Universität Tübingen
Classification of taxonomic units for biology and conservation in the cases of Lathyrus pannonicus and Oxytropis pilosa - Evaluation of morphological and phytosociological studies integrating molecular genetic data
Abstract
In order to conserve biodiversity and develop taxon-specific conservation measures it is important to define and identify taxonomic units, which require protection. In this thesis, the differentiation processes in two species of the Fabaceae, the Hungarian Pea Lathyrus pannonicus (Jacq.) Garcke and the Wolly Milkvetch Oxytropis pilosa DC., are investigated using a combination of phytosociological surveys (using the Braun-Blanquet method) and molecular sequence data, and a set of analyses which include entirely novel approaches. Both species are relict species and elements of the Pontian-Pannonian floristic province. In the case of the generally more variable Lathyrus pannonicus correlations are found between ecological, morphological and genetic inter-stand distances. Mean Ellenberg indicator values calculated for stands (based on the Braun-Blanquet relevés) allowed to characterise the ecological properties of members of all subspecies, and to conclude that the genetic differentiation found in L. pannonicus is closely linked to Ellenberg’s moisture figure “F”. Lathyrus pannonicus and its subspecies fall into two major lineages in Europe: (1) a dry-adapted lineage (subspecies collinus, suevicus, and varius) thriving in habitats with mean “F” values of < 4, and (2) a moist-preferring lineage (subspecies asphodeloides, longestipulatus, pannonicus, and the intermediate Rovere type) occurring in habitats with mean “F” values of > 4. Oxytropis pilosa is genetically less variable than Lathyrus pannonicus, which corresponds to its highly conserved morphology and ecology. Nevertheless, two major genetic variants are present. Using non-hierarchical clustering it is shown that this intra-specific variation in O. pilosa is as high or higher than inter-species divergence in other subclades of the Astragalus/Oxytropis genus complex. The two main genetic types reflect geographic differentiation. Pure and mixed populations are found, all of which ought to be protected to maintain current levels of biodiversity. The results of the plant phytosociological and genetic analyses of both target species are discussed in the context of conservation strategies: rather than maintaining mere high numbers of (currently accepted or proposed) species, it is important to select and preserve the populations, which provide the genetic resources within a species. The importance of taxon-specific conservation means is highlighted, and a recommendation is given how to preserve biodiversity.
Author and committee
dc:creator, dc:contributor.*- Author
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- Schlee, Matthias
Identifiers
dc:identifier.*- Identifier
- hdl:10900/64170