title: Drivers of genetic differentiation in a generalist insect-pollinated herb across spatial scales.
abstract: The isolation-by-distance model (IBD) predicts that genetic differentiation among populations increases with geographic distance. Yet, empirical studies show that a variety of ecological, topographic and historical factors may override the effect of geographic distance on genetic variation. This may particularly apply to species with narrow but highly heterogeneous distribution ranges, such as those occurring along elevational gradients. Using nine SSR markers, we study the genetic differentiation of the montane pollination-generalist herb, Erysimum mediohispanicum. Because the effects of any given factor may depend on the geographic scale considered, we investigate the contribution of different environmental and historical factors at three different spatial scales. We evaluate five competing models that put forward the role of geographic distance, local environmental factors [biotic interactions (IBEb) and climatic variables (IBEa)], landscape resistance (IBR) and phylogeographic patterns (IBP), respectively. We find significant IBD regardless of the spatial scale and the genetic distance estimator considered. However, IBEa and IBP also play a prominent role in shaping genetic differentiation patterns at the larger spatial scales, and IBR is significant at the fine spatial scale. Overall, our results highlight the importance of combining different estimators, statistical approaches and spatial scales to disentangle the relative importance of the various ecological factors contributing to the shaping of genetic divergence patterns in natural populations.
authors.affiliation: Plant Biology, CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Laboratório Associado, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal.|Departamento de Genética, Universidad de Granada, Granada, Spain.
authors.forename: A J
authors.initials: AJ
authors.lastname: Muñoz-Pajares
authors.affiliation: Plant Biology, CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Laboratório Associado, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal.
authors.forename: C
authors.initials: C
authors.lastname: García
authors.affiliation: Departamento de Genética, Universidad de Granada, Granada, Spain.|Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK.
authors.forename: M
authors.initials: M
authors.lastname: Abdelaziz
authors.affiliation: CREAF (Centre de Recerca Ecològica i Aplicacions Forestals), Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Bosch
authors.affiliation: Departamento de Genética, Universidad de Granada, Granada, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Perfectti
authors.affiliation: Departamento de Ecología, Universidad de Granada, Granada, Spain.|Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Aridas (EEZACSIC), Almería, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Gómez
mesh_terms: D000818:Animals; D019607:Brassicaceae / Q000235:genetics* / Q000502:physiology; D040961:Genetic Drift; D014644:Genetic Variation; D005828:Genetics, Population; D007313:Insecta; D058974:Phylogeography; D054817:Pollination; D062206:Spatial Analysis
keywords: genetic structure; isolation by distance; landscape genetics; plant-pollinator interactions; spatial scale