@article{LauterbachRistowGemeinholzer2012,
  author    = {Lauterbach, Daniel and Ristow, Michael and Gemeinholzer, Birgit},
  title     = {Population genetics and fitness in fragmented populations of the dioecious and endangered Silene otites (Caryophyllaceae)},
  series = {Plant systematics and evolution},
  volume    = {298},
  journal   = {Plant systematics and evolution},
  number    = {1},
  publisher = {Springer},
  address   = {Wien},
  issn      = {0378-2697},
  doi       = {10.1007/s00606-011-0533-0},
  pages     = {155 -- 164},
  year      = {2012},
  abstract  = {Population fragmentation is often correlated with loss of genetic diversity and reduced fitness. Obligate out-crossing (dioecy) is expected to enhance genetic diversity, reduce genetic differentiation, and avoid inbreeding depression through frequent gene flow. However, in highly fragmented populations dioecy has only diminishing effects upon genetic structure as pollination limitations (e.g. flight distance of pollinators) most often restrict inter-population gene flow in insect pollinated species. In fragmented dry grasslands in northeastern Germany, we analysed genetic structure, fitness, and habitat quality of the endangered dioecious Silene otites (Caryophyllaceae). Using AFLP markers, a high level of differentiation among ten populations was found (F (st) = 0.36), while the intra-population genetic diversities (H (E) = 0.165-0.240) were similar as compared to hermaphroditic species. There was neither a correlation between geographic and genetic distance nor between genetic diversity and population size, which indicates reduced gene flow among populations and random genetic drift. Plant size was positively correlated with genetic diversity. Seed set and number of juveniles were positively related to population size. Higher total coverage resulted in reduced plant fitness, and the number of juveniles was negatively correlated to cryptogam cover. Additionally, we found a sex ratio bias towards more male plants in larger populations. Overall, our results indicate that on a regional geographic scale dioecy does not necessarily prevent genetic erosion in the case of habitat fragmentation, especially in the absence of long distance seed and pollen dispersal capacity.},
  language  = {en}
}
@article{KlossFischerDurka2011,
  author    = {Kloss, Lena and Fischer, Markus and Durka, Walter},
  title     = {Land-use effects on genetic structure of a common grassland herb a matter of scale},
  series = {Basic and applied ecology : Journal of the Gesellschaft f{\"u}r {\"O}kologie},
  volume    = {12},
  journal   = {Basic and applied ecology : Journal of the Gesellschaft f{\"u}r {\"O}kologie},
  number    = {5},
  publisher = {Elsevier},
  address   = {Jena},
  issn      = {1439-1791},
  doi       = {10.1016/j.baae.2011.06.001},
  pages     = {440 -- 448},
  year      = {2011},
  abstract  = {The most common management practices in European grasslands are grazing by livestock and mowing for silage and hay. Grazing and mowing differ in their potential effects on plant gene flow and resulting population genetic structure. After assessing its breeding system, we investigated the effect of land use on the population genetic structure in the common grassland plant Veronica chamaedrys using 63 study populations on meadows, mown pastures and pastures in three regions in Germany, the so-called Biodiversity Exploratories. We determined plant density and analysed the genetic diversity, differentiation and small-scale genetic structure using amplified fragment length polymorphism (AFLP) markers. The breeding system of V chamaedrys turned out as self-incompatible and outcrossing. Its genetic diversity did not differ among land-use types. This may be attributed to large population sizes and the strong dispersal ability of the species, which maintains genetically diverse populations not prone to genetic drift. Genetic differentiation among populations was low (overall F(ST) = 0.075) but significant among the three regions. Land use had only weak effects on population differentiation in only one region. However, land use affected small-scale genetic structure suggesting that gene flow within plots was more restricted on meadows than on mown and unmown pastures. Our study shows that land use influences genetic structure mainly at the small scale within populations, despite high gene flow.},
  language  = {en}
}