Resource managers are often challenged by the lack of adequate benchmarks, or reference conditions, for assessing the biological condition of streams. Increasing human alteration of landscapes reduces the availability of minimally-disturbed stream sites that can be used to represent a reference condition in regional assessments. Historical data offer an alternative point of reference for gauging the relative deviation of current conditions from an established minimally-disturbed condition and can thereby contribute to better-informed management decisions within the context of present-day land uses and range of attainable conditions. This collection of over 150 annotated references represents a significant portion of the literature that reports historical conditions and changes due to human impacts that have occurred since European settlement relevant to fish, aquatic insects, amphibians, and physical habitat. Its intent is to provide sources of information for those involved in historical reconstructions of stream conditions. Key references providing the most comprehensive syntheses at basin or regional scales in the western United States were selected for the bibliography. Bibliographic subsections are tailored toward EPA's Environmental Monitoring and Assessment Program (EMAP), although the information should be useful in a wide range of environmental assessments and restorations that address basin- or regional-scale stream conditions.

"EPA/600/R-06/163." "December 2006." "Contract EP-D-06-013." "Work Assignment Contracting Officer Representative: Paul Ringold."