Title Genetic diversity and fitness in Scabiosa columbaria in the Swiss Jura in relation to population size
Author/s Andrea R. Pluess, Jürg Stöcklin
Year 2004
Journal Conservation Genetics 5:145-156
DOI 0.1023/B:COGE.0000029999.10808.c2
Publisher The original publication is available at www.springerlink.com.
Abstract Due to changes in land use, remnants of unfertilised, nutrient-poor calcareous grassland in the Swiss Jura are small in area and are highly fragmented. We selected 89 seed families from eleven populations of various sizes of Scabiosa columbaria for a study of molecular diversity, and used the same material in a greenhouse experiment to measure variation in fitness-related traits and the ability of populations to cope with competition. Using RAPD-PCR we detected 71 RAPD-phenotypes among 87 genotypes. Molecular variation within populations was variable and relatively high, with an expected heterozygosity He ranging from 0.09 to 0.24. He, the Shannon index (SI) and the percentage of polymorphic bands were not correlated with population size, but the smallest populations had the lowest molecular variation (He, SI). Population differentiation was moderate with 12 % of the molecular variation among populations. Measures of fitness in the greenhouse differed among seed families (p < 0.001), but not among populations. Mean above-ground biomass was largely reduced when plants had to compete with Bromus. Mean fitness of populations decreased when molecular variation (He) was low, but only when plants had to compete with Bromus (p = 0.02). Accordingly, the relative competition ability of Scabiosa plants decreased when molecular variation (He) was low (p = 0.01). Our results suggest an increased risk of local extinction of Scabiosa columbaria in the Swiss Jura caused by a decreased viability and reduced phenotypic plasticity due to genetic erosion in small populations.
Keywords competition ability · conservation · genetic erosion · molecular variation · population differentiation
Research project Global Change and the Genetic Structure of Grassland Species
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