03004nas a2200277   4500008004100000020001400041245012700055210006900182300001200251520209300263653003102356653003702387653002202424653001802446653001802464653001102482653002702493653002702520653002402547653002402571100002102595700002102616700002202637700002302659856004402682       2014                        eng d  a1365-269900aInfluence of climatic niche suitability and geographical overlap on hybridization patterns among southern Californian oaks0 aInfluence of climatic niche suitability and geographical overlap  an/a-n/a3 aAim Information on the association between geographical patterns of hybridization and the climatic niche requirements and co-occurrence of the species involved can provide important insights that further our understanding of the factors promoting the formation of hybrid zones. Here, we test whether climatic niche suitability explains patterns of hybridization beyond spatial overlap in distributions of the geographically restricted Engelmann oak (Quercus engelmannii) and the widespread scrub oak species complex (Quercus spp.). Location Southern California, USA. Methods We sampled Engelmann and scrub oaks across 31 localities and genotyped 343 individuals at nine microsatellite loci. We used climatic niche modelling to assess the suitability of habitats for each parental species and hybrids and to analyse whether climatic niche suitability in addition to co-occurrence are associated with observed spatial patterns of hybridization. Results Our data indicated that hybrid zones are located in areas that are geographically constrained by the presence of scattered patches of Engelmann oak within a matrix broadly occupied by scrub oaks. However, the climatic niche of hybrids differed from that occupied by both Engelmann and scrub oaks, suggesting the importance of climate on their establishment and persistence beyond the simple role of geographical overlap of parental species distributions. We also found that even moderate levels of introgression contributed to increased genetic diversity in Engelmann oak but not in scrub oaks. Main conclusions These results show that hybrid zones follow a mosaic pattern constrained by the presence of scattered patches occupied by Engelmann oak and climatically suitable areas that favour the establishment of hybrids. The low rates of ongoing hybridization and the bimodal distribution of parental genotypes found here suggest that hybridization is not threatening Engelmann oak and this phenomenon could instead be promoting the acquisition of favourable alleles that may increase the adaptive potential of this vulnerable species.10aEcological niche modelling10aextinction through hybridization10agenetic diversity10aHYBRIDIZATION10aintrogression10aMaxent10amicrosatellite markers10aperipheral populations10aQuercus engelmannii10asouthern California1 aOrtego, Joaquín1 aGugger, Paul, F.1 aRiordan, Erin, C.1 aSork, Victoria, L.  uhttps://quercus.myspecies.info/node/16602794nas a2200253   4500008004100000020001400041245012200055210006900177300001200246520196400258653001502222653002302237653003102260653001402291653002202305653002202327653002502349653003302374653002402407100002102431700002102452700002302473856004402496       2014                        eng d  a1365-269900aClimatically stable landscapes predict patterns of genetic structure and admixture in the Californian canyon live oak0 aClimatically stable landscapes predict patterns of genetic struc  an/a-n/a3 aAim We studied which factors shape contemporary patterns of genetic structure, diversity and admixture in the canyon live oak (Quercus chrysolepis). Specifically, we tested two alternative hypotheses: (1) that areas with high habitat suitability and stability since the Last Glacial Maximum (LGM) sustain higher effective population sizes, resulting in increased levels of genetic diversity; and (2) that populations from areas with lower habitat stability show higher levels of genetic admixture due to their recurrent colonization by individuals originating from genetically differentiated populations. Furthermore, we analysed the relative importance of past and current habitat suitability and their additive effects on contemporary patterns of genetic structure. Location California, USA. Methods We sampled 160 individuals from 33 localities across the distribution range of the canyon live oak in California and then combined information from 13 nuclear microsatellite DNA markers and climate niche modelling to study patterns of genetic variation in this species. We used Bayesian clustering analyses to analyse geographical patterns of genetic structure and admixture, and circuit theory to generate isolation-by-resistance (IBR) distance matrices. Results We found that the degree of genetic admixture was higher in localities with lower inferred population stability, but that genetic diversity was not associated with habitat suitability or stability. Landscape genetic analyses identified habitat stability as the primary driver of population genetic differentiation. Main conclusions This study shows that habitat stability can be a major factor shaping genetic variation in wind-pollinated trees and supports the idea that stable regions contribute to genetic connectivity across different climatic periods. To our knowledge, this study is the first to report an association between patterns of genetic admixture and stability of local habitat.10aCalifornia10aclimatic stability10aEcological niche modelling10agene flow10agenetic diversity10agenetic structure10ainterglacial refugia10apalaeodistribution modelling10aQuercus chrysolepis1 aOrtego, Joaquín1 aGugger, Paul, F.1 aSork, Victoria, L.  uhttps://quercus.myspecies.info/node/167