Divergent and narrower climatic niches characterize polyploid species of European primroses inPrimulasect.Aleuritia

Abstract

AbstractAimIt is hypothesized that the ecological niches of polyploids should be both distinct and broader than those of diploids – characteristics that might have allowed the successful colonization of open habitats by polyploids during the Pleistocene glacial cycles. Here, we test these hypotheses by quantifying and comparing the ecological niches and niche breadths of a group of European primroses.LocationEurope.MethodsWe gathered georeferenced data of four related species inPrimulasect.Aleuritiaat different ploidy levels (diploid, tetraploid, hexaploid and octoploid) and used seven bioclimatic variables to quantify niche overlap between species by applying a series of univariate and multivariate analyses combined with modelling techniques. We also employed permutation‐based tests to evaluate niche similarity between the four species. Niche breadth for each species was evaluated both in the multivariate environmental space and in geographical space.ResultsThe four species differed significantly from each other in mono‐dimensional comparisons of climatological variables and occupied distinct habitats in the multi‐dimensional environmental space. The majority of the permutation‐based tests either indicated that the four species differed significantly in their habitat preferences and ecological niches or did not support significant niche similarity. Furthermore, our results revealed narrower niche breadths and geographical ranges in species ofP. sect.Aleuritiaat higher ploidy levels.Main conclusionsThe detected ecological differentiation between the four species ofP. sect.Aleuritiaat different ploidy levels is consistent with the hypothesis that polyploids occupy distinct ecological niches that differ from those of their diploid relative. Contrary to expectations, we find that polyploid species ofP. sect.Aleuritiaoccupy narrower environmental and geographical spaces than their diploid relative. These results on the ecological niches of closely related polyploid and diploid species highlight factors that potentially contribute to the evolution and distribution of polyploid species.