Hierarchical subdivisions of the Columbia Plateau and Blue Mountains ecoregions, Oregon and Washington.

Abstract

This document presents two spatial scales of a hierarchical, ecoregional framework and provides a connection to both larger and smaller scale ecological classifications. The two spatial scales are subregions (1:250,000) and landscape-level ecoregions (1:100,000), or Level IV and Level V ecoregions. Level IV ecoregions were developed by the Environmental Protection Agency because the resolution of national-scale ecoregions provided insufficient detail to meet the needs of state agencies for establishing biocriteria, reference sites, and attainability goals for water-quality regulation. For this project, two ecoregions—the Columbia Plateau and the Blue Mountains—were subdivided into more detailed Level IV ecoregions. Similarly, the finer scale landscape-level ecoregions (Level V) were developed to address local land management issues. The landscape-level ecoregions for northeast Oregon and southeast Washington were created specifically to address the issue of anadromous fish habitat. Their delineation, however, employed landscape information similar to that used in other levels of the ecoregion hierarchy, thereby indicating the potential for general application of these regions to both terrestrial and aquatic research questions. The study area for the landscape-level ecoregions was defined by contiguous watersheds within the ecoregions of the Columbia Plateau and Blue Mountains to merge the ecoregional information with units corresponding to fish distribution.

Citation

Clarke, Sharon E.; Bryce, Sandra A., eds. 1997. Hierarchical subdivisions of the Columbia Plateau and Blue Mountains ecoregions, Oregon and Washington. Gen. Tech. Rep. PNW-GTR-395. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 114 p