Many environmental impact analyses, including those pursuant to the
National Environmental Policy Act of 1969, as amended, do not identify the
spatial and temporal scales used in the analysis. Without definition of
analytical scales, the reader is left to infer scale, which could confound
decision making when different readers infer different scales of analysis.
For ecological analysis, site-specific spatial and temporal scales based on
unique natural features and phenomena are most appropriate, given the
inability of ecological resources to restrict themselves according to
political boundaries or arbitrary time lines. Definition of scale in the
environmental impact document allows the reader or decision maker to
consider the impacts in the intended context. Scales of ecological analysis
should be based on ecological principles as applied to a specific study area
and the ecological resources that may be affected by the proposed action or
activity. The multiscalar concept of biological connectivity should be
addressed in spatial and temporal analysis, which inherently includes
cross-scale considerations such as those for potential effects on
metapopulations. Definition of spatial and temporal scales is critical to
bound the impact analysis and to inform readers and decision makers, and
suggested guidelines are provided as an example of an acceptable method.
Although several different scales could be correctly chosen, analysts should
identify and define spatial and temporal scales used to promote consistent
interpretations of results and to facilitate the decision-making
process.
Environmental Practice 16: 281–286 (2014)