Résumé
Alpine and subalpine grasslands experience strong seasonal climatic variations, with snow cover for over six months maintaining steady soil temperature and moisture. This seasonal structure limits plant growth and strongly influences microbial activity, which together control key ecosystem functions like soil organic matter (SOM) inputs, mineralization, and greenhouse gas fluxes, ultimately influencing the composition and quantity of SOM. In our study, we monitored soil pedoclimate (temperature and moisture) and net ecosystem exchange (CO2 flux) at both plot and local footprint scales, using discrete measurements and flux tower, to characterize the seasonal context of alpine and subalpine grasslands. Meanwhile, we investigated the seasonal properties of topsoil organic matter (SOM) at six key times throughout the hydrological year: before snow cover, before snowmelt, after snowmelt, during the growing season, at vegetation peak, and during senescence. SOM properties were analyzed through the combination of methods including DRIFT spectroscopy, RockEval® thermal analysis, water-extractable organic carbon and permanganate-oxidizable carbon (POxC). Finally, soil incubations were conducted to assess microbial respiration sensitivity to temperature and moisture across these six periods, enhancing our understanding of seasonality’s impact on microbial features. Our study integrates in situ and in vitro measurements across multiple scales (soil sample, plot, and landscape), traditionally analyzed separately. This approach bridges microbial mechanisms with SOM quality and links them to ecosystem-scale carbon exchanges. Our findings highlighted a clear seasonality in SOM properties, offering valuable insights into the functioning of these grasslands. We identified a labile seasonal pool of SOM that persists through the winter due to low temperatures and low-carbon outputs, maintaining its availability for mineralization at the onset of the growing season—when primary producers have the highest nutrient demand. This labile pool decreases over the growing season, as microbial activity peaks and organic matter inputs decline. Additionally, seasonal shifts in microbial responses to temperature and humidity indicate functional acclimations: enhanced cold tolerance in winter, waterlogged tolerance during snowmelt, and increased capacity to degrade complex organic molecules during the growing season.
Auteurs, date et publication :
Auteurs Nicolas Bonfanti , Jérôme Poulenard , Pierre Barre , François Baudin , Didier Voisin , Jean-Christophe Clement
Publication : Ecosystems
Date : 2025
Volume : 28
Issue : 3
Pages : 29
Catégorie(s)
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Streambank erosion control and management are experiencing a significant paradigm shift, particularly in mountainous regions. There is an increasing demand for Nature-based Solutions such as soil and water bioengineering techniques (SWBE) with living plant material to protect both human assets and biodiversity from streambank erosion. The success of these techniques is highly dependent on vegetation growth and requires solid knowledge of the local species used. However, our knowledge of appropriate subalpine species is still limited, thus hindering the advancement of effective SWBE in these environments. To address this gap, we established an ex-situ experiment to study the biotechnical traits of subalpine species that contribute to streambank protection. Four species were cultivated in a growth chamber for four months: Salix caesia Vill., Salix foetida Schleich. ex DC. and Salix hastata Vill., restricted to the subalpine belt, and Salix purpurea L., a ubiquitous species. We then assessed both aerial and root traits (number, length and biomass) to evaluate the species’ potential for use in erosion control. The survival rate was excellent - up to 96%. S. hastata had high belowground biomass, promising for substrate stabilization, while S. purpurea produced numerous long shoots appropriate for surface protection. The two other willow species provided intermediate benefits, but their presence could promote biodiversity in SWBE structures. Our study reveals promising potential for the use of these species in high-elevation SWBE. Their morphological differences suggest that the four species should be used in accordance with specific streambank contexts.
Auteurs, date et publication :
Auteurs Juliette Rousset , Sarah Menoli , Adeline François , Stéphanie Gaucherand , André Evette
Publication : Environmental Management
Date : 2025
Volume : 75
Issue : 8
Pages : 1950-1962
Catégorie(s)
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The process of species delimitation, defined as the act of recognising biologically meaningful taxonomic units, enables the detection of overall biodiversity and the exploration of speciation processes. Given the complex nature of the origin of biodiversity, a significant number of cryptic Alpine plant groups exhibit ambiguity regarding their phylogenetic relationships and species circumscription. In this study, we attempt to apply the principles of integrative taxonomy to a complex of cryptic alpine plants from the genus Noccaea, which are often described as substrate specialists. We benefited from an extensive sampling across the Alps combined with high-throughput genotyping to apply a modern and standardised method of species delimitation. We find that the Noccaea rotundifolia complex is represented by five species within the Alps, which exhibit a restricted geographic distribution. Four of these species diverged approximately 350 ka ago (259–429), indicating a recent diversification. Instead of recognizing species with different substrate affinities, as done by current taxonomy, we rather find that the most widespread species are substrate generalists but with allopatric distributions. Our findings indicate that N. rotundifolia is growing exclusively in the west of the well-known biogeographic barrier of the Aosta Valley. N. corymbosa is found to grow between the Aosta Valley barrier and the Lake Como one. N. cepaeifolia, in turn, is observed in the eastern Alps, separated by the Brenner valley. Overall, this study provides a detailed systematic review, supporting the pivotal role of the recognized Alpine biogeographic barriers, in shaping species distribution and speciation.
Auteurs, date et publication :
Auteurs Camille Voisin , Philippe Choler , Camille Vacher , Christophe Perrier , Julien Renaud , Delphine Rioux , Florian C. Boucher
Publication : Molecular Phylogenetics and Evolution
Date : 2025
Volume : 211
Pages : 108381
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Soil contamination with trace metals and metalloids (TMM) can negatively impact biota in ways not captured by chemical analyses alone. This study evaluates the effectiveness of two integrated biological indices (Total Enzyme activity Index – TEI, Integrated Biomarker Response – IBR) in detecting toxicity effects on biota in soils subjected to long-term TMM contamination. An ex situ biotest using soils from Peisey-Nancroix (France), a former Pb–Ag mining site, was conducted with the sensitive plant Arabidopsis thaliana to identify relevant biomarkers and develop key biological indices. The results demonstrate clear TMM toxicity, reflected in decreased microbial functioning (evidenced by reduced TEI) and impaired plant growth (shown by elevated IBR). These indices were then assessed in situ at the same site. Unexpectedly, TEI—despite its status as an early indicator of soil degradation—showed no relationship with long-term TMM toxicity or Pb-mobility, whereas IBR—derived from endogenous plant biomarkers—strongly correlated with TMM contamination and bioavailable Pb levels, particularly in the sensitive species Geranium sylvaticum. These results indicate that IBR is a reliable proxy for ecological risk and TMM bioavailability in chronically contaminated soils.
Auteurs, date et publication :
Auteurs Marion Sarah Deville-Cavellin , Floriane Guillevic , Christelle Gonindard-Melodelima , Sylvain Campillo-Cressot , Frédéric Laporte , Cindy Arnoldi , Magali Rossi , Arnaud Foulquier , Muriel Raveton
Publication : Chemosphere
Date : 2025
Volume : 393
Pages : 144770
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Increasing climate warming and summer droughts are known to affect mountain plant communities, their functional traits and life strategies. However, little is known about how strongly and efficiently communities respond to climate change, and how tightly plant responses are linked to responses of ecosystem functions. To test this, we transplanted alpine plant communities to subalpine conditions, exposing them to warming and drying. We compared these transplanted communities to alpine and subalpine control communities to assess their responses. Five years after transplantation, we found slower growth (e.g. lower leaf nitrogen) and more outsourcing strategies (e.g. lower specific root length) in the warmer and drier subalpine control communities compared to the alpine controls, probably due to drought. Traits of warmed alpine communities shifted toward subalpine controls. However, neither below- nor aboveground traits nor productivity of plants fully acclimated to subalpine conditions. Nevertheless, standard litter decomposition rates, arbuscular colonization and bacterial biomass showed no acclimation lag to the subalpine controls. Significant but insufficient acclimation of plant functional traits and strategies is prone to result in maladapted plant productivity, impairing competitiveness with better adapted subalpine species and leading to the temporally delayed loss of ecosystem features specific to alpine environments.
Auteurs, date et publication :
Auteurs Billur Bektaş , Gemma Rutten , Amélie Saillard , Rodrigue Friaud , Cindy Arnoldi , Julien Renaud , Maya Guéguen , Arnaud Foulquier , Jérôme Poulenard , Emilie Lyautey , Jean-Christophe Clément , Wilfried Thuiller , Tamara Münkemüller
Publication : New Phytologist
Date : 2026
Volume : 249
Issue : 3
Pages : 1173-1187
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Global warming is changing plant communities due to the arrival of new species from warmer regions and declining abundance of cold-adapted species. However, experimentally testing predictions about trajectories and rates of community change is challenging because we normally lack an expectation for future community composition, and most warming experiments fail to incorporate colonization by novel species. To address these issues, we analyzed data from 44 whole-community transplant experiments along 22 elevational gradients across the Northern Hemisphere. In these experiments, high-elevation communities were transplanted to lower elevations to simulate warming, while also removing dispersal barriers for lower-elevation species to establish. We quantified the extent and pace at which warmed high-elevation communities shifted towards the taxonomic composition of lower elevation communities. High-elevation plant communities converged towards the composition of low-elevation communities, with higher rates under stronger experimental warming. Strong community shifts occurred in the first year after transplantation then slowed over time, such that communities remained distinct from both origin and destination control by the end of the experimental periods (3-9 years). Changes were driven to a similar extent by both new species colonization and abundance shifts of high-elevation species, but with substantial variation across experiments that could be partly explained by the magnitude and duration of experimental warming, plot size and functional traits. Our macroecological approach reveals that while warmed high-elevation communities increasingly resemble communities at lower elevations today, the slow pace of taxonomic shifts implies considerable colonization and extinction lags, where a novel taxonomic composition of both low- and high-elevation species could coexist for long periods of time. The important contribution of the colonizing species to community change also indicates that once dispersal barriers are overcome, warmed high-elevation communities are vulnerable to encroachment from lower elevation species.
Auteurs, date et publication :
Auteurs Billur Bektaş , Chelsea Chisholm , Dagmar Egelkraut , Joshua Lynn , Sebastián Block , Thomas Deola , Fanny Dommanget , Brian J. Enquist , Deborah E. Goldberg , Sylvia Haider , Aud H. Halbritter , Yongtao He , Renaud Jaunatre , Anke Jentsch , Kari Klanderud , Paul Kardol , Susanne Lachmuth , Gregory Loucougaray , Tamara Münkemüller , Georg Niedrist
Publication : Ecography
Date : 1970
Volume : n/a
Issue : n/a
Pages : e07378
Catégorie(s)
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Auteurs Sandra Lavorel , Karl Grigulis , Pénélope Lamarque , Marie-Pascale Colace , Denys Garden , Jacky Girel , Gilles Pellet , Rolland Douzet
Publication : Journal of Ecology
Date : 2025
Volume : 99
Issue : 1
Pages : 135-147
Catégorie(s)
#CNRS #Lautaret #UGARésumé
The concept of ecosystem services is increasingly being used by scientists and policy makers. However, most studies in this area have focussed on factors that regulate ecosystem functions (i.e. the potential to deliver ecosystem services) or the supply of ecosystem services. In contrast, demand for ecosystem services (i.e. the needs of beneficiaries) or understanding of the concept and the relative ranking of different ecosystem services by beneficiaries has received limited attention. The aim of this study was to identify in three European mountain regions the ecosystem services of grassland that different stakeholders identify (which ecosystem services for whom), the relative rankings of these ecosystem services, and how stakeholders perceive the provision of these ecosystem services to be related to agricultural activities. We found differences: (1) between farmers’ perceptions of ecosystem services across regions and (2) within regions, between knowledge of ecosystem services gained by regional experts through education and farmers’ local field-based knowledge.
Auteurs, date et publication :
Auteurs Pénélope Lamarque , Ulrike Tappeiner , Catherine Turner , Melanie Steinbacher , Richard D. Bardgett , Ute Szukics , Markus Schermer , Sandra Lavorel
Publication : Regional Environmental Change
Date : 2025
Volume : 11
Issue : 4
Pages : 791-804
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Constance Laureau , Richard Bligny , Peter Streb
Publication : Physiologia Plantarum
Date : 2025
Volume : 143
Issue : 3
Pages : 246-260
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Guillaume Lentendu , Lucie Zinger , Stéphanie Manel , Eric Coissac , Philippe Choler , Roberto A. Geremia , Christelle Melodelima
Publication : Fungal Diversity
Date : 2025
Volume : 49
Issue : 1
Pages : 113-123