Past and future patterns of freshwater mussel extinctions in North America during the Holocene
Humans have had profound impacts on the ecology of North America both before and since colonization by Europeans. Modern-day human impacts extend to nearly every type of habitat, but evidence for pre-Columbian human impacts is limited almost exclusively to terrestrial ecosystems. In pre-Columbian times, human activities, especially burning and agriculture, transformed significant areas of North America (Delcourt and Delcourt 2004; Mann . 2005; see also Chapter 11 in this volume) and, in some cases, even short-term, small-scale agriculture resulted in persistent ecosystem changes (Briggs et al. 2006). The linkage between current-day landuse practices and freshwater ecosystem integrity is clear and central to some of the most pressing contemporary conservation issues (e.g. Diaz and Rosenberg 1995; Malakoff 1998), but this linkage has not been shown widely for pre-Columbian human land use. Recent studies in the Americas and Europe have shown that prehistoric Holocene human activities, including low-intensity agriculture, caused long-lasting and sometimes drastic changes in productivity, faunal composition, and water chemistry of small lakes and ponds (Douglas et al. 2004; Ekdahl et al. 2004; Miettinen et al. 2005).