Common and multiple ice-age refugia in two southern beeches (Nothofagus spp.).

AZPILICUETA, M.M.; MARCHELLI, P.; GALLO, L.

Brisbane, Australia.

Congreso; XXII IUFRO World Congress; 2005

IUFRO

The current distribution area of southern South America Temperate Forests was highly affected during Quaternary ages by glacial movement and climatic changes. Multiple ice-free areas, both in Coastal and Andes regions, where species survived were suggested in several recent single-specific studies. Assuming a common life history, joint analysis of two inter-fertile important species of these forests, Nothofagus nervosa and N.obliqua, was carried out. Chloroplast DNA genetic markers were analysed in 26 and 25 populations respectively through a PCR-RFLP technique (trnD-trnT/TaqI and trnF-trnV/TaqI). Six haplotypes were observed, three of them common for both species, with a coincident geographic distribution. A differentiation between Andes and Coastal Mountains was evident and higher haplotype diversity was detected in the coast. The two most frequent haplotypes had a north-south distribution pattern in the Andes. Intrapopulation variation was only detected in three populations of N.nervosa, east of the Andes. These results indicates the existence of at least four common ice age refugia where both species survived the glacial period. Coastal regions could have been a location for two of such refugia, being the other two located east or west of the Andes region.