NHI combined these efforts to create a wildlife habitat map that depicts historic (potential) conditions of the Columbia River Basin in the U.S. The result is a historic map that is a theoretical construct with a coarse (1-km square pixel size) level of resolution designed to give a regional perspective. This map can provide only initial approximations of the presence and distribution of wildlife habitat types within specific subbasins and watersheds because of the need for more detailed information at these levels. Specifically, wildlife-habitat types that are typically small or linear in size or shape (like riparian or herbaceous wetlands) would be under-represented in the Historic Condition Map.
Because of the limitations with the historic map, no validation of this map was done. We are unaware of any previously collected detailed information for all the subbasins and watersheds throughout the specific geographic areas of basin addressed in this project. Further, because there are no recognized historical data sets that would give such a basin perspective, validation would be difficult. Hence, the historic map best depicts gross generalizations of gains or loses of specific wildlife habitat types. Additionally, it can give a user an idea of what the potential may have existed within provinces and within larger subbasins.