Cololejeunea schaeferi spec. nov., ein verkanntes Lebermoos in Makaronesien

Abstract

Cololejeunea (subg. Cololejeunea) schaeferi n. sp. is described and figured from the Canaries. Somewhat deviating plants from Madeira are included. A key to the species of subgenus Cololejeunea in Europe arid Macaronesia is given. All records of C. calcarea (Libert) Schiffn. and C. rossettiana (Mass.) Schiffn. from Macaronesia are rejected.     

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.     

Morphological and phytochemical studies of Plagiochila papillifolia Steph., a Neotropical liverwort new to Europe

Abstract

The Neotropical liverwort Plagiochila papillifolia Steph. is conspecific with P. caespiticia Spruce ex Herzog (nom. inval.), P . deciduifolia Steph., P . solmsii Steph. and P . verruculosa R.M.Schust.; it is reported from the Azores, new to Europe. Morphologically it shows affinity with sect. Bidentes Carl; phytochemically, several of its lipophilic secondary metabolites are the same as those of P . retrorsa Gottsche, another Neotropical species reported only recently from Macaronesia.     

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.     

Grimmia agassizii (Sull. & Lesq.) Jaeg. in Britain

Abstract

The marked differences between Plagiochila spinulosa (Dicks.) Dum. and P. killarniensis Pears. pointed out by Paton (1977) are confirmed and added to by further ones. As a result the two species are placed in different sections Spinulosae and Zonatae, respectively. For each of the two species the full synonymy including new synonyms and new lectotypifications and a comprehensive list of studied specimens and a distribution map are presented. In appendix, P. porelloides (Torrey ex Nees) Lindenb. is recorded from Madeira, a species new to Macaronesia.     

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.     

An annotated checklist of the mosses of Europe and Macaronesia

Abstract

The moss flora of Europe and Macaronesia comprises 278 genera, 1292 species, 46 subspecies and 118 varieties. Of the total 1292 species, 53 are confined to Macaronesia and 21 are thought to be non-native. The checklist was derived from those for the various component countries and regions. It is based on results published up to the end of 2005. Subspecies and varieties are included; hybrids are omitted. The taxonomic hierarchy is based on one published by Goffinet & Buck in 2004. While it has been strongly influenced by results of modern molecular methods, there are still many remaining uncertainties, even at family level. Because of these uncertainties, taxonomic innovation has generally been avoided. There are four new combinations and one change of status.     

Tracing the introduction history of the brown seaweed Dictyota cyanoloma (Phaeophyceae,Dictyotales) in Europe

Dictyota cyanoloma has recently been described from the Mediterranean Sea and Macaronesia but doubt had arisen as to whether this species was truly native in Europe. The species is mainly found on non-natural substrata (harbour walls, marinas, boat hulls, etc.), strongly suggesting that it is an introduction. Molecular sequence information from historical herbarium samples proves the presence of D. cyanoloma in the Adriatic Sea as early as 1935. Since approximately the year 2000, however, the number of records as well as the geographic range of the species has expanded significantly. The present-day distribution of D. cyanoloma occupies most of the Mediterranean Sea, Macaronesia, NW Africa and southern Portugal, but recent records from Galicia and SW England (Falmouth, Cornwall) indicate that the species is rapidly expanding northward. Collections from Australia demonstrated that the species is also present from Perth in Western Australia, over much of the southern Australian coastline up to Minnie Water in New South Wales. Phylogenetic analyses resolve D. cyanoloma in a sister clade to a previously unreported Australian Dictyota species. Analysis of genetic diversity of the mitochondrial markers (nad6–nad11 and atp9–orf11) reveals that even though Australian populations contain a much higher haplotype richness, European populations are also fairly diverse. Furthermore, only two out of 25 haplotypes are shared between both regions. These somewhat counterintuitive results could be indicative of a more complicated introduction history.     

Lobophora (Dictyotales) Species Richness,Ecology and Biogeography Across the North-Eastern Atlantic Archipelagos and Description of Two New Species1

The brown alga Lobophora (Dictyotales, Phaeophyceae) is an important macroalga in the North-eastern Atlantic archipelagos (i.e., Macaronesia). Notably in the Canaries it can dominate benthic assemblages. While the genus has been the subject of several ecological studies in the Canaries, no study has yet been conducted to assess species-level diversity of Lobophora in Macaronesia. We reassessed the diversity of Lobophora in Macaronesia, reporting the presence of seven species (L. caboverdeana sp. nov., L. canariensis, L. dagamae sp. nov., L. delicata, L. dispersa, L. littlerorum, and L. schneideri). Lobophora spp. from Macaronesia are morphologically and ecologically distinguishable. In the Canaries, L. schneideri dominates the photophilic assemblages from the intertidal to 20-30 m depth. Lobophora dagamae sp. nov. grows in less illuminated shallow habitats, and replaces L. schneideri from 30 to ~80 m. Lobophora canariensis also has a wide vertical distribution, from the intertidal to deep waters, while L. delicata, L. dispersa and L. littlerorum grow in shallow waters. The dominance of species with an upright habit versus prostrate or crustose species may be mediated by the pressure of herbivores. Four species have an amphi-Atlantic distribution: L. littlerorum, L. canariensis, L. delicata, and L. schneideri. Lobophora schneideri and L. delicata are furthermore distributed in the Mediterranean Sea. By sampling a pivotal region in the Atlantic, this study significantly improves our knowledge of Lobophora biogeography in the Atlantic Ocean. Macaronesia constitutes a species–poor region for Lobophora where no diversification events occurred, and a region of overlap between the Greater Caribbean and the Indo-Pacific.     

The barriers to oceanic island radiation in bryophytes: insights from the phylogeography of the moss Grimmia montana

Aim In contrast to angiosperms, bryophytes do not appear to have radiated in Macaronesia and the western Mediterranean. We evaluate if: (1) the apparent lack of radiation in bryophytes reflects our failure to recognize cryptic endemic species; (2) bryophytes are characterized by extremely low evolutionary rates; or (3) bryophytes have a high dispersal ability, which prevents genetic isolation. Location Worldwide, with a special emphasis on Macaronesia and the western Mediterranean. Methods Three chloroplast regions were sequenced from samples of the moss Grimmia montana from its entire distribution range. Network analyses, Fst and Nst statistics were used to describe and interpret the phylogeographical signal in the data. Results Despite significant phylogeographical signal in the chloroplast genome, which demonstrates limits to gene flow at the continental scale, repeated sister group relationships observed among accessions from different geographical areas suggest recurrent colonization patterns. These observations are consistent with mounting evidence that intercontinental distributions exhibited by many bryophyte species result from long‐distance dispersal rather than continental drift. Madeiran and western Mediterranean island haplotypes are either shared by, or closely related to, European and North American ones. Fst values between Madeira, western Mediterranean islands, North America and Europe are not significantly different from zero, and suggest that Madeira and the south‐western Mediterranean are subject to strong transatlantic gene flow. By contrast, haplotypes found in the Canary Islands are shared or closely related to those of populations from south‐western Europe or southern Africa. Main conclusions Multiple origins and colonization events are not consistent with the hypothesis of a relictual origin of the Macaronesian moss flora. One possible reason for the failure of taxa that experienced multiple colonization events to radiate is niche pre‐emption. We suggest that strong gene flow, coupled with the occupancy of all suitable niches, either by earlier conspecific colonizers or by other species, could be the mechanism preventing island radiation in G. montana and other cryptogams with high long‐distance dispersal abilities.     

Repeated jumps from Northwest Africa to the European continent: The case of peripheral populations of an annual plant

Peripheral populations (i.e., those occurring on the edge of a species’ distribution range) can have different origins and genetic characteristics, and they may be critical for the conservation of genetic diversity. We investigated European peripheral populations of Scrophularia arguta, a widespread, annual plant distributed from Arabia to Northwest Africa and Macaronesia. Only two small disjunct population groups of this species occur in Europe, specifically in West‐Central and Southeast Iberia. To disclose the origin of these populations and determine their importance for the conservation of S. arguta genetic diversity, we analyzed DNA sequences from two nuclear and two plastid regions and amplified fragment length polymorphism markers in populations sampled mainly across the western distribution range of the species, and modeled the species distribution under present and late Quaternary conditions. The analyses revealed the presence of three distinct lineages of S. arguta in Europe, as a result of multiple colonization waves at different times in the Quaternary. Two of these lineages, occurring in Southeast Iberia, are the result of more or less recent dispersal from Northwest Africa. In contrast, West‐Central Iberian populations are strongly differentiated from the remaining range of S. arguta and can be considered as peripheral relict populations. Our study is the first to demonstrate the occurrence of at least three colonizations of the European continent from Africa by a native plant species. The diverse histories and genetic makeup of the resulting populations confirm the importance of peripheral populations, and particularly of ancient relict populations, for the conservation of global genetic diversity in widespread species.     

Intercontinental disjunctions in Cryptotaenia (Apiaceae, Oenantheae): an appraisal using molecular data

Aim The angiosperm genus Cryptotaenia (family Apiaceae, tribe Oenantheae) exhibits an anomalous distribution pattern, with five of its eight species being narrow endemics geographically isolated from their presumed relatives. We examined the monophyly of the genus and ascertained the phylogenetic placements of its constituent members in order to explain their distribution patterns. Location Eastern North America, eastern Asia, the Caucasus, southern Italy, Macaronesia and Africa. Methods In total, 173 accessions were examined for nuclear rDNA ITS sequence variation, representing nearly all major lineages of Apiaceae subfamily Apioideae and seven species of Cryptotaenia. Sampling of tribes Oenantheae, Scandiceae and Pimpinelleae was comprehensive. Phylogenetic analyses included Bayesian, maximum parsimony and neighbour‐joining methods; biogeographical scenarios were inferred using dispersal–vicariance analysis (diva ). Results Cryptotaenia is polyphyletic and includes three distant lineages. (1) Cryptotaenia sensu stricto (C. canadensis, C. japonica, C. flahaultii and C. thomasii) is maintained within tribe Oenantheae; C. canadensis and C. japonica, representing an eastern North American–eastern Asian disjunction pattern, are confirmed to be sister species. (2) Cryptotaenia elegans, endemic to the Canary Islands, is placed within Scandiceae subtribe Daucinae along with two woody endemics of Madeira, Monizia edulis and Melanoselinum decipiens. The phylogeny of these Canarian and Madeiran endemics is unresolved. Either they constitute a monophyletic sister group to a clade comprising some Mediterranean and African species of Daucus and their relatives, or they are paraphyletic to this clade. The herbaceous/woody genus Tornabenea from Cape Verde, once included in Melanoselinum, is not closely related to the other Macaronesian endemics but to Daucus carota. (3) The African members of Cryptotaenia (C. africana, C. calycina and possibly C. polygama) comprise a clade with some African and Madagascan umbellifers; this entire clade is sister group to Eurasian Pimpinella. Main conclusions Elucidating the phylogeny of the biogeographically anomalous Cryptotaenia sensu lato enabled hypotheses on the biogeography of its constituent lineages. Cryptotaenia sensu stricto exhibits a holarctic distribution pattern, with its members occurring in regions that were important glacial refugia. The genus probably originated in eastern Asia and from there dispersed to Europe and North America. For the Macaronesian endemic species –C. elegans, M. edulis and M. decipiens–diva reconstructs either a single dispersal event to Macaronesia from the Mediterranean/African region, or a single dispersal followed by a back‐dispersal to the mainland. The radiation of Tornabenea from Cape Verde followed a second dispersal of Daucinae to Macaronesia. Woodiness in Melanoselinum/Monizia and Tornabenea, therefore, is a derived and independently acquired trait. The African members of Cryptotaenia are derived from an ancestor arriving from the Middle East.     

An integrative systematic approach to species diversity and distribution in the genus Mesophyllum (Corallinales,Rhodophyta) in Atlantic and Mediterranean Europe

For the first time, a comprehensive assessment of Mesophyllum species diversity and their distribution in Atlantic Europe and the Mediterranean Sea is presented based on molecular (COI-5P, psbA) and morphological data. The distribution ranges were redefined for the four species collected in this study: M. alternans, M. expansum, M. macroblastum and M. sphaericum. Mesophyllum sphaericum, which was previously known only from a single maerl bed in Galicia (NW Spain), is reported from the Mediterranean Sea. The known range of M. expansum (Mediterranean and Macaronesia) was extended to the Atlantic Iberian Peninsula. The occurrence of M. alternans was confirmed along the Atlantic French coast south to Algarve (southern Portugal). Mesophyllum lichenoides was only recorded from the Atlantic, whereas M. macroblastum appears to be restricted to the Mediterranean Sea. A positive correlation was observed between maximum Sea Surface Temperature (SSTmax) and the depth at which M. expansum was collected, suggesting that this species may compensate for higher SST by growing in deeper habitats where the temperature is lower. The latter indicates that geographic shifts in the distribution of coastal species as a result of global warming can possibly be mitigated by changes in the depth profile at which these species occur. Mesophyllum expansum, an important builder of Mediterranean coralligenous habitats, may be a good target species to assess its response to climate change.     

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.     

Arbuscular mycorrhiza and water and nutrient supply differently impact seedling performance of dry woodland species with different acquisition strategies

Background: We recently demonstrated that dwarf male plants are much more common among mosses than hitherto thought. Dwarf plants, producing functional male sexual organs occur in 10–20% of the moss species worldwide.

Aims: We investigated how an inadvertent omission of dwarf males affects estimates of male sex expression rates and sex ratios.

Methods: We recorded frequencies of specimens with female-expressing plants, male-expressing normal-sized and/or dwarf plants, and sporophytes in herbarium material of five model species from Macaronesia. We analysed how frequency estimates of male occurrence and sex ratios were affected by excluding dwarf males.

Results: Occurrence of dwarf males was positively associated with sporophyte formation. When dwarf males were excluded, male mate availability was missed in 51–61% of specimens (in 74–76% of sporophyte-containing specimens). Specimen-level sex ratio was balanced in material with sporophytes in the three species exhibiting male dwarfism, but strongly female biased if dwarf males were omitted.

Conclusions: We provide the first quantitative evidence that sex-expressing dwarf males are essential for sexual reproduction and sporophyte production in mosses that form such males. Considering its abundance, male dwarfism therefore deserves more attention among plant biologists. Innovative approaches are required to further study the minute male plants.     

Some additions to the bryophyte flora of the Azores

Abstract

This paper lists the noteworthy bryophytes collected by the authors in 1980 and 1992 on five of the nine islands of the Azores. Twenty-one species are new to the Azores three of these (Riccia beyrichiana, Dicranella schreberiana and Ephemerum cohaerens) being new to Macaronesia. Reasons are given for regarding Ptychomitrium azoricum as a synonym of P. polyphyllum and Tortella cirrifolia as a variety or subspecies of T. nitida.     

Noteworthy bryophytes on disturbed soil in N.E. Tanzania

Abstract

Schistidium occidentale (E. Lawton) Churchill is reported for the first time in Europe, from the Sierra Nevada (Spain). Previously it was known only from the mountains of southwestern North America. The species is illustrated, and notes are given on its distribution and ecology.     

Weissia papillosissima Laz. (Pottiaceae,Musci), a species new to the European bryophyte flora

Abstract

Weissia papillosissima Laz. is reported for the first time in Europe at different localities in the Iberian Peninsula. Previously it was known only from Tadhikistan in the former Soviet Union. The. species is described and illustrated and its distribution mapped and discussed.