Potato cultivation in the Andean regions of Peru dates to at least the fifth millennium BC, based on evidence found at sites near Ayacucho, in the south-central Andes, as well as at various Peruvian coastal sites (Cowan and Watson 1992, p. 188). Further evidence that this region is within the potato's center of origin is supported by studies indicating a very high species richness of wild potatoes in northern to central Peru (in the contemporary departments of Ancash, southern Cajamarca, La Libertad and Lima), and an area in the Cusco Department of southern Peru (Hijmans and Spooner 2001). More recent research by David Spooner (2005) provides further evidence for a more specific site of origin in Peru, just north of Lake Titicaca.