Glacial history of high alpine Ranunculus glacialis (Ranunculaceae) in the European Alps in a comparative phylogeographical context

There is considerable controversy concerning the fate of Alpine plants during Pleistocene glaciations. While some studies have found evidence for nunatak survival, others have explained the present genetic patterns by survival only in peripheral refugia. We investigated 75 populations of high alpine Ranunculus glacialis from its entire Alpine distribution. Phylogeographical analyses of AFLP data revealed four groups of populations. Two of them, located in the western Alps, were genetically isolated from each other and from the eastern groups, whereas the two eastern Alpine groups were genetically more similar to each other. This suggests longer isolation and/or lower levels of gene flow in the two western groups. As all groups are close to, or overlap with, presumed glacial refugia, invoking glacial survival on nunataks is unnecessary to explain the present genetic pattern. Similar to the phylogeographical patterns of R. glacialis , the previously investigated alpine Phyteuma globulariifolium and Androsace alpina , which are also confined to siliceous bedrock, showed strong geographical affinities to peripheral refugial areas and there were large-scale congruencies in the location of these refugia for all three species.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 183–195.     

Several Pleistocene refugia detected in the high alpine plant Phyteuma globulariifolium sternb & hoppe (Campanulaceae) in the European Alps

Phyteuma globulariifolium is a high alpine plant species growing in the European Alps and the Pyrenees. In order to elucidate its glacial history, 325 individuals from 69 populations were analysed using the amplified fragment length polymorphism (AFLP) technique. A strongly hierarchical phylogeographical pattern was detected: Two major east-west vicariant groups can be separated along a gap in the distributional area. A further subdivision into at least four populational groups is in congruence with presumed peripheral glacial refugia. There is no indication for survival on unglaciated mountain tops (nunataks) in the interior of the Pleistocene ice shield covering the Alps. Our results favour glacial survival in peripheral, unglaciated or not fully glaciated areas. Populations of P. globulariifolium in the Pyrenees are the result of relatively recent long-distance dispersal. Within the Alps, there is strong differentiation among groups of populations, whereas within them the differentiation is weak. This suggests high levels of gene-flow over short to middle distances.     

Inferring the colonization of a mountain range--refugia vs. nunatak survival in high alpine ground beetles

It has long been debated whether high alpine specialists survived ice ages in situ on small ice-free islands of habitat, so-called nunataks, or whether glacial survival was restricted to larger massifs de refuge at the periphery. We evaluate these alternative hypotheses in a local radiation of high alpine carabid beetles (genus Trechus) in the Orobian Alps, Northern Italy. While summits along the northern ridge of this mountain range were surrounded by the icesheet as nunataks during the last glacial maximum, southern areas remained unglaciated. We analyse a total of 1366 bp of mitochondrial (Cox1 and Cox2) data sampled from 150 individuals from twelve populations and 530 bp of nuclear (PEPCK) sequence sampled for a subset of 30 individuals. Using Bayesian inference, we estimate ancestral location states in the gene trees, which in turn are used to infer the most likely order of recolonization under a model of sequential founder events from a massif de refuge from the mitochondrial data. We test for the paraphyly expected under this model and for reciprocal monophyly predicted by a contrasting model of prolonged persistence of nunatak populations. We find that (i) only three populations are incompatible with the paraphyly of the massif de refuge model, (ii) both mitochondrial and nuclear data support separate refugial origins for populations on the western and eastern ends of the northern ridge, and (iii) mitochondrial node ages suggest persistence on the northern ridge for part of the last ice age.     

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     

History and evolution of alpine plants endemic to the Qinghai-Tibetan Plateau: Aconitum gymnandrum (Ranunculaceae)

How Quaternary climatic oscillations affected range distributions and intraspecific divergence of alpine plants on the Qinghai‐Tibetan Plateau (QTP) remains largely unknown. Here, we report a survey of chloroplast DNA (cpDNA) and nuclear ribosomal internal transcribed spacer (ITS) DNA variation aimed at exploring the phylogeographical history of the QTP alpine endemic Aconitum gymnandrum. We sequenced three cpDNA fragments (rpl20–rps12 intergenic spacer, the trnV intron and psbA‐trnH spacer) and also the nuclear (ITS) region in 245 individuals from 23 populations sampled throughout the species’ range. Two distinct lineages, with eastern and western geographical distributions respectively, were identified from a phylogenetic analysis of ITS sequence variation. Based on a fast substitution rate, these were estimated to have diverged from each other in the early Pleistocene approximately 1.45 Ma. The analysis of cpDNA variation identified nine chlorotypes that clustered into two major clades that were broadly congruent in geographical distribution with the two ITS lineages. The east–west split of cpDNA divergence was supported by an amova which partitioned approximately half of the total variance between these two groups of populations. Analysis of the spatial distribution of chlorotypes showed that each clade was subdivided into two groups of populations such that a total of four population groups existed in the species. It is suggested that these different groups derive from four independent glacial refugia that existed during the Last Glacial Maximum (LGM), and that three of these refugia were located at high altitude on the QTP platform itself at that time. Coalescent simulation of chlorotype genealogies supported both an early Pleistocene origin of the two main cpDNA clades and also the ‘four‐refugia’ hypothesis during the LGM. Two previous phylogeographical studies of QTP alpine plants indicated that such plants retreated to refugia at the eastern/south‐eastern plateau edge during the LGM and/or previous glacial maxima. However, the results for A. gymnandrum suggest that at least some of these cold‐tolerant species may have also survived centrally on the QTP platform throughout the Quaternary.     

Resistance or emigration: response of the high-alpine plant Eritrichium nanum (L.) Gaudin to the ice age within the Central Alps

Two main possibilities regarding glacial survival of the mountain flora of the Alps during the Quaternary have been discussed: the tabula rasa and the nunatak hypotheses. Eritrichium nanum (L.) Gaudin (Boraginaceae) is a perennial cushion plant, occurring at high elevations of the Central Alps and having a preference for extreme habitats. It belongs to a group of high-alpine plants, for which in situ glacial survival on nunataks is ecologically possible. By investigating 20 populations of E. nanum of potential nunatak and peripheral refugial regions using amplified fragment length polymorphism, considerable genetic differences between populations from the Central Alps and populations from peripheral refugia were detected; hence, the latter probably did not serve as potential sources for the re-colonization of the Central Alps after glaciation. Genetic variation was hierarchically structured (AMOVA), and three genetically distinct regions could be identified in the Central Alps. Two of these, the Penninic and Rhaetic Alps, correspond to nunatak regions proposed in the biogeographic literature. Populations from the Lepontic Alps formed a third genetic group. Genetic correlation (Mantel statistics) was highest within populations, with a modest decline among populations within specific nunatak regions and a negative correlation outside the genetic influence of specific nunatak regions. In situ glacial survival in E. nanum could be a model for the Quaternary history of other alpine plants, especially those that also occur at high elevations and in similar habitats.     

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.     

A re-appraisal of nunatak survival in arctic-alpine phylogeography

A long standing and at times fervid debate in biogeography revolves around the question whether arctic and high alpine organisms survived Pleistocene ice ages on small island-like areas protruding above the ice-sheet, socalled nunataks, or whether they did so in peripheral nonglaciated refugial areas. A common picture emerging from a plethora of molecular phylogeographic studies in the last decade is that both in the Arctic and in temperate mountain ranges such as the European Alps nunatak survival needs to be only rarely invoked to explain observed genetic patterns (for a rare example see Stehlik et al. 2002). As two studies in this issue show, depreciation of the nunatak hypothesis is, however, not warranted. In this issue of Molecular Ecology Westergaard et al. (2011) investigate genetic patterns of two arctic-alpine plant species distributed on both sides of the Atlantic exclusively in areas that were mostly covered by ice-sheets during Pleistocene glacial advances. In both species, amplified fragment length polymorphism (AFLP) data identified divergent and partly genetically diverse groups east and west of the Atlantic. This suggests, for the first time in Arctic plants, in situ survival on nunataks. In an entirely different geographic setting and on a different geographic scale, Lohse et al. (2011, this issue) study the colonization of high alpine areas in the Orobian Alps, situated within and adjacent to a prominent peripheral refugial area (massif de refuge) in the Southern Alps of northern Italy, by dispersal-limited carabid ground beetles. Using explicit hypothesis testing and inference of ancestral locations in a Bayesian framework, stepwise colonization from two separate southern refugia is found to shape the genetic pattern of these beetles, but at the northern edge, populations survived at least parts of the last glaciation in situ on nunataks.     

Genetic discontinuity, breeding-system change and population history of Arabis alpina in the Italian Peninsula and adjacent Alps

Arabis alpina is a widespread plant of European arctic and alpine environments and belongs to the same family as Arabidopsis thaliana. It grows in all major mountain ranges within the Italian glacial refugia and populations were sampled over a 1300 km transect from Sicily to the Alps. Diversity was studied in nuclear and chloroplast genome markers, combining phylogeographical and population genetic approaches. Alpine populations had significantly lower levels of nuclear genetic variation compared to those in the Italian Peninsula, and this is associated with a pronounced change in within-population inbreeding. Alpine populations were significantly inbred (F(IS) = 0.553), possibly reflecting a change to the self-incompatibility system during leading edge colonization. The Italian Peninsula populations were approaching Hardy-Weinberg equilibrium (outbreeding, F(IS) = 0.076) and genetic variation was highly structured, consistent with independent local 'refugia within refugia' and the fragmentation of an established population by Quaternary climate oscillations. There is very little evidence of genetic exchange between the Alps and the Italian Peninsula main distribution ranges. The Alps functioned as a glacial sink for A. alpina, while the Italian Peninsula remains a distinct and separate long-term refugium. Comparative analysis indicated that inbreeding populations probably recolonized the Alps twice: (i) during a recent postglacial colonization of the western Alps from a Maritime Alps refugium; and (ii) separately into the central Alps from a source outside the sampling range. The pronounced geographical structure and inbreeding discontinuities are significant for the future development of A. alpina as a model species.     

Saponaria pumila (caryophyllaceae) and the ice age in the European alps

The polymerase chain reaction (PCR)-based amplified fragment length polymorphism (AFLP) technique was applied to elucidate the glacial history of the alpine cushion plant Saponaria pumila in the European Alps. Special emphasis was given to a dense sampling of populations. Our data support a survival of S. pumila during the last ice age in at least three refugia, which are characterized by unique marker sets. Patterns of genetic diversity and divergence can be explained by survival in peripheral refugia and additional in situ survival within the ice sheet on peripheral nunataks. A nunatak survival in interior parts of the Alps needs not be postulated to explain our results. The level of genetic diversity is dramatically different between populations (Shannon's diversity index: 0.87-19.86). Some peripheral populations are characterized by a high number of rare fragments indicating long isolation, but not necessarily by a high level of genetic diversity. Parts of the present distributional area were recolonized via recent long-distance dispersal, leading to severely bottlenecked populations lacking private or rare fragments. The combination of our data with palaeogeological and palaeoclimatological evidence allows us to confine Pleistocene refugia to certain regions and to draw a detailed scenario of the glacial and postglacial history of S. pumila.     

Concordant genetic breaks, identified by combining clustering and tessellation methods, in two co-distributed alpine plant species

Natural genetic breaks may indicate limitations to gene flow or the presence of contact zones of previously isolated populations. Molecular evidence suggests that genetic breaks have aggregated in distinct geographical areas. We propose a new application of well-established statistical methods for analysing multilocus genetic data to identify intraspecific genetic breaks. The methodological approach combines Bayesian clustering with a spatially explicit maximum-difference algorithm to visualize and quantify breaks between clusters. We used amplified fragment length polymorphism data of two co-distributed, silicicolous alpine plant species, Geum montanum and Geum reptans , exhaustively sampled on a consistent, regular grid over their entire range of the European Alps and the Carpathians. We found a distinct and highly similar allocation of genetic breaks in both species. The pattern of breaks did not conform to scenarios of glacial refugial survival, alternatively in peripheral refugia or on nunataks, as expected because of the species' ecologies (late-successional low alpine vs. early-successional high alpine). Our findings rather substantiated the postulate of a general pattern of genetic breaks in alpine plants and corresponded well with biogeographical regions formerly described. Our approach could serve as a tool not only for landscape genetics and comparative phylogeography, but also for floristics or faunistics to compare biogeographic with phylogeographic breaks.     

Comparative phylogeography of the Veronica alpina complex in Europe and North America

The Veronica alpina complex comprises eight species of alpine habitats over a wide range of mountain systems in the Northern Hemisphere. The occurrence of sympatric species in the European and North American mountain systems allowed us not only to investigate the effect of the ice ages on intraspecific phylogeographical patterns and genetic diversity in different continents of the Northern Hemisphere, but also to compare these patterns in closely related species. Plastid DNA trnL-F sequences and AFLP (amplified fragment length polymorphism) fingerprints were used to infer the phylogenetic history of the group and phylogeographical patterns within species. Hybrid origin of tetraploid eastern North American V. wormskjoldii from western North American V. nutans (= V. wormskjoldii s.l.) and Eurasian V. alpina is suggested. A number of phylogeographical groups have been found both in V. alpina from Europe and in V. nutans from western North America. Phylogeographical substructuring in the Alps is inferred for V. alpina but not for V. bellidioides, which is moreover characterized by an overall very low genetic diversity. Western North American V. cusickii is much more genetically diverse than its sympatric relative, V. nutans, an effect that is likely due to differences in the breeding system. Populations of V. nutans are differentiated into three groups, those from the Cascades and from the southern and the northern Rocky Mountains. Genetic diversity seems to be higher in the North American V. nutans than in the morphologically and ecologically similar European V. alpina. A possible scenario to explain this pattern is suggested.     

Initial diversification,glacial survival,and continuous range expansion of Gentiana straminea (Gentianaceae) in the Qinghai–Tibet Plateau

The Qinghai–Tibet Plateau (QTP) has been considered as one of the most sensitive regions to climate change on Earth, and the growth and distribution of alpine species on this plateau have been suggested to depend greatly on their ability to survive within a small range of temperatures. However, the responses of most species in the QTP to the Quaternary climatic oscillation remain largely unknown. We sequenced two cpDNA fragments and nrITS to examine genetic variations in 22 natural populations across the range of distribution in this region to investigate the phylogeographical distributional pattern of Gentiana straminea (Gentianaceae) in the QTP. The high haplotype diversity from populations on the platform suggested the existence of intraspecific diversification. Molecular dating estimated that all haplotypes have differentiated before the Last Glacial Maximum (LGM). Moreover, the haplotype distribution map based on both cpDNA and nrDNA data suggested expansions from QTP to its outer edges. Finally, ecological niche modeling further demonstrated the glacial survival of this species on the platform and continuous expansion to the platform edge. These findings imply that G. straminea should have experienced initial diversification, glacial survival on the platform, and continuous expansion to the QTP edge during the glacial period.     

An explicit test of Pleistocene survival in peripheral versus nunatak refugia in two high mountain plant species

Pleistocene climate fluctuations had profound influence on the biogeographical history of many biota. As large areas in high mountain ranges were covered by glaciers, biota were forced either to peripheral refugia (and possibly beyond to lowland refugia) or to interior refugia (nunataks). However, nunatak survival remains controversial as it relies solely on correlative genetic evidence. Here, we test hypotheses of glacial survival using two high alpine plant species (the insect‐pollinated Pedicularis asplenifolia and wind‐pollinated Carex fuliginosa) in the European Alps. Employing the iDDC (integrative Distributional, Demographic and Coalescent) approach, which couples species distribution modelling, spatial and temporal demographic simulation and Approximate Bayesian Computation, we explicitly test three hypotheses of glacial survival: (a) peripheral survival only, (b) nunatak survival only and (c) peripheral plus nunatak survival. In P. asplenifolia the peripheral plus nunatak survival hypothesis was supported by Bayes factors (BF> 100), whereas in C. fuliginosa the peripheral survival only hypothesis, although best supported, could not be unambiguously distinguished from the peripheral plus nunatak survival hypothesis (BF = 5.58). These results are consistent with current habitat preferences (P. asplenifolia extends to higher elevations) and the potential for genetic swamping (i.e., replacement of local genotypes via hybridization with immigrating genotypes [expected to be higher in the wind‐pollinated C. fuliginosa]). Although the persistence of plants on nunataks during glacial periods has been debated and studied over decades, this is one of the first studies to explicitly test the hypothesis instead of solely using correlative evidence.     

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.     

Integrating species distribution models (SDMs) and phylogeography for two species of Alpine Primula

The major intention of the present study was to investigate whether an approach combining the use of niche-based palaeodistribution modeling and phylo-geography would support or modify hypotheses about the Quaternary distributional history derived from phylogeographic methods alone. Our study system comprised two closely related species of Alpine Primula. We used species distribution models based on the extant distribution of the species and last glacial maximum (LGM) climate models to predict the distribution of the two species during the LGM. Phylogeographic data were generated using amplified fragment length polymorphisms (AFLPs). In Primula hirsuta, models of past distribution and phylogeographic data are partly congruent and support the hypothesis of widespread nunatak survival in the Central Alps. Species distribution models (SDMs) allowed us to differentiate between alpine regions that harbor potential nunatak areas and regions that have been colonized from other areas. SDMs revealed that diversity is a good indicator for nunataks, while rarity is a good indicator for peripheral relict populations that were not source for the recolonization of the inner Alps. In P. daonensis, palaeo-distribution models and phylogeographic data are incongruent. Besides the uncertainty inherent to this type of modeling approach (e.g., relatively coarse 1-km grain size), disagreement of models and data may partly be caused by shifts of ecological niche in both species. Nevertheless, we demonstrate that the combination of palaeo-distribution modeling with phylogeographical approaches provides a more differentiated picture of the distributional history of species and partly supports (P. hirsuta) and partly modifies (P. daonensis and P. hirsuta) hypotheses of Quaternary distributional history. Some of the refugial area indicated by palaeodistribution models could not have been identified with phylogeographic data.     

Glacial in situ survival in the Western Alps and polytopic autopolyploidy in Biscutella laevigata L. (Brassicaceae)

Past climatic changes and especially the ice ages have had a great impact on both the distribution and the genetic composition of plant populations, but whether they promoted speciation is still controversial. The autopolyploid complex Biscutella laevigata is a classical example of polyploidy linked to glaciations and is an interesting model to explore migration and speciation driven by climate changes in a complex alpine landscape. Diploid taxa survived the last glacial maximum in several never-glaciated areas and autotetraploids are clearly dominant in the central parts of the Alps; however, previous range-wide studies failed to identify their diploid ancestor(s). This study highlights the phylogeographical relationships of maternal lineages in the Western Alps and investigates the polyploidy process using plastid DNA sequences (trnS-trnG and trnK-intron) combined with plastid DNA length polymorphism markers, which were transferable among Brassicaceae species. Twenty-one distinct plastid DNA haplotypes were distinguished in 67 populations densely sampled in the Western Alps and main lineages were identified by a median-joining network. The external Alps harboured high levels of genetic diversity, while the Central Alps contained only a subset of haplotypes due to postglacial recolonization. Several haplotypes were restricted to local peripheral refugia and evidence of in situ survival in central nunataks was detected by the presence of highly differentiated haplotypes swamped by frequent ones. As hierarchical genetic structure pointed to an independent evolution of the species in different biogeographical districts, and since tetraploids displayed haplotypes belonging to different lineages restricted to either the northern or the southern parts of the Alpine chain, polytopic autopolyploidy was also apparent in the Western Alps.     

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.     

Pleistocene glaciation leaves deep signature on the freshwater crab Aegla alacalufi in Chilean Patagonia

Quaternary glacial cycles have played an important role in shaping the biodiversity in temperate regions. This is well documented in Northern Hemisphere, but much less understood for Southern Hemisphere. We used mitochondrial DNA and nuclear elongation factor 1α intron sequences to examine the Pleistocene glacial impacts on the phylogeographical pattern of the freshwater crab Aegla alacalufi in Chilean Patagonia. Phylogenetic analyses, which separated the glaciated populations on eastern continent into a north group (seven populations) and a south group (one population), revealed a shallow phylogenetic structure in the north group but a deep one in the non-glaciated populations on western islands, indicating the significant influence of glaciation on these populations. Phylogenies also identified the Yaldad population on Chiloé Island as a potentially unrecognized new species. The non-glaciated populations showed higher among population genetic divergence than the glaciated ones, but lower population genetic diversity was not detected in the latter. The two glaciated groups, which diverged from the non-glaciated populations at ~96 800–29 500 years ago and ~104 200–73 800 years ago, respectively, seem to have different glacial refugia. Unexpectedly, the non-glaciated islands did not serve as refugia for them. Demographic expansion was detected in the glaciated north group, with a constant population increase after the last glacial maximum. Nested clade analyses suggest a possible colonization from western islands to eastern continent. After arriving on the continent and surviving the last glacial period there, populations likely have expanded from high to low altitude, following the flood of melting ice. Aegla alacalufi genetic diversity has been primarily affected by Pleistocene glaciation and minimally by drainage isolation.     

Contrasting phylogeographies inferred for the two alpine sister species Cardamine resedifolia and C. alpina (Brassicaceae)

Aim We use Cardamine alpina and C. resedifolia as models to address the detailed history of disjunctions in the European alpine system. These species grow on siliceous bedrock: C. alpina in the Alps and Pyrenees, and C. resedifolia in several mountain ranges from the Sierra Nevada to the Balkans. We explore differentiation among their disjunct populations as well as within the contiguous Alpine and Pyrenean ranges, and compare the phylogeographical histories of these diploid sister species. We also include samples of the closely related, arctic diploid C. bellidifolia in order to explore its origin and post‐glacial establishment. Location European alpine system, Norway and Iceland. Methods We employed amplified fragment length polymorphisms (AFLPs). AFLP data were analysed using principal coordinates analysis, neighbour joining and Bayesian clustering, and measures of diversity and differentiation were computed. Results For the snow‐bed species C. alpina (27 populations, 203 plants) we resolved two strongly divergent lineages, corresponding to the Alps and the Pyrenees. Although multiple glacial refugia were invoked in the Pyrenees, we inferred only a single one in the Maritime Alps – from which rapid post‐glacial colonization of the entire Alps occurred, accompanied by a strong founder effect. For C. resedifolia (33 populations, 247 plants), which has a broader ecological amplitude and a wider distribution, the genetic structuring was rather weak and did not correspond to the main geographical disjunctions. This species consists of two widespread and largely sympatric main genetic groups (one of them subdivided into four geographically more restricted groups), and frequent secondary contacts exist between them. Main conclusions The conspicuously different histories of these two sister species are likely to be associated with their different ecologies. The more abundant habitats available for C. resedifolia may have increased the probability of its gradual migration during colder periods and also of successful establishment after long‐distance dispersal, whereas C. alpina has been restricted by its dependence on snow‐beds. Surprisingly, the arctic C. bellidifolia formed a very divergent lineage with little variation, contradicting a scenario of recent, post‐glacial migration from the Alps or Pyrenees.