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Alexandre Buttler - One of the best experts on this subject based on the ideXlab platform.
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Vascular Plant mediated controls on atmospheric carbon assimilation and peat carbon decomposition under climate change
Global Change Biology, 2018Co-Authors: Alexandre Buttler, Remy Albrecht, Konstantin Gavazov, Ellen Dorrepaal, Mark H GarnettAbstract:Climate change can alter peatland Plant community composition by promoting the growth of Vascular Plants. How such vegetation change affects peatland carbon dynamics remains, however, unclear. In order to assess the effect of vegetation change on carbon uptake and release, we performed a Vascular‐Plant removal experiment in two Sphagnum‐dominated peatlands that represent contrasting stages of natural vegetation succession along a climatic gradient. Periodic measurements of net ecosystem CO2 exchange revealed that Vascular Plants play a crucial role in assuring the potential for net carbon uptake, particularly with a warmer climate. The presence of Vascular Plants, however, also increased ecosystem respiration, and by using the seasonal variation of respired CO2 radiocarbon (bomb‐14C) signature we demonstrate an enhanced heterotrophic decomposition of peat carbon due to rhizosphere priming. The observed rhizosphere priming of peat carbon decomposition was matched by more advanced humification of dissolved organic matter, which remained apparent beyond the Plant growing season. Our results underline the relevance of rhizosphere priming in peatlands, especially when assessing the future carbon sink function of peatlands undergoing a shift in vegetation community composition in association with climate change.
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Peatland Vascular Plant functional types affect dissolved organic matter chemistry
Plant and Soil, 2016Co-Authors: Bjorn J. M. Robroek, Alexandre Buttler, Remy Albrecht, Samuel Hamard, Adrian Pulgarin, Luca Bragazza, Vincent E. J. JasseyAbstract:Northern peatlands are large repositories of carbon. Peatland Vascular Plant community composition has been functionally associated to a set of biogeochemical processes such as carbon cycling. Yet, we do not fully understand to what extent Vascular Plant functional types (PFTs) affect the quality of dissolved organic matter, and if there is any feedback on soil microbial activity. Using a longer–term Plant removal experiment in a boreo–nemoral peatland in Southern Sweden, we relate the dominance of different Vascular Plant functional types (i.e. ericoids and graminoids) to the chemistry of the dissolved organic matter (DOM) and microbial enzymatic activities (fluorescein diacetate hydrolysis, FDA). Our results show that PFTs modifies the composition of DOM moieties, with a decrease of low molecular weight organic compounds after Vascular Plant removal. The decrease of enzymatic activity by up to 68 % in the Plant removal plots suggests a reduction in DOM mineralization in the absence of Vascular Plants. Our results show that Plant–derived low molecular organic compounds enhance peatland microbial activity, and suggest that an increase of Vascular Plant cover in response to climate change can potentially destabilize the OM in peatlands, leading to increased carbon losses.
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Peatland Vascular Plant functional types affect dissolved organic matter chemistry
Plant and Soil, 2015Co-Authors: Bjorn J. M. Robroek, Alexandre Buttler, Samuel Hamard, Adrian Pulgarin, Luca Bragazza, Remy J. H. Albrecht, Vincent E. J. JasseyAbstract:Background and aims: Northern peatlands are large repositories of carbon. Peatland Vascular Plant community composition has been functionally associated to a set of biogeochemical processes such as carbon cycling. Yet, we do not fully understand to what extent Vascular Plant functional types (PFTs) affect the quality of dissolved organic matter, and if there is any feedback on soil microbial activity.\ud Methods: Using a longer–term Plant removal experiment in a boreo–nemoral peatland in Southern Sweden, we relate the dominance of different Vascular Plant functional types (i.e. ericoids and graminoids) to the chemistry of the dissolved organic matter (DOM) and microbial enzymatic activities (fluorescein diacetate hydrolysis, FDA). Results Our results show that PFTs modifies the composition ofDOMmoieties, with a decrease of lowmolecular weight organic compounds after Vascular Plant removal. The decrease of enzymatic activity by up to 68 % in the Plant removal plots suggests a reduction in DOM mineralization in the absence of Vascular Plants.\ud Conclusions: Our results show that Plant–derived low molecular organic compounds enhance peatland microbial activity, and suggest that an increase of Vascular Plant cover in response to climate change can potentially destabilize the OM in peatlands, leading to increased carbon losses
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linking soil microbial communities to Vascular Plant abundance along a climate gradient
New Phytologist, 2015Co-Authors: Alexandre Buttler, Luca Bragazza, Richard D Bardgett, Edward A D MitchellAbstract:The ongoing expansion of shrub cover in response to climate change represents a unique opportunity to explore the link between soil microbial communities and vegetation changes. This link is particularly important in peatlands where shrub expansion is expected to feed back negatively on the carbon sink capacity of these ecosystems. Microbial community structure and function were measured seasonally in four peatlands located along an altitude gradient representing a natural gradient of climate and associated Vascular Plant abundance. We show that increased soil temperature and reduced water content are associated with greater Vascular Plant biomass, in particular that of ericoids, and that this, in turn, is correlated with greater microbial biomass. More specifically, microbial community structure is characterized by an increasing dominance of fungi over bacteria with improved soil oxygenation. We also found that the carbon and nitrogen stoichiometry of microbial biomass differs in relation to soil microbial community structure and that this is ultimately associated with a different investment in extracellular enzymatic activity. Our findings highlight the fact that the determination of the structural identity of microbial communities can help to explain the biogeochemical dynamics of organic matter and provide a better understanding of ecosystem response to environmental changes.
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Patterns of bryophyte and Vascular Plant richness in European subalpine springs
Plant Ecology, 2011Co-Authors: Lucia Sekulová, Michal Hájek, Petra Hájková, Eva Mikulášková, Alexandre Buttler, Vít Syrovátka, Zuzana RozbrojováAbstract:The diversity of spring habitats can be determined not only by local environmental conditions, but also by large-scale biogeographical effects. The effects can differ across various groups of organisms. We compared α-, β- and γ-diversity patterns of bryophytes and Vascular Plants of (sub)alpine springs in three contrasting mountain ranges: Alps (Switzerland), Balkans (Bulgaria), Western Carpathians (Slovakia, Poland). We used univariate and multivariate statistics to test for the effects of pH, conductivity, altitude, slope, mean annual temperature and annual precipitation on diversity patterns of both taxonomic groups and compared diversity patterns among the regions for particular pH and conductivity classes. We identified acidophyte and basiphyte, calcifuge and calcicole species using species response modelling. All regions displayed significant relationship between conductivity and α-diversity of Vascular Plants. Bulgaria showed the highest α-diversity of Vascular Plants for the middle part of the conductivity gradient. For both taxonomic groups, the β-diversity in the middle part of gradient was highest in Swiss Alps. The total species pool was lowest in Bulgaria. The percentage of basiphyte and calcicole species was highest in the Alps. In (sub)alpine springs, mineral richness was a better determinant of Vascular Plant α-diversity than pH, and the extent of the alpine area did not coincide with α-diversity. Observed inter-regional differences in diversity patterns could be explained by the different proportion of limestone bedrock and different biogeographic history. The differences in α-diversity between both taxonomic groups are presumably result of the different rates of adaptation processes.
Luca Bragazza - One of the best experts on this subject based on the ideXlab platform.
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Peatland Vascular Plant functional types affect dissolved organic matter chemistry
Plant and Soil, 2016Co-Authors: Bjorn J. M. Robroek, Alexandre Buttler, Remy Albrecht, Samuel Hamard, Adrian Pulgarin, Luca Bragazza, Vincent E. J. JasseyAbstract:Northern peatlands are large repositories of carbon. Peatland Vascular Plant community composition has been functionally associated to a set of biogeochemical processes such as carbon cycling. Yet, we do not fully understand to what extent Vascular Plant functional types (PFTs) affect the quality of dissolved organic matter, and if there is any feedback on soil microbial activity. Using a longer–term Plant removal experiment in a boreo–nemoral peatland in Southern Sweden, we relate the dominance of different Vascular Plant functional types (i.e. ericoids and graminoids) to the chemistry of the dissolved organic matter (DOM) and microbial enzymatic activities (fluorescein diacetate hydrolysis, FDA). Our results show that PFTs modifies the composition of DOM moieties, with a decrease of low molecular weight organic compounds after Vascular Plant removal. The decrease of enzymatic activity by up to 68 % in the Plant removal plots suggests a reduction in DOM mineralization in the absence of Vascular Plants. Our results show that Plant–derived low molecular organic compounds enhance peatland microbial activity, and suggest that an increase of Vascular Plant cover in response to climate change can potentially destabilize the OM in peatlands, leading to increased carbon losses.
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Peatland Vascular Plant functional types affect dissolved organic matter chemistry
Plant and Soil, 2015Co-Authors: Bjorn J. M. Robroek, Alexandre Buttler, Samuel Hamard, Adrian Pulgarin, Luca Bragazza, Remy J. H. Albrecht, Vincent E. J. JasseyAbstract:Background and aims: Northern peatlands are large repositories of carbon. Peatland Vascular Plant community composition has been functionally associated to a set of biogeochemical processes such as carbon cycling. Yet, we do not fully understand to what extent Vascular Plant functional types (PFTs) affect the quality of dissolved organic matter, and if there is any feedback on soil microbial activity.\ud Methods: Using a longer–term Plant removal experiment in a boreo–nemoral peatland in Southern Sweden, we relate the dominance of different Vascular Plant functional types (i.e. ericoids and graminoids) to the chemistry of the dissolved organic matter (DOM) and microbial enzymatic activities (fluorescein diacetate hydrolysis, FDA). Results Our results show that PFTs modifies the composition ofDOMmoieties, with a decrease of lowmolecular weight organic compounds after Vascular Plant removal. The decrease of enzymatic activity by up to 68 % in the Plant removal plots suggests a reduction in DOM mineralization in the absence of Vascular Plants.\ud Conclusions: Our results show that Plant–derived low molecular organic compounds enhance peatland microbial activity, and suggest that an increase of Vascular Plant cover in response to climate change can potentially destabilize the OM in peatlands, leading to increased carbon losses
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linking soil microbial communities to Vascular Plant abundance along a climate gradient
New Phytologist, 2015Co-Authors: Alexandre Buttler, Luca Bragazza, Richard D Bardgett, Edward A D MitchellAbstract:The ongoing expansion of shrub cover in response to climate change represents a unique opportunity to explore the link between soil microbial communities and vegetation changes. This link is particularly important in peatlands where shrub expansion is expected to feed back negatively on the carbon sink capacity of these ecosystems. Microbial community structure and function were measured seasonally in four peatlands located along an altitude gradient representing a natural gradient of climate and associated Vascular Plant abundance. We show that increased soil temperature and reduced water content are associated with greater Vascular Plant biomass, in particular that of ericoids, and that this, in turn, is correlated with greater microbial biomass. More specifically, microbial community structure is characterized by an increasing dominance of fungi over bacteria with improved soil oxygenation. We also found that the carbon and nitrogen stoichiometry of microbial biomass differs in relation to soil microbial community structure and that this is ultimately associated with a different investment in extracellular enzymatic activity. Our findings highlight the fact that the determination of the structural identity of microbial communities can help to explain the biogeochemical dynamics of organic matter and provide a better understanding of ecosystem response to environmental changes.
Vanessa R Invernon - One of the best experts on this subject based on the ideXlab platform.
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the french museum national d histoire naturelle Vascular Plant herbarium collection dataset
Scientific Data, 2017Co-Authors: Gwenael Le Bras, Marc Pignal, Marc L Jeanson, Serge Muller, Cecile Aupic, Benoit Carre, Gregoire Flament, Myriam Gaudeul, Claudia Goncalves, Vanessa R InvernonAbstract:We provide a quantitative description of the French national herbarium Vascular Plants collection dataset. Held at the Museum national d’histoire naturelle, Paris, it currently comprises records for 5,400,000 specimens, representing 90% of the estimated total of specimens. Ninety nine percent of the specimen entries are linked to one or more images and 16% have field-collecting information available. This major botanical collection represents the results of over three centuries of exploration and study. The sources of the collection are global, with a strong representation for France, including overseas territories, and former French colonies. The compilation of this dataset was made possible through numerous national and international projects, the most important of which was linked to the renovation of the herbarium building. The Vascular Plant collection is actively expanding today, hence the continuous growth exhibited by the dataset, which can be fully accessed through the GBIF portal or the MNHN database portal (available at: https://science.mnhn.fr/institution/mnhn/collection/p/item/search/form ). This dataset is a major source of data for systematics, global Plants macroecological studies or conservation assessments. Machine-accessible metadata file describing the reported data (ISA-Tab format)
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The French Muséum national d’histoire naturelle Vascular Plant herbarium collection dataset
Scientific Data, 2017Co-Authors: Gwenaël Le Bras, Marc Pignal, Marc L Jeanson, Serge Muller, Cecile Aupic, Benoit Carre, Gregoire Flament, Myriam Gaudeul, Claudia Goncalves, Vanessa R InvernonAbstract:We provide a quantitative description of the French national herbarium Vascular Plants collection dataset. Held at the Muséum national d’histoire naturelle , Paris, it currently comprises records for 5,400,000 specimens, representing 90% of the estimated total of specimens. Ninety nine percent of the specimen entries are linked to one or more images and 16% have field-collecting information available. This major botanical collection represents the results of over three centuries of exploration and study. The sources of the collection are global, with a strong representation for France, including overseas territories, and former French colonies. The compilation of this dataset was made possible through numerous national and international projects, the most important of which was linked to the renovation of the herbarium building. The Vascular Plant collection is actively expanding today, hence the continuous growth exhibited by the dataset, which can be fully accessed through the GBIF portal or the MNHN database portal (available at: https://science.mnhn.fr/institution/mnhn/collection/p/item/search/form ). This dataset is a major source of data for systematics, global Plants macroecological studies or conservation assessments. Design Type(s) data integration objective • database creation objective Measurement Type(s) taxonomic inventory Technology Type(s) digital curation Factor Type(s) Sample Characteristic(s) Tracheophyta Machine-accessible metadata file describing the reported data (ISA-Tab format)
Yongsong Huang - One of the best experts on this subject based on the ideXlab platform.
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major evolutionary trends in hydrogen isotope fractionation of Vascular Plant leaf waxes
PLOS ONE, 2014Co-Authors: Erika J Edwards, Yongbo Zeng, Yongsong HuangAbstract:Hydrogen isotopic ratios of terrestrial Plant leaf waxes (δD) have been widely used for paleoclimate reconstructions. However, underlying controls for the observed large variations in leaf wax δD values in different terrestrial Vascular Plants are still poorly understood, hampering quantitative paleoclimate interpretation. Here we report Plant leaf wax and source water δD values from 102 Plant species grown in a common environment (New York Botanic Garden), chosen to represent all the major lineages of terrestrial Vascular Plants and multiple origins of common Plant growth forms. We found that leaf wax hydrogen isotope fractionation relative to Plant source water is best explained by membership in particular lineages, rather than by growth forms as previously suggested. Monocots, and in particular one clade of grasses, display consistently greater hydrogen isotopic fractionation than all other Vascular Plants, whereas lycopods, representing the earlier-diverging Vascular Plant lineage, display the smallest fractionation. Data from greenhouse experiments and field samples suggest that the changing leaf wax hydrogen isotopic fractionation in different terrestrial Vascular Plants may be related to different strategies in allocating photosynthetic substrates for metabolic and biosynthetic functions, and potential leaf water isotopic differences.
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differential hydrogen isotopic ratios of sphagnum and Vascular Plant biomarkers in ombrotrophic peatlands as a quantitative proxy for precipitation evaporation balance
Geochimica et Cosmochimica Acta, 2010Co-Authors: J E Nichols, Robert K Booth, Stephen T Jackson, Elise Pendall, Yongsong HuangAbstract:Abstract We have developed a new approach to quantitatively reconstruct past changes in evaporation based on compound-specific hydrogen isotope ratios of Vascular Plant and Sphagnum biomarkers in ombrotrophic peatland sediments. We show that the contrast in H isotopic ratios of water available to living Sphagnum (top 20 cm) and in the rooting zone of peatland Vascular Plants can be used to estimate “ƒ”—the fraction of water remaining after evaporation. Vascular Plant leaf waxes record H isotopic ratios of acrotelm water, which carries the D/H ratio signature of precipitation and is little affected by evaporation, whereas the Sphagnum biomarker, C 23 n -alkane, records H isotopic ratios of the water inside its cells and between its leaves, which is strongly affected by evaporation at the bog surface. Evaporation changes can then be deduced by comparing H isotopic ratios of the two types of biomarkers. We calibrated D/H ratios of C 23 n -alkane to source water with lab-grown Sphagnum . We also tested our isotopic model using modern surface samples from 18 ombrotrophic peatlands in the Midwestern United States. Finally, we generated a 3000-year downcore reconstruction from Minden Bog, Michigan, USA. Our new record is consistent with records of other parameters from the same peatland derived from different proxies and allows us to differentiate precipitation supply and evaporative loss.
Javier Lopatin - One of the best experts on this subject based on the ideXlab platform.
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comparing generalized linear models and random forest to model Vascular Plant species richness using lidar data in a natural forest in central chile
Remote Sensing of Environment, 2016Co-Authors: Mauricio Galleguillos, Javier Lopatin, Klara Dolos, H J Hernandez, Fabian Ewald FassnachtAbstract:Abstract Biodiversity is considered to be an essential element of the Earth system, driving important ecosystem services. However, the conservation of biodiversity in a quickly changing world is a challenging task which requires cost-efficient and precise monitoring systems. In the present study, the suitability of airborne discrete-return LiDAR data for the mapping of Vascular Plant species richness within a Sub-Mediterranean second growth native forest ecosystem was examined. The Vascular Plant richness of four different layers (total, tree, shrub and herb richness) was modeled using twelve LiDAR-derived variables. As species richness values are typically count data, the corresponding asymmetry and heteroscedasticity in the error distribution has to be considered. In this context, we compared the suitability of random forest (RF) and a Generalized Linear Model (GLM) with a negative binomial error distribution. Both models were coupled with a feature selection approach to identify the most relevant LiDAR predictors and keep the models parsimonious. The results of RF and GLM agreed that the three most important predictors for all four layers were altitude above sea level, standard deviation of slope and mean canopy height. This was consistent with the preconception of LiDAR's suitability for estimating species richness, which is its capacity to capture three types of information: micro-topographical, macro-topographical and canopy structural. Generalized Linear Models showed higher performances (r2: 0.66, 0.50, 0.52, 0.50; nRMSE: 16.29%, 19.08%, 17.89%, 21.31% for total, tree, shrub and herb richness respectively) than RF (r2: 0.55, 0.33, 0.45, 0.46; nRMSE: 18.30%, 21.90%, 18.95%, 21.00% for total, tree, shrub and herb richness, respectively). Furthermore, the results of the best GLM were more parsimonious (three predictors) and less biased than the best RF models (twelve predictors). We think that this is due to the mentioned non-symmetric error distribution of the species richness values, which RF is unable to properly capture. From an ecological perspective, the predicted patterns agreed well with the known vegetation composition of the area. We found especially high species numbers at low elevations and along riversides. In these areas, overlapping distributions of thermopile sclerophyllos species, water demanding Valdivian evergreen species and species growing in Nothofagus obliqua forests occur. The three main conclusions of the study are: 1) appropriate model selection is crucial when working with biodiversity count data; 2) the application of RF for data with non-symmetric error distributions is questionable; and 3) structural and topographic information derived from LiDAR data is useful for predicting local Plant species richness.
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Using a Multistructural Object-Based LiDAR Approach to Estimate Vascular Plant Richness in Mediterranean Forests With Complex Structure
IEEE Geoscience and Remote Sensing Letters, 2015Co-Authors: Javier Lopatin, Mauricio Galleguillos, Fabian Ewald Fassnacht, Andrés Ceballos, Jaime HernándezAbstract:A multistructural object-based LiDAR approach to predict Plant richness in complex structure forests is presented. A normalized LiDAR point cloud was split into four height ranges: 1) high canopies (points above 16 m); 2) middle-high canopies (8-16 m); 3) middle-low canopies (2-8 m); and 4) low canopies (0-2 m). A digital canopy model (DCM) was obtained from the full normalized LiDAR point cloud, and four pseudo-DCMs (pDCMs) were obtained from the split point clouds. We applied a multiresolution segmentation algorithm to the DCM and the four pDCMs to obtain crown objects. A partial least squares path model (PLS-PM) algorithm was applied to predict total Vascular Plant richness using object-based image analysis (OBIA) variables, derived from the delineated crown objects, and topographic variables, derived from a digital terrain model. Results showed that the object-based model was able to predict the total richness with an r2 of 0.64 and a root-mean-square error of four species. Topographic variables showed to be more important than the OBIA variables to predict richness. Furthermore, high-medium canopies (8-16 m) showed the biggest correlation with the total Plant richness within the structural segments of the forest.
