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Sanz M.,University of Barcelona | Schonswetter P.,University of Innsbruck | Valles J.,University of Barcelona | Schneeweiss G.M.,University of Vienna | Vilatersana R.,Botanical Institute of Barcelona IBB CSIC ICUB
Botanical Journal of the Linnean Society | Year: 2014

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. Source


Canellas-Bolta N.,Botanical Institute of Barcelona IBB CSIC ICUB | Rull V.,CSIC - Institute of Earth Sciences Jaume Almera | Saez A.,University of Barcelona | Margalef O.,Ecological Research Center and Forestry Applications | And 3 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2016

Easter Island is a paradigmatic example of human impact on ecosystems. The role of climate changes in recent vegetation shifts has commonly been rejected without proper assessment. A palynological study of a long sediment core from Raraku Lake documents the vegetation dynamics for the last 34 ka and investigates their driving forces, particularly the effects of climate variability on vegetation changes. Significant relationships between pollen assemblage changes and sedimentary and geochemical proxies demonstrate the rapid response of vegetation to lake crater basin hydrology and climatic changes. The lake surroundings were occupied by an open mixed palm grove during the Last Glacial period. Poaceae and Sophora increased at the expense of palms and Triumfetta, and Coprosma practically disappeared, in response to slightly wetter and/or colder climate during the Last Glacial Maximum. Palms and Triumfetta thrived in a warmer and/or drier climate during the deglaciation. Minor vegetation changes (a slight increase in Sophora and a drop in Asteraceae and Poaceae) occurred between 13.2 and 11.8 cal. ka BP and can be related to rapid changes in the Younger Dryas chronozone. The increase in herbaceous taxa indicates a gradual shallowing of the lake and development of a mire during the Holocene, caused by sediment infilling and warmer and drier climate. Relatively rapid vegetation changes in the Holocene were caused by climate and by plant succession on the expanding mire. The rates of vegetation change observed in the mire were similar to those at the initial stages of human impact identified in a previous study. These results reveal significant vegetation changes prior to human presence, due to the interplay of climate variations (temperature and moisture), changes in lake basin form by infilling and intrinsic dynamics of plant succession. Hence, the potential contribution of these factors in vegetation shifts during the period of human presence should not be neglected. © 2016 Elsevier B.V. Source


Nogue S.,University of Oxford | Nogue S.,University of Bergen | Rull V.,Botanical Institute of Barcelona IBB CSIC ICUB | Vegas-Vilarrubia T.,University of Barcelona
Diversity and Distributions | Year: 2013

Aim: The aim of the present study was to describe the diversity patterns along elevational gradients that are crucial for conservation management and for understanding diversification processes in montane environments. This article analyses the distributional range and elevation patterns of endemic and non-endemic (NE) vascular plants living on a unique set of Neotropical table mountains (tepuis). To investigate the potential causes of the high degree of diversity and endemism we tested the role of elevation, area and the mid-domain effect (MDE). We also aimed to discuss the origin of the current tepuian biota. Location: The Guayana Highlands (northern South America). Emphasis is placed on the mountaintops above 1500 m elevation, which form the highly biodiverse Pantepui biogeographical province. Methods: We examined the distribution patterns of vascular plant species richness in relation to elevation, area, and the MDE using generalized additive models. We used Range Model for the MDE. Results: We found that regional endemics richness show a hump-shaped curve in relation to elevation. Single-tepui endemics (STE) increase with elevation, whereas NE and total species richness decrease. Area and MDE influence this pattern for Pantepui and STE, but not for NE. We also observed that the spatial distribution of endemic richness displays a left-skewed distribution pattern due to the dominance of STE. Main conclusions: Our results demonstrate that a combination of elevation, area and MDE provide a basic explanation for the diversity of vascular plants in Pantepui. In addition, the present study indicates that maxima of STE are located at the highest altitudes, where the possibility of biotic connection (via migration) and gene flux has been minimal, even during glacial phases when most migration pathways amongst the tepui mountains were open. We also suggest that climatic filtering due to the extreme conditions atop the tepuis and low dispersal capacity stand out as the main drivers of the decline in NE species richness with elevation. © 2012 John Wiley & Sons Ltd. Source


Hidalgo O.,University of Barcelona | Hidalgo O.,Jodrell Laboratory | Valles J.,University of Barcelona | Romo A.,Botanical Institute of Barcelona IBB CSIC ICUB | And 2 more authors.
Caryologia | Year: 2015

The genome is structurally and functionally influenced by ecological factors during adaptive processes. Several natural factors can cause this, and here we present the effects of different growth conditions on the genome size. Genome size assessments were carried out by flow cytometry for a set of 19 taxa for each of three growing conditions: (i) wild plants growing in their natural habitats used as a control group; (ii) potted plants; and (iii) bonsai plants. Our results show a large variation in the genome size of bonsai and potted plants compared to their wild representatives. The most important conclusion is that 1Cx values measured in potted plants can be up to 8.48% lower and in bonsai plants up to 26.83% higher than the values assessed for the respective wild individuals. In the case of Juniperus thurifera, this divergence largely exceeded the genome size variation previously estimated along the natural geographical range of the species. Such deviation from expected values could be interpreted as genuine genome size variation, or to result from biochemical or/and DNA compactness changes triggered by growth conditions. The present results provide evidence for plant response to human-induced environmental changes, thus making the current approach potentially interesting for the prediction of the influence of climate change on plants and for other applications. © 2015 Dipartimento di Biologia Evoluzionistica, Università di Firenze. Source


Gouja H.,Arid Regions Institute | Gouja H.,Tunis el Manar University | Gouja H.,Botanical Institute of Barcelona IBB CSIC ICUB | Garcia-Fernandez A.,Botanical Institute of Barcelona IBB CSIC ICUB | And 3 more authors.
Turkish Journal of Botany | Year: 2014

The species of the genus Calligonum L. (Polygonaceae) that appear in Tunisian deserts play an important role in maintaining local ecosystems and supply important natural resources in these regions. In this study, 31 individuals belonging to the 3 hypothetical species of the genus Calligonum (Calligonum arich Le Houér., Calligonum azel Maire, and Calligonum comosum L'Hér.) were collected from 12 populations in 6 localities of the Tunisian desert and examined to assess the relationship between species. Phylogenetic analyses using 1 nuclear (ITS) and 2 plastid regions (trnL-trnF and rbcL) and genome size assessments are used in this study to evaluate the relationships between these hypothetical species. C-value results suggest the existence of 3 different species, which is also supported by phylogenetic tree topology. The paraphyletic pattern of C. comosum and the plausible origin of C. arich from C. azel suggest the existence of several mechanisms of isolation and speciation in the Sahara Desert for this genus. Additional studies are necessary to evaluate the population size, demographic tendency, and conservation status of these desert species and their genetic relationships with other congeners. © Tübi̇tak. Source

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