Résumé
Across the globe, invasive alien species cause severe environmental changes, altering species composition and ecosystem functions. So far, mountain areas have mostly been spared from large-scale invasions. However, climate change, land-use abandonment, the development of tourism and the increasing ornamental trade will weaken the barriers to invasions in these systems. Understanding how alien species will react and how native communities will influence their success is thus of prime importance in a management perspective. Here, we used a spatially and temporally explicit simulation model to forecast invasion risks in a protected mountain area in the French Alps under future conditions. We combined scenarios of climate change, land-use abandonment and tourism-linked increases in propagule pressure to test if the spread of alien species in the region will increase in the future. We modelled already naturalized alien species and new ornamental plants, accounting for interactions among global change components, and also competition with the native vegetation. Our results show that propagule pressure and climate change will interact to increase overall species richness of both naturalized aliens and new ornamentals, as well as their upper elevational limits and regional range-sizes. Under climate change, woody aliens are predicted to more than double in range-size and herbaceous species to occupy up to 20% of the park area. In contrast, land-use abandonment will open new invasion opportunities for woody aliens, but decrease invasion probability for naturalized and ornamental alien herbs as a consequence of colonization by native trees. This emphasizes the importance of interactions with the native vegetation either for facilitating or potentially for curbing invasions. Overall, our work highlights an additional and previously underestimated threat for the fragile mountain flora of the Alps already facing climate changes, land-use transformations and overexploitation by tourism.
Auteurs, date et publication :
Auteurs Marta Carboni , Maya Guéguen , Ceres Barros , Damien Georges , Isabelle Boulangeat , Rolland Douzet , Stefan Dullinger , Guenther Klonner , Mark van Kleunen , Franz Essl , Oliver Bossdorf , Emily Haeuser , Matthew V. Talluto , Dietmar Moser , Svenja Block , Luisa Conti , Iwona Dullinger , Tamara Münkemüller , Wilfried Thuiller
Publication : Global Change Biology
Date : 2025
Volume : 24
Issue : 1
Pages : e289-e302
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Thomas Pommier , Amélie A. M. Cantarel , Karl Grigulis , Sandra Lavorel , Nicolas Legay , Catherine Baxendale , Richard D. Bardgett , Michael Bahn , Franck Poly , Jean-Christophe Clément , Marney Isaac
Publication : Journal of Applied Ecology
Date : 2025
Volume : 55
Issue : 1
Pages : 49-58
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Kévin Cilleros , Alice Valentini , Luc Allard , Tony Dejean , Roselyne Etienne , Gaël Grenouillet , Amaia Iribar , Pierre Taberlet , Régis Vigouroux , Sébastien Brosse
Publication : Molecular Ecology Resources
Date : 2025
Catégorie(s)
#⛔ No DOI found #CNRS #FORET NouraguesRésumé
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
Intrinsic water-use efficiency (iWUE) characterizes the physiological control on the simultaneous exchange of water and carbon dioxide in terrestrial ecosystems. Knowledge of iWUE is commonly gained from leaf-level gas exchange measurements, which are inevitably restricted in their spatial and temporal coverage. Flux measurements based on the eddy covariance (EC) technique can overcome these limitations, as they provide continuous and long-term records of carbon and water fluxes at the ecosystem scale. However, vegetation gas exchange parameters derived from EC data are subject to scale-dependent and method-specific uncertainties that compromise their ecophysiological interpretation as well as their comparability among ecosystems and across spatial scales. Here, we use estimates of canopy conductance and gross primary productivity (GPP) derived from EC data to calculate a measure of iWUE (G1, “stomatal slope”) at the ecosystem level at six sites comprising tropical, Mediterranean, temperate, and boreal forests. We assess the following six mechanisms potentially causing discrepancies between leaf and ecosystem-level estimates of G1: (i) non-transpirational water fluxes; (ii) aerodynamic conductance; (iii) meteorological deviations between measurement height and canopy surface; (iv) energy balance non-closure; (v) uncertainties in net ecosystem exchange partitioning; and (vi) physiological withincanopy gradients. Our results demonstrate that an unclosed energy balance caused the largest uncertainties, in particular if it was associated with erroneous latent heat flux estimates. The effect of aerodynamic conductance on G1 was sufficiently captured with a simple representation. G1 was found to be less sensitive to meteorological deviations between canopy surface and measurement height and, given that data are appropriately filtered, to non-transpirational water fluxes. Uncertainties in the derived GPP and physiological within-canopy gradients and their implications for parameter estimates at leaf and ecosystem level are discussed. Our results highlight the importance of adequately considering the sources of uncertainty outlined here when ECderived water-use efficiency is interpreted in an ecophysiological context.
Auteurs, date et publication :
Auteurs Jürgen Knauer , Sönke Zaehle , Belinda E. Medlyn , Markus Reichstein , Christopher A. Williams , Mirco Migliavacca , Martin G. De Kauwe , Christiane Werner , Claudia Keitel , Pasi Kolari , Jean-Marc Limousin , Maj-Lena Linderson
Publication : Global Change Biology
Date : 2025
Volume : 24
Issue : 2
Pages : 694-710
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