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

PeerJ

article

Gabriele Casazza¹  Carmelo Macrì²  Davide Dagnino²  Maria Guerrina²  Marianick Juin¹  Luigi Minuto²  John D. Thompson³  Alex Baumel¹  Frédéric Médail¹ 

[1] Institut Méditerranéen de Biodiversité et d’Ecologie marine et continentale ,(IMBE), Aix Marseille Université, Avignon Université;Department for the Earth, Environment and Life Sciences ,(DISTAV), University of Genoa;CEFE

关键词: Genetic diversity;    Genetic differentiation;    Environmental gradient;    Geographic range;   

DOI  :  10.7717/peerj.11039

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

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 We tested the concordance between geographical and environmental gradients and the genetic predictions of center-periphery hypothesis for endemic Lilium pomponium 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 diversity and increasing differentiation toward the geographical periphery may not be respected.

【 授权许可】

CC BY