Molecular Ecology and Evolution
Sonnleitner, Michaela , Hülber, Karl , Escobar Garcia, Pedro , Schneeweiss, Gerald M. , Schoenswetter, Peter .
Polyploid evolution and ecological segregation of cytotypes in the Alpine plant Senecio carniolicus (Asteraceae).
Senecio carniolicus (Asteraceae) is a frequent species of acidophilic alpine meadows occurring in the Eastern Alps and the Carpathians. Although the taxon was previously believed to be uniformly hexaploid, in the Eastern Alps diploid, tetraploid and hexaploid cytotypes were encountered. Cytotype mixture is frequent, with diploids and hexaploid individuals co-occurring most frequently. I will summarise published and unpublished results and present a new project exploring origin and maintenance of intrapopulational cytotype mixture in S. carniolicus following two complementary research avenues. First, origin and evolutionary relationships among different cytotypes are investigated in both space and time using a phylogenetic and phylogeographic approach mainly based on DNA sequence data. Second, mechanisms for maintenance of the cytotype mixture are explored with respect to the potential role of several pre- and postzygotic isolation mechanisms. Investigation of an altitudinal gradient on a mountain slope where di- and hexaploids co-occurred, suggested a narrow altitudinal range of the hexaploid cytotype in the low-alpine belt and a much wider range of the diploid one, spanning both low-alpine and high alpine zones. Focussing on ecological segregation and spatial autocorrelation of di- and hexaploids within a c. 20 x 60 m plot with varied micro-topography revealed that ecological factors that are correlated with micro-topography are strongly predicting the occurrence of either cytotype. The taller-growing hexaploids were restricted to fairly dense alpine grassland vegetation with presumed long snow-cover, whereas the low-growing diploids were only occurring in open habitats on a wind-blown ridge.
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1 - University of Vienna, Department of Biogeography, Rennweg 14, Vienna, Vienna, A-1030, Austria
2 - University of Vienna, Department of Conservation Biology, Vegetation- and Landscape Ecology, Rennweg 14, Vienna, Vienna, A-1030, Austria
3 - Universitry of Vienna, Department of Biogeography, Rennweg 14, Vienna, Vienna, A-1030, Austria
4 - University of Vienna, Department of Biogeography, Rennweg 14, Vienna, A-1030, Austria
Presentation Type: Oral Paper:Papers for Topics
Location: Maybird/Cliff Lodge - Level C
Date: Tuesday, July 28th, 2009
Time: 8:00 AM