@misc{PlathHermannSchroederetal.2010,
  author    = {Plath, Martin and Hermann, Bernd and Schr{\"o}der, Christine and Riesch, R{\"u}diger and Tobler, Michael and Garc{\´i}a de Le{\´o}n, Francisco J. and Schlupp, Ingo and Tiedemann, Ralph},
  title     = {Locally adapted fish populations maintain small-scale genetic differentiation despite perturbation by a catastrophic flood event},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-48599},
  year      = {2010},
  abstract  = {Background: Local adaptation to divergent environmental conditions can promote population genetic differentiation even in the absence of geographic barriers and hence, lead to speciation. Perturbations by catastrophic events, however, can distort such parapatric ecological speciation processes. Here, we asked whether an exceptionally strong flood led to homogenization of gene pools among locally adapted populations of the Atlantic molly (Poecilia mexicana, Poeciliidae) in the Cueva del Azufre system in southern Mexico, where two strong environmental selection factors (darkness within caves and/or presence of toxic H2S in sulfidic springs) drive the diversification of P. mexicana. Nine nuclear microsatellites as well as heritable female life history traits (both as a proxy for quantitative genetics and for trait divergence) were used as markers to compare genetic differentiation, genetic diversity, and especially population mixing (immigration and emigration) before and after the flood. Results: Habitat type (i.e., non-sulfidic surface, sulfidic surface, or sulfidic cave), but not geographic distance was the major predictor of genetic differentiation. Before and after the flood, each habitat type harbored a genetically distinct population. Only a weak signal of individual dislocation among ecologically divergent habitat types was uncovered (with the exception of slightly increased dislocation from the Cueva del Azufre into the sulfidic creek, El Azufre). By contrast, several lines of evidence are indicative of increased flood-induced dislocation within the same habitat type, e.g., between different cave chambers of the Cueva del Azufre. Conclusions: The virtual absence of individual dislocation among ecologically different habitat types indicates strong natural selection against migrants. Thus, our current study exemplifies that ecological speciation in this and other systems, in which extreme environmental factors drive speciation, may be little affected by temporary perturbations, as adaptations to physico-chemical stressors may directly affect the survival probability in divergent habitat types.},
  language  = {en}
}
@article{ToblerSchluppHeubeletal.2006,
  author    = {Tobler, Michael and Schlupp, Ingo and Heubel, Katja U. and Riesch, Rudiger and Garcia de Leon, Francisco J. and Giere, Olav and Plath, Martin},
  title     = {Life on the edge: hydrogen sulfide and the fish communities of a Mexican cave and surrounding waters},
  series = {Extremophiles : life under extreme conditions},
  volume    = {10},
  journal   = {Extremophiles : life under extreme conditions},
  publisher = {Springer},
  address   = {Tokyo},
  issn      = {1431-0651},
  doi       = {10.1007/s00792-006-0531-2},
  pages     = {577 -- 585},
  year      = {2006},
  abstract  = {Most eucaryotic organisms classified as living in an extreme habitat are invertebrates. Here we report of a fish living in a Mexican cave (Cueva del Azufre) that is rich in highly toxic H2S. We compared the water chemistry and fish communities of the cave and several nearby surface streams. Our study revealed high concentrations of H2S in the cave and its outflow (El Azufre). The concentrations of H2S reach more than 300 mu M inside the cave, which are acutely toxic for most fishes. In both sulfidic habitats, the diversity of fishes was heavily reduced, and Poecilia mexicana was the dominant species indicating that the presence of H2S has an all-or-none effect, permitting only few species to survive in sulfidic habitats. Compared to habitats without H2S, P. mexicana from the cave and the outflow have a significantly lower body condition. Although there are microhabitats with varying concentrations of H2S within the cave, we could not find a higher fish density in areas with lower concentrations of H2S. We discuss that P. mexicana is one of the few extremophile vertebrates. Our study supports the idea that extreme habitats lead to an impoverished species diversity.},
  language  = {en}
}