Descripteur
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externesEtendre la recherche sur niveau(x) vers le bas
The relationship between climate and the intra-annual oxygen isotope patterns from pine trees: a case study along an elevation gradient on Corsica, France / Sonja Szymczak in Annals of Forest Science [en ligne], Vol 76 n° 3 (September 2019)
Titre : The relationship between climate and the intra-annual oxygen isotope patterns from pine trees: a case study along an elevation gradient on Corsica, France Type de document : Article/Communication Auteurs : Sonja Szymczak, Auteur ; Achim Bräuning, Auteur ; Martin Häusser, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : 14 p Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] carbone
[Termes descripteurs IGN] changement climatique
[Termes descripteurs IGN] Corse
[Termes descripteurs IGN] croissance végétale
[Termes descripteurs IGN] dendrologie
[Termes descripteurs IGN] gradient d'altitude
[Termes descripteurs IGN] humidité du sol
[Termes descripteurs IGN] isotope
[Termes descripteurs IGN] oxygène (O²)
[Termes descripteurs IGN] Pinus nigra corsicana
[Termes descripteurs IGN] Pinus pinaster
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) Key message: Intra-annual oxygen isotope patterns of tree-ring cellulose from Pinus nigra subsp. laricio and Pinus pinaster along an elevation gradient can be divided into four distinct patterns ((1) high values in the beginning of the tree ring, declining trend afterwards; (2) low values in the beginning, increasing trend afterwards; (3) high values in the middle of the tree ring; (4) declining trend over the whole tree ring). These patterns reflect the dependency on local site conditions and different water sources.
Context: Intra-annual oxygen isotope chronologies from tree-ring cellulose can serve as a proxy for past climate conditions at inter- or even intra-seasonal resolution.
Aims: We explore the potential of these chronologies from pine trees (Pinus nigra J.F. Arn subsp. laricio (Poiret) Maire var Corsicana Hyl. and Pinus pinaster Aiton) growing on the Mediterranean island of Corsica, France, along an elevation gradient ranging from sea level to 1600 m asl.
Methods: We developed high-resolution intra-annual oxygen isotope chronologies from tree-ring cellulose of eight trees from five sites along the elevation gradient. The analysis period covers the decade 2007–2016 for seven trees and the period 1987–2016 for one tree, respectively.
Results: The chronologies show a high variability between trees, sites, and years. We identified four different intra-annual oxygen isotope patterns which reflect the dependency of tree growth on different water sources (precipitation during the growing season vs. deeper soil water reservoirs) and climate conditions during the growth season. Trees at coastal sites have access to groundwater, while trees growing in high elevations mostly depend on precipitation during the growth season as water source.
Conclusion: The different patterns can be attributed to the use of different water sources. The intra-annual chronology covering 30 years indicates an increasing frequency of dry-warm summers after 2007.Numéro de notice : A2019-304 Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-019-0860-9 date de publication en ligne : 29/07/2019 En ligne : https://doi.org/10.1007/s13595-019-0860-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93237
in Annals of Forest Science [en ligne] > Vol 76 n° 3 (September 2019) . - 14 p[article]
Titre : Analysis and modelling of remote sensing reflectance during anoxic crisis in the Thau lagoon using satellite images Type de document : Article/Communication Auteurs : Manchun Lei Congrès : Oceans Europe 2019, MTS / IEEE (17 - 20 juin 2019; Marseille, France) Editeur : New York : Institute of Electrical and Electronics Engineers IEEE Année de publication : 2019 Projets : 1-Pas de projet / Importance : pp 1 - 6 Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes descripteurs IGN] capteur multibande
[Termes descripteurs IGN] image Envisat-MERIS
[Termes descripteurs IGN] oxygène (O²)
[Termes descripteurs IGN] pollution des eaux
[Termes descripteurs IGN] réflectance spectrale
[Termes descripteurs IGN] Thau (bassin de)Mots-clés libres : bactéries du soufre Résumé : (auteur) This study concerns the spectral behavior of remote sensing reflectance R rs of Thau lagoon water during the anoxic crisis in the summer of 2003 and 2006. The proliferation of photosynthetic sulfur-oxidizing bacteria (SOB) in anoxic water make the water color becomes opaque and turbid until milky. An identification method using 665 nm, 709 nm and 754 nm bands of Medium Resolution Imaging Spectrometer (MERIS) sensor is proposed to identify the total anoxic water filled by SOB. The reflectance of the SOB layer is described as a specific reflectance relating to the SOB concentration. The results show that SOB contaminated water during the anoxic crisis can be quantitatively remote sensed by multispectral sensor. Numéro de notice : C2019-021 Thématique : IMAGERIE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1109/OCEANSE.2019.8867565 date de publication en ligne : 14/10/2019 En ligne : http://doi.org/10.1109/OCEANSE.2019.8867565 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93845
Titre : Can forest structural diversity be a response to anthropogenic stress? A case study in old-growth fir Abies alba Mill. stands Type de document : Article/Communication Auteurs : Rafał Podlaski, Auteur Année de publication : 2018 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] Abies alba
[Termes descripteurs IGN] action anthropique
[Termes descripteurs IGN] arbre mort
[Termes descripteurs IGN] biodiversité végétale
[Termes descripteurs IGN] croissance végétale
[Termes descripteurs IGN] diamètre à hauteur de poitrine
[Termes descripteurs IGN] diamètre des arbres
[Termes descripteurs IGN] dioxyde de soufre
[Termes descripteurs IGN] émission de gaz
[Termes descripteurs IGN] gaz à effet de serre
[Termes descripteurs IGN] parc naturel national
[Termes descripteurs IGN] Pologne
[Termes descripteurs IGN] structure d'un peuplement forestier
[Termes descripteurs IGN] structure de la végétation
[Termes descripteurs IGN] surveillance forestière
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) From 1973 to 1991, Polish SO 2 emissions above 3250 Gg/year resulted in a decline of fir Abies alba Mill. After stresses connected with these emissions, five main diameter at breast height (DBH) structural types were described. This type of heterogeneous forest structure is supposed to increase forest resistance and resilience to abiotic, biotic and anthropogenic disturbances. The analyses of forest structure are important under the current scenario of global change, since heterogeneous structures allow for better responses to disturbances. Forests with more complex structures should present greater vitality. The main hypotheses were as follows: (1) the temporal changes of atmospheric SO2 emissions caused (a) the abrupt changes in the tree DBH radial increment and (b) the death of fir trees; and (2) atmospheric SO2 emissions and related fir decline and recovery processes ultimately result in the development of stands characterised by diverse DBH structures. Radial growth trends of 49 and 215 fir trees in the older and younger generations, respectively, and 85 dead fir trees were evaluated. Using data collected in 32 stands, the DBH structural types were identified, and the shapes of these types were illustrated. The structural diversification of forest patches may influence forest resistance and resilience to disturbances; five main structural types were identified: ML1 and ML2 represent DBH distributions of multi-layered stands, and OS, TS1 and TS2 represent DBH distributions of one- and two-storied stands. Structural diversity of forests was a response to SO2 emissions; fir trees had the ability to increase their radial growth, although there were still high SO2 emissions. Numéro de notice : A2018-548 Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-018-0777-8 date de publication en ligne : 20/11/2018 En ligne : https://doi.org/10.1007/s13595-018-0777-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91591
in Annals of Forest Science [en ligne] > vol 75 n° 4 (December 2018)[article]
Titre : Enhancing plant diversity and mitigating BVOC emissions of urban green spaces through the introduction of ornamental tree species Type de document : Article/Communication Auteurs : Yuan Ren, Auteur ; Ying Ge, Auteur ; Danping Ma, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 305 - 313 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] arbre urbain
[Termes descripteurs IGN] biodiversité
[Termes descripteurs IGN] espace vert
[Termes descripteurs IGN] milieu urbain
[Termes descripteurs IGN] ozone
[Termes descripteurs IGN] pollution atmosphérique
[Termes descripteurs IGN] service écosystémique
[Termes descripteurs IGN] urbanisme
[Termes descripteurs IGN] ville
[Vedettes matières IGN] Economie forestièreRésumé : (auteur) Promoting the plant diversity of urban green spaces is crucial to increase ecosystem services in urban areas. While introducing ornamental plants can enhance the biodiversity of green spaces it risks environmental impacts such as increasing emissions of biogenic volatile organic compounds (BVOCs) that are harmful to air quality and human health. The present study, taking Qingdao City as a case study, evaluated the plant diversity and BVOC emissions of urban green spaces and tried to find out a solution to increase biodiversity while reducing BVOC emissions. Results showed that: (1) the species diversity and phylogenetic diversity of trees in urban green spaces were 22% and 16% lower than rural forest of this region; (2) urban areas had higher BVOC emission intensity (2.6 g C m−2 yr−1) than their rural surroundings (2.1 g C m−2 yr−1); (3) introducing the selected 11 tree species will increase 15% and 11% of species diversity and phylogenetic diversity, respectively; and (4) the BVOC emissions from green spaces will more than triple by 2050, but a moderate introduction of the selected low-emitting trees species could reduce 34% of these emissions. The scheme of introducing low-emitting ornamental species leads to a win–win situation and also has implications for the sustainable green space management of other cities. Numéro de notice : A2017-560 Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.1016/j.ufug.2017.08.011 En ligne : https://doi.org/10.1016/j.ufug.2017.08.011 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86639
in Urban Forestry & Urban Greening > vol 27 (October 2017) . - pp 305 - 313[article]
Titre : Biodiversity effects on ecosystem functioning in a 15-year grassland experiment: patterns, mechanisms, and open questions Type de document : Article/Communication Auteurs : Wolfgang W. Weisser, Auteur ; Christiane Roscher, Auteur ; Sebastian Meyer, Auteur ; et al., Auteur Année de publication : 2017 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Ecologie
[Termes descripteurs IGN] azote
[Termes descripteurs IGN] biomasse
[Termes descripteurs IGN] carbone
[Termes descripteurs IGN] écosystème
[Termes descripteurs IGN] gaz à effet de serre
[Termes descripteurs IGN] nutriment
[Termes descripteurs IGN] placette d'échantillonnage
[Termes descripteurs IGN] potassium
[Termes descripteurs IGN] puits de carbone
[Termes descripteurs IGN] richesse floristique
[Termes descripteurs IGN] sol
[Termes descripteurs IGN] stabilitéRésumé : (auteur) In the past two decades, a large number of studies have investigated the relationship between biodiversity and ecosystem functioning, most of which focussed on a limited set of ecosystem variables. The Jena Experiment was set up in 2002 to investigate the effects of plant diversity on element cycling and trophic interactions, using a multi-disciplinary approach. Here, we review the results of 15 years of research in the Jena Experiment, focussing on the effects of manipulating plant species richness and plant functional richness. With more than 85,000 measures taken from the plant diversity plots, the Jena Experiment has allowed answering fundamental questions important for functional biodiversity research.
First, the question was how general the effect of plant species richness is, regarding the many different processes that take place in an ecosystem. About 45% of different types of ecosystem processes measured in the ‘main experiment’, where plant species richness ranged from 1 to 60 species, were significantly affected by plant species richness, providing strong support for the view that biodiversity is a significant driver of ecosystem functioning. Many measures were not saturating at the 60-species level, but increased linearly with the logarithm of species richness. There was, however, great variability in the strength of response among different processes. One striking pattern was that many processes, in particular belowground processes, took several years to respond to the manipulation of plant species richness, showing that biodiversity experiments have to be long-term, to distinguish trends from transitory patterns. In addition, the results from the Jena Experiment provide further evidence that diversity begets stability, for example stability against invasion of plant species, but unexpectedly some results also suggested the opposite, e.g. when plant communities experience severe perturbations or elevated resource availability. This highlights the need to revisit diversity-stability theory.
Second, we explored whether individual plant species or individual plant functional groups, or biodiversity itself is more important for ecosystem functioning, in particular biomass production. We found strong effects of individual species and plant functional groups on biomass production, yet these effects often occurred mostly in addition to, but not instead of, effects of plant species richness.
Third, the Jena Experiment assessed the effect of diversity on multitrophic interactions. The diversity of most organisms responded positively to increases in plant species richness, and the effect was stronger for above- than for belowground organisms, and stronger for herbivores than for carnivores or detritivores. Thus, diversity begets diversity. In addition, the effect on organismic diversity was stronger than the effect on species abundances.
Fourth, the Jena Experiment aimed to assess the effect of diversity on N, P and C cycling and the water balance of the plots, separating between element input into the ecosystem, element turnover, element stocks, and output from the ecosystem. While inputs were generally less affected by plant species richness, measures of element stocks, turnover and output were often positively affected by plant diversity, e.g. carbon storage strongly increased with increasing plant species richness. Variables of the N cycle responded less strongly to plant species richness than variables of the C cycle.
Fifth, plant traits are often used to unravel mechanisms underlying the biodiversity-ecosystem functioning relationship. In the Jena Experiment, most investigated plant traits, both above- and belowground, were plastic and trait expression depended on plant diversity in a complex way, suggesting limitation to using database traits for linking plant traits to particular functions.
Sixth, plant diversity effects on ecosystem processes are often caused by plant diversity effects on species interactions. Analyses in the Jena Experiment including structural equation modelling suggest complex interactions that changed with diversity, e.g. soil carbon storage and greenhouse gas emission were affected by changes in the composition and activity of the belowground microbial community. Manipulation experiments where particular organisms, e.g. belowground invertebrates, were excluded from plots in split-plot experiments, supported the important role of the biotic component for element and water fluxes.
Seventh, the Jena Experiment aimed to put the results into the context of agricultural practices in managed grasslands. The effect of increasing plant species richness from 1 to 16 species on plant biomass was, in absolute terms, as strong as the effect of a more intensive grassland management, using fertiliser and increasing mowing frequency. Potential bioenergy production from high-diversity plots was similar to that of conventionally used energy crops. These results suggest that diverse ‘High Nature Value Grasslands’ are multifunctional and can deliver a range of ecosystem services including production-related services.
A final task was to assess the importance of potential artefacts in biodiversity–ecosystem functioning relationships, caused by the weeding of the plant community to maintain plant species composition. While the effort (in hours) needed to weed a plot was often negatively related to plant species richness, species richness still affected the majority of ecosystem variables. Weeding also did not negatively affect monoculture performance; rather, monocultures deteriorated over time for a number of biological reasons, as shown in plant-soil feedback experiments.
To summarize, the Jena Experiment has allowed for a comprehensive analysis of the functional role of biodiversity in an ecosystem. A main challenge for future biodiversity research is to increase our mechanistic understanding of why the magnitude of biodiversity effects differs among processes and contexts. It is likely that there will be no simple answer. For example, among the multitude of mechanisms suggested to underlie the positive plant species richness effect on biomass, some have received limited support in the Jena Experiment, such as vertical root niche partitioning. However, others could not be rejected in targeted analyses. Thus, from the current results in the Jena Experiment it seems likely that the positive biodiversity effect results from several mechanisms acting simultaneously in more diverse communities, such as reduced pathogen attack, the presence of more plant growth promoting organisms, less seed limitation, and increased trait differences leading to complementarity in resource uptake. Distinguishing between different mechanisms requires careful testing of competing hypotheses. Biodiversity research has matured such that predictive approaches testing particular mechanisms are now possible.Numéro de notice : A2017-352 Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.1016/j.baae.2017.06.002 En ligne : https://doi.org/10.1016/j.baae.2017.06.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85690
in Basic and Applied Ecology > vol [26/06/2017][article]Permalinkn° 13 - février 2017 - Chiffres clés de l'énergie, édition 2016 (Bulletin de Datalab) / CGDD Commissariat Général au Développement Durable
PermalinkPermalinkPermalinkChiffres clés de l'énergie, édition 2015 / CGDD Commissariat Général au Développement Durable (2015)
PermalinkPermalinkPermalinkPermalinkPermalinkPermalink
