Abstract Detail

Systematics Section

Flatscher, Ruth [1], Sonnleitner, Michaela [2], Escobar Garcia, Pedro [3], Hülber, Karl [4], Schoenswetter, Peter [5], Schneeweiss, Gerald M. [6].

Polyploid speciation in Senecio carniolicus Willd. (Asteraceae)- Cytogeography, morphological and ecological differentiation among and within cytotypes.

Over the last few decades, the importance of polyploidy as a driving force in angiosperm evolution and as a causal factor for speciation and diversification events has been increasingly acknowledged. Despite the strong interest in this phenomenon and a large number of cytological and cytogeographical studies emerging every year, comprehensive and synthetic approaches studying various aspects of polyploid complexes are still necessary to unravel the patterns and processes underlying polyploid speciation. One of the shortcomings in polyploid research is the scarcity of experimental field studies concerning habitat segregation, competitive and reproductive behaviour of different cytotypes.
Our model study system, the European alpine endemic herb Senecio carniolicus Willd. (Asteraceae), has recently been identified as a polyploid complex with three main ploidy levels (di-, tetra- and hexaploids). Within its distribution range spanning the siliceous areas of the Eastern Alps and the Carpathians, cytotypes show a clearly non-random distribution pattern which is most likely shaped by range shifts due to varying extent of glaciation during the Pleistocene. Molecular genetics as well as ecological and morphological investigations indicate a substantial degree of differentiation among the main ploidy levels. The rarity of intermediate or odd cytotypes (c. 1%) suggests the presence of strong crossing barriers resulting in almost complete reproductive isolation. Thus, the three main cytotypes of S. carniolicus are in an advanced stage of a polyploid speciation process and already function as independent biological species with separate evolutionary histories.

Broader Impacts:

1 - University of Vienna, Department of Biogeography, Rennweg 14, Vienna, 1030, Austria
2 - University of Vienna, Department of Biogeography, 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 Conservation Biology, Vegetation- and Landscape Ecology, Rennweg 14, Vienna, Vienna, A-1030, Austria
5 - University of Innsbruck, Department of Systematics, Palynology and Geobotany, Institute of Botany, Sternwartestrasse 15, Innsbruck, A-6020, Austria
6 - University of Vienna, Department of Biogeography, Rennweg 14, Vienna, A-1030, Austria

Keywords:
Asteraceae
autopolyploidy
cytogeography
habitat segregation
Morphometrics
polyploid evolution
Senecio carniolicus
reproductive isolation
Speciation.

Presentation Type: Oral Paper:Papers for Sections
Session: 38
Location: 555A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 1:15 PM
Number: 38002
Abstract ID:313