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(550) The small end of "scale": dealing with individuals.
Turner, Larry*,1, 1 U. S. Environmental Protection Agency, Washington, DC, U.S.A.
ABSTRACT- Experimental science historically adopted a reductionist approach to remove extraneous variables and to be able to make cause-effect conclusions. Yet in biology it appeared that when considering an individual, the whole was arguably more than the sum of its parts. With the development of ecology, it became apparent that populations, then communities, then ecosystems all had characteristics beyond the individual or other level of organization. Holistic approaches were needed to address the differing factors inherent to each organizational criterion. In recent years, the development of analytical tools such as geographic information systems and the use of remotely sensed data have markedly enhanced the ability of scientists to look at broader spatial scales while retaining information on some elements of finer detail. But individuals still matter, as in the case of endangered species. Indeed, some endangered species are in such a precarious position that the typical characteristics of populations and communities are nonexistent or highly skewed. And, from a legal perspective, all individuals of an endangered species are worthy of consideration. To protect individuals, it is necessary to know what are the primary factors affecting these individuals. Using watersheds as study boundaries can tell us much about the various, usually multiple, stressors that might be impacting populations or individuals. But in many cases, the presumably holistic watershed unit cannot identify or may not even contain the one or two major stressors that may need most to be controlled to protect and recover an endangered species. It may require a more focused, reductionist approach to identify the primary stressor on a species, or even on a population, since some species may have sub-populations subject to rather different stressors in different geographic regions. These theoretical issues will be addressed with respect to the very real need to formulate and apply actions necessary for the protection of individuals of listed endangered and threatened species.
Key words: endangered species, multiple stressors
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