Landscape genetics and ecological niche modeling: tools for the biogeographic reconstruction, restoration, and conservation of woody species from Yungas and Austral Temperate forest

PREMOLI, A.C.; ARBETMAN, M.; KITZBERGER, T.; MATHIASEN, P.; QUIROGA, MP.; C.P. SOUTO

Aguas de Lindoia

Congreso; 57º Congreso Brasileiro de Genética; 2011

Current landscapes result from physical factors of the environments and species? interactions and ecological attributes. Changing climates produce range shifts which in turn affect genetic patterns within species. Although the fossil record is used to reconstruct biogeographic history, for many taxa is either incomplete or fossils of species of interest are morphologically undistinguishable from others with contrasting ecological traits. For such cases, molecular markers may contribute to elucidate spatial structure, understand past history, and predict future scenarios. This is reinforced by the use of ecological niche modeling (ENM) that provides an independent proxy to track species? distributions under distinct climates. The main goal was to combine molecular markers (isozymes, microsatellites, and DNA sequences of the chloroplast) and ENM to test biogeographic scenarios of widespread trees with contrasting ecological attributes endemic to southern South America. We analyze the hypothesis that cold-tolerant species were able to locally survive the ice eras while warm-loving trees became locally extinct and recolonized after ice receded. Cold-tolerant taxa were the montane subtropical Podocarpus parlatorei and the cold-temperate Nothofagus pumilio whereas cold-sensitive species was Austrocedrus chilensis inhabiting warm temperate forests. ENM of cold-hardy species yielded a more widespread and continuous range during ice ages in the subtropics and survival in multiple locations in temperate areas as far as in Tierra del Fuego. As a result, southern (i.e. historically colder) locations were either more or similarly genetically diverse than northern populations. In contrast, ENM of the warm-loving species endemic of Patagonia yielded increased suitability and genetic diversity in northern (i.e. historically warmer) areas which strongly suggests recent long distance dispersal towards the south. These results show that long-lasting persistance of cold-tolerant taxa has preserved genetic diversity which should be considered in conservation actions. In addition, genetic structure along dispersal routes of cold-sensitive trees may guide restoration actions.