Résumé
The Mediterranean evergreen oak coppices of Southern Europe are increasingly vulnerable to drought because of both the ongoing climate change that increases drought length and intensity, and the lack of forest management that induces a structural aging of the stands. Decreasing stand density through thinning has been widely regarded as a means to improve the resistance of evergreen oak forests to climate change by decreasing the competition for water amongst the remaining stems.
Auteurs, date et publication :
Auteurs Antoine Cabon , Florent Mouillot , Morine Lempereur , Jean-Marc Ourcival , Guillaume Simioni , Jean-Marc Limousin
Publication : Forest Ecology and Management
Date : 2025
Volume : 409
Pages : 333-342
Catégorie(s)
#CNRS #FORET PuechabonRésumé
Agriculture is undergoing important changes in order to meet sustainable soil management with respect to biodiversity (namely agroecology). Within this context, alternative solutions to mineral fertilizers such as agricultural biostimulants are thus promoted and being developed. The mechanisms by which some soil biostimulants sustain soil biological functioning and indirectly increase crop yields are still unknown. Our goal in the present study was to demonstrate if and to what extent the application of a soil biostimulant affects the soil heterotrophic microbial communities that are involved in organic matter decomposition and carbon mineralization. We hypothesized that the addition of a biostimulant results in changes in the composition and in the biomass of soil microbial communities. This in turn increases the mineralization of the organic matter derived from crop residues. We performed soil microcosm experiments with the addition of crop residues and a biostimulant, and we monitored the organic carbon (orgC) mineralization and the microbial biomass, along with the microbial community composition by sequencing 16S rRNA gene and ITS amplicons. The addition of a soil biostimulant caused a pH neutralizing effect and simultaneous enhancement of the orgC mineralization of crop residues (+ 400 μg orgC g-1 dry soil) and microbial biomass (+ 60 μg orgC g-1 dry soil) that were linked to changes in the soil microbial communities. Our findings suggest that the soil carbon mineralization enhancement in the presence of the biostimulant was supported by the specific recruitment of soil bacteria and fungi. Whereas archaea remained stable, several operational taxonomic units (OTUs) of indigenous soil bacteria and fungi were enriched and affiliated with known microbial decomposers such as Cytophagaceae, Phaselicystis sp., Verrucomicrobia, Pseudomonas sp., Ramicandelaber sp., and Mortierella sp., resulting in lower soil microbial richness and diversity.
Auteurs, date et publication :
Auteurs Eve Hellequin , Cécile Monard , Achim Quaiser , Morgane Henriot , Olivier Klarzynski , Françoise Binet
Publication : PLOS ONE
Date : 2025
Volume : 13
Issue : 12
Pages : e0209089
Catégorie(s)
#CNRS #EcoGenO #Université de RennesRésumé
Methods: A manipulative experiment tested the reciprocal effects of mowing cessation and mowing resumption for ten years. We analysed floristic composition data following four steps. First, we used the Community Structure Integrity Index (CSII) (Jaunatre et al. 2013) to obtain qualitative and quantitative summaries of taxonomic responses. The second step focused on taxonomic biodiversity using species richness, Simpson and Pielou indices, and on responsive species identified in the first step. Third, we analyzed functional diversity responses using functional groups and community weighted mean (CWM) of vegetative plant traits. Finally, we quantified ecosystem services impacts by estimating fodder quantity and quality using trait-based models.
Results: The mowing manipulation demonstrated the high resilience of P. paniculata grasslands, and revealed reversibility of transitions between mown and unmown states. By reducing the abundance of P. paniculata, the resumption of mowing restored forage quality. Supported by a complementary case study on post-disturbance resowing in hay meadows, this study demonstrates the resilience of mown subalpine grasslands to management change and explores underlying belowground mechanisms of vegetative regeneration and belowground reserves.
Conclusion: Our novel multi-indicator approach provides multi-faceted mechanistic understanding necessary to anticipate impacts of socio-ecological changes and to maintain the multiple benefits of mountain grasslands. Addressing the different facets of biodiversity from abundance data that is systematically collected in impact or monitoring assessment, this approach provides a common framework, widely applicable for different types of restoration or management interventions, across regions and biota.
Auteurs, date et publication :
Auteurs Iris Lochon , Marie-Pascale Colace , Caroline Devaux , Karl Grigulis , Ricarda Rettinger , Sandra Lavorel
Publication : Applied Vegetation Science
Date : 2025
Volume : 21
Issue : 4
Pages : 636-646
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Nitrogen (N) emissions associated with urbanization exacerbate the atmospheric N influx to remote ecosystems – like mountains –, leading to well-documented detrimental effects on ecosystems (e.g., soil acidification, pollution of freshwaters). Here, the importance and fate of N deposition in a watershed was evaluated along a montane to urban gradient, using a multi-isotopic tracers approach (Δ17O, δ15N, δ18O of nitrate, δ2H and δ18O of water). In this setting, the montane streams had higher proportions of atmospheric nitrate compared to urban streams, and exported more atmospheric nitrate on a yearly basis (0.35 vs 0.10 kg-N ha−1 yr−1). In urban areas, nitrate exports were driven by groundwater, whereas in the catchment head nitrate exports were dominated by surface runoff. The main sources of nitrate to the montane streams were microbial nitrification and atmospheric deposition, whereas microbial nitrification and sewage leakage contributed most to urban streams. Based on the measurement of δ15N and δ18O-NO− 3 , biological processes such as denitrification or N assimilation were not predominant in any streams in this study. The observed low δ15N and δ18O range of terrestrial nitrate (i. e., nitrate not coming from atmospheric deposition) in surface water compared to literature suggests that atmospheric deposition may be underestimated as a direct source of N.
Auteurs, date et publication :
Auteurs Ilann Bourgeois , Joel Savarino , Julien Némery , Nicolas Caillon , Sarah Albertin , Franck Delbart , Didier Voisin , Jean-Christophe Clément
Publication : Science of The Total Environment
Date : 2025
Volume : 633
Pages : 329-340
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Elodie A. Courtois , Clément Stahl , Joke Van den Berge , Laëtitia Bréchet , Leandro Van Langenhove , Andreas Richter , Ifigenia Urbina , Jennifer L. Soong , Josep Peñuelas , Ivan A. Janssens
Publication : Ecosystems
Date : 2018
Pages : 1–14
Catégorie(s)
#ANR-Citation #CIRAD #CNRS #FORET NouraguesRésumé
Nitrogen fixation in the legume root-nodule symbiosis has a critical importance in natural and agricultural ecosystems and depends on the proper choice of the symbiotic partners. However, the genetic determinism of symbiotic specificity remains unclear. To study this process, we inoculated three Lupinus species (L. albus, L. luteus, L. mariae-josephae), belonging to the under-investigated tribe of Genistoids, with two Bradyrhizobium strains (B. japonicum, B. valentinum) presenting contrasted degrees of symbiotic specificity depending on the host. We produced the first transcriptomes (RNA-Seq) from lupine nodules in a context of symbiotic specificity. For each lupine species, we compared gene expression between functional and non-functional interactions and determined differentially expressed (DE) genes. This revealed that L. luteus and L. mariae-josephae (nodulated by only one of the Bradyrhizobium strains) specific nodulomes were richest in DE genes than L. albus (nodulation with both microsymbionts, but non-functional with B. valentinum) and share a higher number of these genes between them than with L. albus. In addition, a functional analysis of DE genes highlighted the central role of the genetic pathways controlling infection and nodule organogenesis, hormones, secondary, carbon and nitrogen metabolisms, as well as the implication of plant defence in response to compatible or incompatible Bradyrhizobium strains.
Auteurs, date et publication :
Auteurs J. Keller , J. Imperial , T. Ruiz-Argüeso , K. Privet , O. Lima , S. Michon-Coudouel , M. Biget , A. Salmon , A. Aïnouche , F. Cabello-Hurtado
Publication : Plant Science
Date : 2018
Volume : 266
Pages : 102-116
Catégorie(s)
#CNRS #EcoGenO #Université de RennesAuteurs, date et publication :
Auteurs Alicia Ledo , Keryn I. Paul , David F. R. P. Burslem , John J. Ewel , Craig Barton , Michael Battaglia , Kim Brooksbank , Jennifer Carter , Tron Haakon Eid , Jacqueline R. England , Anthony Fitzgerald , Justin Jonson , Maurizio Mencuccini , Kelvin D. Montagu , Gregorio Montero , Wilson Ancelm Mugasha , Elizabeth Pinkard , Stephen Roxburgh , Casey M. Ryan , Ricardo Ruiz-Peinado
Publication : NEW PHYTOLOGIST
Date : 2018
Volume : 217
Issue : 1
Pages : 8-11
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
The main goal of this paper is to derive a method for a daily gross primary production (GPP) product over Europe and Africa taking the full advantage of the SEVIRI/MSG satellite products from the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) sensors delivered from the Satellite Application Facility for Land Surface Analysis (LSA SAF) system. Special attention is paid to model the daily GPP response from an optimized Montheith's light use efficiency model under dry conditions by controlling water shortage limitations from the actual evapotranspiration and the potential evapotranspiration (PET). The PET was parameterized using the mean daily air temperature at 2m (Ta) from ERA-Interim data. The GPP product (MSG GPP) was produced for 2012 and assessed by direct site-level comparison with GPP from eddy covariance data (EC GPP). MSG GPP presents relative bias errors lower than 40% for the most forest vegetation types with a high agreement (r>0.7) when compared with EC GPP. For drylands, MSG GPP reproduces the seasonal variations related to water limitation in a good agreement with site level GPP estimates (RMSE=2.11gm−2day−1; MBE=−0.63gm−2day−1), especially for the dry season. A consistency analysis against other GPP satellite products (MOD17A2 and FLUXCOM) reveals a high consistency among products (RMSD3.0gm−2day−1) and over dry biomes with MSG GPP estimates lower than FLUXCOM (MBD up to −3.0gm−2day−1). This newly derived product has the potential for analysing spatial patterns and temporal dynamics of GPP at the MSG spatial resolutions on a daily basis allowing to better capture the GPP dynamics and magnitude.
Auteurs, date et publication :
Auteurs B. Martínez , S. Sanchez-Ruiz , M. A. Gilabert , A. Moreno , M. Campos-Taberner , F. J. García-Haro , I. F. Trigo , M. Aurela , C. Brümmer , A. Carrara , A. De Ligne , D. Gianelle , T. Grünwald , J. M. Limousin , A. Lohila , I. Mammarella , M. Sottocornola , R. Steinbrecher , T. Tagesson
Publication : International Journal of Applied Earth Observation and Geoinformation
Date : 2018
Volume : 65
Pages : 124-136
Catégorie(s)
#CNRS #FORET PuechabonRésumé
The "PLAteforme expérimentale Nationale d'écologie
AQUAtique" is a multi-scale experimental infrastructure created in 2011
to make possible the analysis of human disturbance on aquatic
biodiversity, community structure, and ecosystem functioning. It is
funded by the "Investissements d'avenir Equipex" program and is partner
of the ANAEE-France research infrastructure. PLANAQUA provides the
scientific community with access to experimental highly instrumented
platforms available year round through calls for projects open to all
researchers around the world. It includes: 1) Microcosms (1-6 L),
developed for studying plankton ecology and physiology under highly
controlled environmental conditions in the dedicated laboratory or in
the climatic rooms of the Ecotron IleDeFrance. Organisms and ecosystems
activity and dynamics are precisely monitored by a series of dedicated
sensors and instruments. 2) Mesocosms (1-15 m3), have a high degree of
replication. They are installed outdoors and can house complex
communities of organisms. Among them a series of twelve is equipped with
beaters that generate waves, making possible to control the physical
structure of the water column thus to study the link between physical
constraints and functioning of aquatic systems. 3) Macrocosms, sixteen
artificial lakes (650 m3) dedicated to understand the functioning of
complex natural communities with heterogeneous spatial distributions;
they will allow ascertaining the consequences of anthropogenic pressures
on biodiversity, up to the top of the food chains. They are equipped
with automated sensors and data loggers for high-frequency data
collection of the main physical-chemical parameters. PLANAQUA is located
at the CEREEP research center (CNRS-ENS, UMS 3194) near Paris.
Keywords: Aquatic ecosystems functioning and dynamics, plankton
eco-physiology, biodiversity, environmental changes, experimental
platform, multi-scale studies, instruments and sensors
Auteurs, date et publication :
Auteurs Sarah Fiorini , Alexis Millot , Simon Chollet , Florent Massot , Jean-François Le Galliard , Emma Rochelle-Newall , Gerard Lacroix
Date : 2018
Volume : 20
Pages : 9724
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENS #PLANAQUARésumé
Although the impacts of eutrophication on freshwater biodiversity are
relatively well known, how eutrophication impacts the quality of
dissolved organic carbon (DOC) is less known, despite its importance for
microbial nutrition. Chromophoric dissolved organic matter (CDOM) is the
fraction of the bulk DOC pool that absorbs light and shifts in the
absorption and fluorescence of this component indicate an alteration in
the quality of the DOC present. Here we looked at the impact of small
phosphorus additions on CDOM absorption and fluorescence in a series of
16, newly constructed and filled, experimental lakes (Plateforme
Planaqua, UMS CEREEP, France). Eight of the lakes received small
additions (+ 100 µM) of phosphorus during late spring and summer
2015. We show that there was a distinct seasonal pattern to DOC and to
all measured CDOM parameters, regardless of nutrient status. We also
show that despite a lack of significant difference between the lakes in
terms of DOC concentrations, there were striking differences in the
carbon-normalised CDOM parameters. For example, we observed a
significant increase in the carbon normalized absorption at 254 nm
(SUVA254) in the lakes with addition of P, this was also the case for
fluorescence (ex350/em450) normalized to carbon concentration. These
changes were also accompanied by shifts in the relative intensities of
the components in the fluorescence excitation-emission matrices (EEM).
We propose that even small shifts in phosphorus availability can induce
strong shifts in carbon quality and that this may well have
repercussions up the food web should this more aromatic CDOM prove to be
less bioavailable. These results also imply that the brownification
observed in lakes in northern Europe may also be partially due to small
shifts in nutrient concentrations combined with increased carbon and
suspended solids imports from the surrounding catchments.
Auteurs, date et publication :
Auteurs Emma Rochelle-Newall , Lydie Blottière , Colombe Consortium
Date : 2018
Volume : 20
Pages : 9464