Ecosystems Analysis 



Fundamentally, the ecosystems diagram functions as an analytical tool to 

 predict and evaluate impacts. The preceding descriptive analysis of the 

 components, flows, and regulating factors in each ecosystem is the basis for 

 ecosystems diagrams (see Use of Ecosystems Diagrams, Chapter 3). The diagrams 

 are visualizations of the ecological dynamics of each system, expressed in 

 energy circuit language. Energy is the common connecting link between system 

 components. The diagrammatic visualization of the ecosystems is not intended 

 to be inclusive of all details, subtleties, or complexities of any of the 

 systems. It is used with the previously described primary ecological altera- 

 tions in systematically analyzing changes in ecological attributes resulting 

 from development activities. 



The operational aspects of ESD analysis divide into four major stages: 

 (1) establishment of an analytical framework, (2) entering the ecosystems 

 diagram with primary ecological alterations, (3) analysis of environmental 

 alterations, and (4) synthesis of resulting impacts. 



The analytical framework stage consists of establishing those ground 

 rules and assumptions which guide the analysis. The ecosystems diagrams used 

 are qualitative models which require operational rules in order to ensure 

 analytical consistency at points lacking quantitative data. Important consid- 

 erations include the following: 



1. Establishment of working definitions and points of difference for 

 items such as activity site, ecological community, ecosystem, etc. 



2. Establishment of a temporal framework; i.e., definition of short- 

 term and long-term effects and their points of reference 



3. Establishment of a spatial framework; i.e., what are the relative 

 sizes of the site and the community? Site and ecosystem? How large 

 is the ecosystem? 



4. Determination of analytical objectives; i.e., should the analysis 

 detect any and all changes? Detect only changes relevant to biota? 



5. Determination of critical ecosystem components which may be espe- 

 cially sensitive to particular developmental aspects; what/where are 

 these critical components? 



6. Establishment of general "significance levels," given the site 

 characteristics, development type and size, and the points considered 

 above 



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