Wildlife Encounters by Lewis and Clark: A Spatial Analysis of Interactions between Native Americans and Wildlife

H reference conditions are often used as a baseline for comparison with current and future natural resource management regimes (Aronson et al. 1995). There may be much debate about which point in time, what area, and what spatial extent should be used as a reference condition (Wagner et al. 2000), but understanding the past is undeniably important to the proper management of present and future ecosystem conditions. First-hand explorer journals offer one way to assess the past. The journals of Lewis and Clark’s 1804–1806 expedition provide the earliest and most detailed written descriptions of a large part of the United States before Euro-American settlement, as well as geographic coordinates of daily campsites. Human influence on North American ecosystems before European settlement has to be considered, because indigenous peoples brought about changes to the environment long before the arrival of the first Europeans. Native people used fire, modified vegetation, and influenced animal populations, with the result that North America was not a pristine wilderness (White and Cronon 1998). It is well known that Lewis and Clark found an abundance of wildlife in the Plains but encountered little game in parts of the Rocky Mountains and the Columbia Basin, where they often had to rely on dogs and horses for sustenance (Cutright 1969, Ronda 1984). On the basis of those observations, we hypothesized that predation attributable to humans was at least in part responsible for the observed wildlife distribution and abundance. This hypothesis leads to the prediction that wildlife would be more abundant farther from human settlements. In this article, we assess the role of humans and other underlying causes for the observed wildlife distribution and abundance along the Lewis and Clark trail.