Southern isolation and northern long‐distance dispersal shaped the phylogeography of the widespread,but highly disjunct,European high mountain plant Artemisia eriantha (Asteraceae)

We investigated the range dynamics of Artemisia eriantha, a widespread, but rare, mountain plant with a highly disjunct distribution in the European Alpine System. We focused on testing the roles of vicariance and long‐distance dispersal in shaping the current distribution of the species. To this end, we collected AFLP and plastid DNA sequence data for 17 populations covering the entire distributional range of the species. Strong phylogeographical structure was found in both datasets. AFLP data suggested that almost all populations were genetically strongly differentiated, with 58% of the overall genetic variation partitioned among populations. Bayesian clustering identified five groups of populations: Balkans, Pyrenees, Central Apennines, one southwestern Alpine population and a Widespread cluster (eastern Pyrenees, Alps, Carpathians). Major groups were supported by neighbor‐joining and NeighbourNet analyses. Fourteen plastid haplotypes were found constituting five strongly distinct lineages: Alps plus Pyrenees, Apennines, Balkans, southern Carpathians, and a Widespread group (eastern Pyrenees, northern Carpathians, Mt. Olympus). Plastid DNA data suggested that A. eriantha colonized the European Alpine System in a westward direction. Although, in southern Europe, vicariant differentiation among the Iberian, Italian and Balkan Peninsulas predominated, thus highlighting their importance as glacial refugia for alpine species, in temperate mountain ranges, long‐distance dispersal prevailed. This study emphasizes that currently highly disjunct distributions can be shaped by both vicariance and long‐distance dispersal, although their relative importance may be geographically structured along, for instance, latitude, as in A. eriantha. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 214–226.     

Differentiation and speciation in mountain streams: a case study in the caddisfly Rhyacophila aquitanica (Trichoptera)

Few studies have analysed the biogeography of mountain aquatic organisms, although this habitat provides stable conditions in which many species survived Pleistocene climatic oscillations, usually in the geographical vicinity of their present distribution ranges. The mountain caddisfly Rhyacophila aquitanica was selected as a model organism for this habitat type. Morphological measurements of genitalia and external characters of male individuals were obtained from almost the entire range of distribution of the species. Morphometric results were analysed by cluster analysis and multivariate statistics. Important differences were discovered among three population groups of R. aquitanica inhabiting different European mountain ranges: (i) mountain ranges north‐west of the Alps (Massif Central, Vosges, Schwarzwald and Fribourg); (ii) the southern Alps (Lombardia and Carinthia); and (iii) the western part of the southern Carpathians. This divergence suggests a long‐term isolation among these groups, which presumably took place long before the last Pleistocene glaciation, with no secondary contact among these populations. The differentiation centres of the southern Alps and Carpathian groups may have been mostly homotopic to their actual ranges, whereas the western group must have been distributed in the areas west or north‐west of the Alps with secondary expansions and disjunctions.     

Effects of recent and past climatic shifts on the genetic structure of the high mountain Yellow‐spotted ringlet butterfly Erebia manto (Lepidoptera,Satyrinae): a conservation problem

Mountain species have evolved important genetic differentiation due to past climatic fluctuations. The genetic uniqueness of many of these lineages is now at risk due to global warming. Here, we analyse allozyme polymorphisms of 1306 individuals (36 populations) of the mountain butterfly Erebia manto and perform Species Distribution Models (SDMs). As a consensus of analyses, we obtained six most likely genetic clusters: (i) Pyrenees with Massif Central; (ii) Vosges; (iii–v) Alps including the Slovakian Carpathians; (vi) southern Carpathians. The Vosges population showed the strongest genetic split from all other populations, being almost as strong as the split between E. manto and its sister species Erebia eriphyle. The distinctiveness of the Pyrenees‐Massif Central group and of the southern Carpathians group from all other groups is also quite high. All three groups are assumed to have survived more than one full glacial–interglacial cycle close to their current distributions with up‐hill and down‐slope shifts conforming climatic conditions. In contrast with these well‐differentiated groups, the three groups present in the Alps and the Slovakian Carpathians show a much shallower genetic structure and thus also should be of a more recent origin. As predicted by our SDM projections, rising temperatures will strongly impact the distribution of E. manto. While the populations in the Alps are predicted to shrink, the survival of the three lineages present here should not be at risk. The situation of the three other lineages is quite different. All models predict the extinction of the Vosges lineage in the wake of global warming, and also the southern Carpathians and Pyrenees‐Massif Central lineages might be at high risk to disappear. Thus, albeit global warming will therefore be unlikely to threaten E. manto as a species, an important proportion of the species’ intraspecific differentiation and thus uniqueness might be lost.     

From connectivity to isolation: genetic consequences of population fragmentation in capercaillie across Europe

The capercaillie inhabits a continuous range in large parts of the Palearctic boreal forest, but is patchily distributed in temperate Europe. An ongoing population decline, largely related to human land use changes, has been most pronounced in central and western Europe, where some local populations have become extinct. In this study, we document the genetic differentiation of capercaillie populations at different stages along a gradient of spatial structuring from high connectivity (continuous range in the boreal forest) to a metapopulation systems (Alps) and recent (central Europe) and historic (Pyrenees) isolation. Four hundred and sixty individuals from 14 sample sites were genotyped at 10 polymorphic microsatellite loci to assess genetic structure and variation of capercaillie populations across its European range. As expected, differentiation was least pronounced within the continuous range in the boreal forest. Within the metapopulation system of the Alps, differentiation was less than among the isolated populations of central Europe (Black Forest, Fichtelgebirge, Thuringia, Vosges). In the long-isolated population of the Pyrenees, and the recently isolated populations of central Europe, genetic diversity was significantly reduced compared with the Alps and boreal forest. Our results agree with the concept of a gradual increase in genetic differentiation from connectivity to isolation, and from recent to historic isolation. Anthropogenic habitat deterioration and fragmentation thus not only leads to range contractions and extinctions, but may also have significant genetic and evolutionary consequences for surviving populations. To maintain high levels of genetic variation in species in fragmented habitats, conservation should aim at securing connectivity between spatially distinct populations.     

Species radiation in the Alps: multiple range shifts caused diversification in Ringlet butterflies in the European high mountains

The distributions of European high mountain species are often characterised by small and geographically isolated populations and, in many cases, have highly complex biogeographic histories. The butterfly genus Erebia represents one of the best examples for small-scale diversification in the European high mountain systems and therefore to understand speciation processes and associated range dynamics of high mountain species. In this study, we analysed 17 polymorphic allozyme loci of 1731 individuals from 49 populations representing four species, one of which has three subspecies: Erebia nivalis; Erebia tyndarus; Erebia ottomana; and Erebia cassioides cassioides, Erebia cassioides arvernensis, and Erebia cassioides neleus. Samples were collected in the high mountain systems of Europe (i.e. Pyrenees, Massif Central, Alps, Apennines, Carpathians, Balkan high mountains). Genetic analyses supported all previously accepted species. However, the genetic differentiation within E. cassioides sensu lato into three geographically delimited groups is justifying species rank: E. arvernensis distributed in the Pyrenees, Massif Central and western Alps; E. cassioides sensu stricto in the eastern Alps and Apennines; and E. neleus in the Balkan mountains and the south-western Carpathians. While the differentiation between western Alps and Massif Central as well as eastern Alps and Apennines was low, the Pyrenees as well as the south-western Carpathians were significantly differentiated from the other regions within the respective taxon. In general, the differentiation among the populations of E. neleus was stronger than between populations of the other taxa. Within E. cassioides, we found a west-east gradient of genetic similarity over the eastern Alps. Based on the obtained genetic structures, we are able to delineate glacial refugia and interglacial range modifications. Based on the genetic structures and genetic diversity patterns, we conclude that, triggered by the glacial-interglacial cycles, repeated range modifications have taken place with subsequent differentiation and speciation in the region of the Alps and Balkans. Colonisations to Pyrenees (E. arvernensis pseudomurina, E. arvernensis pseudocarmenta), Massif Central (E. ottomana tardenota, E. a. arvernensis) and Apennines (E. cassioides majellana) appear to be recent and most probably not older than the last interglacial period.     

Post-glacial history of the dominant alpine sedge Carex curvula in the European Alpine System inferred from nuclear and chloroplast markers

The alpine sedge Carex curvula ssp. curvula is a clonal, dominant graminoid found in the European Alps, the Carpathians, the Pyrenees and in some of the Balkan Mountains. It is a late-successional species of acidophilous alpine meadows that occurs on sites that were covered by ice during the last glacial maximum (LGM). By applying the amplified fragment length polymorphism (AFLP) fingerprinting and chloroplast DNA (cpDNA) sequencing, we attempted to identify the recolonization routes followed by the species after the last ice retreat. We relied on the genetic diversity of 37 populations covering the entire distributional range of the species. As a wind-pollinated species, C. curvula is characterized by a low level of population genetic differentiation. Nuclear and chloroplast data both support the hypothesis of a long-term separation of Eastern (Balkans and Carpathians) and Western (Alps and Pyrenees) lineages. In the Alps, a continuum of genetic depauperation from the east to the west may be related to a recolonization wave originating in the eastern-most parts of the chain, where the main glacial refugium was likely located. The Pyrenean populations are nested within the western Alps group and show a low level of genetic diversity, probably due to recent long-distance colonization. In contrast to the Alps, we found no phylogeographical structure in the Carpathians. The combination of reduced ice extension during the Würm period and the presence of large areas of siliceous substrate at suitable elevation suggest that in contrast to populations in the Alps, the species in the Carpathians underwent a local vertical migration rather than extinction and recolonization over long distance.     

Genetic structure of Hypochaeris uniflora (Asteraceae) suggests vicariance in the Carpathians and rapid post-glacial colonization of the Alps from an eastern Alpine refugium

Aim The range of the subalpine species Hypochaeris uniflora covers the Alps, Carpathians and Sudetes Mountains. Whilst the genetic structure and post‐glacial history of many high‐mountain plant taxa of the Alps is relatively well documented, the Carpathian populations have often been neglected in phylogeographical studies. The aim of the present study is to compare the genetic variation of the species in two major European mountain systems – the Alps and the Carpathians. Location Alps and Carpathians. Methods The genetic variation of 77 populations, each consisting of three plants, was studied using amplified fragment length polymorphism (AFLP). Results Neighbour joining and principal coordinate analyses revealed three well‐supported phylogeographical groups of populations corresponding to three disjunct geographical regions – the Alps and the western and south‐eastern Carpathians. Moreover, two further clusters could be distinguished within the latter mountain range, one consisting of populations from the eastern Carpathians and the second consisting of populations from the southern Carpathians. Populations from the Apuseni Mountains had an intermediate position between the eastern and southern Carpathians. The genetic clustering of populations into four groups was also supported by an analysis of molecular variance, which showed that most genetic variation (almost 46%) was found among these four groups. By far the highest within‐population variation was found in the eastern Carpathians, followed by populations from the southern and western Carpathians. Generally, the populations from the Alps were considerably less variable and displayed substantially fewer region‐diagnostic markers than those from the south‐eastern Carpathians. Although no clear geographical structure was found within the Alps, based on neighbour joining or principal coordinate analyses, some trends were obvious: populations from the easternmost part were genetically more variable and, together with those from the south‐western part, exhibited a higher proportion of rare AFLP fragments than populations in other areas. Moreover, the total number of AFLP fragments per population, the percentage of polymorphic loci and the proportion of rare AFLP fragments significantly decreased from east to west. Main conclusions Deep infraspecific phylogeographical gaps between the populations from the Alps and the western and south‐eastern Carpathians suggest the survival of H. uniflora in three separate refugia during the last glaciation. Our AFLP data provide molecular evidence for a long‐term geographical disjunction between the eastern and western Carpathians, previously suggested from the floristic composition at the end of 19th century. It is likely that Alpine populations survived the Last Glacial in the eastern part of the Alps, from where they rapidly colonized the rest of the Alps after the ice sheet retreated. Multiple founder effects may explain a gradual loss of genetic variation during westward colonization of the Alps.     

Phylogeography of a subalpine tall‐herb Ranunculus platanifolius (Ranunculaceae) reveals two main genetic lineages in the European mountains

A phylogeographical analysis of Ranunculus platanifolius, a typical European subalpine tall‐herb species, indicates the existence of two main genetic lineages based on amplified fragment length polymorphism (AFLP) markers. One group comprises populations from the Balkan Peninsula and the south‐eastern Carpathians and the other includes the remaining part of the range of the species, encompassing the western Carpathians, Sudetes, Alps, Pyrenees and Scandinavia. The main phylogeographical break observed in this species runs across the Carpathians and separates the main parts of this range (western and south‐eastern Carpathians), supporting a distinct glacial history of populations in these areas. The high genetic similarity of the Balkan Peninsula and south‐eastern Carpathian populations could indicate a common glacial refugium for these contemporarily isolated areas of species distribution. The western and northern part of the species range displays an additional weak differentiation into regional phylogeographical groups, which could have been shaped by isolation in glacial refugia or even by a postglacial isolation. The observed weak phylogeographical structure could also be linked with ecological requirements, allowing survival along streams in relatively low, forested mountain ranges. © 2013 The Linnean Society of London     

Mountain coniferous forests, refugia and butterflies

The boreal coniferous forests form the most extended vegetation zone of the Northern Hemisphere. As opposed to North America, they are disconnected from the mountain coniferous forests in Europe, because of the dominant east-west direction of the mountain chains. Consequently, the mountain forests show some unique characteristic features of glacial survival and postglacial history, as well. The mountain coniferous forests have numerous common floral and faunal elements with the boreal zone. However, the few unique faunal elements of the European mountain coniferous forests can be used to unravel the peculiar patterns and processes of this biome. In this issue of Molecular Ecology, Thomas Schmitt and Karola Haubrich (2008) use the relatively common and taxonomically well-studied butterfly, the large ringlet (Erebia euryale) to identify the last glacial refugia and postglacial expansion routes.     

A dark shell hiding great variability: a molecular insight into the evolution and conservation of melanic Daphnia populations in the Alps

Zooplanktonic microcrustaceans of the Daphnia pulex group appear highly differentiated at high altitudes as a result of alternative colonizations and quick local adaptation to harsh environments. In particular, the occurrence of deeply differentiated mountain lineages of European Daphnia pulicaria (EuPC) is highly related to glacial advances and retreats during the Pleistocene. Nowadays, one single ancient EuPC lineage survives in the Pyrenees, with another inhabiting the High Tatra Mountains. Much less is known about populations inhabiting the Alps, where EuPC populations are extremely rare. Recently, four new melanic populations have been discovered in lakes in the Western Italian Alps, offering the opportunity to study their origin and adaptations. We inferred phylogenetic relationships of melanic high‐mountain populations in order to disentangle their history and clarify the colonization patterns of alpine populations. Molecular data suggest that dark populations originated from at least two ancestors, one genetically close to boreal haplotypes, the other apparently related to refugial populations that survived in southern Europe. Therefore, dark pigmentation and obligate parthenogenesis evolved independently within both lineages inhabiting the studied lakes as extreme local adaptations to the alpine environment. Finally, since impacts of human‐related activities and climate changes on mountain species are known to be dramatic, we pose strong issues for the conservation of these extremely localized endemisms. © 2014 The Linnean Society of London     

Multiple cryptic refugia of forest grass Bromus benekenii in Europe as revealed by ISSR fingerprinting and species distribution modelling

Despite not having been fully recognized, the cryptic northern refugia of temperate forest vegetation in Central and Western Europe are one of the most important in the Holocene history of the vegetation on the subcontinent. We have studied a forest grass Bromus benekenii in 39 populations in Central, Western and Southern Europe with the use of PCR-ISSR fingerprinting. The indices of genetic population diversity, multivariate, and Bayesian analyses, supplemented with species distribution modelling have enabled at least three putative cryptic northern refugial areas to be recognized: in Western Europe—the Central and Rhenish Massifs, in Central Europe—the Bohemia–Moravia region and in the Eastern/Western Carpathians. Central Poland is the regional genetic melting-pot where several migratory routes might have met. Southern Poland had a different postglacial history and was under the influence of an Eastern/Western Carpathian cryptic refugium. More forest species should be checked in a west–east gradient in Europe to corroborate the hypothesis on the Western European glacial refugia.     

Higher genetic diversity in recolonized areas than in refugia of Alnus glutinosa triggered by continent‐wide lineage admixture

Genetic admixture is supposed to be an important trigger of species expansions because it can create the potential for selection of genotypes suitable for new climatic conditions. Up until now, however, no continent‐wide population genetic study has performed a detailed reconstruction of admixture events during natural species expansions. To fill this gap, we analysed the postglacial history of Alnus glutinosa, a keystone species of European swamp habitats, across its entire distribution range using two molecular markers, cpDNA and nuclear microsatellites. CpDNA revealed multiple southern refugia located in the Iberian, Apennine, Balkan and Anatolian Peninsulas, Corsica and North Africa. Analysis of microsatellites variation revealed three main directions of postglacial expansion: (i) from the northern part of the Iberian Peninsula to Western and Central Europe and subsequently to the British Isles, (ii) from the Apennine Peninsula to the Alps and (iii) from the eastern part of the Balkan Peninsula to the Carpathians followed by expansion towards the Northern European plains. This challenges the classical paradigm that most European populations originated from refugial areas in the Carpathians. It has been shown that colonizing lineages have met several times and formed secondary contact zones with unexpectedly high population genetic diversity in Central Europe and Scandinavia. On the contrary, limited genetic admixture in southern refugial areas of A. glutinosa renders rear‐edge populations in the Mediterranean region more vulnerable to extinction due to climate change.     

High genetic differentiation in the alpine plant Campanula alpina Jacq. (Campanulaceae): evidence for glacial survival in several Carpathian regions and long-term isolation between the Carpathians and the Alps

A survey of amplified fragment length polymorphism (AFLP) and chloroplast DNA (cpDNA) variation was conducted to elucidate the phylogeography of Campanula alpina , a key species of silicicolous alpine grasslands in the Carpathians with a disjunct distribution in the Eastern European Alps. The Carpathians experienced a different glacial history from the Alps: local glaciers were present only in the highest massifs, while alpine habitats extended over larger areas related to their present distribution in this region. We asked: (i) whether in the Carpathians a high-mountain plant exhibits a complex phylogeographical structure or rather signatures of recent migrations, and (ii) whether the disjunct part of the species' distribution in the Alps resulted from a recent colonization from the Carpathians or from a restricted expansion from separate Eastern Alpine refugia. Our study revealed a clear phylogeographical pattern in AFLPs supported by congruent groups of distinct cpDNA haplotypes. Highest genetic differentiation was observed between the Alps and the Carpathians, indicating a long-term isolation between populations from these two mountain ranges. Further genetic division within the Carpathians suggests that current species' distribution is composed of several groups which have been isolated from each other for a long period. One genetic break separates Western from Southeastern Carpathian material, which is in line with a classical biogeographical boundary. A further, strongly supported genetic group was identified at the southwestern edge of the Carpathian arch. In the Eastern Alps, genetic traces of glacial survival in separate refugial areas in the calcareous northern part and the siliceous central part were found.     

Long-distance dispersal vs vicariance: the origin and genetic diversity of alpine plants in the Spanish Sierra Nevada

Here, we investigated the origin and genetic diversity of four alpine plant species co-occurring in the Spanish Sierra Nevada and other high mountains in south-western Europe by analysis of amplified fragment length polymorphisms (AFLPs). In Kernera saxatilis, Silene rupestris and Gentiana alpina we found intraspecific phylogroups corresponding to mountain regions as predicted by the vicariance hypothesis. Moreover, genetic distances between Sierra Nevada and Pyrenees populations were always higher than those between populations from the Pyrenees and the south-western Alps/Massif Central. This suggests successive disruption of gene exchange between mountain ranges as postglacial climatic warming proceeded from south to north. In Papaver alpinum, our data indicate that a central Pyrenean population arose via long-distance dispersal from the Sierra Nevada, and that vicariant separation events between the Sierra Nevada and the Pyrenees and between the Pyrenees and the south-western Alps occurred simultaneously. Overall, Sierra Nevada populations of all species investigated here preserve unexpectedly high (or not exceptionally reduced) genetic diversity. This testifies to the important influence of long-term isolation, i.e. vicariance, on genetic diversity through fostering the accumulation of new mutations and/or the fixation of ancestral ones.     

The role of geography and ecology in shaping repeated patterns of morphological and genetic differentiation between European minnows (Phoxinus phoxinus) from the Pyrenees and the Alps

Neutral and selective processes can drive repeated patterns of evolution in different groups of populations experiencing similar ecological gradients. In this paper, we used a combination of nuclear and mitochondrial DNA markers, as well as geometric morphometrics, to investigate repeated patterns of morphological and genetic divergence of European minnows in two mountain ranges: the Pyrenees and the Alps. European minnows (Phoxinus phoxinus) are cyprinid fish inhabiting most freshwater bodies in Europe, including those in different mountain ranges that could act as major geographical barriers to gene flow. We explored patterns of P. phoxinus phenotypic and genetic diversification along a gradient of altitude common to the two mountain ranges, and tested for isolation by distance (IBD), isolation by environment (IBE) and isolation by adaptation (IBA). The results indicated that populations from the Pyrenees and the Alps belong to two well differentiated, reciprocally monophyletic mtDNA lineages. Substantial genetic differentiation due to geographical isolation within and between populations from the Pyrenees and the Alps was also found using rapidly evolving AFLPs markers (isolation by distance or IBD), as well as morphological differences between mountain ranges. Also, morphology varied strongly with elevation and so did genetic differentiation to a lower extent. Despite moderate evidence for IBE and IBA, and therefore of repeated evolution, substantial population heterogeneity was found at the genetic level, suggesting that selection and population specific genetic drift act in concert to affect genetic divergence.     

Multiple glacial refugia and complex postglacial range shifts of the obligatory woodland plant Polygonatum verticillatum (Convallariaceae)

The phylogeography of typical alpine plant species is well understood in Europe. However, the genetic patterns of boreo-montane species are mostly unstudied. Therefore, we analysed the AFLPs of 198 individuals of Polygonatum verticillatum over a major part of its European distribution. We obtained a total of 402 reproducible fragments, of which 96.8% were polymorphic. The average Φ _ST over all samples was high (73.0%). The highest number of private fragments was observed in the Cantabrian Mountains; the highest genetic diversities of the populations were detected in populations from the Alps. BAPS, Principal Coordinates and Cluster analyses revealed a deep split between the Cantabrian population and all other samples. The latter further distinguished two major groups in western and eastern Europe. These results suggest a complex biogeographical history of P. verticillatum . The Cantabrian population was most probably isolated for the longest time. Furthermore, putative glacial survival centres might have existed in the western group around the glaciated Alps and in the eastern group in the foothills of the Carpathian and Balkan mountain systems. The origin of the Scandinavian populations is still unresolved, but an origin from the southeastern Alps or the western Balkans appears the most likely scenario.     

Searching for the glacial refugia of Erebia euryale (Lepidoptera,Nymphalidae) – insights from mtDNA‐ and nDNA‐based phylogeography in the Western Carpathians

The refugial history and postglacial re‐colonization routes of Western Carpathian insects are insufficiently understood. Therefore, we investigated the spatio‐genetic structure (phylogeography) of Western Carpathian populations of Erebia euryale (Esper, 1805) (Lepidoptera, Nymphalidae) and inferred their colonization routes over the postglacial period. Our results provide new insights into the phylogeography and origin of Erebia euryale in the rarely studied region of the Western Carpathian Mountains. Their phylogeography, including glacial refugia and Pleistocene expansion routes, was reconstructed based on two mitochondrial (COI and CR) and three nuclear markers (CAD, MDH and IDH). Statistical parsimony networks showed the following geographic coherences: (1) populations from Romania and the Bukovské Mountains (Kremenec) grouped together; (2) a ?ergov group containing populations only from the ?ergov Mountains; (3) a Volovské Mountains group with populations from Koj?ovská ho?a and Slovak Paradise grouped together, most likely due to the lack of geographic isolation between the areas; (4) haplotypes characterized from the Volovské Mountains populations were widespread. Comparisons of Western Carpathian E. euryale COI‐haplotypes with haplotypes from the Southern Carpathians and Balkans suggest that the refugial areas were located in south‐eastern Europe in the Balkan region and Southern Carpathians. We also hypothesize possible central European contact zones in Slovakia for E. euryale in the Western Carpathians. Our results indicate that the Western Carpathians could have served as one of the contact zones between Eastern and Western populations, and additionally as an extra refugium in the southern part of the Volovské Mountains for populations also occurring in Czech mountain regions.     

Out of the Alps: colonization of Northern Europe by East Alpine populations of the Glacier Buttercup Ranunculus glacialis L. (Ranunculaceae)

Ranunculus glacialis ssp. glacialis is an arctic-alpine plant growing in central and southern European and Scandinavian mountain ranges and the European Arctic. In order to elucidate the taxon's migration history, we applied amplified fragment length polymorphism (AFLP) to populations from the Pyrenees, Tatra mountains and Northern Europe and included data from a previous study on Alpine accessions. Populations from the Alps and the Tatra mountains were genetically highly divergent and harboured many private AFLP fragments, indicating old vicariance. Whereas nearly all Alpine populations of R. glacialis were genetically highly variable, the Tatrean population showed only little variation. Our data suggest that the Pyrenees were colonized more recently than the separation of the Tatra from the Alps. Populations in Northern Europe, by contrast, were similar to those of the Eastern Alps but showed only little genetic variation. They harboured no private AFLP fragments and only a subset of East Alpine ones, and they exhibited no phylogeographical structure. It is very likely therefore that R. glacialis colonized Northern Europe in postglacial times from source populations in the Eastern Alps.     

Molecular biogeography of the arctic-alpine disjunct burnet moth species Zygaena exulans (Zygaenidae, Lepidoptera) in the Pyrenees and Alps

Aim The phylogeography of ‘southern’ species is relatively well studied in Europe. However, there are few data about ‘northern’ species, and so we studied the population genetic structure of the arctic‐alpine distributed burnet moth Zygaena exulans as an exemplar. Location and methods The allozymes of 209 individuals from seven populations (two from the Pyrenees, five from the Alps) were studied by electrophoresis. Results All 15 analysed loci were polymorphic. The mean genetic diversities were moderately high (A: 1.99; H_e: 11.5; P: 65%). Mean genetic diversities were significantly higher in the Alps than in the Pyrenees in all cases. F_ST was 5.4% and F_IS was 10%. Genetic distances were generally low with a mean of 0.022 between large populations. About 62% of the variance between populations was between the Alps and the Pyrenees. The two samples from the Pyrenees had no significant differentiation, whereas significant differentiation was detected between the populations from the Alps (F_ST = 2.8%, P = 0.02). Main conclusion Zygaena exulans had a continuous distribution between the Alps and the Pyrenees during the last ice age. Most probably, the species was not present in Iberia, and the samples from the Pyrenees are derived from the southern edge of the glacial distribution area and thus became genetically impoverished. Post‐glacial isolation in Alps and Pyrenees has resulted in a weak genetic differentiation between these two disjunct high mountain systems.     

Imprints of multiple glacial refugia in the Pyrenees revealed by phylogeography and palaeodistribution modelling of an endemic spider

Mediterranean mountain ranges harbour highly endemic biota in islandlike habitats. Their topographic diversity offered the opportunity for mountain species to persist in refugial areas during episodes of major climatic change. We investigate the role of Quaternary climatic oscillations in shaping the demographic history and distribution ranges in the spider Harpactocrates ravastellus, endemic to the Pyrenees. Gene trees and multispecies coalescent analyses on mitochondrial and nuclear DNA sequences unveiled two distinct lineages with a hybrid zone around the northwestern area of the Catalan Pyrenees. The lineages were further supported by morphological differences. Climatic niche‐based species distribution models (SDMs) identified two lowland refugia at the western and eastern extremes of the mountain range, which would suggest secondary contact following postglacial expansion of populations from both refugia. Neutrality test and approximate Bayesian computation (ABC) analyses indicated that several local populations underwent severe bottlenecks followed by population expansions, which in combination with the deep population differentiation provided evidence for population survival during glacial periods in microrefugia across the mountain range, in addition to the main Atlantic and Mediterranean (western and eastern) refugia. This study sheds light on the complexities of Quaternary climatic oscillations in building up genetic diversity and local endemicity in the southern Europe mountain ranges.