How cold-sensitive species endure ice ages? Phylogeographic and paleodistribution models of postglacial range expansion of the mesothermic drought tolerant conifer Austrocedrus chilensis

SOUTO, C.; KITZBERGER, T.; ARBETMAN, M.; PREMOLI, A.C.

NEW PHYTOLOGIST

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 208 p. 960 - 972

0028-646X

In view of global climate change, it is important to understand the responses of tree speciesto climate changes in the past. Combinations of phylogeographic analysis of genetic evidence,coupled with species distribution models (SDMs), are improving our understanding on thissubject. We combined SDMs and microsatellite data from populations of the entire range ofAustrocedrus chilensis, a dominant mesotherm (cold-sensitive) conifer of dryland forests ofthe southern Andes, to test the hypothesis of long-distance postglacial migration from northernand warmer refugia at the Last Glacial Maximum (LGM). The SDM indicated suitable conditions for Austrocedrus in northern Chile (western) at theLGM and largely unsuitable conditions in Argentina (eastern). Population genetic diversityand effective population sizes within populations decreased southward along the Andes, consistentwith the hypothesis of long-distance dispersal from a northern refugium. Results support the hypothesis of one (or a few) warmer (low latitude) refugia in Chile forAustrocedrus. On balance, the evidence suggests that in contrast to cold-tolerant tree taxawith the capacity to fast-track postglacial warming thanks to local refugia, cold-sensitive speciesmight have undergone long-distance range expansion, lagging behind progressive climatechange throughout the Holocene.