Résumé
Plant species influence soil microbial communities, mainly through their functional traits. However, mechanisms underlying these effects are not well understood, and in particular how plant/ microorganism interactions are affected by plant identities and/or environmental conditions. Here, we performed a greenhouse experiment to assess the effects of three plant species on arbuscular mycorrhizal fungal (AMF) colonization, bacterial potential nitrification (PNA) and denitrification activities (PDA) through their functional traits related to nitrogen acquisition and turnover. Three species with contrasting functional traits and strategies (from exploitative to conservative), Dactylis glomerata (L.), Bromus erectus (Hudson) and Festuca paniculata (Schinz and Tellung), were cultivated in monocultures on soil grassland with or without N fertilization. Fertilization impacted some plant traits related to nutrient cycling (leaf and root N concentration, root C:N) but did not affect directly microbial parameters. The highest PDA and PNA were observed in D. glomerata and F. paniculata monocultures, respectively. The highest AMF colonization was obtained for F. paniculata, while B. erectus exhibited both the lowest AMF colonization and bacterial activities. Bacterial activities were influenced by specific above-ground plant traits across fertilization treatments: above-ground biomass for PDA, shoot:root ratio and leaf C:N ratio for PNA. Mycorrhizal colonization was influenced by below-ground traits either root dry matter content or root C:N. Hence, AMF colonization and bacterial activities were impacted differently by species-specific plant biomass allocation, root traits and nutrient requirement. We suggest that such effects may be linked to distinct root exudation patterns and plant abilities for nutrient acquisition and/or nutrient competition.
Auteurs, date et publication :
Auteurs N. Legay , F. Grassein , M.N. Binet , C. Arnoldi , E. Personeni , S. Perigon , F. Poly , T. Pommier , J. Puissant , J.C. Clément , S. Lavorel , B. Mouhamadou
Publication : Applied Soil Ecology
Date : 2025
Volume : 98
Pages : 132-139
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs P. Lamarque , S. Lavorel , M. Mouchet , F. Quetier
Publication : Proceedings of the National Academy of Sciences
Date : 2014
Volume : 111
Issue : 38
Pages : 13751-13756
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Ecosystems provide a variety of ecosystem services (ES), which act as key linkages between social and ecological systems. ES respond spatially and temporally to abiotic and biotic variation, and to management. Thus, resistant and resilient ES provision is expected to remain within a stable range when facing disturbances. In this study, generic indicators to evaluate resistance, potential resilience and capacity for transformation of ES provision are developed and their relevance demonstrated for a mountain grassland system. Indicators are based on plant trait composition (i.e. functional composition) and abiotic parameters determining ES provision at community, meta-community and landscape scales. First the resistance of an ES is indicated by its normal operating range characterized by observed values under current conditions. Second its resilience is assessed by its potential operating range − under hypotheses of reassembly from the community’s species pool. Third its transformation potential is assessed for reassembly at metacommunity and landscape scales. Using a state-and-transition model, possible management-related transitions between mountain grassland states were identified, and indicators calculated for two provisioning and two regulating ES. Overall, resilience properties varied across individual ES, supporting a focus on resilience of specific ES. The resilience potential of the two provisioning services was greater than for the two regulating services, both being linked to functional complementarity within communities. We also found high transformation potential reflecting functional redundancy among communities within each meta-community, and across meta-communities in the landscape. Presented indicators are promising for the projection of future ES provision and the identification of management options under environmental change.
Auteurs, date et publication :
Auteurs Marina Kohler , Caroline Devaux , Karl Grigulis , Georg Leitinger , Sandra Lavorel , Ulrike Tappeiner
Publication : Ecological Indicators
Date : 2025
Volume : 73
Pages : 118-127
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Food preferences and food availability are two major determinants of the diet of generalist herbivores and of their spatial distribution. How do these factors interact and eventually lead to diet differentiation in co-occurring herbivores? We quantified the diet of four grasshopper species co-occurring in subalpine grasslands using DNA barcoding of the plants contained in the faeces of individuals sampled in the field. The food preferences of each grasshopper species were assessed by a choice (cafeteria) experiment from among 24 plant species common in five grassland plots, in which the four grasshoppers were collected, while the habitat was described by the relative abundance of plant species in the grassland plots. Plant species were characterised by their leaf economics spectrum (LES), quantifying their nutrient vs. structural tissue content. The grasshoppers' diet, described by the mean LES of the plants eaten, could be explained by their plant preferences but not by the available plants in their habitat. The diet differed significantly across four grasshopper species pairs out of six, which validates food preferences assessed in standardised conditions as indicators for diet partitioning in nature. In contrast, variation of the functional diversity (FD) for LES in the diet was mostly correlated to the FD of the available plants in the habitat, suggesting that diet mixing depends on the environment and is not an intrinsic property of the grasshopper species. This study sheds light on the mechanisms determining the feeding niche of herbivores, showing that food preferences influence niche position whereas habitat diversity affects niche breadth.
Auteurs, date et publication :
Auteurs Sébastien Ibanez , Olivier Manneville , Christian Miquel , Pierre Taberlet , Alice Valentini , Serge Aubert , Eric Coissac , Marie-Pascale Colace , Quentin Duparc , Sandra Lavorel , Marco Moretti
Publication : Oecologia
Date : 2013
Volume : 173
Issue : 4
Pages : 1459-1470
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Relationships between plants and nitrogen-related microbes may vary with plant growth. We investigated these dynamic relationships over three months by analyzing plant functional traits (PFT), arbuscular mycorrhizal fungal (AMF) colonization, potential N mineralization (PNM), potential nitrification (PNA) and denitrification activities (PDA) in Dactylis glomerata cultures. D. glomerata recruited AMF during early growth, and thereafter maintained a constant root colonization intensity. This may have permitted high enough plant nutrient acquisition over the three months as to offset reduced soil inorganic N. PFT changed with plant age and declining soil fertility, resulting in higher allocation to root biomass and higher root C:N ratio. Additional to root AMF presence, PFT changes may have favored denitrification over mineralization through changes in soil properties, particularly increasing the quality of the labile carbon soil fraction. Other PFT changes, such as N uptake, modified the plants’ ability to compete with bacterial groups involved in N cycling.
Auteurs, date et publication :
Auteurs N. Legay , J. C. Clément , F. Grassein , S. Lavorel , S. Lemauviel-Lavenant , E. Personeni , F. Poly , T. Pommier , T. M. Robson , B. Mouhamadou , M. N. Binet
Publication : Fungal Ecology
Date : 2020
Volume : 44
Pages : 100910
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Helianthemum is the largest, most widely distributed and most taxonomically complex genus of the Cistaceae. To examine the intrageneric phylogenetic relationships in Helianthemum, we used sequence data from plastid DNA (ndhF, psbA-trnH, trnLtrnF) and the nuclear ITS region. The ingroup consisted of 95 species and subspecies (2 subgenera, 10 sections) from throughout the range of Helianthemum, while the outgroup was composed of 30 species representing all the genera in the Cistaceae (Cistus Crocanthemum, Fumana, Halimium, Hudsonia, Lechea, Tuberaria) plus Anisoptera thurifera subsp. polyandra (Dipterocarpaceae). To infer phylogenetic relationships, we analysed three different matrices (cpDNA, nrDNA, cpDNA + nrDNA concatenated) using maximum likelihood and Bayesian inference, and performed molecular dating to estimate the ages of origin of the main clades using a Bayesian approach. The cpDNA + nrDNA concatenated dataset provided the highest Bayesian posterior probabilities and bootstrap support values, and the results supported the monophyly of the genus Helianthemum and its sister relationship to a clade consisting of all species of Cistus, Crocanthemum, Halimium, Hudsonia and Tuberaria. This result means that we did not retrieve the sister relationship between Helianthemum and Crocanthemum (plus Hudsonia) that could be expected according to previous published studies. Despite their different statistical support, the topology of the inner branches of all the consensus trees showed that Helianthemum is characterized by the emergence of three major clades in agreement with above-species taxonomy, although unresolved polytomies still remain towards the tips of the trees (species and subspecies). Clade I (mainly distributed in Mediterranean and alpine environments in European and western Asiatic mountain chains) fully coincided with subg. Plectolobum, whereas subg. Helianthemum was retrieved in clade II (arid and semi-arid environments from Macaronesia, the Mediterranean, subtropical northern Africa, Anatolia and central Asia) and clade III (Mediterranean ecosystems around the Mediterranean Basin). The burst of diversification during the Plio-Pleistocene detected in the three main clades of Helianthemum is concomitant with the Messinian salinity crisis, the onset of Mediterranean climatic conditions, and Quaternary glaciations, as found in many other groups of Mediterranean plants. Thus, the general lack of resolution in the trees can be attributed to rapid species diversification and events of reticulate evolution. A series of further taxonomic and evolutionary inferences can be drawn from our analyses: (i) no species occupied an early-diverging position with regard the rest of the species; (ii) a close relationship between H. caput-felis and subg. Plectolobum; (iii) an unexpected close relationship between H. squamatum/H. syriacum (and H. motae), H. lunulatum/ H. pomeridianum and among H. songaricum/H. antitauricum/H. germanicopolitanum; (iv) a close relationship between incertae sedis species and sect. Eriocarpum; and (v) the existence of a monophyletic lineage consisting of Canary Islands species formerly ascribed to sect. Argyrolepis or sect. Lavandulaceum within sect. Helianthemum.
Auteurs, date et publication :
Auteurs Abelardo Aparicio , Sara Martín-Hernanz , Clara Parejo-Farnés , Juan Arroyo , Sébastien Lavergne , Emine B. Yeşilyurt , Ming-Li Zhang , Encarnación Rubio , Rafael G. Albaladejo
Publication : Taxon
Date : 2017
Volume : 66
Issue : 4
Pages : 868-885
Catégorie(s)
#CNRS #Lautaret #UGARésumé
PREMISE Events of accelerated species diversification represent one of Earth's most celebrated evolutionary outcomes. Northern Andean high-elevation ecosystems, or páramos, host some plant lineages that have experienced the fastest diversification rates, likely triggered by ecological opportunities created by mountain uplifts, local climate shifts, and key trait innovations. However, the mechanisms behind rapid speciation into the new adaptive zone provided by these opportunities have long remained unclear. METHODS We address this issue by studying the Venezuelan clade of Espeletia, a species-rich group of páramo-endemics showing a dazzling ecological and morphological diversity. We performed several comparative analyses to study both lineage and trait diversification, using an updated molecular phylogeny of this plant group. RESULTS We showed that sets of either vegetative or reproductive traits have conjointly diversified in Espeletia along different vegetation belts, leading to adaptive syndromes. Diversification in vegetative traits occurred earlier than in reproductive ones. The rate of species and morphological diversification showed a tendency to slow down over time, probably due to diversity dependence. We also found that closely related species exhibit significantly more overlap in their geographic distributions than distantly related taxa, suggesting that most events of ecological divergence occurred at close geographic proximity within páramos. CONCLUSIONS These results provide compelling support for a scenario of small-scale ecological divergence along multiple ecological niche dimensions, possibly driven by competitive interactions between species, and acting sequentially over time in a leapfrog pattern.
Auteurs, date et publication :
Auteurs Charles Pouchon , Sébastien Lavergne , Ángel Fernández , Adriana Alberti , Serge Aubert , Jesús Mavárez
Publication : American Journal of Botany
Date : 2025
Volume : 108
Issue : 1
Pages : 113–128
Catégorie(s)
#CNRS #eDNA #Lautaret #UGAAuteurs, date et publication :
Auteurs Bahar Shahnavaz , Lucie Zinger , Sébastien Lavergne , Philippe Choler , Roberto A. Geremia
Publication : Arctic, Antarctic, and Alpine Research
Date : 2025
Volume : 44
Issue : 2
Pages : 232-238
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Abstract. This paper examines the ability of optical reflectance data assimilation to improve snow depth and snow water equivalent simulations from a chain of models with the SAFRAN meteorological model driving the detailed multilayer snowpack model Crocus now including a two-stream radiative transfer model for snow, TARTES. The direct use of reflectance data, allowed by TARTES, instead of higher level snow products, mitigates uncertainties due to commonly used retrieval algorithms.Data assimilation is performed with an ensemble-based method, the Sequential Importance Resampling Particle filter, to represent simulation uncertainties. In snowpack modeling, uncertainties of simulations are primarily assigned to meteorological forcings. Here, a method of stochastic perturbation based on an autoregressive model is implemented to explicitly simulate the consequences of these uncertainties on the snowpack estimates.Through twin experiments, the assimilation of synthetic spectral reflectances matching the MODerate resolution Imaging Spectroradiometer (MODIS) spectral bands is examined over five seasons at the Col du Lautaret, located in the French Alps. Overall, the assimilation of MODIS-like data reduces by 45% the root mean square errors (RMSE) on snow depth and snow water equivalent. At this study site, the lack of MODIS data on cloudy days does not affect the assimilation performance significantly. The combined assimilation of MODIS-like reflectances and a few snow depth measurements throughout the 2010/2011 season further reduces RMSEs by roughly 70%. This work suggests that the assimilation of optical reflectances has the potential to become an essential component of spatialized snowpack simulation and forecast systems. The assimilation of real MODIS data will be investigated in future works.
Auteurs, date et publication :
Auteurs Luc Charrois , Emmanuel Cosme , Marie Dumont , Matthieu Lafaysse , Samuel Morin , Quentin Libois , Ghislain Picard
Publication : The Cryosphere
Date : 2016
Volume : 10
Issue : 3
Pages : 1021-1038
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Jean-Pierre Dedieu , Bradley Carlson , Sylvain Bigot , Pascal Sirguey , Vincent Vionnet , Philippe Choler
Publication : Remote Sensing
Date : 2016
Volume : 8
Issue : 6
Pages : 481