title: Long-distance dispersal maximizes evolutionary potential during rapid geographic range expansion.
abstract: Conventional wisdom predicts that sequential founder events will cause genetic diversity to erode in species with expanding geographic ranges, limiting evolutionary potential at the range margin. Here, we show that invasive European starlings (Sturnus vulgaris) in South Africa preserve genetic diversity during range expansion, possibly as a result of frequent long-distance dispersal events. We further show that unfavourable environmental conditions trigger enhanced dispersal, as indicated by signatures of selection detected across the expanding range. This brings genetic variation to the expansion front, counterbalancing the cumulative effects of sequential founding events and optimizing standing genetic diversity and thus evolutionary potential at range margins during spread. Therefore, dispersal strategies should be highlighted as key determinants of the ecological and evolutionary performances of species in novel environments and in response to global environmental change.
authors.affiliation: Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
authors.forename: Cécile
authors.initials: C
authors.lastname: Berthouly-Salazar
authors.forename: Cang
authors.initials: C
authors.lastname: Hui
authors.forename: Tim M
authors.initials: TM
authors.lastname: Blackburn
authors.forename: Coline
authors.initials: C
authors.lastname: Gaboriaud
authors.forename: Berndt J
authors.initials: BJ
authors.lastname: van Rensburg
authors.forename: Bettine Jansen
authors.initials: BJ
authors.lastname: van Vuuren
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: Le Roux
mesh_terms: D063147:Animal Distribution; D000818:Animals; D005075:Biological Evolution; D004272:DNA, Mitochondrial / Q000235:genetics; D014644:Genetic Variation; D005828:Genetics, Population; D058865:Introduced Species; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D011157:Population Dynamics; D012641:Selection, Genetic; D013019:South Africa; D046749:Starlings / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial
keywords: genetic diversity; invasion; long-distance dispersal; range expansion; selection signature