Abstract

The location of glacial refugia of tree taxa in Patagonia is determined primarily using data from the fossil pollen record. These data suggest that cold-tolerant conifers such as Fitzroya cupressoides probably survived the Last Glacial Maximum in coastal areas of southern Chile, where vegetation types corresponded to those currently found at relatively high altitudes in the Chilean Coastal Range. Much of this region is thought to have been covered by ice. However, the question remains whether F. cupressoides could have persisted locally in ice-free areas within the Central Depression of Chile. In this area, the species has been almost eliminated by human activities that have occurred since the l6th century. Geographic patterns of isozyme variation within 21 populations of F. cupressoides indicated that lowland populations showed high within-population isozyme variation. In addition, lowland populations were clearly differentiated genetically from those on the coast or in the Andes. These results strongly suggest that populations of F. cupressoides persisted in the Central Depression throughout glacial times. This implies that ice caps in the south-western Andes were probably not continuous, but, instead, the existence of ice-free areas in lowland valleys allowed the local survival of cold-temperate woody taxa.