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

• Published in: Journal of Biogeography
• Main Authors: Lagostina, Elisa, Andreev, Mikhail, Dal Grande, Francesco, Grewe, Felix, Lorenz, Aline, Lumbsch, H. Thorsten, Rozzi, Ricardo, Ruprecht, Ulrike, Sancho, Leopoldo García, Søchting, Ulrik, Scur, Mayara, Wirtz, Nora, Printzen, Christian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2021
• Subjects: Ecology; Ecology, Evolution, Behavior and Systematics; Antarctic; Drake Passage; The Antarctic; Antarc*; Antarctica; Usnea antarctica
• Online Access: http://dx.doi.org/10.1111/jbi.14101; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jbi.14101; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/jbi.14101

Abstract Aim The homogenisation of historically isolated gene pools has been recognised as one of the most serious conservation problems in the Antarctic. Lichens are the dominant components of terrestrial biotas in the Antarctic and in high mountain ranges of southern South America. We study the effects of dispersal strategy and migration history on their genetic structure to better understand the importance of these processes and their interplay in shaping population structure as well as their relevance for conservation. Location Maritime Antarctic and southern South America. Methods Populations of three fruticose lichen species, Usnea aurantiacoatra , U. antarctica and Cetraria aculeata , were collected in different localities in the Maritime Antarctic and southern South America. Usnea aurantiacoatra reproduces sexually by ascospores, whereas the other two species mostly disperse asexually by symbiotic diaspores. Samples were genotyped at 8–22 microsatellite loci. Different diversity and variance metrics, Bayesian cluster analyses and Discriminant Analysis of Principal Components (DAPC) were used to study population genetic structure. Historical migration patterns between southern South America and the Antarctic were investigated for U. aurantiacoatra and C. aculeata by approximate Bayesian computation (ABC). Results The two vegetative species display lower levels of genetic diversity than U. aurantiacoatra . Antarctic populations of C. aculeata and South American populations of U. aurantiacoatra display much stronger genetic differentiation than their respective counterparts on the opposite side of the Drake Passage. Usnea antarctica was not found in South America but shows comparably low levels of genetic differentiation in Antarctica as those revealed for U. aurantiacoatra . Phylogeographic histories of lichens in the region differ strongly with recent colonisation in some instances and potential in situ persistence during Last Glacial Maximum (LGM) in others. Patterns of genetic diversity indicate the ...