from the leadership of government agencies. The effectiveness of that legislation is diminished because regulations to enforce it often compromise legislative goals (Greider, 1992; Karr, 1990).

Underfunding--the chronic complaint from all bureaucracies and scientists--is not, however, the most important problem. Failure to set a clear societal goal and develop a comprehensive assessment and planning effort to accomplish that goal is unacceptable. Too often, as in the implementation of the Clean Water Act, a least-cost option to reduce water discharge is selected on the basis of available technology, a political need for equity, and narrow medium-specific goals. Environmental protection should emphasize the need to minimize insults to the total environment--land, water, and atmosphere. We can no longer afford to implement the Clean Water Act as if crystal-clear, distilled water running down concrete conduits were the objective.


The quantitative expectations that constitute biological integrity vary geographically. Criteria developed for chemical contaminants have been applied uniformly for diverse water bodies. But the idea that the same chemical criteria should apply to all waters is ludicrous, for the underlying physical and chemical properties of streams vary regionally. Evolutionary and biogeographic variation are key components of biological integrity.


Because biological systems are complex, multiple components of biology should be protected. Measurement of all components is logistically impossible. Thus, we must define a reasonable set of biological attributes that reliably track biological condition. Extensive experience in aquatic and terrestrial systems suggests that four key biological features should be tracked: species richness, species composition, individual health, and trophic (food web) structure. Collectively, these attributes detect (1) changes in species, including the identity and number of species present in the regional biota (elements); (2) ecological processes such as nutrient dynamics and energy flow through food webs; and (3) health of individuals, which is likely to influence demographic processes.

Several approaches have been developed in the past decade to integrate complex biological data. The development of a multimetric approach (multiple biological attributes are evaluated to assess resource condition) for use in freshwater streams in the United States (Fausch et al., 1984; Karr, 1981, 1991; Karr et al., 1986) stimulated researchers and agency staff to adopt a similar method in water resource evaluations over a wider geographic area (Crumby et al., 1990; Deegan et al., 1993; Fausch and Schrader, 1987; Hughes and Gammon, 1987; Leonard and Orth, 1986; Lyons, 1992; Oberdorff and Hughes, 1992; Steedman, 1988) and with a variety of taxa (Kerans and Karr, 1994; Ohio EPA, 1988; Plafkin et al., 1989).

The multimetric approach works because it recognizes biology as fundamentally important, selects only biologically meaningful and reliable measures, and is easy to communicate to policymakers and citizens. The multimetric approach

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