Title Glacial history and local adaptation explain differentiation in phenotypic traits in the Alpine grassland herb Campanula barbata
Author/s Scheepens JF, Stöcklin J
Year 2011
Journal Plant Ecology and Diversity 4:403-413
Abstract Background: Quaternary glaciations have affected the phylogeographic structure of many widespread plant species of the European Alps. Survival of plants in isolated refugia on the fringes of the Alps has been proposed as a main driver for molecular differentiation within species across the Alps, and could also be responsible for phenotypic differentiation.
Aims: To establish if phenotypic differentiation is in accordance with phylogeographic structure and if population differentiation reflects adaptive processes. Methods: In a common garden we measured vegetative and reproductive traits of plants from 15 populations of two phylogeographic lineages of Campanula barbata from subalpine grasslands across the Alps.
Results: The two phylogeographic lineages were differentiated in plant height and number of inflorescences, suggesting that glacial history affected phenotypic differentiation, either through neutral processes or adaptation. Furthermore, negative correlations of number of leaves, plant height, number of flowers and above-ground biomass with altitude of population origin indicated that part of the observed differentiation among populations was due to adaptation to current altitude-related conditions either during or after recolonisation.
Conclusions: Our results suggest that phenotypic differentiation across the investigated regions may be due to glacial history-related processes as well as due to more recent processes of local adaptation.
Keywords altitude; common garden; European Alps; genetic drift; phylogeography
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