By the middle Holocene, Native American groups developed semi-sedentary villages in the Columbia River basin of the Pacific Northwest. The economic basis for these villages is thought to have been predicated on the acquisition of bulk food resources, such as salmon and camas, for delayed consumption during the winter. In Idaho's lower Salmon River canyon, semi-sedentary pit house villages are absent until after 2000 14C yr BP. Floodplain geochronology shows channel incision and terrace formation occurred at ca. 2000 14C yr BP, caused by fluvial response to neotectonic displacement along a normal fault. The delayed appearance of pit house sites and other markers of the Winter Village Pattern in the canyon is argued to be directly related to neotectonically-induced changes in fluvial conditions after 2000 14C yr BP, which significantly improved aquatic habitats for anadromous fishes and led to the development of a predictable, productive salmon fishery.
Fire catalyzed rapid ecological change in lowland coniferous forests of the Pacific Northwest over the past 14,000 years