Auteurs, date et publication :
Auteurs Cécile H. Albert , Francesco de Bello , Isabelle Boulangeat , Gilles Pellet , Sandra Lavorel , Wilfried Thuiller
Publication : Oikos
Date : 2025
Volume : 121
Issue : 1
Pages : 116-126
Catégorie(s)
#CNRS #Lautaret #UGARésumé
We combined imagery from multiple sources (MODIS, Landsat-5, 7, 8) with land cover data to test for long-term (1984–2015) greening or browning trends of vegetation in a temperate alpine area, the Ecrins National Park, in the context of recent climate change and domestic grazing practices. We showed that over half (56%) of the Ecrins National Park displayed significant increases in peak normalized difference vegetation index (NDVImax) over the last 16 years (2000–2015). Importantly, the highest proportional increases in NDVImax occurred in rocky habitats at high elevations (> 2500 m a.s.l.). While spatial agreement in the direction of change in NDVImax as detected by MODIS and Landsat was high (76% overlap), correlations between log-response ratio values were of moderate strength (approx. 0.3). In the context of above treeline habitats, we found that proportional increases in NDVImax were higher between 1984 and 2000 than between 2000 and 2015, suggesting a slowing of greening dynamics during the recent decade. The timing of accelerated greening prior to 2000 coincided with a pronounced increase in the amount of snow-free growing degree-days that occurred during the 1980s and 1990s. In the case of grasslands and low-shrub habitats, we did not find evidence for a negative effect of grazing on greening trends, possibly due to the low grazing intensity typically found in the study area. We propose that the emergence of a longer and warmer growing season enabled high-elevation plant communities to produce more biomass, and also allowed for plant colonization of habitats previously characterized by long-lasting snow cover. Increasing plant productivity in an alpine context has potential implications for biodiversity trajectories and for ecosystem services in mountain landscapes. The presented evidence for long-term greening trends in a representative region of the European Alps provides the basis for further research on mechanisms of greening in alpine landscapes.
Auteurs, date et publication :
Auteurs Bradley Z Carlson , Monica C Corona , Cédric Dentant , Richard Bonet , Wilfried Thuiller , Philippe Choler
Publication : Environmental Research Letters
Date : 2017
Volume : 12
Issue : 11
Pages : 114006
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Bruley, E., B. Locatelli, and S. Lavorel. 2021. Nature’s contributions to people: coproducing quality of life from multifunctional landscapes. Ecology and Society 26(1):12. https://doi.org/10.5751/ES-12031-260112
Auteurs, date et publication :
Auteurs Enora Bruley , Bruno Locatelli , Sandra Lavorel
Publication : Ecology and Society
Date : 2021
Volume : 26
Issue : 1
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Reintroductions inherently involve a small number of founders leading reintroduced populations to be prone to genetic drift and, consequently, to inbreeding depression. Assessing the origins as the genetic diversity and structure of reintroduced populations compared to native populations are thus crucial to foresee their future. Here, we aim to clarify the origins of the Alpine marmots reintroduced in the Pyrenees and to evaluate the genetic consequences of this reintroduction after almost 30 years without monitoring. We search for the origins and compare the genetic structure and the genetic variability of three reintroduced Pyrenean and eight native Alpine populations using pairwise genetic distances, Bayesian clustering method and multivariate analyses. Our results reveal that the Alpine marmots reintroduced in the Pyrenees originated both from the Northern and the Southern Alps, and that, despite these multiple origins, none of the current Pyrenean marmots are admixed. The reintroduction led to a strong genetic differentiation and to a decrease in genetic diversity. This pattern likely results from the small number of founders and the low dispersal capacities of Alpine marmots and thus, highlight the necessity to consider both genetic characteristics and natural history when reintroducing a species.
Auteurs, date et publication :
Auteurs Coraline Bichet , Sandrine Sauzet , Laetitia Averty , Pierre Dupont , Mariona Ferrandiz-Rovira , Caterina Ferrari , Irene Figueroa , Marion Tafani , Célia Rézouki , Bernat C. López , Aurélie Cohas
Publication : Conservation Genetics
Date : 2016
Volume : 17
Issue : 5
Pages : 1157-1169
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Mountain social-ecological systems (SES) supply important ecosystem services that are threatened by climate change. In mountain SES there is a paradox between high community capacity to cope with extremes, and governance structures and processes that constrain that capacity from being realised. Climate adaptation that maintains livelihoods and supply of ecosystem services can catalyse this innate adaptive capacity if new adaptive governance arrangements can be created. Using the French Alps as a case study, we outline a participative framework for transformative adaptation that links adaptive capacity and governance to provide social innovation and ecosystem-based adaptation solutions for mountain SES. Grassland management was the main entry point for adaptation: bundles of adaptation services supplied by the landscape mosaic of biodiverse grassland types can maintain agricultural production and tourism and facilitate income diversification. Deliberate management for core adaptation services like resilient fodder production, erosion control, shade or aesthetic value generates co-benefits for future transformation ability. People activate bundles of adaptation services along adaptation pathways and realise benefits via co-production with other forms of capital including traditional knowledge or social networks. Common and distinctive adaptation services in each pathway create options for transformation if barriers from interactions between values and rules across scales can be overcome. For example conserving mown terraces which is a critical adaptation nexus reflects a complex interplay of values, markets and governance instruments from local to European scales. We conclude that increasing stakeholders capacity to mobilise adaptation services is critical for empowering them to implement adaptation to global change.
Auteurs, date et publication :
Auteurs Sandra Lavorel , Matthew J. Colloff , Bruno Locatelli , Russell Gorddard , Suzanne M. Prober , Marine Gabillet , Caroline Devaux , Denis Laforgue , Véronique Peyrache-Gadeau
Publication : Environmental Science & Policy
Date : 2025
Volume : 92
Pages : 87-97
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Our knowledge of the factors influencing the distribution of soil organisms is limited to specific taxonomic groups. Consequently, our understanding of the drivers shaping the entire soil multitrophic network is constrained. To address this gap, we conducted an extensive soil biodiversity monitoring program in the French Alps, using environmental DNA to obtain multi-taxon data from 418 soil samples. The spatial structure of resulting soil multitrophic networks varied significantly between and within habitats. From forests to grasslands, we observed a shift in the abundance of trophic groups from fungal to bacterial feeding channels, reflecting different ecosystem functioning. Furthermore, forest soil networks were more strongly spatially structured which could only partly be explained by abiotic conditions. Grassland soil networks were more strongly driven by plant community composition and soil characteristics. Our findings provide valuable insights into how climate and land-use changes may differentially affect soil multitrophic networks in mountains.
Auteurs, date et publication :
Auteurs Irene Calderon-Sanou , Marc Ohlmann , Tamara Munkemuller , Lucie Zinger , Mickael Hedde , Clement Lionnet , Camille Martinez-Almoyna , Amelie Saillard , Julien Renaud , Nicolas Le Guillarme , Ludovic Gielly , Wilfried Thuiller , Orchamp Consortium
Publication : SOIL BIOLOGY & BIOCHEMISTRY
Date : 2024
Volume : 190
Catégorie(s)
#ANR-Citation #CNRS #Lautaret #UGARésumé
Abstract. The surface temperature controls the temporal evolution of the snowpack, playing a key role in metamorphism and snowmelt. It shows large spatial variations in mountainous areas because the surface energy budget is affected by the topography, for instance because of the modulation of the short-wave irradiance by the local slope and the shadows and the short-wave and long-wave re-illumination of the surface from surrounding slopes. These topographic effects are often neglected in large-scale models considering the surface to be flat and smooth. Here we aim at estimating the surface temperature of snow-covered mountainous terrain in clear-sky conditions in order to evaluate the relative importance of the different processes that control the spatial variations. For this, a modelling chain is implemented to compute the surface temperature in a kilometre-wide area from local radiometric and meteorological measurements at a single station. The first component of this chain is the Rough Surface Ray-Tracing (RSRT) model. Based on a photon transport Monte Carlo algorithm, this model quantifies the incident and reflected short-wave radiation on every facet of the mesh describing the snow-covered terrain. The second component is a surface scheme that estimates the terms of the surface energy budget from which the surface temperature is eventually estimated. To assess the modelling chain performance, we use in situ measurements of surface temperature and satellite thermal observations (Landsat 8) in the Col du Lautaret area, in the French Alps. The results of the simulations show (i) an agreement between the simulated and measured surface temperature at the station for a diurnal cycle in winter within 0.2 ∘C; (ii) that the spatial variations in surface temperature are on the order of 5 to 10 ∘C in the domain and are well represented by the model; and (iii) that the topographic effects ranked by importance are the modulation of solar irradiance by the local slope, followed by the altitudinal variations in air temperature (lapse rate), the re-illumination by long-wave thermal emission from surrounding terrain, and the spectral dependence of snow albedo. The changes in the downward long-wave flux because of variations in altitude and the absorption enhancement due to multiple bounces of photons in steep terrain play a less significant role. These results show the necessity of considering the topography to correctly assess the energy budget and the surface temperature of snow-covered complex terrain.
Auteurs, date et publication :
Auteurs Alvaro Robledano , Ghislain Picard , Laurent Arnaud , Fanny Larue , Inès Ollivier
Publication : The Cryosphere
Date : 2022
Volume : 16
Issue : 2
Pages : 559-579
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs J. Pottier , Z. Malenovsky , A. Psomas , L. Homolova , M. E. Schaepman , P. Choler , W. Thuiller , A. Guisan , N. E. Zimmermann
Publication : Biology Letters
Date : 2014
Volume : 10
Issue : 7
Pages : 20140347-20140347
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Bradley Z. Carlson , Philippe Choler , Julien Renaud , Jean-Pierre Dedieu , Wilfried Thuiller
Publication : Annals of Botany
Date : 2025
Volume : 116
Issue : 6
Pages : 1023-1034
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Abstract. Among mountainous permafrost landforms, rock glaciers are mostly abundant in periglacial areas, as tongue-shaped heterogeneous bodies. Passive seismic monitoring systems have the potential to provide continuous recordings sensitive to hydro-mechanical parameters of the subsurface. Two active rock glaciers located in the Alps (Gugla, Switzerland, and Laurichard, France) have been instrumented with seismic networks. Here, we analyze the spectral content of ambient noise to study the modal sensitivity of rock glaciers, which is directly linked to the system's elastic properties. For both sites, we succeed in tracking and monitoring resonance frequencies of specific vibrating modes of the rock glaciers over several years. These frequencies show a seasonal pattern characterized by higher frequencies at the end of winters and lower frequencies in warm periods. We interpret these variations as the effect of the seasonal freeze–thawing cycle on elastic properties of the medium. To assess this assumption, we model both rock glaciers in summer, using seismic velocities constrained by active seismic acquisitions, while bedrock depth is constrained by ground-penetrating radar surveys. The variations in elastic properties occurring in winter due to freezing were taken into account thanks to a three-phase Biot–Gassmann poroelastic model, where the rock glacier is considered a mixture of a solid porous matrix and pores filled by water or ice. Assuming rock glaciers to be vibrating structures, we numerically compute the modal response of such mechanical models by a finite-element method. The resulting modeled resonance frequencies fit well the measured ones over seasons, reinforcing the validity of our poroelastic approach. This seismic monitoring allows then a better understanding of the location, intensity and timing of freeze–thawing cycles affecting rock glaciers.
Auteurs, date et publication :
Auteurs Antoine Guillemot , Laurent Baillet , Stéphane Garambois , Xavier Bodin , Agnès Helmstetter , Raphaël Mayoraz , Eric Larose
Publication : The Cryosphere
Date : 2021
Volume : 15
Issue : 2
Pages : 501-529