Effects of dispersal strategy and migration history on genetic diversity and population structure of Antarctic lichens

Aim The homogenisation of historically isolated gene pools has been recognised as one the most serious conservation problems in Antarctic. Lichens are dominant components terrestrial biotas Antarctic and high mountain ranges southern South America. We study effects dispersal strategy migration history on their genetic structure to better understand importance these processes interplay shaping population well relevance for conservation. Location Maritime Methods Populations three fruticose lichen species, Usnea aurantiacoatra, U. antarctica Cetraria aculeata, were collected different localities aurantiacoatra reproduces sexually by ascospores, whereas other two species mostly disperse asexually symbiotic diaspores. Samples genotyped at 8–22 microsatellite loci. Different diversity variance metrics, Bayesian cluster analyses Discriminant Analysis Principal Components (DAPC) used structure. Historical patterns between America investigated C. aculeata approximate computation (ABC). Results vegetative display lower levels than aurantiacoatra. populations American much stronger differentiation respective counterparts opposite side Drake Passage. was not found but shows comparably low Antarctica those revealed Phylogeographic histories lichens region differ strongly with recent colonisation some instances potential situ persistence during Last Glacial Maximum (LGM) others. Patterns indicate presence glacial refugia near Navarino Island (South America) Shetland Islands. ABC suggest that colonised from Patagonia after LGM. ambiguous, indicating a more complex expressed simplified scenarios. Main Conclusions Mode propagation affects diversity, location postglacial explains displayed each species. evidence survival both sides Passage aculeata. Maintaining strong requires strict measures, exposed risk due higher connectivity.