confirmed that of 

 these resources, wildlife is an integral component. 



Past wildlife studies and inventories have proceeded without the benefit of an 

 integrated system. Biologists often had to depend on any available, sometimes 

 inadequate, information or devise their own habitat" classification, usually a map 

 featuring forest cover. Many investigators gathered disconnected bits of descriptive 

 information on habitat without a classification framework to give them meaning. 

 Without such a framework, it was very difficult and sometimes impossible to 

 integrate wildlife information with other information for evaluating trade-offs or 

 interactions within the wildlife and fish resource and between it and other natural 

 resources. As of 1970, there was no national approach to integrating wildlife 

 information. A new tool was needed to help biologists do their jobs better. 



In the early 1970s, new federal legislation such as the Resources Planning Act, with 

 regulations and executive orders, required greatly increased consideration of 

 environmental consequences of natural resources management. This development 

 generated concerted efforts by various federal agencies'to develop a comprehensive 

 classification of land. These efforts have encountered a number of difficulties. The 

 greatest lies in formulating a common base for the many prospective users. Certain 

 land attributes must be included for some users, but these attributes may be of 

 marginal interest to other users. For example, according to Thomas, animal habitat 

 is the arrangement of food, cover, and water required to meet the biological needs of 

 one or more individuals of a species.^ Habitat classification, based on an analysis of 

 these needs, has long been a basic tool of wildlife and fisheries management. Because 

 different species rarely have the same needs, the classification of a land area for one 

 species must often be revised for another. The result is likely to be that the pattern of 

 units will differ for each species considered. 



This approach does not satisfy the needs for integrated information about the land 

 and its wildlife resources. Interactions among species as well as between wildlife and 

 other resource outputs for the same unit of land must be considered if environmental 



The Author: Robert G. Bailey is geographer. Resources Evaluation Techniques Program, USDA Forest 

 Service, Rocky Mountain Forest and Range Experiment Station. Fort Collins, Colorado 80526. He holds a 

 PhD degree in geography from the University of California, Los Angeles, and has authored several 

 publications in the field of ecological land classification. 



"Throughout this paper, the term "habitat" is used generally to denote both wildlife and fish. The term 

 "wildlife information" denotes both population and habitat. 



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