Auteurs, date et publication :
Auteurs Benoit De Thoisy , Ibrahim Fayad , Luc Clément , Sébastien Barrioz , Eddy Poirier , Valéry Gond
Publication : PloS one
Date : 2025
Volume : 11
Issue : 11
Pages : e0165362
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Johanne Lebrun Thauront , Severin Luca Bellè , Marcus Schiedung , Amicie Delahaie , Marija Stojanova , François Baudin , Pierre Barré , Samuel Abiven
Date : 2024
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
Pyrogenic carbon (PyC) is a continuum of aromatic and condensed organic molecules. It represents about 15 % of organic carbon in soils and sediments1. However, there is a discrepancy in the literature regarding quantification of PyC: different methods that are currently considered as reference differ largely in their results1,2. Indeed, most methods used to quantify PyC are based on different operational principles (e.g. chemical, thermal or physical stability of PyC, molecular markers) and consequently, they do not cover the same range of the PyC continuum2. In addition, most of them are expensive and/or time consuming. Here, we propose a new PyC quantification method based on Rock-Eval® thermal analysis, thought to be rapid, inexpensive and comparable to the previous methods toolbox. Rock-Eval® thermal analysis has been successfully introduced to the field of soil carbon analysis in the last two decades and allowed to distinguish between various pools of soil carbon (inorganic carbon, stable and active organic carbon) using a single analysis of combined pyrolysis and thermal oxidation3,4. In this study, we formulate the hypothesis that Rock-Eval® thermal analysis in combination with predictive modelling is suitable to quantify PyC in soil matrices.To build and validate such a model, we chose soil samples originating from contrasting climate zones and parent material and with varying properties including clay content and mineralogy, iron oxide speciation and content, pH, cation-exchange capacity and organic carbon content. We measured PyC using a set of established methods (i.e. CTO-375, BPCA and HyPy) and acquired Rock-Eval® thermograms. Then, we identified the relevant features for PyC quantification in the thermograms by applying several machine-learning approaches. This work adds a new soil carbon pool to the ones already accessible from Rock-Eval® thermal analysis and allows an efficient and rapid quantification of PyC in soils, which is needed for large-scale studies of soil carbon pools.(1) Reisser, M.; Purves, R. S.; Schmidt, M. W. I.; Abiven, S. Pyrogenic Carbon in Soils: A Literature-Based Inventory and a Global Estimation of Its Content in Soil Organic Carbon and Stocks. Front. Earth Sci. 2016, 4 (August), 1-14. https://doi.org/10.3389/feart.2016.00080.(2) Hammes, K.; Smernik, R. J.; Skjemstad, J. O.; Schmidt, M. W. I. Characterisation and Evaluation of Reference Materials for Black Carbon Analysis Using Elemental Composition, Colour, BET Surface Area and 13C NMR Spectroscopy. Appl. Geochemistry 2008, 23 (8), 2113-2122. https://doi.org/10.1016/j.apgeochem.2008.04.023.(3) Disnar, J. R.; Guillet, B.; Keravis, D.; Di-Giovanni, C.; Sebag, D. Soil Organic Matter (SOM) Characterization by Rock-Eval Pyrolysis: Scope and Limitations. Org. Geochem. 2003, 34 (3), 327-343. https://doi.org/10.1016/S0146-6380(02)00239-5.(4) Cécillon, L.; Baudin, F.; Chenu, C.; Houot, S.; Jolivet, R.; Kätterer, T.; Lutfalla, S.; Macdonald, A.; Van Oort, F.; Plante, A. F.; Savignac, F.; Soucémarianadin, L. N.; Barré, P. A Model Based on Rock-Eval Thermal Analysis to Quantify the Size of the Centennially Persistent Organic Carbon Pool in Temperate Soils. Biogeosciences 2018, 15 (9), 2835-2849. https://doi.org/10.5194/bg-15-2835-2018.
Auteurs, date et publication :
Auteurs Johanne Lebrun Thauront , Severin Luca Bellè , Marcus Schiedung , Amicie Delahaie , Marija Stojanova , François Baudin , Pierre Barré , Samuel Abiven
Date : 2024
Pages : 16551
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
Synthetic Aperture Radar (SAR) texture has been demonstrated to have the potential to improve forest biomass estimation using backscatter. However, forests are 3D objects with a vertical structure. The strong penetration of SAR signals means that each pixel contains the contributions of all the scatterers inside the forest canopy, especially for the P-band. Consequently, the traditional texture derived from SAR images is affected by forest vertical heterogeneity, although the influence on texture-based biomass estimation has not yet been explicitly explored. To separate and explore the influence of forest vertical heterogeneity, we introduced the SAR tomography technique into the traditional texture analysis, aiming to explore whether TomoSAR could improve the performance of texture-based aboveground biomass (AGB) estimation and whether texture plus tomographic backscatter could further improve the TomoSAR-based AGB estimation. Based on the P-band TomoSAR dataset from TropiSAR 2009 at two different sites, the results show that ground backscatter variance dominated the texture features of the original SAR image and reduced the biomass estimation accuracy. The texture from upper vegetation layers presented a stronger correlation with forest biomass. Texture successfully improved tomographic backscatter-based biomass estimation, and the texture from upper vegetation layers made AGB models much more transferable between different sites. In addition, the correlation between texture indices varied greatly among different tomographic heights. The texture from the 10 to 30 m layers was able to provide more independent information than the other layers and the original images, which helped to improve the backscatter-based AGB estimation.
Auteurs, date et publication :
Auteurs Zhanmang Liao , Binbin He , Xingwen Quan
Publication : International Journal of Applied Earth Observation and Geoinformation
Date : 2020
Volume : 88
Pages : 102049
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
The ongoing decline in biodiversity has fuelled concerns about its impact on ecosystem functioning. Mediterranean oak forests may prove very sensitive to global change, which could strongly influence the species composition of plant communities and thereby affect ecosystem processes. To determine the potential outcome of shifts in species composition on litter decomposition dynamics, we conducted a full-factorial decomposition experiment over a gradient of litter species diversity in a Mediterranean Downy oak (Quercus pubescens Willd.) forest. We used litter from the three dominant tree species naturally present in the Downy oak forest and litter from Aleppo pine (Pinus halepensis Mill.) in anticipation of its possible spread in the future with global change. Litter water holding capacity and N/P ratio were the most important and positive drivers of decomposition process. In contrast to other ecosystems where synergistic non-additive effects are prevalent, we observed 54% of additive and 46% of non-additive effects on litter mass loss in our Mediterranean ecosystem. These results could indicate less complementarity among decomposers for decomposition of diverse plant material in such a stressful climate. Moreover, dominant tree species are of key importance for nutrient availability, and the arrival of Aleppo pine would strongly reduce the N release during the decomposition process. Based on calculations of an annual partial nutrient budget at the ecosystem level, we showed that a shift in plant communities could affect nutrient release, ranging from 5 to 36% for N and 63 to 83% for P depending on the co-occurring tree species in the Downy oak forest.
Auteurs, date et publication :
Auteurs Mathieu Santonja , Virginie Baldy , Catherine Fernandez , Jérôme Balesdent , Thierry Gauquelin
Publication : Ecosystems
Date : 2015
Volume : 18
Issue : 7
Pages : 1253-1268
Catégorie(s)
#CNRS #FORET O3HPAuteurs, date et publication :
Auteurs Elodie Merlier , Gabriel Hmimina , Matthieu Bagard , Eric Dufrêne , Kamel Soudani
Publication : Photochemical & Photobiological Sciences
Date : 2025
Volume : 16
Issue : 8
Pages : 1238-1251
Catégorie(s)
#ANR-Citation #CNRS #Ecotron IleDeFrance #ENSRésumé
Climate change will increase the level of drought stress experienced by plant communities, but the spatial distribution of projected changes in dryness remains highly uncertain. Species can, to some extent, deal with climate uncertainty through natural variation in adaptive responses to environmental heterogeneity and predictability. Biodiversity conservation could thus target populations pre-adapted to climatic heterogeneity to anticipate climate uncertainty. Disentangling adaptive evolution of trait means versus trait plasticity, however, requires a sampling design with genetic replicates grown under distinct environmental conditions. Here, we applied three soil moisture treatments to genetic replicates of Fragaria vesca plants raised from seeds that were sampled in distinct topographical settings, to study adaptive trait and plasticity divergence in response to drought. We demonstrate that various plant traits evolved along distinct topographical gradients. Populations on south-exposed slopes, for example, retained high levels of both flowering and runner formation under drought stress, while north-faced populations hardly flowered under reduced soil moisture levels. Aspect but not elevation was found to coincide with variation in plant traits, suggesting that microenvironmental variation rather than general clines in elevation drive evolution in mountainous landscapes. Our results also indicate that traits and their plasticity can evolve independently in response to distinct topographical stressors. Synthesis. We conclude that heterogeneous landscapes (a) harbour micro-refugia of adaptive genetic diversity that protect natural populations against environmental change, and (b) represent invaluable sources of quantitative genetic variation that could support conservation where climate projections are inconclusive.
Auteurs, date et publication :
Auteurs Hanne De Kort , Bart Panis , Kenny Helsen , Rolland Douzet , Steven B. Janssens , Olivier Honnay
Publication : Journal of Ecology
Date : 2025
Volume : 108
Issue : 4
Pages : 1465-1474
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Sarah Chaloupka , Camilo Rodríguez
Publication : Herpetology Notes
Date : 2025
Volume : 14
Pages : 209-213
Catégorie(s)
#⛔ No DOI found #CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs B. Urbani , D. Youlatos , M. M. Kowalewski
Publication : Primate Biology
Date : 2025
Volume : 7
Issue : 2
Pages : 25–33
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Elodie A Courtois , Kevin Pineau , Benoit Villette , Dirk S Schmeller , Philippe Gaucher
Publication : Phyllomedusa
Date : 2025
Volume : 11
Pages : 63-70