Figure 2. Diagrammatic representation of potential interrelationships between 

 species in two communities : (a) a complex community with a large number 

 of stabilizing interactions, and (b) a simple community with relatively few 

 stabilizing interactions.^ 



practical considerations, numerous aesthetic and ethical concerns, including obliga- 

 tions to future generations and respect for the integrity of the biosphere, are 

 compelling reasons for protecting animals and their habitats. 



METHODS OF ASSESSMENT AND PREDICTION 



The suitability of available habitat for fish and wildlife, and possible impacts on 

 this habitat need to be assessed in order to predict the effects of potential changes in 

 the resource, whether it is altered or left alone. The ability to manage fish and wildlife 

 resources is generally no better than the tools at hand for assessment and prediction 

 of environmental conditions and organismic responses to these conditions. Uni- 

 formity of both approaches to and methods of system-specific assessment and 

 prediction is essential, particularly in studies of a long-term nature. 



Legislation can be used to protect and preserve natural resources. This past decade 

 witnessed the birth and development of perhaps today's most widely used tool — the 

 environmental impact assessment process (EIA). Although NEPA does not include 

 specific guidelines for environmental impact statement (EIS) preparation or for 

 public involvement in the process, various federal agencies have developed broad 

 criteria and proposed approaches for public participation. Impact statements serve 

 as guidelines for making decisions by presenting a report of the present and predicted 

 future state of the environment as it might be affected by proposed actions.'" 

 Development, use, and evaluation of the process have been reviewed in detail. 1 1,12, 13,14, is 



Species diversity indices are often included in environmental impact analyses, and 

 are used as a management tool in their own right. Species lists are useful in describing 

 the status of an ecosystem,'* but uncritical use of numerical indices assumes too much 

 resolution. The systematics of many groups of organisms remains inadequate for 

 effective use of various species composition indices. In addition, recognition of 

 unnaturally altered ecosystem behavior is obscured by significant natural spatial and 

 temporal variations in biotic communities. Peet,'^ in a comprehensive review of 

 diversity indices, indicates that many indices are but special cases of more 

 encompassing formulations, and suggests that diversity is essentially defined by the 

 indices used to measure it. Various environmental indices are widely used.'* 

 Assessment procedures frequently involve lengthy and costly biological analyses 



60 



