When ecological marginality is not geographically peripheral: exploring genetic predictions of the centre-periphery hypothesis in the endemic plant Lilium pomponium

作者：Gabriele Casazza, Carmelo Macrì, Davide Dagnino, María Guerrina, Marianick Juin, Luigi Minuto, John D. Thompson, Alex Baumel, Frédéric Mèdail · 发表于：PeerJ · 年份：2021 · DOI：10.7717/peerj.11039 · 被引用次数：13 · 研究领域：Genetic diversity and population structure、Plant and animal studies、Animal Behavior and Reproduction

BACKGROUND: Quantifying variation of genetic traits over the geographical range of species is crucial for understanding the factors driving their range dynamics. The center-periphery hypothesis postulates, and many studies support, the idea that genetic diversity decreases and genetic differentiation increases toward the geographical periphery due to population isolation. The effects of environmental marginality on genetic variation has however received much less attention. METHODS: in the southern Alps. RESULTS: We found little evidence for concordance between genetic variation and both geographical and environmental gradients. Although the prediction of increased differentiation at range limits is met, genetic diversity does not decrease towards the geographical periphery. Increased differentiation among peripheral populations, that are not ecologically marginal, may be explained by a decrease in habitat availability that reduces population connectivity. In contrast, a decrease of genetic diversity along environmental but not geographical gradients may be due to the presence of low quality habitats in the different parts of the range of a species that reduce effective population size or increase environmental constraints. As a result, environmental factors may affect population dynamics irrespective of distance from the geographical center of the range. In such situations of discordance between geographical and environmental gradients, the predictions of decreasing genetic ...