Research across waters and forests
Karr’s work encompasses stream ecology, watershed management, ornithology, tropical forests, landscape ecology and environmental policy. He worked at the University of Washington and is listed among the School of Aquatic and Fishery Sciences’ emeritus faculty.
Assessing fish communities in 1981
His 1981 paper proposed assessing biotic integrity through a series of fish-community attributes, including species composition and ecological structure. Rather than examining only whether a particular fish survives, the approach considers the community; the paper’s preliminary trials reflected the condition of both fishes and their supporting environment.
References: [2]
Beyond contaminant measurements
The paper identified altered watershed hydrology, modified habitat and changing energy sources alongside contaminants as influences on fishes. Chemical measurements therefore cannot substitute for assessing living systems. Karr’s index of biotic integrity brought community condition into aquatic assessment.
Ecological condition and management
Karr also helped clarify biological integrity in relation to the restoration and maintenance goals of the U.S. Clean Water Act. A 2004 University of Washington account documented the application of these approaches in aquatic-management programmes.
References: [1]