under a Creative Commons License. Climate of the Past Predicting Pleistocene climate from vegetation in North America

Abstract. Climates at the Last Glacial Maximum have been inferred from fossil pollen assemblages, but these inferred climates are colder for eastern North America than those pro-duced by climate simulations. It has been suggested that low CO2 levels could account for this discrepancy. In this study biogeographic evidence is used to test the CO2 effect model. The recolonization of glaciated zones in eastern North Amer-ica following the last ice age produced distinct biogeographic patterns. It has been assumed that a wide zone south of the ice was tundra or boreal parkland (Boreal-Parkland Zone or BPZ), which would have been recolonized from southern refugia as the ice melted, but the patterns in this zone dif-fer from those in the glaciated zone, which creates a major biogeographic anomaly. In the glacial zone, there are few en-demics but in the BPZ there are many across multiple taxa