Phylogeographical analyses of Patagonian terrestrial gastropods as a tool for understanding regional late Quaterary glacial dynamics

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The evolution of the Patagonian ice fields since the Last Glacial Maximum (LGM) is not only of interest in respect of palaeoclimate research, as these are presently the largest outside the polar regions, but also with regard to the peopling of the southern cone of South America. Although existing data indicate that the western extension of the ice sheets during LGM was somehow off shore, there is some evidence that it was not as homogeneous as generally believed. It is possible that ice free areas along the western edge existed, possibly quite deeply indented into the LGM ice sheets. On the one hand, these areas could have been used by people migrating by boats as far south as the Land of Fire, and on the other hand represented refugia for certain organisms. This hypothesis shall be tested by a new approach using molecular markers including AFLP fingerprinting on narrow-range and low mobility terrestrial gastropods being extant along the southern Chilean Pacific coast. With this approach, it can be shown whether certain gastropod populations sustained during the LGM or if they migrated to their modern habitats after the ice had retreated. The data to be obtained will be evaluated in the context of bio-geographical and palaeoenvironmental investigations. The combined approach to be applied here will be further developed in order to receive higher spatial and temporal resolutions.