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Nieto-Lugilde D.,University of Granada | Nieto-Lugilde D.,University of Aarhus | Lenoir J.,University of Aarhus | Lenoir J.,University of Picardie Jules Verne | And 17 more authors.
Ecography | Year: 2015

The role of competition for light among plants has long been recognised at local scales, but its importance for plant species distributions at larger spatial scales has generally been ignored. Tree cover modifies the local abiotic conditions below the canopy, notably by reducing light availability, and thus, also the performance of species that are not adapted to low-light conditions. However, this local effect may propagate to coarser spatial grains, by affecting colonisation probabilities and local extinction risks of herbs and shrubs. To assess the effect of tree cover at both the plot- and landscape-grain sizes (approximately 10-m and 1-km), we fit generalised linear models (GLMs) for the plot-level distributions of 960 species of herbs and shrubs using 6935 vegetation plots across the European Alps. We ran four models with different combinations of variables (climate, soil and tree cover) at both spatial grains for each species. We used partial regressions to evaluate the independent effects of plot- and landscape-grain tree cover on plot-level plant communities. Finally, the effects on species-specific elevational range limits were assessed by simulating a removal experiment comparing the species distributions under high and low tree cover. Accounting for tree cover improved the model performance, with the probability of the presence of shade-tolerant species increasing with increasing tree cover, whereas shade-intolerant species showed the opposite pattern. The tree cover effect occurred consistently at both the plot and landscape spatial grains, albeit most strongly at the former. Importantly, tree cover at the two grain sizes had partially independent effects on plot-level plant communities. With high tree cover, shade-intolerant species exhibited narrower elevational ranges than with low tree cover whereas shade-tolerant species showed wider elevational ranges. These findings suggest that forecasts of climate-related range shifts for herb and shrub species may be modified by tree cover dynamics. © 2014 The Authors. Source

Ouattara D.N.,University of Geneva | Ouattara D.N.,Laboratoire Of Systematique Vegetale Et Biodiversite | Stauffer F.W.,Laboratoire Of Systematique Vegetale Et Biodiversite | Bakayoko A.,Nangui Abrogoua University
Adansonia | Year: 2014

During a botanical survey undertaken in Western Africa in 1905, Auguste Chevalier (1873-1956) collected a new palm species that he described and published in 1908 under the name of Raphia sudanica A. Chev. Two specimens are cited in the protologue, but the herbarium where they were deposited was not indicated. Research in the herbarium of the Muséum national d'Histoire naturelle, Paris (P), in France enabled us to locate the two specimens. Neither of them was designated as holotype and a lectotypification is required for a better definition of the taxon; this lectotypification is proposed in this study. The morphological description, distribution, ecology and socio-economic importance of the species are also provided. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris. Source

Manen J.-F.,University of Geneva | Manen J.-F.,Laboratoire Of Systematique Vegetale Et Biodiversite | Barriera G.,Laboratoire Of Systematique Vegetale Et Biodiversite | Loizeau P.-A.,University of Geneva | And 3 more authors.
Molecular Phylogenetics and Evolution | Year: 2010

The history and diversification of the genus Ilex (Aquifoliaceae), based on 108 different species (116 specimens), are inferred from the analysis of two nuclear (ITS and nepGS) and three plastid (rbcL, trnL-F and atpB. -rbcL) sequences. Nuclear and plastid trees are highly incongruent and the nuclear tree is more compatible with current taxonomic classifications than the plastid one. The most recent common ancestor (MRCA) of extant species is dated from the Miocene, although the Ilex stem lineage can be traced back to the late Cretaceous, according to fossil records. This suggests extensive lineage extinctions between the Cretaceous and Miocene and may also explain the difficulties encountered in defining the relationships between Ilex and its closest relatives. The MRCA ancestral area was identified as being in the North Hemisphere (North America and/or East Asia). Several bidirectional North America/East Asia and North America/South America dispersal events are proposed to explain observed geographic and phylogenetic patterns. Hybridization and introgression events between distantly related lineages are also inferred, indicating weak reproductive barriers between species in Ilex. © 2010 Elsevier Inc. Source

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