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101.
JAN CHRISTIAN HABEL THOMAS SCHMITT MARC MEYER ALINE FINGER DENNIS RÖDDER THORSTEN ASSMANN FRANK EMMANUEL ZACHOS 《Biological journal of the Linnean Society. Linnean Society of London》2010,101(1):155-168
Cold‐adapted species are thought to have had their largest distribution ranges in central Europe during the glacial periods. Postglacial warming caused severe range shifts of such taxa into higher latitudes and altitudes. We selected the boreomontane butterfly Lycaena helle (Denis & Schiffermüller, 1775) as an example to demonstrate the genetic effects of range changes, and to document the recent status of highly fragmented remnant populations. We analysed five polymorphic microsatellite loci in 1059 individuals sampled at 50 different localities scattered over the European distribution area of the species. Genetic differentiation was strong among the mountain ranges of western Europe, but we did not detect similarly distinct genetic groups following a geographical pattern in the more eastern areas. The Fennoscandian populations form a separate genetic group, and provide evidence for a colonization from southern Finland via northern Scandinavia to south‐central Sweden. Species distribution modelling suggests a large extension of the spatial distribution during the last glacial maximum, but highlights strong retractions to a few mountain areas under current conditions. These findings, combined with our genetic data, suggest a more or less continuous distribution of L. helle throughout central Europe at the end of the last ice age. As a consequence of postglacial warming, the species retreated northwards to Fennoscandia and escaped increasing temperatures through altitudinal shifts. Therefore, the species is today restricted to population remnants located at the mountain tops of western Europe, genetically isolated from each other, and evolved into genetically unique entities. Rising temperatures and advancing habitat destruction threaten this wealth of biodiversity. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 155–168. 相似文献
102.
PETER TYRER ROGER MULDER MIKE CRAWFORD GILES NEWTON‐HOWES ERIK SIMONSEN DAVID NDETEI NESTOR KOLDOBSKY ANDREA FOSSATI JOSEPH MBATIA BARBARA BARRETT 《World psychiatry》2010,9(1):56-60
Personality disorder is now being accepted as an important condition in
mainstream psychiatry across the world. Although it often remains unrecognized
in ordinary practice, research studies have shown it is common, creates considerable
morbidity, is associated with high costs to services and to society, and interferes,
usually negatively, with progress in the treatment of other mental disorders.
We now have evidence that personality disorder, as currently classified, affects
around 6% of the world population, and the differences between countries show
no consistent variation. We are also getting increasing evidence that some
treatments, mainly psychological, are of value in this group of disorders.
What is now needed is a new classification that is of greater value to clinicians,
and the WPA Section on Personality Disorders is currently undertaking this
task. 相似文献
103.
104.
Are mature forest trees carbon limited at current CO2 concentrations? Will ‘mid‐life’, 35 m tall deciduous trees grow faster in a CO2‐enriched atmosphere? To answer these questions we exposed ca. 100‐year‐old temperate forest trees at the Swiss Canopy Crane site near Basel, Switzerland to a ca. 540 ppm CO2 atmosphere using web‐FACE technology. Here, we report growth responses to elevated CO2 for 11 tall trees (compared with 32 controls) of five species during the initial four treatment years. Tested across all trees, there was no CO2 effect on stem basal area (BA) increment (neither when tested per year nor cumulatively for 4 years). In fact, the 4th year means were almost identical for the two groups. Stem growth data were standardized by pretreatment growth (5 years) in order to account for a priori individual differences in vigor. Although this experiment was not designed to test species specific effects, one species, the common European beech, Fagus sylvatica, showed a significant growth enhancement in the first year, which reoccurred during a centennial drought in the third year. None of the other dominant species (Quercus petraea, Carpinus betulus) showed a growth response to CO2 in any of the 4 years or for all years together. The inclusion or exclusion of single individuals of Prunus avium and Tilia platyphyllos did not change the picture. In elevated CO2, lateral branching in terminal shoots was higher in Fagus in 2002, when shoots developed from buds that were formed during the first season of CO2 enrichment (2001), but there was no effect in later years and no change in lateral branching in any of the other species. In Quercus, there was a steady stimulation of leading shoot length in high‐CO2 trees. Phenological variables (bud break, leaf fall, leaf duration) were highly species specific and were not affected by elevated CO2 in any consistent way. Our 4‐year data set reflects a very dynamic and species‐specific response of tree growth to a step change in CO2 supply. Stem growth after 4 years of exposure does not support the notion that mature forest trees will accrete wood biomass at faster rates in a future CO2‐enriched atmosphere. 相似文献
105.
JENNIFER N. LOHR CHRISTIAN LAFORSCH HENRIKE KOERNER JUSTYNA WOLINSKA 《The Journal of eukaryotic microbiology》2010,57(4):328-336
ABSTRACT. Caullerya mesnili is a protozoan endoparasite in the gut epithelium of Daphnia, which causes regular epidemics in lakes throughout Europe. Its classification has remained unchanged for over a century, leaving it placed with the Haplosporidia, despite speculation that this position is incorrect. The difficulty in classifying C. mesnili stems from its few known morphological and ecological characteristics, as well as a lack of genetic markers. Here we sequenced the nuclear small subunit (SSU) and internal transcribed spacer rDNA regions of C. mesnili samples from 10 locations. Based on sequence similarities, we suggest the re‐classification of C. mesnili to the Ichthyosporea, a class of protists near the animal–fungi divergence. We report average intragenomic variation of 0.75% and 2.27% in the SSU and internal transcribed spacer regions, respectively. From electron micrographs and light microscopy of histological sections we determined that C. mesnili spores grow within the intestinal epithelium where they establish themselves intercellularly. In addition, we confirmed previous accounts regarding the high virulence of this parasite. Caullerya mesnili reduces host lifespan, the number of clutches, and the total number of offspring. This high selection pressure placed on hosts supports the importance of C. mesnili as a model parasite for the study of host–parasite biology in permanent lakes. 相似文献
106.
Abstract. We investigate the diversity of the North American tiger moth genus Grammia Rambur (Lepidoptera: Noctuidae) by comparing mitochondrial DNA (mtDNA) ‘barcode’ fragments of cytochrome oxidase I with non‐molecular characters such as morphology, ecology, behaviour and distribution. Mitochondrial DNA genealogy is strikingly at odds with morpho‐species taxonomy for most of the 28 sampled species, as haplotypic polyphyly not only is taxonomically widespread, but involves multiple shared haplotypes among two to four species. Morpho‐ecological traits show that those species sharing haplotypes are often not closely related. Furthermore, high mtDNA divergences occur within species. Haplotypic variation is highly discordant with species taxonomy, but variation at a continental scale reveals significant geographic structuring of haplogroups, transcending morpho‐species boundaries. A nested clade analysis and comparison of non‐molecular with mtDNA data indicate that most discordance between mtDNA and taxonomy in Grammia is explained best by taxonomically and geographically widespread ongoing hybridization events resulting in mtDNA introgression. We hypothesize that broad areas of sympatry, interspecifically compatible genitalic structure, and species overlap in pheromone components facilitate hybridization, with disparate interspecies abundances promoting mitochondrial introgression. The molecular evolution of Grammia challenges the view that interspecific gene exchange occurs rarely and is restricted to recently diverged species. These results show the value of mtDNA in detecting cryptic hybridization, while highlighting the inherent dangers of drawing taxonomic conclusions based solely on mtDNA. 相似文献
107.
DIMITRIOS SARRIS DIMITRIOS CHRISTODOULAKIS CHRISTIAN KÖRNER† 《Global Change Biology》2007,13(6):1187-1200
We present evidence of a recent drying in the eastern Mediterranean, based on weather and tree‐ring data for Samos, an island of the eastern Aegean Sea. Rainfall declined rapidly after the late 1970s following trends for the entire Mediterranean and was associated with reduced tree‐ring width in Pinus brutia. The most recent decline led to the lowest annual radial stem increment after the last 100 years (as far as records reach). As moisture availability decreased best correlations of tree growth with rainfall were obtained for progressively longer integration periods (1–2 years in moister periods, 5–6 years during the severe dryness of 20th century's last decades), suggesting increasing dependency in deep soil water. Such long‐term integration periods of tree‐growth responses to precipitation have not been reported before. They may reflect a tree‐rooting pattern adapted to cope with even several successive dry years. In late summer 2000, moisture reserves became exhausted, however, and a substantial fraction of low altitude pines died, including some 80‐year‐old trees, which underlines the exceptional extent this trend had reached. Our findings provide empirical support for Intergovernmental Panel on Climate Change projections derived from global circulation models that the Mediterranean, its eastern basin in particular, should become drier as temperature rises, as was the case in the recent past. 相似文献
108.
Electron transfer of dissolved organic matter and its potential significance for anaerobic respiration in a northern bog 总被引:6,自引:0,他引:6
TOBIAS HEITMANN TOBIAS GOLDHAMMER JULIA BEER CHRISTIAN BLODAU 《Global Change Biology》2007,13(8):1771-1785
We investigated electron transfer processes of dissolved organic matter (DOM) and their potential importance for anaerobic heterotrophic respiration in a northern peatland. Electron accepting and donating capacities (EAC, EDC) of DOM were quantified using dissolved H2S and ferric iron as reactants. Carbon turnover rates were obtained from porewater profiles (CO2, CH4) and inverse modeling. Carbon dioxide was released at rates of 0.2–5.9 mmol m−2 day−1 below the water table. Methane (CH4) formation contributed <10%, and oxygen consumption 2% to 40%, leaving a major fraction of CO2 production unexplained. DOM oxidized H2S to thiosulfate and was reduced by dissolved ferric iron. Reduction with H2S increased the subsequently determined EDC compared to untreated controls, indicating a reversibility of the electron transfer. In situ redox capacities of DOM ranged from 0.2 to 6.1 mEq g−1 C (EAC) and from 0.0 to 1.4 mEq g−1 C (EDC), respectively. EAC generally decreased with depth and changed after a water table drawdown and rebound by 20 and −45 mEq m−2, respectively. The change in EAC during the water table fluctuation was similar to CH4 formation rates. In peatlands, electron transfer of DOM may thus significantly contribute to the oxidation of reduced organic substrates by anaerobic heterotrophic respiration, or by maintaining the respiratory activity of sulfate reducers via provision of thiosulfate. Part of the anaerobic electron flow in peat soils is thus potentially diverted from methanogenesis, decreasing its contribution to the total carbon emitted to the atmosphere. 相似文献
109.
110.
Field and laboratory experiments on net uptake of nitrate and ammonium by the roots of spruce (Picea abies) and beech (Fagus sylvatica) trees 总被引:4,自引:0,他引:4