such as species composition and community metabolism. This has prompted a search 

 for adequate, simple, physical-chemical measurements that chronicle biological 

 events.'*^ 



Laboratory testing of potentially harmful substances under standardized condi- 

 tions is another frequently used tool of assessment. Mount and Gillett present the 

 "state-of-the-art" in single species to.xicity testing, and note the developing concern 

 for communities as opposed to single important species. The failings of the single 

 species approach are well known. 20 For example, acute toxicity effects have been 

 emphasized, yet these are of limited value in predicting effects of chronic exposure. 

 Guidelines proposed for use of bioassays in determining safe levels of potential 

 toxicants bear little known relationship to the largely unknown consequences of 

 introduction into natural environments. 2' 



Other assessment tools include the determination of major controlling variables in 

 an attempt to increase predictability. Commonly used variables include percentage 

 available sunlight, precipitation, and temperature. Given these variables and hypoth- 

 eses about the way they affect the system of interest, conceptual'''^: a^id mathe- 

 matical'^''*'" models may be developed to provide predictive power based on the 

 present state of knowledge. In this section. Patten uses a marine ecosystem model to 

 illustrate the importance of indirect as opposed to direct causality factors, and 

 Holling discusses methods and procedures of adaptive environmental assessment 

 and management (AEAM). The latter was developed to integrate disciplines and to 

 bridge gaps between experts and policy designers. Stalnaker reports that research 

 and development relevant to instream flow assessment during the 1970s were 

 primarily directed at physical microhabitat models used to evaluate usability of a 

 resource under different streamflow regimes. Although the "systems approach" is not 

 the "only way to achieve necessary refinements enabling precision and deftness in the 

 attack on environmental problems" (Patten), it nonetheless represents a means of 

 analysis that can be of value when used within its limitations.-*'-' 



Classification is an important assessment tool for dealing with the vastly different 

 ecosystems that occur throughout the United States. Some classifications are made 

 according to uses of populations or ecosystems, and thus provide little basis for 

 management. Classifications, such as Bailey's-^ ecoregions, attempt to define and 

 order hierarchical "ecosystems" in ways useful for understanding and management. 

 Franklin's-' classification for establishing biological reserves and Warren's^" for 

 classification of watersheds and stream systems are in the latter tradition. 



The tools we now have may not be adequate to do the task before us — which is not 

 so much to control the environment as to arrive at enough understanding of basic 

 ecological processes and cycles that proposed steps can be seen and evaluated in light 

 of their impact on ecosystems. Concerted effort is required to ensure that the 

 thoughtful, thorough, and conscientious use of assessment tools be coupled with the 

 wisdom of experienced persons, and that we remain open and receptive to potentially 

 improved methods of analysis. Solutions to fish and wildlife problems need to be 

 based on recognition that environmental management requires not only the 

 information made available through the scientific method, but economic, social, and 

 ethical judgments as well. ^''^2 



TRENDS IN ASSESSMENT AND PREDICTION OF EFFECTS OF 



MAN-MADE IMPACTS ON FISH AND WILDLIFE 



Progress during the 1970s in assessment and prediction of man-made impacts on 

 fish and wildlife might be illustrated by major studies. Analysis of relevant case 

 histories alone, however, would neglect almost entirely many efforts that have not yet 

 come to fruition. Changes in attitudes, perception, and awareness have emerged and 

 developed, in part, from national commitment to environmental protection. The 

 following discussion of trends in assessment and prediction of man-made impacts on 

 fish and wildlife represents some of the predominant changes. 



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