Macaronesia: a source of hidden genetic diversity for post‐glacial recolonization of western Europe in the leafy liverwort Radula lindenbergiana

Aim Bryophytes exhibit apparently low rates of endemism in Macaronesia and differ from angiosperms in their diversity patterns by the widespread occurrence of endemics within and among archipelagos. This paper investigates the phylogeography of the leafy liverwort Radula lindenbergiana to determine: (1) whether or not morphologically cryptic diversification has occurred in Macaronesia, and (2) the relationships between Macaronesian and continental populations. Location Macaronesia, Europe, Africa. Methods Eighty‐four samples were collected across the species’ distribution range and sequenced at four chloroplast DNA (cpDNA) loci (atpB–rbcL, trnG, trnL and rps4). Phylogenetic reconstructions and Bayesian ancestral area reconstructions were used in combination with population genetics statistics (H, N_ST, F_ST) to describe the pattern of present genetic diversity in R. lindenbergiana and infer its biogeographic history. Results Patterns of genetic diversity in R. lindenbergiana exhibit a striking westwards gradient, wherein haplotype (0.90) and nucleotide (0.0038 ± 0.0019) diversity peak in Macaronesia, with a substantial endemic component. We found 20.9% of the genetic variance between biogeographic regions, and most pairwise F_ST comparisons between regions are significantly different from zero. The global N_ST (0.78) is significantly higher than the global F_ST (0.20), providing evidence for the presence of phylogeographic signal in the data. Ancestral area reconstructions suggest that the haplotypes currently found in western Europe share a Macaronesian common ancestor. Main conclusions The haplotype diversification exhibited by R. lindenbergiana in Macaronesia is comparable to that reported for many angiosperm groups at the species level. The apparent lack of radiation among Macaronesian bryophytes may thus reflect the reduced morphology of bryophytes in comparison with angiosperms. The high diversity found among Macaronesian haplotypes, especially in Madeira and the Canary Islands, and the significant N_ST/F_ST ratio between Macaronesia and all the other biogeographic regions (an indication that mutation rate exceeds dispersal rates) suggest that Macaronesian archipelagos could have served as a refugium during the Quaternary glaciations. Many haplotypes currently found in Europe share a Macaronesian common ancestor, and this further suggests that Macaronesia might have played a key role in the back‐colonization of the continent.     

Recent origin,active speciation and dispersal for the lichen genus Nephroma (Peltigerales) in Macaronesia

Aim We reconstructed the phylogeny of the lichen genus Nephroma (Peltigerales) to assess the relationships of species endemic to Macaronesia. We estimated dates of divergences to test the hypothesis that the species arose in Macaronesia (neo‐endemism) versus the oceanic archipelagos serving as refugia for formerly widespread taxa (palaeo‐endemism). Location Cosmopolitan with a special focus on the archipelagos of the Azores, Madeira and the Canary Islands. Methods DNA sequences were obtained from 18 species for three loci and analysed using maximum parsimony, maximum likelihood and Bayesian inferences. Divergence dates were estimated for the internal transcribed spacer (ITS)‐based phylogeny using a relaxed molecular clock. Reconstruction of the ancestral geographical range was conducted using the Bayesian 50% majority rule consensus tree under a parsimony method. Results The backbone phylogenetic tree was fully supported, with Nephroma plumbeum as sister to all other species. Four strongly supported clades were detected: the Nephroma helveticum, the N. bellum, the N. laevigatum and the N. parile clades. The latter two share a common ancestor and each includes a widespread Holarctic species (N. laevigatum and N. parile, respectively) and all species endemic to Macaronesia. The data suggest a neo‐endemic origin of Macaronesian taxa, a recent range expansion from Macaronesia of both widespread species, a range expansion limited to the Mediteranean Basin and south‐western Europe for another taxon, and a long dispersal event that resulted in a speciation event in the western parts of North America. Main conclusions The Macaronesian endemic species belong to two sister clades and originated from a most recent common ancestor (MRCA) shared with one widely distributed taxon, either N. parile or N. laevigatum. Estimates of the mean divergence dates suggest that the endemics originated in the archipelagos after the rise of the volcanic islands, along with the ancestor to the now widespread species, which probably expanded their range beyond Macaronesia via long‐distance dispersal. This study provides the first phylogenetic evidence of Macaronesian neo‐endemism in lichenized fungi and provides support for the hypothesis that oceanic islands may serve as a source for the colonization of continents. However, further data are needed to properly assess the alternative hypothesis, namely colonization from western North America.     

Late Neogene history of the laurel tree (Laurus L., Lauraceae) based on phylogeographical analyses of Mediterranean and Macaronesian populations

Aim The post‐glacial range dynamics of many European plant species have been widely investigated, but information rapidly diminishes as one moves further back in time. Here we infer the historical range shifts of Laurus, a paradigmatic tree of the Tethyan flora that has covered southern Eurasia since the Oligo‐Miocene, by means of phylogenetic and phylogeographical analyses. Location Mediterranean Basin, Black Sea and Macaronesian archipelagos (Azores, Madeira, Canary Islands). Methods We analysed plastid DNA (cpDNA) sequence (trnK–matK, trnD–trnT) variation in 57 populations of Laurus and three Lauraceae genera. Phylogenetic methods (maximum parsimony and Bayesian inference) and statistical parsimony networks were used to reconstruct relationships among haplotypes. These results were contrasted with the fossil record and bioclimatic niche‐based model predictions of past distributions to infer the migration routes and location of refugia. Results The phylogenetic tree revealed monophyly for Laurus. Overall sequence variability was low within Laurus, but six different haplotypes were distinguished and a single network retrieved, portraying three lineages primarily related to geography. A strongly divergent eastern lineage occupied Turkey and the Near East, a second clade was located in the Aegean region and, lastly, a western clade grouped all Macaronesian and central and western Mediterranean populations. A close relationship was observed between the Macaronesian populations of L. azorica and the western populations of L. nobilis. Main conclusions The phylogeographical structure of Laurus preserves the imprints of an ancient contraction and break‐up of the range that resulted in the evolution of separate cpDNA lineages in its western‐ and easternmost extremes. Intense range dynamics in the western Mediterranean and multiple glacial refugia contributed to the generation and long‐term conservation of this phylogeographical pattern, as shown by the fit between the haplotype ranges and past suitable areas inferred from bioclimatic models. Finally, our results challenge the taxonomic separation of Laurus into two distinct species.     

Phylogenetic reconstruction of key traits in the evolution of ivies (Hedera L.)

The Mediterranean harbours the highest number of Hedera (Araliaceae) species, lineages, ploidy levels, and trichome morphologies of any area where the genus occurs. Previous molecular and cytogenetic studies identified two main centres of diversity for Hedera (Araliaceae), the eastern and western parts of the Mediterranean region. An explicit analysis of key traits was performed to investigate geographical patterns and ancestral character states of ivy lineages. Interestingly, the greatest diversity of Hedera was found in the western Mediterranean, including the three species of Macaronesia (H. azorica in the Azores, H. maderensis in Madeira and H. canariensis in the Canary Islands). Phylogenetic and phylogeographical analyses of the nrITS and plastid trnT-L sequences revealed multiple connections between the Mediterranean region and Asia, and suggest recurrent colonization between these two areas. Reconstruction of three important characters long used to distinguish members of the genus (trichome types, ploidy levels, and geographical areas) suggests that a diploid species with scale-like trichomes from the Mediterranean basin was the most recent common ancestor of the extant species of Hedera.     

Inverted patterns of genetic diversity in continental and island populations of the heather Erica scoparia s.l.

Aim Using the heather Erica scoparia s.l. as a model, this paper aims to test theoretical predictions that island populations are genetically less diverse than continental ones and to determine the extent to which island and continental populations are connected by pollen‐ and seed‐mediated gene flow. Location Macaronesia, Mediterranean, Atlantic fringe of Europe. Methods Patterns of genetic diversity are described based on variation at two chloroplast DNA (cpDNA) loci and one nuclear DNA (nDNA) locus for 109 accessions across the entire distribution range of the species. Global patterns of genetic differentiation were investigated using principal coordinates analysis. Genetic differentiation between island and continental areas, estimations of pollen‐ and seed‐mediated gene flow, and the presence of phylogeographical signal were assessed by means of F_st /N_ST (continental scale) and F_ij/N_ij (local scale). Extant and past distribution ranges of the species were inferred from niche modelling using layers describing present and Last Glacial Maximum (LGM) macroclimatic conditions. Results The Azores exhibited a significantly higher genetic diversity than the continent. The lowest levels of genetic differentiation were observed between the Azores and the western Mediterranean, and the diversity observed in the Azores resulted from at least two colonization waves. Within the Azores, kinship coefficients showed a significant and much steeper decrease with geographical distance in the cpDNA than in the nDNA. The distribution predicted by LGM models was markedly different from the current potential distribution, particularly in western Europe, where no suitable areas were predicted by LGM models, and along the Atlantic coast of the African continent, where LGM models predicted highly suitable climatic conditions. Main conclusions The higher diversity observed in Azorean than in continental populations is inconsistent with MacArthur and Wilson’s equilibrium model and derived theoretical population genetic expectations. This inverted pattern may be the result of extinction on the continent coupled with multiple island colonization events and subsequent allopatric diversification and lineage hybridization in the Azores. The results highlight the role of allopatric diversification in explaining diversification on islands and suggest that this process has played a much more significant role in shaping Azorean biodiversity than previously thought.     

Long-distance colonization of the Western Mediterranean by Cistus ladanifer (Cistaceae) despite the absence of special dispersal mechanisms

Aim There are few biogeographical and evolutionary studies that address plant colonization and lineage origins in the Mediterranean. Cistus serves as an excellent model with which to study diaspore dispersal and distribution patterns of plants exhibiting no special long‐distance dispersal mechanisms. Here we analyse the pattern of genetic variation and divergence times to infer whether the African–European disjunction of C. ladanifer L. is the result of long‐distance dispersal or of vicariance events. Location Principally the Western Mediterranean region, with a focus on the Strait of Gibraltar. Methods We used DNA sequence phylogenetic approaches, based on plastid (rbcL/trnK‐matK) and nuclear (ITS) sequence data sets, and the penalized likelihood method, to date the diversification of the 21 species of Cistus. Phylogenetic relationships and phylogeographical patterns in 47 populations of C. ladanifer were also analysed using two plastid DNA regions (trnS‐trnG, trnK‐matK). These sequence data were analysed using maximum parsimony, Bayesian inference and statistical parsimony. Results Dating estimates indicated divergence dates of the C. ladanifer lineage in the Pleistocene. Eight nucleotide‐substitution haplotypes distributed on the European (four haplotypes) and African (five haplotypes) sides of the Strait of Gibraltar were revealed from C. ladanifer sequences. Both the haplotype network and the phylogenetic analyses depicted two main Cistus lineages distributed in both Europe and North Africa. An Iberian haplotype forms part of the North African lineage, and another haplotype distributed on both continents is related to the European lineage. Haplotype relationships with respect to outgroup sequences supported the hypothesis that the centre of genetic diversity is in northern Africa. Main conclusions Based on lineage divergence‐time estimates and disassociation between geographical and lineage haplotype distributions, we inferred at least two intercontinental colonization events of C. ladanifer post‐dating the opening of the Strait of Gibraltar (c. 5 Ma). This result supports a hypothesis of long‐distance dispersal rather than a hypothesis of vicariance. We argue that, despite limited dispersal abilities, preference for disturbed habitats was integral to historical colonization after the advent of the Mediterranean climate (c. 3.2 Ma), when Cistus species diverged and became established as a dominant element in the Mediterranean scrub.     

Insights into Neogene Mediterranean biogeography based on phylogenetic relationships of mountain and lowland lineages of Narcissus (Amaryllidaceae)

Aim Our aims were: (1) to reconstruct the phylogenetic relationships of daffodils (Narcissus), focusing on the lowland subgenus Hermione and the mountain section Apodanthi; (2) to estimate the temporal setting of diversification; (3) to reconstruct the migration patterns of the lineages; and (4) to examine the microevolutionary differentiation of the wide‐ranging Narcissus tazetta group across the Mediterranean. Location The Mediterranean Basin. Methods Plastid (trnT–L, trnL–F and ndhF) sequences were obtained from 63 populations representing 23 species of Narcissus and combined with published data from 16 species. Phylogenetic relationships and dating were inferred by Bayesian analysis based on geological events and divergence estimates of closely related taxa. A dispersal–extinction–cladogenesis analysis was performed using maximum likelihood methods to infer ancestral geographical distributions, and phylogeographical reconstruction was performed using coalescence analysis. Results Subgenus Hermione is not recognized as a monophyletic group because two of the nine species were found to have a close relationship with the subgenus Narcissus. The results on section Apodanthi confirmed previous findings of its monophyly and phylogenetic relationships within this mountain group. Molecular dating and ancestral range reconstructions suggest that the ancestor of Narcissus originated in the Iberian Peninsula during the Late Oligocene–Early Miocene. Eastward expansion of the lineage range proceeded from the western Mediterranean and involved colonization of mountain ranges in northern Africa. The phylogeography of the N. tazetta group revealed a widespread distribution of certain haplotypes, suggesting wide dispersal and a high level of colonization in the Mediterranean Basin. Main conclusions Our study points to the role of three key historical events in Narcissus diversification: tectonic shifts of the Alboran domain in the western Mediterranean, the Messinian salinity crisis, and the onset of the Mediterranean climate followed by periods of repeated glaciation. Diversification of section Apodanthi probably resulted from allopatric speciation, while subgenus Hermione may have shown more sympatric speciation and high dispersal, despite the lack of apparent adaptations to long‐distance dispersal. This is best exemplified by the presence of both ancestral and recent haplotypes of N. tazetta across the Mediterranean.     

Out of Africa: north‐westwards Pleistocene expansions of the heather Erica arborea

Aim The heather Erica arborea L. is a dominant element of the circum‐Mediterranean region. Its broad, disjunct distribution, ranging from Macaronesia to eastern Africa, is consistent with the fragmentation of the evergreen tropical and subtropical forests that dominated Europe and North Africa in the Tertiary. This study aims to investigate phylogeographical patterns in E. arborea and to determine whether the current disjunct distribution of the species is a relict of a once wider distribution, or a recent range expansion in response to the establishment of suitable conditions. Location Mediterranean, Macaronesia, North and eastern Africa. Methods A total of 105 samples were collected across the species’ distribution range and sequenced at four cpDNA loci (atpB–rbcL, matK, trnH–psbA and rpl16). Phylogenetic reconstructions, molecular dating techniques and Bayesian ancestral area reconstructions were used in combination with population genetic statistics (haplotype diversity, N_ST, F_ST, Fu’s F_S) to describe the pattern of present genetic diversity in E. arborea and infer its biogeographical history. Results Haplotype diversity in Macaronesia and the east and central Mediterranean is much lower than that observed in eastern Africa/Arabia and the western Mediterranean. Bayesian ancestral area reconstructions and molecular dating suggest that E. arborea colonized the Mediterranean westwards from eastern Africa/Arabia at least twice during a time period ranging between the upper Miocene and the upper Pleistocene. Main conclusions The phylogeography of E. arborea involves a complex history of range expansions and contractions, which has resulted in a pattern of distribution that mimics that expected for a Tertiary vicariance event. Despite the presence of a late Tertiary refugium in the Iberian Peninsula, the current distribution of the species throughout the Mediterranean is explained by a Pleistocene expansion originating from eastern Africa. One explanation for the isolation of the Iberian refugium is the rapidity of the most recently identified colonization wave, as inferred by the absence of global phylogeographical signal in the data and significantly negative values of Fu’s F_S statistic for European populations. Macaronesia was colonized during each of these two expansion waves, confirming that the laurisilva (laurel forest flora) is a complex entity including both ancient relicts and recent colonizers.     

Identification of glacial refugia in south-eastern North America by phylogeographical analyses of a forest understorey plant, Trillium cuneatum

Aim We examine several hypotheses emerging from biogeographical and fossil records regarding glacial refugia of a southern thermophilic plant species. Specifically, we investigated the glacial history and post‐glacial colonization of a forest understorey species, Trillium cuneatum. We focused on the following questions: (1) Did T. cuneatum survive the Last Glacial Maximum (LGM) in multiple refugia, and (if so) where were they located, and is the modern genetic structure congruent with the fossil record‐based reconstruction of refugia for mesic deciduous forests? (2) What are the post‐glacial colonization patterns in the present geographical range? Location South‐eastern North America. Methods We sampled 45 populations of T. cuneatum throughout its current range. We conducted phylogeographical analyses based on maternally inherited chloroplast DNA (cpDNA haplotypes) and used TCS software to reconstruct intraspecific phylogeny. Results We detected six cpDNA haplotypes, geographically highly structured into non‐overlapping areas. With one exception, none of the populations had mixed haplotype composition. TCS analysis resulted in two intraspecific cpDNA lineages, with one clade subdivided further by shallower diversification. Main conclusions Our investigation revealed that T. cuneatum survived the LGM in multiple refugia, belonging to two (western, eastern) genealogical lineages geographically structured across south‐eastern North America. The western clade is confined to the south‐western corner of T. cuneatum’s modern range along the Lower Mississippi Valley, where fossil records document a major refugium of mesic deciduous forest. For the eastern clade, modern patterns of cpDNA haplotype distribution suggest cryptic vicariance, in the form of forest contractions and subsequent expansions associated with Pleistocene glacial cycles, rather than simple southern survival and subsequent northward colonization. The north–south partitioning of cpDNA haplotypes was unexpected, suggesting that populations of this rather southern thermophilic species may have survived in more northern locations than initially expected based on LGM climate reconstruction, and that the Appalachian Mountains functioned as a barrier to the dispersal of propagules originating in more southern refugia. Furthermore, our results reveal south‐west to north‐east directionality in historical migration through the Valley and Ridge region of north‐west Georgia.     

Is it really you,Orthotrichum acuminatum? Ascertaining a new case of intercontinental disjunction in mosses

Intercontinental disjunct distributions are a main issue in current biogeography. Bryophytes usually have broad distribution ranges and therefore constitute an interesting subject of study in this context. During recent fieldwork in western North America and eastern Africa, we found new populations of a moss morphologically similar to Orthotrichum acuminatum. So far this species has been considered to be one of the most typical epiphytic mosses of the Mediterranean Basin. The new findings raise some puzzling questions. Do these new populations belong to cryptic species or do they belong to O. acuminatum, a species which then has a multiple‐continent disjunct range? In the latter case, how could such an intercontinental disjunction be explained? To answer these questions, an integrative study involving morphological and molecular approaches was conducted. Morphological results reveal that Californian and Ethiopian samples fall within the variability of those from the Mediterranean Basin. Similarly, phylogenetic analyses confirm the monophyly of these populations, showing that O. acuminatum is one of the few moss species with a distribution comprising the western Nearctic, the western Palaearctic and Palaeotropical eastern Africa. Pending a further genetic and phylogeographical study to support or reject the hypothesis, a process of long‐distance dispersal (LDD) is hypothesized to explain this distribution and the origin of the species is suggested to be the Mediterranean Basin, from where diaspores of the species may have migrated to California and Ethiopia. The spore release process in O. acuminatum is revisited to support the LDD hypothesis, © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 180 , 30–49.     

Thoughts on the ecology and evolution of the intertidal biota of the Azores and other Atlantic islands

The special features of the intertidal ecosystems of remote islands are reviewed briefly before focusing on the littoral zone of Macaronesia (Azores, Madeira and Canaries). Distribution patterns are briefly compared with other European shores. Species missing from the Azores compared with Madeira, the Canaries and continental European shores are listed. The degree of genetic differentiation within and amongst selected important species of gastropods (Patella spp.) and barnacles (Chthamalus spp.) in Macaronesia is reviewed. The role of isolated islands in allopatric speciation of these organisms is discussed in relation to dispersal. Possible threats to the populations and communities of rocky shores in Macaronesia are considered in the context of the endemic nature of certain species. The importance of studies of basic ecology and genetics to inform resource management and conservation is highlighted. Future research directions are indicated, emphasizing the usefulness of Macaronesia as a model system to explore speciation in intertidal organisms.     

Chloroplast DNA variation in dactylis glomerata L. taxa endemic to the macaronesian islands

In the Dactylis glomerata infraspecific polyploid grass complex, restriction fragment length polymorphisms (RFLPs) of chloroplast DNA (cpDNA) were studied in diploid and tetraploid populations of several taxa endemic to Macaronesia (Madeira and the Canary islands) and in populations from the African and European continental areas closest to Macaronesia. Two chlorotypes, which differed by a single 290-bp length mutation, were observed in the Macaronesian and the continental populations. Chlorotype I, which is predominant in the whole D. glomerata complex, was found in the majority of continental populations. It was also observed in the most western Macaronesian islands, in the two diploid taxa endemic to the lowland scrub and the high elevation heath of Tenerife, respectively, and in tetraploids endemic to Madeira and La Palma. These island populations were growing under the influence of humid trade winds. Chlorotype II was found in the eastern part of the Archipelago (closer to Africa), which experienced subarid Mediterranean climate conditions, and in very few diploid and tetraploid Mediterranean populations growing at high elevation on the continent. This geographical and climatic distribution of chlorotype variation in Macaronesia is consistent with that reported previously for morphological, allozyme and phenolic variation in the same plant material. Chlorotype II was, however, also observed in tetraploid populations from La Gomera island and in one of the seven tetraploid populations analysed from Madeira, which all showed clearly subtropical characters for morphology, allozymes and phenolic compounds. This result suggests that cpDNA introgression has occurred more than once from the Mediterranean material into the subtropical one and may indicate that colonization between the mainland and islands, or among the islands, probably played a major role in the geographical pattern observed for that marker.     

Bird–flower interactions in the Macaronesian islands

Aims Several bird‐pollinated or ornithophilous flowers are present on the Macaronesian archipelagos, the Canary Islands and Madeira, but absent from nearby NW Africa and Europe. In Macaronesia, no specialist nectar‐feeding birds are found, but several generalist passerine bird species visit flowers for nectar. Two hypotheses attempt to explain the origin and evolution of ornithophily in the Macaronesian flora. According to ‘the island de novo hypothesis’, bird‐flowers evolved from mainland insect‐pollinated ancestors after island colonization. Alternatively, ancestors of the ornithophilous Macaronesian plant species evolved bird‐flowers before reaching the islands (‘the relict hypothesis’). In this study we first compile information of Macaronesian bird–flower interactions from the literature and our own field observations. Secondly, we discuss the two hypotheses of origin of ornithophily in the light of evidence from recent molecular plant phylogenies, palaeontology, historical biogeography of the African avifauna and flora, and present‐day ecological patterns. Location Madeira and Canary Islands. Results At least eleven endemic Macaronesian plant species from six genera have typical ornithophilous floral traits. These genera are: Canarina and Musschia (Campanulaceae), Isoplexis (Scrophulariaceae), Echium (Boraginaceae), Lotus (Fabaceae) and Lavatera (Malvaceae). These lineages have clear affinities to the Mediterranean region, except for Canarina whose closest relatives grow in East African mountains. Six generalist passerine bird species of Sylvia, Phylloscopus (Sylviidae), Serinus (Fringillidae) and Parus (Paridae) visit this flora for nectar. Main conclusion We suggest that the origin and evolution of ornithophilous traits in these plant species took place mostly in mainland areas prior to island colonization. In Canarina and Lavatera, it is well supported that ornithophily is a relict condition, which originated in mainland areas possibly in association with specialist nectar‐feeding birds. For the remaining plant species except Echium wildpretii bird floral traits probably also are a relict condition. These species may be derived from ancestors, which were visited by specialist nectar‐feeding birds during geological periods when the Mediterranean and the Ethiopian vegetation were intermingled in mainland Africa. Probably, these mainland ancestors went extinct due to severe climatic fluctuations, while their Macaronesian descendants survived in ‘refuge’ on the islands. Finally, the island de novo hypothesis may explain the evolution of a mixed bird/insect‐pollination system in the neo‐endemic red‐flowered Echium wildpretii.     

The evolution of north‐east Atlantic gadfly petrels using statistical phylogeography

Macaronesia (north‐east Atlantic archipelagos) has been host to complex patterns of colonization and differentiation in many groups of organisms including seabirds such as gadfly petrels (genus Pterodroma). Considering the subspecies of widely distributed soft‐plumaged petrel for many years, the taxonomic status of the three gadfly petrel taxa breeding in Macaronesia is not yet settled, some authors advocating the presence of three, two or one species. These birds have already been the subject of genetic studies with only one mtDNA gene and relatively modest sample sizes. In this study, using a total of five genes (two mitochondrial genes and three nuclear introns), we investigated the population and phylogeographical histories of petrel populations breeding on Madeira and Cape Verde archipelagos. Despite confirming complete lineage sorting with mtDNA, analyses with nucDNA failed to reveal any population structuring and Isolation with Migration analysis revealed the absence of gene flow during the differentiation process of these populations. It appears that the three populations diverged in the late Pleistocene in the last 150 000 years, that is 10 times more recently than previous estimates based solely on one mtDNA gene. Finally, our results suggest that the Madeira petrel population is ancestral rather than that from Cape Verde. This study strongly advocates the use of nuclear loci in addition to mtDNA in demographical and phylogeographical history studies.     

How do temperate bryophytes face the challenge of a changing environment? Lessons from the past and predictions for the future

Bryophytes are a group of early land plants, whose specific ecophysiological and biological features, including poikilohydry, sensitivity to moderately high temperature and high dispersal ability, make them ideal candidates for investigating the impact of climate changes. Employing a combined approach of species distribution modelling (SDM) and molecular phylogeography in the temperate moss Homalothecium sericeum, we explore the significance of the Mediterranean refugia, contrasting the southern and northern refugia hypotheses, determine the extent to which recolonization of previously glaciated areas has been facilitated by the high dispersal ability of the species and make predictions on the extent to which it will be impacted by ongoing climate change. The Mediterranean areas exhibit the highest nucleotidic diversities and host a mixture of ancestral, endemic and more recently derived haplotypes. Extra‐Mediterranean areas exhibit low genetic diversities and Euro‐Siberian populations display a significant signal of expansion that is identified to be of Euro‐Siberian origin, pointing to the northern refugia hypothesis. The SDMs predict a global net increase in range size owing to ongoing climate change, but substantial range reductions in southern areas. Presence of a significant phylogeographical signal at different spatial scales suggests, however, that dispersal limitations might constitute, as opposed to the traditional view of spore‐producing plants as efficient dispersers, a constraint for migration. This casts doubts about the ability of the species to face the massive extinctions predicted in the southern areas, threatening their status of reservoir of genetic diversity.     

Mitochondrial differentiation and biogeography of Hyla meridionalis (Anura: Hylidae): an unusual phylogeographical pattern

Aim To study the patterns of genetic variation and the historical events and processes that influenced the distribution and intraspecific diversity in Hyla meridionalis Boettger, 1874. Location Hyla meridionalis is restricted to the western part of the Mediterranean region. In northern Africa it is present in Tunisia, Algeria and Morocco. In south‐western Europe it is found in the south of France, north‐western Italy and north‐eastern and south‐western Iberian Peninsula. There are also insular populations, as in the Canaries and Menorca. Methods Sampling included 112 individuals from 36 populations covering the range of the species. We used sequences of mitochondrial DNA Cytochrome Oxidase I (COI) for the phylogeographical analysis (841 bp) and COI plus a fragment including part of tRNA lysine, ATP synthase subunits 6 and 8 and part of Cytochrome Oxidase III for phylogenetic analyses (2441 bp). Phylogenetic analyses were performed with paup *4.0b10 (maximum likelihood, maximum parsimony) and Mr Bayes 3.0 (Bayesian analysis). Nested clade analysis was performed using tcs 1.18 and Geo Dis 2.2. A dispersal‐vicariant analysis was performed with diva 1.0 to generate hypotheses about the geographical distribution of ancestors. Results We found little genetic diversity within samples from Morocco, south‐western Europe and the Canary Islands, with three well‐differentiated clades. One is distributed in south‐western Iberia and the High Atlas, Anti‐Atlas and Massa River in Morocco. The second is restricted to the Medium Atlas Mountains. The third one is present in northern Morocco, north‐eastern Iberia, southern France and the Canaries. These three groups are also represented in the nested clade analysis. Sequences from Tunisian specimens are highly divergent from sequences of all other populations, suggesting that the split between the two lineages is ancient. diva analysis suggests that the ancestral distribution of the different lineages was restricted to Africa, and that an explanation of current distribution of the species requires three different dispersal events. Main conclusions Our results support the idea of a very recent colonization of south‐western Europe and the Canary Islands from Morocco. South‐western Europe has been colonized at least twice: once from northern Morocco probably to the Mediterranean coast of France and once from the western coast of Morocco to southern Iberia. Human transport is a likely explanation for at least one of these events. Within Morocco, the pattern of diversity is consistent with a model of mountain refugia during hyperarid periods within the Pleistocene. Evaluation of the phylogenetic relationships of Tunisian haplotypes will require an approach involving the other related hylid taxa in the area.     

Testing phylogenetic hypotheses for reconstructing the evolutionary history of Dolichopoda cave crickets in the eastern Mediterranean

Aim To investigate the molecular phylogenetic divergence and historical biogeography of cave crickets belonging to the genus Dolichopoda (Orthoptera, Rhaphidophoridae). Location Caves in continental and insular Greece. Methods We sequenced 1967 bp of mitochondrial DNA, corresponding to three fragments of the small and large subunit of the ribosomal RNA (16S and 12S rRNA, respectively) and to the subunit I of cytochrome oxidase (COI), to reconstruct phylogenetic relationships among all 30 known Greek species of Dolichopoda. Alternative hypotheses about the colonization of the Hellenic Peninsula by Dolichopoda species were tested by comparing the degree of discordance between species trees and gene trees under four plausible biogeographical scenarios. Results The present study revealed a rather well resolved phylogeny at species level, identifying a number of clades that represent long‐separated lineages and diverse evolutionary histories within the genus Dolichopoda. Two main clades were revealed within Hellenic–Aegean species, identifying a north‐western and a south‐eastern species group. Based on Bayesian analysis, we applied a relaxed molecular clock to estimate the divergence times between the lineages. The results revealed that the origins of eastern Mediterranean lineages are much older than those of previously studied western Mediterranean Dolichopoda. Tests of alternative biogeographical hypotheses showed that a double colonization of the Hellenic Peninsula, following separate continental and trans‐Aegean routes during the Messinian stage, best accounts for the present distribution of Greek Dolichopoda species. Main conclusions Reconstruction and biogeographical hypothesis testing indicated that the colonization of Greece by Dolichopoda species comprised two episodes and two different routes. The southern lineage probably arose from a trans‐Aegean colonization during the Messinian salinity crisis (5.96–5.33 Ma). The northern lineage could be the result of dispersal from the north through the Balkan Peninsula. The opening of the Mid‐Aegean Trench could have promoted an initial diversification within the uprising Anatolian Plateau, while the Messinian marine regression offered the conditions for a rapid dispersal through the whole Aegean–Hellenic region. In addition, climatic events during the Plio‐Pleistocene may have been responsible for the speciation within each of the two different phylogeographical units, principally attributable to vicariance events.     

A molecular phylogenetic appraisal of the systematics of the Aglaopheniidae (Cnidaria: Hydrozoa,Leptothecata) from the north‐east Atlantic and west Mediterranean

The hydrozoan family Aglaopheniidae (Cnidaria) is widespread worldwide and contains some of the most easily recognizable hydroids because of their large colony size and characteristic microscopic structure. The systematics of the group has, however, been controversial and dedicated molecular analyses are lacking. We therefore analysed existing and new 16S rRNA sequences of Aglaopheniidae, in a total of 98 16S sequences corresponding to 25 putative species (25 nominal and three undescribed) from seven genera. The monophyly of the subfamilies Gymnangiinae and Aglaopheniinae, and tribes Aglaopheniini and Cladocarpini were not verified with 16S sequence data. The genera Gymnangium and Aglaophenia can only be considered valid if both Gymnangium gracicaule and Aglaophenia latecarinata are removed from their respective genera. The phenotypically similar Cladocarpus and Streptocaulus are probably monophyletic and clearly distinct genetically. The genus Lytocarpia may be polyphyletic. The nominal species Aglaophenia pluma, Aglaophenia tubiformis, and Aglaophenia octodonta are probably conspecific, as are also the species Aglaophenia acacia and Aglaophenia elongata. The 16S data revealed the existence of two potentially unnamed species of Aglaophenia respectively from the Azores and Madeira. The phylogeographical structure of the taxa with the greatest representation of haplotypes from the north‐east Atlantic and Mediterranean, revealed the influence of Mediterranean waters in Madeira and the Azores, and gene flow between deep waters of the Mediterranean and Atlantic. The last glaciations in Europe may have caused genetic bottlenecks but also high intraspecific haplotype diversity. Finally, Macrorhynchia philippina was detected in samples from Madeira and possibly represents an invasive species. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 717–727.     

The colonization history of Olea europaea L. in Macaronesia based on internal transcribed spacer 1 (ITS-1) sequences, randomly amplified polymorphic DNAs (RAPD), and intersimple sequence repeats (ISSR)

Phylogenetic relationships in the Olea europaea complex and the phylogeography of 24 populations of the Macaronesian olive (O. europaea ssp. cerasiformis) were assessed by using three molecular markers: nuclear ribosomal internal transcribed spacer 1 (ITS-1) sequences, randomly amplified polymorphic DNAs (RAPD), and intersimple sequence repeats (ISSR). Parsimony analysis of the ITS-1 sequences and Neighbour-joining (NJ) analyses of RAPD and ISSR banding variation revealed four major lineages in the O. europaea complex: (1) ssp. cuspidata; (2) ssp. cerasiformis from Madeira; (3) ssp. laperrinei; and (4) ssp. cerasiformis from the Canary Islands plus ssp. europaea. These results provide unequivocal support for two independent dispersal events of Olea to the Madeira and Canary Islands. Molecular and morphological evidence led to recognition of two separate olive taxa in Macaronesia, to date included in ssp. cerasiformis. NJ analyses of the combined RAPD and ISSR data suggest that the colonization of the Canaries by O. europaea may have followed an east to west stepping-stone model. An interisland dispersal sequence can be recognized, starting from the continent to Fuerteventura, Gran Canaria, Tenerife, La Gomera, and finally La Palma. High dispersal activity of the lipid-rich Olea fruits by birds in the Mediterranean region is congruent with multiple dispersal of olives to Macaronesia and successive colonization of the archipelagos. The observation of strong genetic isolation between populations of different islands of the Canary Islands suggests, however, that subsequent interisland dispersal and establishment has been very rare or may not have occurred at all.     

Genetic isolation of insular populations of the Maghrebian bat,Myotis punicus,in the Mediterranean Basin

Aim We investigate the population genetic structure of the Maghrebian bat, Myotis punicus, between the mainland and islands to assess the island colonization pattern and current gene flow between nearby islands and within the mainland. Location North Africa and the Mediterranean islands of Corsica and Sardinia. Methods We sequenced part of the control region (HVII) of 79 bats across 11 colonies. The phylogeographical pattern was assessed by analysing molecular diversity indices, examining differentiation among populations and estimating divergence time. In addition, we genotyped 182 bats across 10 colonies at seven microsatellite loci. We used analysis of molecular variance and a Bayesian approach to infer nuclear population structure. Finally, we estimated sex‐specific dispersal between Corsica and Sardinia. Results Mitochondrial analyses indicated that colonies between Corsica, Sardinia and North Africa are highly differentiated. Within islands there was no difference between colonies, while at the continental level Moroccan and Tunisian populations were highly differentiated. Analyses with seven microsatellite loci showed a similar pattern. The sole difference was the lack of nuclear differentiation between populations in North Africa, suggesting a male‐biased dispersal over the continental area. The divergence time of Sardinian and Corsican populations was estimated to date back to the early and mid‐Pleistocene. Main conclusions Island colonization by the Maghrebian bats seems to have occurred in a stepping‐stone manner and certainly pre‐dated human colonization. Currently, open water seems to prevent exchange of bats between the two islands, despite their ability to fly and the narrowness of the strait of Bonifacio. Corsican and Sardinian populations are thus currently isolated from any continental gene pool and must therefore be considered as different evolutionarily significant units (ESU).