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28 results on '"Sebastià, M.-T."'

7. Elemental Composition of Natural Nanoparticles and Fine Colloids in European Forest Stream Waters and Their Role as Phosphorus Carriers

Author

Gottselig, Nina, Amelung, W, Kirchner, J W, Bol, R, Eugster, Werner, Granger, S J, Hernández-Crespo, C, Herrmann, F, Keizer, J. J, Korkiakoski, M, Laudon, H, Lehner, I, Löfgren, S, Lohila, A, Macleod, C J A, Mölder, M, Müller, C, Nasta, P, Nischwitz, V, Paul-Limoges, Eugénie, Pierret, M C, Pilegaard, K, Romano, N, Sebastià, M T, Stähli, M, Voltz, M, Vereecken, H, Siemens, J, Klumpp, E, University of Zurich, Klumpp, E, Gottselig, N., Amelung, W., Kirchner, J. W., Bol, R., Eugster, W., Granger, S. J., Hernandez-Crespo, C., Herrmann, F., Keizer, J. J., Korkiakoski, M., Laudon, H., Lehner, I., Löfgren, S., Lohila, A., Macleod, C. J. A., Mã¶lder, M., Mölder, C., Nasta, Paolo, Nischwitz, V., Paul-Limoges, E., Pierret, M. C., Pilegaard, K., Romano, Nunzio, Sebastià, M. T., Stähli, M., Voltz, M., Vereecken, H., Siemens, J., and Klumpp, E.

Subjects
2300 General Environmental Science, 10122 Institute of Geography, 2304 Environmental Chemistry, Hidrologia, 1902 Atmospheric Science, ddc:550, chemical composition, chemical element, colloid, forested catchment, headwater, nanoparticle, organic carbon, phosphorus, stream water, Europe, 2306 Global and Planetary Change, 910 Geography & travel, Aigua--Contaminació, Aigua--Química, Cursos d'aigua
Abstract

Biogeochemical cycling of elements largely occurs in dissolved state, but many elements may also be bound to natural nanoparticles (NNP, 1-100 nm) and fine colloids (100-450 nm). We examined the hypothesis that the size and composition of stream water NNP and colloids vary systematically across Europe. To test this hypothesis, 96 stream water samples were simultaneously collected in 26 forested headwater catchments along two transects across Europe. Three size fractions (1-20 nm, >20-60 nm, >60 nm) of NNP and fine colloids were identified with Field Flow Fractionation coupled to inductively coupled plasma mass-spectrometry and an organic carbon detector. The results showed that NNP and fine colloids constituted between 2±5% (Si) and 53±21% (Fe; mean ± SD) of total element concentrations, indicating a substantial contribution of particles to element transport in these European streams, especially for P and Fe. The particulate contents of Fe, Al and organic C were correlated to their total element concentrations, but those of particulate Si, Mn, P and Ca were not. The fine colloidal fractions >60 nm were dominated by clay minerals across all sites. The resulting element patterns of NNP

Published
2017

8. Phenology and plant functional type dominance drive CO2 exchange in seminatural grasslands in the Pyrenees.

Author

Ibañez, M., Altimir, N., Ribas, A., Eugster, W., and Sebastià, M.-T.

Abstract

Understanding the mechanisms underlying net ecosystem CO2 exchange (NEE) in mountain grasslands is important to quantify their relevance in the global carbon budget. However, complex interactions between environmental variables and vegetation on NEE remain unclear; and there is a lack of empirical data, especially from the high elevations and the Mediterranean region. A chamber-based survey of CO2 exchange measurements was carried out in two climatically contrasted grasslands (montane v. subalpine) of the Pyrenees; assessing the relative contribution of phenology and environmental variables on CO2 exchange at the seasonal scale, and the influence of plant functional type dominance (grasses, forbs and legumes) on the NEE light response. Results show that phenology plays a crucial role as a CO2 exchange driver, suggesting a differential behaviour of the vegetation community depending on the environment. The subalpine grassland had a more delayed phenology compared to the montane, being more temperature than water constrained. However, temperature increased net CO2 uptake at a higher rate in the subalpine than in the montane grassland. During the peak biomass, productivity (+74%) and net CO2 uptake (NEE +48%) were higher in the subalpine grassland than in the montane grassland. The delayed phenology at the subalpine grassland reduced vegetation's sensitivity to summer dryness, and CO2 exchange fluxes were less constrained by low soil water content. The NEE light response suggested that legume dominated plots had higher net CO2 uptake per unit of biomass than grasses. Detailed information on phenology and vegetation composition is essential to understand elevation and climatic differences in CO2 exchange. [ABSTRACT FROM AUTHOR]

Published
2020
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9. Elemental composition of natural nanoparticles and fine colloids in European forest stream waters and their role as phosphorus carriers

Author

Gottselig, N., Amelung, W., Kirchner, J. W., Bol, R., Eugster, W., Granger, S. J., Hernández-Crespo, C., Herrmann, F., Keizer, J. J., Korkiakoski, M., Laudon, H., Lehner, I., Löfgren, S., Lohila, A., Macleod, C. J. A., Mölder, M., Müller, C., Nasta, P., Nischwitz, V., Paul-Limoges, E., Pierret, M. C., Pilegaard, K., Romano, N., Sebastià, M. T., Stähli, M., Voltz, M., Vereecken, H., Siemens, J., Klumpp, E., Gottselig, N., Amelung, W., Kirchner, J. W., Bol, R., Eugster, W., Granger, S. J., Hernández-Crespo, C., Herrmann, F., Keizer, J. J., Korkiakoski, M., Laudon, H., Lehner, I., Löfgren, S., Lohila, A., Macleod, C. J. A., Mölder, M., Müller, C., Nasta, P., Nischwitz, V., Paul-Limoges, E., Pierret, M. C., Pilegaard, K., Romano, N., Sebastià, M. T., Stähli, M., Voltz, M., Vereecken, H., Siemens, J., and Klumpp, E.

Abstract

Biogeochemical cycling of elements largely occurs in dissolved state, but many elements may also be bound to natural nanoparticles (NNP, 1–100 nm) and fine colloids (100-450 nm). We examined the hypothesis that the size and composition of stream water NNP and colloids vary systematically across Europe. To test this hypothesis, 96 stream water samples were simultaneously collected in 26 forested headwater catchments along two transects across Europe. Three size fractions (~1–20 nm, >20–60 nm, >60 nm) of NNP and fine colloids were identified with Field Flow Fractionation coupled to inductively coupled plasma mass-spectrometry and an organic carbon detector. The results showed that NNP and fine colloids constituted between 2±5% (Si) and 53±21% (Fe; mean ± SD) of total element concentrations, indicating a substantial contribution of particles to element transport in these European streams, especially for P and Fe. The particulate contents of Fe, Al and organic C were correlated to their total element concentrations, but those of particulate Si, Mn, P and Ca were not. The fine colloidal fractions >60 nm were dominated by clay minerals across all sites. The resulting element patterns of NNP <60 nm changed from North to South Europe from Fe- to Ca-dominated particles, along with associated changes in acidity, forest type and dominant lithology.

Published
2017

10. Elemental Composition of Natural Nanoparticles and Fine Colloids in European Forest Stream Waters and Their Role as Phosphorus Carriers

Author

Gottselig, N., primary, Amelung, W., additional, Kirchner, J. W., additional, Bol, R., additional, Eugster, W., additional, Granger, S. J., additional, Hernández-Crespo, C., additional, Herrmann, F., additional, Keizer, J. J., additional, Korkiakoski, M., additional, Laudon, H., additional, Lehner, I., additional, Löfgren, S., additional, Lohila, A., additional, Macleod, C. J. A., additional, Mölder, M., additional, Müller, C., additional, Nasta, P., additional, Nischwitz, V., additional, Paul-Limoges, E., additional, Pierret, M. C., additional, Pilegaard, K., additional, Romano, N., additional, Sebastià, M. T., additional, Stähli, M., additional, Voltz, M., additional, Vereecken, H., additional, Siemens, J., additional, and Klumpp, E., additional

Published
2017
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11. 21st century climate change threatens mountain flora unequally across Europe

Author

Engler, R., Randin, C. F., Thuiller, W., Dullinger, S., Zimmermann, N. E., Araùjo, M. B., Pearman, P. B., Le Lay, G., Piedallu, C., Albert, C. H., Choler, P., Coldea, G., Lamo, X., Dirnböck, T., Gégout, J. C., Gomez Garcia, D., Grytnes, J. A., Heegard, E., Hoistad, F., Nogués Bravo, D., Normand, S., Puscas, M., Sebastià, M. T., Stanisci, Angela, Theurillat, J. P., Trivedi, M. R., Vittoz, P., Guisan, A., Laboratoire d'Ecologie Alpine (LECA), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA), Laboratoire d'Etudes des Ressources Forêt-Bois (LERFoB), AgroParisTech-Institut National de la Recherche Agronomique (INRA), Station alpine Joseph Fourier - UMS 3370 (SAJF), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institute of Biological Research, National Institute of Research and Development for Biological Sciences, Laboratory of Functional Ecology and Global Change (ECOFUN), Centre Tecnològic Forestal de Catalunya, Department for Ecosystem Research & Monitoring, Environment Agency Austria, Instituto Pirenaico de Ecologia, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), National Museum of Natural Sciences, Centre alpien de Phytogéographie, Fondation J.-M. Aubert, Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre de Ciència i Tecnologia Forestal de Catalunya (CTFC), Instituto Pirenaico de Ecologia (IPE), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), and Institut National de la Recherche Agronomique (INRA)-AgroParisTech

Subjects
vascular flora, distribution model, Alpine plants, [SDE.MCG]Environmental Sciences/Global Changes, vascular plant, Europe vegetation, alpine plant, land-use change, climate change, vegetation, European mountains, species distribution, plant-distribution, Global change, global change
Abstract

Continental-scale assessments of 21st century global impacts of climate change on biodiversity have forecasted range contractions for many species. These coarse resolution studies are, however, of limited relevance for projecting risks to biodiversity in mountain systems, where pronounced microclimatic variation could allow species to persist locally, and are ill-suited for assessment of species-specific threat in particular regions. Here, we assess the impacts of climate change on 2632 plant species across all major European mountain ranges, using high-resolution (ca. 100 m) species samples and data expressing four future climate scenarios. Projected habitat loss is greater for species distributed at higher elevations; depending on the climate scenario, we find 36-55% of alpine species, 31-51% of subalpine species and 19-46% of montane species lose more than 80% of their suitable habitat by 2070-2100. While our high-resolution analyses consistently indicate marked levels of threat to cold-adapted mountain florae across Europe, they also reveal unequal distribution of this threat across the various mountain ranges. Impacts on florae from regions projected to undergo increased warming accompanied by decreased precipitation, such as the Pyrenees and the Eastern Austrian Alps, will likely be greater than on florae in regions where the increase in temperature is less pronounced and rainfall increases concomitantly, such as in the Norwegian Scandes and the Scottish Highlands. This suggests that change in precipitation, not only warming, plays an important role in determining the potential impacts of climate change on vegetation.

Published
2011

12. Semi-empirical modeling of abiotic and biotic factors controlling ecosystem respiration across eddy covariance sites

Author

Migliavacca, M., Reichstein, M., Richardson, A.D., Colombo, R., Sutton, M.A., Lasslop, E., Tomelleri, E., Wohlfahrt, G., Carvalhais, N., Cescatti, A., Mahecha, D., Montagnani, L., Papale, D., Zaehle, S., Arain, A., Arneth, A., Black, T.A., Carrara, A., Dore, S., Gianelle, D., Helfter, C., Hollinger, D., Kutsch, W.L., Lafleur, P.M., Nouvellon, Y., Rebmann, C., Da Rocha, H.R., Rodeghiero, M., Roupsard, O., Sebastià, M.-T., Seufert, G., Soussana, J.-F., van der Molen, M.K., Remote Sensing of Environmental Dynamics, University of Milano-Bicocca, Department of Biogeochemical Integration [Jena], Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Department of Organismic and Evolutionary Biology [Cambridge] (OEB), Harvard University [Cambridge], Edinburgh Research Station, Centre for Ecology and Hydrology, Institute of Ecology, University of Innsbruck, Faculdade de Ciências e Tecnologia (FCT NOVA), Universidade Nova de Lisboa (NOVA), JRC Institute for Environment and Sustainability (IES), European Commission - Joint Research Centre [Ispra] (JRC), Department of Environmental Sciences, Swiss Federal Institute of Technology, Servizi Forestali, Provincia Autonoma di Bolzano, Agenzia per l'Ambiente, DISAFRI, University of Tuscia, Biogeochemical Systems Department [Jena], School of Geography & Earth Sciences, McMaster University [Hamilton, Ontario], Department of Physical Geography and Ecosystem Science [Lund], Lund University [Lund], Faculty of Land and Food Systems, University of British Columbia (UBC), School of Forestry, Northern Arizona University [Flagstaff], Centro di Ecologia Alpina, Fondazione Edmund Mach - Edmund Mach Foundation [Italie] (FEM), NE Research Station, USDA Forest Service, Institut für Agrarrelevante Klimaforschung, Johann Heinrich von Thünen Institut, College of Forestry [Corvallis], Oregon State University (OSU), 20- Department of Geography, Trent University, Département Performances des systèmes de production et de transformation tropicaux (Cirad-PERSYST), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Department Biogeochemical Processes [Jena], Micrometeorology Group [Bayreuth], Universität Bayreuth, Department of Atmospheric Sciences [São Paulo], University of São Paulo (USP), CATIE, Centro Agronómico Tropical de Investigación y Enseñanza, Agronomical Engineering School, Universitat de Lleida, Laboratory of Plant Ecology and Botany, Forest Technology Centre of Catalonia, Institut National de la Recherche Agronomique (INRA), Department of Hydrology and Geo-Environmental Sciences [Amsterdam], Vrije Universiteit Amsterdam [Amsterdam] (VU), Università degli Studi di Milano-Bicocca [Milano] (UNIMIB), Faculdade de Ciências e Tecnologia = School of Science & Technology (FCT NOVA), Universidade Nova de Lisboa = NOVA University Lisbon (NOVA), Department of Environmental Systems Science [ETH Zürich] (D-USYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Centro Agronómico Tropical de Investigación y Enseñanza - Tropical Agricultural Research and Higher Education Center (CATIE), Centre de Ciència i Tecnologia Forestal de Catalunya (CTFC), CarboEuropeIP, FAO-GTOS-TCO, iLEAPS, Max Planck Institute for Biogeochemistry, National Science Foundation, US Department of Energy, Model-Data Integration Group of the Max-Planck Institute for Biogeochemistry, Migliavacca, M, Reichstein, M, Richardson, A, Colombo, R, Sutton, M, Lasslop, G, Tomelleri, E, Wohlfahrt, G, Carvalhais, N, Cescatti, A, Mahecha, M, Montagnani, L, Papale, D, Zaehle, S, Arain, A, Arneth, A, Black, T, Carrara, A, Dore, S, Gianelle, D, Helfter, C, Hollinger, D, Kutsch, W, Lafleur, P, Nouvellon, Y, Rebmann, C, Humberto, R, Rodeghiero, M, Roupsard, O, Sebastià, M, Seufert, G, Soussana, J, Michiel, K, and Hydrology and Geo-environmental sciences

Subjects
Ecosystem respiration, [SDV]Life Sciences [q-bio], FLUXNET, Eddy covariance, Facteur climatique, Prairie, Productivité, Savane, Productivity, U10 - Informatique, mathématiques et statistiques, Respiration, Indice de surface foliaire, 000 - Autres thèmes, Life Sciences, Leaf area index, Forêt, Écosystème, Zone tropicale, P33 - Chimie et physique du sol, Carbone, F40 - Écologie végétale, Matière organique du sol, Zone tempérée, Zone froide, Settore BIO/07 - ECOLOGIA, SDG 14 - Life Below Water, Modélisation environnementale, Changement climatique, technology, industry, and agriculture, Zone méditerranéenne, Inverse modeling, GEO/10 - GEOFISICA DELLA TERRA SOLIDA
Abstract

In this study we examined ecosystem respiration (RECO) data from 104 sites belonging to FLUXNET, the global network of eddy covariance flux measurements. The goal was to identify the main factors involved in the variability of RECO: temporally and between sites as affected by climate, vegetation structure and plant functional type (PFT) (evergreen needleleaf, grasslands, etc.). We demonstrated that a model using only climate drivers as predictors of RECO failed to describe part of the temporal variability in the data and that the dependency on gross primary production (GPP) needed to be included as an additional driver of RECO. The maximum seasonal leaf area index (LAIMAX) had an additional effect that explained the spatial variability of reference respiration (the respiration at reference temperature Tref=15°C, without stimulation introduced by photosynthetic activity and without water limitations), with a statistically significant linear relationship (r2=0.52, p70% of the variance for most vegetation types. Exceptions include tropical and Mediterranean broadleaf forests and deciduous broadleaf forests. Part of the variability in respiration that could not be described by our model may be attributed to a series of factors, including phenology in deciduous broadleaf forests and management practices in grasslands and croplands., JRC.H.2-Air and Climate

Published
2010

13. Semiempirical modeling of abiotic and biotic factors controlling ecosystem respiration across eddy covariance sites

Author

Migliavacca, M., Reichstein, M., Richardson, A.D., Colombo, R., Sutton, M.A., Lasslop, G., Tomelleri, E., Wohlfahrt, G., Carvalhais, N., Cescatti, A., Mahecha, M.D., Montagnani, L., Papale, D., Zaehle, S., Arain, A., Arneth, A., Black, T.A., Carrara, A., Dore, S., Gianelle, D., Helfter, C., Hollinger, D., Kutsch, W.L., Lafleur, P.M., Nouvellon, Y., Rebmann, Corinna, Da Rocha, H.R., Rodeghiero, M., Roupsard, O., Sebastià, M.-T., Seufert, G., Soussana, J.-F., Van Der Molen, M.K., Migliavacca, M., Reichstein, M., Richardson, A.D., Colombo, R., Sutton, M.A., Lasslop, G., Tomelleri, E., Wohlfahrt, G., Carvalhais, N., Cescatti, A., Mahecha, M.D., Montagnani, L., Papale, D., Zaehle, S., Arain, A., Arneth, A., Black, T.A., Carrara, A., Dore, S., Gianelle, D., Helfter, C., Hollinger, D., Kutsch, W.L., Lafleur, P.M., Nouvellon, Y., Rebmann, Corinna, Da Rocha, H.R., Rodeghiero, M., Roupsard, O., Sebastià, M.-T., Seufert, G., Soussana, J.-F., and Van Der Molen, M.K.

Abstract

In this study we examined ecosystem respiration (RECO) data from 104 sites belonging to FLUXNET, the global network of eddy covariance flux measurements. The goal was to identify the main factors involved in the variability of RECO: temporally and between sites as affected by climate, vegetation structure and plant functional type (PFT) (evergreen needleleaf, grasslands, etc.). We demonstrated that a model using only climate drivers as predictors of RECO failed to describe part of the temporal variability in the data and that the dependency on gross primary production (GPP) needed to be included as an additional driver of RECO. The maximum seasonal leaf area index (LAIMAX) had an additional effect that explained the spatial variability of reference respiration (the respiration at reference temperature Tref=15 °C, without stimulation introduced by photosynthetic activity and without water limitations), with a statistically significant linear relationship (r2=0.52, P<0.001, n=104) even within each PFT. Besides LAIMAX, we found that reference respiration may be explained partially by total soil carbon content (SoilC). For undisturbed temperate and boreal forests a negative control of total nitrogen deposition (Ndepo) on reference respiration was also identified. We developed a new semiempirical model incorporating abiotic factors (climate), recent productivity (daily GPP), general site productivity and canopy structure (LAIMAX) which performed well in predicting the spatio-temporal variability of RECO, explaining >70% of the variance for most vegetation types. Exceptions include tropical and Mediterranean broadleaf forests and deciduous broadleaf forests. Part of the variability in respiration that could not be described by our model may be attributed to a series of factors, including phenology in deciduous broadleaf forests and management practices in grasslands and croplands.

Published
2011

17. Benefits of sward diversity for agricultural grasslands

Author

Lüscher, A., primary, Finn, J. A., additional, Connolly, J., additional, Sebastià, M. T., additional, Collins, R., additional, Fothergill, M., additional, Porqueddu, C., additional, Brophy, C., additional, Huguenin-Elie, O., additional, Kirwan, L., additional, Nyfeler, D., additional, and Helgadóttir, A., additional

Published
2008
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19. Evenness drives consistent diversity effects in intensive grassland systems across 28 European sites

Author

KIRWAN, L., primary, LÜSCHER, A., additional, SEBASTIÀ, M. T., additional, FINN, J. A., additional, COLLINS, R. P., additional, PORQUEDDU, C., additional, HELGADOTTIR, A., additional, BAADSHAUG, O. H., additional, BROPHY, C., additional, CORAN, C., additional, DALMANNSDÓTTIR, S., additional, DELGADO, I., additional, ELGERSMA, A., additional, FOTHERGILL, M., additional, FRANKOW-LINDBERG, B. E., additional, GOLINSKI, P., additional, GRIEU, P., additional, GUSTAVSSON, A. M., additional, HÖGLIND, M., additional, HUGUENIN-ELIE, O., additional, ILIADIS, C., additional, JØRGENSEN, M., additional, KADZIULIENE, Z., additional, KARYOTIS, T., additional, LUNNAN, T., additional, MALENGIER, M., additional, MALTONI, S., additional, MEYER, V., additional, NYFELER, D., additional, NYKANEN-KURKI, P., additional, PARENTE, J., additional, SMIT, H. J., additional, THUMM, U., additional, and CONNOLLY, J., additional

Published
2007
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20. Conservation of soil organic carbon, biodiversity and the provision of other ecosystem services along climatic gradients in West Africa.

Author

Marks, E., Aflakpui, G. K. S., Nkem, J., Poch, R. M., Khouma, M., Kokou, K., Sagoe, R., and Sebastià, M.-T.

Subjects
BIODIVERSITY, CONSERVATION of natural resources, AGRICULTURAL productivity, ECOSYSTEM management, ECONOMIC development & the environment, EMISSION control
Abstract

Terrestrial carbon resources are major drivers of development in West Africa. The distribution of these resources co-varies with ecosystem type and rainfall along a strong Northeast-Southwest climatic gradient. Soil organic carbon, a strong indicator of soil quality, has been severely depleted in some areas by human activities, which leads to issues of soil erosion and desertification, but this trend can be altered via appropriate management. There is significant potential to enhance existing soil carbon stores in West Africa, with benefits at the global and local scales, for atmospheric CO2 mitigation and supporting, and provisioning ecosystem services, respectively. Three key factors impacting carbon stocks are addressed in this review: climate, biotic factors, and human activities. Climate risks must be considered in a framework of global change, especially in West Africa, where landscape managers have few resources available to adapt to climatic perturbations. Among biotic factors, biodiversity conservation paired with carbon conservation may provide a pathway to sustainable development, as evidence suggests that both may be inter-linked, and biodiversity conservation is also a global priority with local benefits for ecosystem resilience, biomass productivity, and provisioning services such as foodstuffs. Finally, human management has largely been responsible for reduced carbon stocks, but this trend can be reversed through the implementation of appropriate carbon conservation strategies in the agricultural sector, as shown by multiple studies. Owing to the strong regional climatic gradient, country-level initiatives will need to consider carbon sequestration approaches for multiple ecosystem types. Given the diversity of environments, global policies must be adapted and strategised at the national or sub-national levels to improve C storage above and below ground. Initiatives of this sort must act locally at farmer scale, and focus on ecosystem services rather than on carbon sequestration solely. [ABSTRACT FROM AUTHOR]

Published
2008
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21. Aportació al coneixement florístic de l'Alta Ribagorça i la vall d'Aran

Author

Canalís, V., Baulies, Xavier, Sebastià, M. T., and Ballesteros, Enric

Abstract

3 páginas, Some records of vascular flora from the Alta Ribagorc;:a and the Vall d'Aran are commented. Observations about their habitat are given. Findings of Avenula marginata ssp. pyrenaiea, Carex ferruginea, Carum vertleillatum and Ranuneulus trichophyllus ssp. lutulentus seem to be the most interesting ones.

Published
1984

23. Plant diversity greatly enhances weed suppression in intensively managed grasslands

Author

Bélanger, G., Black, A., Brophy, C., Höglind, M., Huguenin-Elie, O., Jørgensen, M., Kadziuliene, Z., Grieu, P., Gustavsson, A. M., Thumm, U., Vliegher, A., Lüscher, A., Connolly, J., Sebastià, M. T., Kirwan, L., Finn, J. A., Lunnan, T., Nykanen-Kurki, P., Ribas, A., Taube, F., Suter, M., Collins, R. P., Porqueddu, C., Helgadottir, A., Baadshaug, O. H., Llurba, R., Čop, J., Dalmannsdottir, S., Delgado, I., Elgersma, A., Fothergill, M., Frankow-Lindberg, B. E., Ghesquiere, A., and Piotr Golinski

Subjects
agroecosystems

24. Carbon-nitrogen interactions in European forests and semi-natural vegetation - Part 1: Fluxes and budgets of carbon, nitrogen and greenhouse gases from ecosystem monitoring and modelling

Author

Flechard, C. R., Ibrom, A., Skiba, U. M., De Vries, W., Van Oijen, M., Cameron, D. R., DIse, N. B., Korhonen, J. F. J., Buchmann, N., Legout, A., Simpson, D., Sanz, M. J., Aubinet, M., Loustau, D., Montagnani, L., Neirynck, J., Janssens, I. A., Pihlatie, M., Kiese, R., Siemens, J., Francez, A.-J., Augustin, J., Varlagin, A., Olejnik, J., Juszczak, R., Aurela, M., Berveiller, D., Chojnicki, B. H., Dämmgen, U., Delpierre, N., Djuricic, V., Drewer, J., Dufrêne, E., Eugster, W., Fauvel, Y., Fowler, D., Frumau, A., Granier, A., Gross, P., Hamon, Y., Helfter, C., Hensen, A., Horvath, L., Kitzler, B., Kruijt, B., Kutsch, W. L., Lobo-Do-Vale, R., Lohila, A., Longdoz, B., Marek, M. V., Matteucci, G., Mitosinkova, M., Moreaux, V., Neftel, A., Ourcival, J.-M., Pilegaard, K., Pita, G., Sanz, F., Schjoerring, J. K., Sebastià, M.-T., Sim Tang, Y., Uggerud, H., Urbaniak, M., Van DIjk, N., Vesala, T., Vidic, S., Vincke, C., Weidinger, T., Zechmeister-Boltenstern, S., Butterbach-Bahl, K., Nemitz, E., and Sutton, M. A.

Subjects
13. Climate action, 15. Life on land
Abstract

The impact of atmospheric reactive nitrogen (N$_{r}$) deposition on carbon (C) sequestration in soils and biomass of unfertilized, natural, semi-natural and forest ecosystems has been much debated. Many previous results of this dC/dN response were based on changes in carbon stocks from periodical soil and ecosystem inventories, associated with estimates of N$_{r}$ deposition obtained from large-scale chemical transport models. This study and a companion paper (Flechard et al., 2020) strive to reduce uncertainties of N effects on C sequestration by linking multi-annual gross and net ecosystem productivity estimates from 40 eddy covariance flux towers across Europe to local measurement-based estimates of dry and wet N$_{r}$ deposition from a dedicated collocated monitoring network. To identify possible ecological drivers and processes affecting the interplay between C and N$_{r}$ inputs and losses, these data were also combined with in situ flux measurements of NO, N$_{2}$O and CH$_{4}$ fluxes; soil NO$_{3}$̅ leaching sampling; and results of soil incubation experiments for N and greenhouse gas (GHG) emissions, as well as surveys of available data from online databases and from the literature, together with forest ecosystem (BASFOR) modelling. Multi-year averages of net ecosystem productivity (NEP) in forests ranged from -70 to 826 gCm$^{-2}$ yr$^{-1}$ at total wet+dry inorganic N$_{r}$ deposition rates (N$_{dep}$) of 0.3 to 4.3 gNm$^{-2}$ yr$^{-1}$ and from -4 to 361 g Cm$^{-2}$ yr$^{-1}$ at N$_{dep}$ rates of 0.1 to 3.1 gNm$^{-2}$ yr$^{-1}$ in short semi-natural vegetation (moorlands, wetlands and unfertilized extensively managed grasslands). The GHG budgets of the forests were strongly dominated by CO$_{2}$ exchange, while CH$_{4}$ and N$_{2}$O exchange comprised a larger proportion of the GHG balance in short semi-natural vegetation. Uncertainties in elemental budgets were much larger for nitrogen than carbon, especially at sites with elevated N$_{dep}$ where N$_{r}$ leaching losses were also very large, and compounded by the lack of reliable data on organic nitrogen and N$_{2}$ losses by denitrification. Nitrogen losses in the form of NO, N$_{2}$O and especially NO$_{3}$̅ were on average 27%(range 6 %–54 %) of N$_{dep}$ at sites with N$_{dep}$ < 1 gNm$^{-2}$ yr$^{-1}$ versus 65% (range 35 %–85 %) for N$_{dep}$ > 3 gNm$^{-2}$ yr$^{-1}$. Such large levels of N$_{r}$ loss likely indicate that different stages of N saturation occurred at a number of sites. The joint analysis of the C and N budgets provided further hints that N saturation could be detected in altered patterns of forest growth. Net ecosystem productivity increased with N$_{r}$ deposition up to 2–2.5 gNm$^{-2}$ yr$^{-1}$, with large scatter associated with a wide range in carbon sequestration efficiency (CSE, defined as the NEP = GPP ratio). At elevated N$_{dep}$ levels (> 2.5 gNm$^{-2}$ yr$^{-1}$), where inorganic N$_{r}$ losses were also increasingly large, NEP levelled off and then decreased. The apparent increase in NEP at low to intermediate N$_{dep}$ levels was partly the result of geographical cross-correlations between N$_{dep}$ and climate, indicating that the actual mean dC/dN response at individual sites was significantly lower than would be suggested by a simple, straightforward regression of NEP vs. N$_{dep}$.

25. Weed suppression greatly increased by plant diversity in intensively managed grasslands: A continental-scale experiment

Author

Connolly, J, Sebastià, M-T, Kirwan, L, Finn, JA, Llurba, R, Suter, M, Collins, RP, Porqueddu, C, Helgadóttir, Á, Baadshaug, OH, Bélanger, G, Black, Alistair, Brophy, C, Čop, J, Dalmannsdóttir, S, Delgado, I, Elgersma, A, Fothergill, M, Frankow-Lindberg, BE, Ghesquiere, A, Golinski, P, Grieu, P, Gustavsson, A-M, Höglind, M, Huguenin-Elie, O, Jørgensen, M, Kadziuliene, Z, Lunnan, T, Nykanen-Kurki, P, Ribas, A, Taube, F, Thumm, U, De Vliegher, A, Lüscher, A, and Inderjit,

Published
2018
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26. Identifying the drivers of changes in the relative abundances of species in agroecosystems

Author

Brophy, C., Finn, J. A., Lüscher, A., Suter, M., Kirwan, L., Sebastià, M. T., Helgadóttir, Á., Baadshaug, O. H., Bélanger, G., Black, Alistair, Collins, R. P., Čop, J., Dalmannsdóttir, S., Delgado, I., Elgersma, A., Fothergill, M., Frankow-Lindberg, B. E., Ghesquiere, A., Golińska, B., Goliński, P., Grieu, P., Gustavsson, A. M., Höglind, M., Huguenin-Elie, O., Jørgensen, M., Kadziuliene, Z., Kurki, P., Llurba, R., Lunnan, T., Porqueddu, C., Thumm, U., Connolly, J., Horan, B., Hennessy, D., O’Donovan, M., Kennedy, E., McCarthy, B., Finn, J. A., and O’Brien, B.

Published
2018

27. Plant diversity greatly enhances weed suppression in intensively managed grasslands

Author

Connolly, J., Sebastià, M. T., Kirwan, L., Finn, J. A., Llurba, R., Suter, M., Collins, R. P., Porqueddu, C., Helgadóttir, A., Baadshaug, O. H., Bélanger, G., Black, Alistair, Brophy, C., Čop, J., Dalmannsdóttir, S., Delgado, I., Elgersma, A., Fothergill, M., Frankow-Lindberg, B. E., Ghesquiere, A., Goliński, P., Grieu, P., Gustavsson, A. M., Höglind, M., Huguenin-Elie, O., Jørgensen, M., Kadziuliene, Z., Lunnan, T., Nykanen-Kurki, P., Ribas, A., Taube, F., Thumm, U., De Vliegher, A., Lüscher, A., Horan, B., Hennessy, D., O'Donovan, M., Kennedy, E., McCarthy, B., Finn, J. A., and O'Brien, B.

Published
2018

28. Biochar application and summer temperatures reduce N 2 O and enhance CH 4 emissions in a Mediterranean agroecosystem: Role of biologically-induced anoxic microsites.

Author

Ribas A, Mattana S, Llurba R, Debouk H, Sebastià MT, and Domene X

Subjects
Agriculture, Ecosystem, Mediterranean Region, Charcoal, Methane analysis, Nitrogen Dioxide analysis, Temperature
Abstract

Biochar applications have been proposed for mitigating some soil greenhouse gas (GHG) emissions. However, results can range from mitigation to no effects. To explain these differences, mechanisms have been proposed but their reliability depends on biochar type, soil and climatic conditions. Furthermore, it is found that the mitigation capacity is dependent on how the biochar is aging under field conditions. The effects on N 2 O, CH 4 and CO 2 emission rates of a gasification pine biochar (applied as 0, 5, and 30 t ha -1 ) were studied between 8 and 21 months of the application in an alkaline soil cropped to barley under Mediterranean climate. Together with GHG, soil chemical and biological properties were assessed, namely, changes in labile organic matter content and nutrient status, and pH, as well as microbial abundance, activity, and functional composition. During the 2 years of the application, significant changes were observed at the highest rate of biochar application such as higher contents of water, K + , Mg 2+ , SO 4 2- , higher basal respiration, and with non-significant changes in microbial community, though with some temporal effects. Regarding GHG, N 2 O decreases coupled with CH 4 increases in the summer sampling were measured, although only for the highest application rate scenario. Such effects were unrelated to pH, bioavailable nitrogen status, or bulk soil microbial community shifts. We hypothesized that the key is the porous structure of our wood biochar, which is able to provide more and diversified microbial microhabitats in comparison to bulk soil. At higher temperatures in summer, biologically-induced anoxic conditions in biochar pores acting as microsites may be promoted, where total denitrification to N 2 occurs which leads to N 2 O uptake, while CH 4 production is promoted., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Published
2019
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