Résumé
Foundation plants shape the composition of local biotic communities and abiotic environments, but the impact of a plant’s intraspecific variations on these processes is poorly understood. We examined these links in the alpine cushion moss campion (Silene acaulis) on two neighboring mountain ranges in the French Alps. Genotyping of cushion plants revealed two genetic clusters matching known subspecies. The exscapa subspecies was found on both limestone and granite, while the longiscapa one was only found on limestone. Even on similar limestone bedrock, cushion soils from the two S. acaulis subspecies deeply differed in their impact on soil abiotic conditions. They further strikingly differed from each other and from the surrounding bare soils in fungal community composition. Plant genotype variations accounted for a large part of the fungal composition variability in cushion soils, even when considering geography or soil chemistry, and particularly for the dominant molecular operational taxonomic units (MOTUs). Both saprophytic and biotrophic fungal taxa were related to the MOTUs recurrently associated with a single plant genetic cluster. Moreover, the putative phytopathogens were abundant, and within the same genus (Cladosporium) or species (Pyrenopeziza brassicae), MOTUs showing specificity for each plant subspecies were found. Our study highlights the combined influences of bedrock and plant genotype on fungal recruitment into cushion soils and suggests the coexistence of two mechanisms, an indirect selection resulting from the colonization of an engineered soil by free‐living saprobes and a direct selection resulting from direct plant–fungi interactions.
Auteurs, date et publication :
Auteurs Julien Roy , Jean-Marc Bonneville , Patrick Saccone , Sébastian Ibanez , Cécile H. Albert , Marti Boleda , Maya Gueguen , Marc Ohlmann , Delphine Rioux , Jean-Christophe Clément , Sébastien Lavergne , Roberto A. Geremia
Publication : Ecology and Evolution
Date : 2025
Volume : 8
Issue : 23
Pages : 11568-11581
Catégorie(s)
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Mycorrhizal fungi or endphytes colonize plant roots and their occurrence and composition depend on biotic and abiotic characteristics of the ecosystem. We investigated the composition of these microbial communities associated with Festuca paniculata, a slow growing species, which dramatically impacts functional plant diversity and the recycling of organic matter in subalpine grasslands. F. paniculata individuals from both mown and unmown grasslands were randomly collected and the microscopic observation of the plant roots revealed a difference in fungal colonization according to management. The ITS regions of root-associated fungi were amplified, cloned and sequenced. Bioinformatic analysis revealed a total of 43 and 35 phylotypes in mown and unmown grasslands respectively, highlighting a remarkable difference in the composition between both fungal communities. The phylotypes were assigned to 9 classes in which two classes Eurotiomycetes and Lecanoromycetes were specific to mown grasslands, while Tremellomycetes were specific to unmown grasslands and only five phylotypes were common to both locations. The comparative analysis of fungal lifestyles indicated the dominance of saprobes and a large proportion of endophytes compared to the mycorrhizal fungi (7/1 and 11/2 phylotypes in mown and unmown grasslands, respectively). Endophyte richness was greater in the unmown gassland than in the mown grassland and their relative proportion was twice higher. Our results suggest that endophytes may offer potential resources to F. paniculata and play an important role in the regulation of plant diversity.
Auteurs, date et publication :
Auteurs Bello Mouhamadou , Claire Molitor , Florence Baptist , Lucile Sage , Jean-Christophe Clément , Sandra Lavorel , Armelle Monier , Roberto A. Geremia
Publication : Fungal Diversity
Date : 2011
Volume : 47
Issue : 1
Pages : 55-63
Catégorie(s)
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Abstract. 3-hydroxy fatty acids (3-OH FAs) with 10 to 18 C atoms are membrane lipids mainly produced by Gram-negative bacteria. They have been recently proposed as temperature and pH proxies in terrestrial settings. Nevertheless, the existing correlations between pH/temperature and indices derived from 3-OH FA distribution (RIAN, RAN15 and RAN17) are based on a small soil dataset (ca. 70 samples) and only applicable regionally. The aim of this study was to investigate the applicability of 3-OH FAs as mean annual air temperature (MAAT) and pH proxies at the global level. This was achieved using an extended soil dataset of 168 topsoils distributed worldwide, covering a wide range of temperatures (5 °C to 30 °C) and pH (3 to 8). The response of 3-OH FAs to temperature and pH was compared to that of established branched GDGT-based proxies (MBT'5Me/CBT). Strong linear relationships between 3-OH FA-derived indices (RAN15, RAN17 and RIAN) and MAAT/pH could only be obtained locally, for some of the individual transects. This suggests that these indices cannot be used as paleoproxies at the global scale using simple linear regression models, in contrast with the MBT'5Me and CBT. However, strong global correlations between 3-OH FA relative abundances and MAAT/pH were shown by using other algorithms (multiple linear regression, k-NN and random forest models). The applicability of the k-NN and random forest models for paleotemperature reconstruction was tested and compared with the MAAT record from a Chinese speleothem. The calibration based on the random forest model appeared to be the most robust. It showed similar trends with previously available records and highlighted known climatic events poorly visible when using local 3-OH FA calibrations. Altogether, these results demonstrate the potential of 3-OH FAs as paleoproxies in terrestrial settings.
Auteurs, date et publication :
Auteurs Pierre Véquaud , Sylvie Derenne , Alexandre Thibault , Christelle Anquetil , Giuliano Bonanomi , Sylvie Collin , Sergio Contreras , Andrew Nottingham , Pierre Sabatier , Norma Salinas , Wesley Philip Scott , Josef P. Werne , Arnaud Huguet
Publication : Biogeosciences Discussions
Date : 2020
Pages : 1-40
Catégorie(s)
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Auteurs N. Legay , C. Baxendale , K. Grigulis , U. Krainer , E. Kastl , M. Schloter , R. D. Bardgett , C. Arnoldi , M. Bahn , M. Dumont , F. Poly , T. Pommier , J. C. Clément , S. Lavorel
Publication : Annals of Botany
Date : 2014
Volume : 114
Issue : 5
Pages : 1011-1021
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Despite considerable efforts devoted to investigate the community assembly processes driving plant invasions, few general conclusions have been drawn so far. Three main processes, generally acting as successive filters, are thought to be of prime importance. The invader has to disperse (1st filter) into a suitable environment (2nd filter) and succeed in establishing in recipient communities through competitive interactions (3rd filter) using two strategies: competition avoidance by the use of different resources (resource opportunity), or competitive exclusion of native species. Surprisingly, despite the general consensus on the importance of investigating these three processes and their interplay, they are usually studied independently. Here we aim to analyse these three filters together, by including them all: abiotic environment, dispersal and biotic interactions, into models of invasive species distributions. We first propose a suite of indices (based on species functional dissimilarities) supposed to reflect the two competitive strategies (resource opportunity and competition exclusion). Then, we use a set of generalised linear models to explain the distribution of seven herbaceous invaders in natural communities (using a large vegetation database for the French Alps containing 5,000 community-plots). Finally, we measure the relative importance of competitive interaction indices, identify the type of coexistence mechanism involved and how this varies along environmental gradients. Adding competition indices significantly improved model’s performance, but neither resource opportunity nor competitive exclusion were common strategies among the seven species. Overall, we show that combining environmental, dispersal and biotic information to model invasions has excellent potential for improving our understanding of invader success.
Auteurs, date et publication :
Auteurs Laure Gallien , Florent Mazel , Sébastien Lavergne , Julien Renaud , Rolland Douzet , Wilfried Thuiller
Publication : Biological Invasions
Date : 2015
Volume : 17
Issue : 5
Pages : 1407-1423
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Background: The advent of molecular techniques in microbial ecology has aroused interest in gaining an understanding about the spatial distribution of regional pools of soil microbes and the main drivers responsible of these spatial patterns. Here, we assessed the distribution of crenarcheal, bacterial and fungal communities in an alpine landscape displaying high turnover in plant species over short distances. Our aim is to determine the relative contribution of plant species composition, environmental conditions, and geographic isolation on microbial community distribution.
Methodology/Principal Findings: Eleven types of habitats that best represent the landscape heterogeneity were investigated. Crenarchaeal, bacterial and fungal communities were described by means of Single Strand Conformation Polymorphism. Relationships between microbial beta diversity patterns were examined by using Bray-Curtis dissimilarities and Principal Coordinate Analyses. Distance-based redundancy analyses and variation partitioning were used to estimate the relative contributions of different drivers on microbial beta diversity. Microbial communities tended to be habitatspecific and did not display significant spatial autocorrelation. Microbial beta diversity correlated with soil pH. Fungal betadiversity was mainly related to soil organic matter. Though the effect of plant species composition was significant for all microbial groups, it was much stronger for Fungi. In contrast, geographic distances did not have any effect on microbial beta diversity.
Conclusions/Significance: Microbial communities exhibit non-random spatial patterns of diversity in alpine landscapes. Crenarcheal, bacterial and fungal community turnover is high and associated with plant species composition through different set of soil variables, but is not caused by geographical isolation.
Auteurs, date et publication :
Auteurs Lucie Zinger , David P. H. Lejon , Florence Baptist , Abderrahim Bouasria , Serge Aubert , Roberto A. Geremia , Philippe Choler , Jack Anthony Gilbert
Publication : Plos One
Date : 2011
Volume : 6
Issue : 5
Pages : e19950
Catégorie(s)
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Auteurs Hannah Loranger , Gerhard Zotz , Maaike Y. Bader
Publication : Oikos
Date : 2025
Volume : 126
Issue : 11
Pages : 1625-1636
Catégorie(s)
#CNRS #Lautaret #UGARésumé
There is a growing demand for spatially explicit assessment of multiple ecosystem services (ES) and remote sensing (RS) can provide valuable data to meet this challenge. In this study, located in the Central French Alps, we used high spatial and spectral resolution RS images to assess multiple ES based on underpinning ecosystem properties (EP) of subalpine grasslands. We estimated five EP (green biomass, litter mass, crude protein content, species diversity and soil carbon content) from RS data using empirical RS methods and maps of ES were calculated as simple linear combinations of EP. Additionally, the RSbased results were compared with results of a plant trait-based statistical modelling approach that predicted EP and ES from land use, abiotic and plant trait data (modelling approach). The comparison between the RS and the modelling approaches showed that RS-based results provided better insight into the fine-grained spatial distribution of EP and thereby ES, whereas the modelling approach reflected the land use signal that underpinned trait-based models of EP. The spatial agreement between the two approaches at a 20-m resolution varied between 16 and 22% for individual EP, but for the total ecosystem service supply it was only 7%. Furthermore, the modelling approach identified the alpine grazed meadows land use class as areas with high values of multiple ES (hot spots) and mown-grazed permanent meadows as areas with low values and only few ES (cold spots). Whereas the RS-based hot spots were a small subset of those predicted by the modelling approach, cold spots were rather scattered, small patches with limited overlap with the modelling results. Despite limitations associated with timing of assessment campaigns and field data requirements, RS offers valuable data for spatially continuous mapping of EP and can thus supply RS-based proxies of ES. Although the RS approach was applied to a limited area and for one type of ecosystem, we believe that the broader availability of high fidelity airborne and satellite RS data will promote RS-based assessment of ES to larger areas and other ecosystems.
Auteurs, date et publication :
Auteurs L. Homolová , M. E. Schaepman , P. Lamarque , J. G. P. W. Clevers , F. de Bello , W. Thuiller , S. Lavorel
Publication : Ecosphere
Date : 2025
Volume : 5
Issue : 8
Pages : art100
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Nicolas Legay , F. Grassein , T. M. Robson , Emmanuelle Personeni , Marie-Paule Bataillé , S. Lavorel , J.-C. Clement
Publication : Biogeosciences
Date : 2025
Volume : 10
Issue : 11
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Assessing trait responses to environmental gradients requires the simultaneous analysis of the information contained in three tables: L (species distribution across samples), R (environmental characteristics of samples), and Q (species traits). Among the available methods, the so-called fourth-corner and RLQ methods are two appealing alternatives that provide a direct way to test and estimate trait–environment relationships. Both methods are based on the analysis of the fourth-corner matrix, which crosses traits and environmental variables weighted by species abundances. However, they differ greatly in their outputs: RLQ is a multivariate technique that provides ordination scores to summarize the joint structure among the three tables, whereas the fourth-corner method mainly tests for individual trait–environment relationships (i.e., one trait and one environmental variable at a time). Here, we illustrate how the complementarity between these two methods can be exploited to promote new ecological knowledge and to improve the study of trait–environment relationships. After a short description of each method, we apply them to real ecological data to present their different outputs and provide hints about the gain resulting from their combined use.
Auteurs, date et publication :
Auteurs Stéphane Dray , Philippe Choler , Sylvain Dolédec , Pedro R. Peres-Neto , Wilfried Thuiller , Sandrine Pavoine , Cajo J. F. ter Braak
Publication : Ecology
Date : 2025
Volume : 95
Issue : 1
Pages : 14-21