56 research outputs found

    Novedades nomenclaturales en el género "Holcus" (Poaceae).

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    Nomenclatural novelties in the genus Holcus (Poaceae)Palabras clave. Nomenclatura, Holcus, Poaceae.Key words. Nomenclature, Holcus, Poaceae

    Population decline in the critically endangered Musschia isambertoi (Campanulaceae) endemic to Desertas Islands (Madeira Archipelago) calls for urgent conservation management

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    Macaronesian islands display a high degree of plant endemicity and correspond to some of the most threatened biodiversity hotspots due to several human driven impacts such as habitat loss, invasive species, overexploitation or climate change. The conservation status of the largest of the two known population of Musschia isambertoi M. Seq., R. Jardim, Magda Silva and L. Carvalho (Campanulaceae) was assessed recently. Field work was done in June 2018 in “Porto das Moças” Deserta Grande (Madeira Archipelago, Portugal), the locus typicus, where in 2006 close to 30 plants were detected with a high variation of age/size between individuals comprising both fully flowering and non-flowering adult plants as well as seedlings, and thus corresponding to a healthy population. This study assesses population size, age and plant size, and genetic, as well as floristic diversity. The total area of the site corresponds to approximately 1500 square meters. Ten individuals were detected, all corresponding to young seedlings not exceeding 15 cm high, and exhibiting approximately the same size and numbers of leaves (4–8). No adult plants or remains of adult plants were seen. Ecological data and direct herbivory evidence suggest that perennial plants are subjected to elimination during the short summer by the feral goat population. Mo lecular data based on ISSR markers show that the nine sampled individuals (out of ten individuals found) are genetically identical, possibly resulting from one parental plant. Results clearly suggest that Musschia isambertoi is very close to extinction. Urgent conservation measures are imperative and should include the immediate fencing of the population followed by the elimination of feral goats from Deserta Grande. The elimination of feral goats was initiated in 1996 (LIFE95 NAT/P/000125, 383,467.00 €) but stopped due to inappropriate conser vation policies of the former Services of the Natural Park of Madeira.info:eu-repo/semantics/publishedVersio

    Understanding intra and inter-archipelago population genetic patterns within a recently evolved insular endemic lineage

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    The recently evolved genus Tolpis Adans. has its major center of diversity located in Macaronesia. Although recent advances have been made to understand the relationships of Tolpis species within Macaronesia, little is still known about the genetic patterns and genetic diversity of the Azorean and Madeiran Tolpis populations. To achieve this, a set of 8 microsatellite loci (SSR) was applied to 478 individuals of Tolpis azorica and T. suc culenta. Genetic structure analysis, in addition to a spatial analysis, confirmed the existence of geographically cir cumscribed genetic patterns allied to a barrier effect by the sea in the Azorean T. azorica and T. succulenta. A detailed analysis of T. azorica revealed three different genetic groups, each group being particular to a different Azorean sub-archipelago, while the analysis conducted with T. succulenta confirmed the occurrence of a differ ential grouping between individuals from Azores and Madeira populations. The impact of catastrophic volcanic events and intense humanization of the habitats is dis cussed, in view of the present genetic diversity and structure of the species. In general, T. azorica populations showed high Fis values and some populations of T. suc culenta both in Azores and in Madeira also showed signs of putative inbreeding. Conservation actions such as the eradication of invasive plant and animal species are advised but translocations of plants or diaspores between islands or between populations of a same island should not be attempted.info:eu-repo/semantics/publishedVersio

    Oceanic Island forests buried by Holocene (Meghalayan) explosive eruptions: palaeobiodiversity in pre-anthropic volcanic charcoal from Faial Island (Azores, Portugal) and its palaeoecological implications

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    In Faial Island (Azores Archipelago, North Atlantic Ocean), charcoalified and mummified wood fossils have been reported within late Holocene (Meghalayan) pyroclastic deposits from the Caldeira Formation. Due to their re cent age, a detailed study conveys a snapshot into Azorean palaeophytodiversity and palaeovegetation, ca. 7–5 centuries before the arrival of Portuguese settlers to the Azores Islands. Here we provide the first detailed ana tomical and taxonomical study of these wood fossils. In total, 41 samples were collected from seven localities, mainly from a ~1200 yr BP ignimbrite. Field work revealed autochthonous and paraautochthonous assemblages, with tree trunks in upright position. The anatomical study of the fossil woods resulted in the identification of Juniperus brevifolia, Laurus azorica, Myrsine retusa, Morella faya, Picconia azorica, Prunus lusitanica subsp. azorica, and Vaccinium cylindraceum. Two fossil assemblages are comparable to the proposed potential natural vegetation (PNV) for the Azores. Surprisingly, P. lusitanica subsp. azorica was the second most abundant fossil wood suggest ing that this tree was more abundant in a recent past in Faial Island and probably in the archipelago. This is cor roborated by historical accounts, and its modern scarcity was certainly anthropically driven. Identifying Holocene plant macrofossils is essential to properly reconstruct oceanic islands terrestrial palaeoecosystems, especially where forests with high percentage of entomophilous taxa are underrepresented in palaeopalynological limnic record. Further work is necessary to reconstruct Faial Island and Azores archipelago palaeovegetation which is essential to provide an ecosystem base-line for restoration and management.info:eu-repo/semantics/publishedVersio

    Genome size variation within Crithmum maritimum: Clues on the colonization of insular environments

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    Angiosperms present an astonishing diversity of genome sizes that can vary intra- or interspecifically. The remarkable new cytogenomic data shed some light on our understanding of evolution, but few studies were performed with insular and mainland populations to test possible correlations with dispersal, speciation, and adaptations to insular environments. Here, patterns of cytogenomic diversity were assessed among geographic samples (ca. 114) of Crithmum maritimum (Apiaceae), collected across the Azores and Madeira archipelagos, as well as in adjacent continental areas of Portugal. Using flow cytometry, the results indicated a significant intraspecific genome size variation, spanning from reduced sizes in the insular populations to larger ones in the mainland populations. Moreover, there was a tendency for an increase in genome size along the mainland populations, associated with lower temperatures, higher precipitation, and lower precipitation seasonality. However, this gradient might be the result of historic phylogeographical events associated with previous dispersal and extinction of local populations. Overall, our findings provided evidence that smaller genome sizes might play a critical role in the colonization of islands, corroborating other studies that argue that organisms with smaller genomes use fewer resources, having a selective advantage under insular environments. Although further studies are needed to improve our understanding of the mechanisms underlying genome size evolution on islands, conservation strategies must be promoted to protect the rich cytogenomic diversity found among C. maritimum populations, which occur in coastal areas that are particularly threatened by human activity, pollution, invasive species, and climate changes.info:eu-repo/semantics/publishedVersio

    Phylogenetic relationships and phylogeography of relevant lineages within the complex Campanulaceae family in Macaronesia

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    Original ResearchMacaronesia has long been recognized as a natural model for studying evolutionary processes in plant diversification. Several studies have attempted to focus on single lineages, and few have covered the diversification of a family across all the archipelagos. We used a comprehensive sample to clarify the phylogenetic relationships and the biogeographic history of the Macaronesian Campanulaceae. Hypotheses related to the colonization of these archipelagos will be used to examine the diversification patterns of different lineages. We sequenced the ITS region and six cpDNA markers (atpB, matK, petD, rbcL, trnL-F, and psbA-trnH) from 10 Campanulaceae species, including seven endemic species in Macaronesia. The phylogeny of these taxa was reconstructed using maximum parsimony, maximum likelihood, and Bayesian inference. To study the relationships within each lineage, haplotype networks were calculated using NeighborNet and TCS algorithms. Moreover, data were combined with fossil information to construct time-calibrated trees for the Macaronesian Campanulaceae species. The phylogenetic analyses are largely congruent with current taxon circumscriptions, and all the endemic genera formed monophyletic clades, namely Azorina in Azores; Musschia in Madeira; and Campanula in Cape Verde. The Azorina clade and the Cape Verde endemic Campanula may share a common ancestor in North Africa, and the divergence was dated ca. 12.3 million years ago (Mya). The divergence of the Musschia clade began in the Pliocene ca. 3.4 Mya. Moreover, several examples of intraspecific variation were revealed among the native species with a clear geographic structured patterns, suggesting that cryptic diversity might exist within the native Macaronesian Campanulaceae when compared to the close mainland taxa (e.g., Campanula erinus, Trachelium caeruleum), but additional studies are needed to support the molecular data. This study highlights the power of combining data (e.g., phylogeny and divergence times, with species distribution data) for testing diversification hypotheses within the unique Macaronesian flora, providing useful information for future conservation efforts.info:eu-repo/semantics/publishedVersio

    An expanded molecular phylogeny of Plumbaginaceae, with emphasis on Limonium (sea lavenders): taxonomic implications and biogeographic considerations

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    Plumbaginaceae is characterized by a history of multiple taxonomic rearrangements and lacks a broad molecular phylogenetic framework. Limonium is the most speciesrich genus of the family with ca. 600 species and cosmopolitan distribution. Its center of diversity is the Mediterranean region, where ca. 70% of all Limonium species are endemic. In this study, we sample 201 Limonium species covering all described infrageneric entities and spanning its wide geographic range, along with 64 species of other Plumbaginaceae genera, representing 23 out of 29 genera of the family. Additionally, 20 species of the sister family Polygonaceae were used as outgroup. Sequences of three chloroplast (trnL‐F, matK, and rbcL) and one nuclear (ITS) loci were used to infer the molecular phylogeny employing maximum likelihood and Bayesian analyses. According to our results, within Plumbaginoideae, Plumbago forms a nonmonophyletic assemblage, with Plumbago europaea sister to Plumbagella, while the other Plumbago species form a clade sister to Dyerophytum. Within Limonioideae, Ikonnikovia is nested in Goniolimon, rejecting its former segregation as genus distinct from Goniolimon. Limonium is divided into two major clades: Limonium subg. Pteroclados s.l., including L. sect. Pteroclados and L. anthericoides, and L. subg. Limonium. The latter is divided into three well‐supported subclades: the monospecific L. sect. Limoniodendron sister to a clade comprising a mostly non‐Mediterranean subclade and a Mediterranean subclade. Our results set the foundation for taxonomic proposals on sections and subsections of Limonium, namely: (a) the newly described L. sect. Tenuiramosum, created to assign L. anthericoides at the sectional rank; (b) the more restricted circumscriptions of L. sect. Limonium (= L. sect. Limonium subsect. Genuinae) and L. sect. Sarcophyllum (for the Sudano‐Zambezian/Saharo‐Arabian clade); (c) the more expanded circumscription of L. sect. Nephrophyllum (including species of the L. bellidifolium complex); and (d) the new combinations for L. sect. Pruinosum and L. sect. Pteroclados subsect. Odontolepideae and subsect. Nobiles.European Union’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 226,506, Grant/Award Number: SYNTHESYS project GB-TAF-5704; Georges‐und‐Antoine‐Claraz‐Schenkung; University of Zurich (Department of Systematic and Evolutionary Botany); Seventh Framework Programme, Grant/ Award Number: FP7, 2007 and 2013; University of Zuric

    Inventory and review of the Mio–Pleistocene São Jorge flora (Madeira Island, Portugal): palaeoecological and biogeographical implications

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    The occurrence of plant fossils on Madeira Island has been known since the mid-nineteenth century. Charles Lyell and George Hartung discovered a leaf bed rich in Lauraceae and fern fossils at S~ao Jorge in 1854. The determinations were controversial but a full review was never performed. Here we propose possible geological settings for the fossiliferous outcrop, and present an inventory and a systematic review of the surviving specimens of the S~ao Jorge macroflora. The S~ao Jorge leaf bed no longer outcrops due to a landslide in 1865. It was possible to establish the two alternative volcano stratigraphical settings in the sedimentary intercalations from the Middle Volcanic Complex, ranging in age from 7 to 1.8 Ma. The descriptions of Heer (1857), Bunbury (1859) and Hartung & Mayer (1864) are reviewed based on 82 surviving specimens. From the initial 37 taxa, we recognize only 20: Osmunda sp., Pteridium aquilinum, Asplenium cf. onopteris, aff. Asplenium, cf. Polystichum, cf. Davallia, Woodwardia radicans, Filicopsida gen. et sp. indet. 1 and 2, Ocotea foetens, Salix sp., Erica arborea, cf. Vaccinium, Rubus sp, cf. Myrtus, Magnoliopsida gen. et sp. indet. 1 to 3, Liliopsida gen. et sp. indet. 1. Magnoliopsida gen. et sp. indet. 4 is based on one previously undescribed flower or fruit. The floristic composition of the S~ao Jorge fossils resembles the current floristic association of temperate stink laurel (Ocotea foetens) forest, suggesting a warm and humid palaeoclimate and indicating that laurel forests were present in Macaronesia at least since the Gelasian, a time when the palaeotropical geofloral elements were almost extinct in Europe.info:eu-repo/semantics/publishedVersio
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