Résumé
Among the multiple forms of freshwater pelagic cyanobacteria, the phycoerythrin-rich species Planktothrix rubescens is well adapted to temperate, deep and large lakes. In Lake Geneva, this filamentous and microcystinproducing species has been the dominant cyanobacterial species observed since the early years of this century. In addition to the trophic state (e.g., the phosphorus level), the influences of air and water temperature on the occurrence and development of cyanobacteria are particularly relevant in the context of global climate change. The latter may indeed be particularly marked for lakes in the Alpine region, with a rate of warming that may be twice as large as the global average. The impact of climate change on P. rubescens is thus an important challenge and it has been analysed in this study through two different approaches: (1) the extreme air temperature events as a proxy for future climate and (2) the multi adaptive regression splines (MARS) model to predict future P. rubescens biomass. These methods allowed us to determine whether Lake Geneva will still sustain an important biomass of P. rubescens in forthcoming years, provided there is no severe over-enrichment with nutrients in the future. The outcomes strongly suggest that the fraction of cyanobacterium could increase with respect to the total phytoplankton community by as much as 34 % by the end of this century and induce a significant change in the microalgal composition.
Auteurs, date et publication :
Auteurs Nicole Gallina , Martin Beniston , Stéphan Jacquet
Publication : Aquatic Sciences
Date : 2025
Volume : 79
Issue : 2
Pages : 249-263
Catégorie(s)
#INRAE #OLAAuteurs, date et publication :
Auteurs N. Marron , C. Gana , D. Gérant , P. Maillard , P. Priault , D. Epron
Publication : J Plant Nutr Soil Sci
Date : 2025
Volume : In press
Catégorie(s)
#FORET AgroTCR #INRAEAuteurs, date et publication :
Auteurs Astrid Genet , Ingrid Seynave , Laurent Saint-André , Élisabeth Leclerc , Sebastien Conil , Serge DIDIER , Bruno SIMON , Jean-Claude GÉGOUT , Jean-Luc DUPOUEY , Claude NYS , Marie-Pierre TURPAULT
Publication : Revue Forestière Française
Date : 2025
Volume : 3
Catégorie(s)
#FORET Montiers #INRAEAuteurs, date et publication :
Auteurs Anne Tréguier , Jean-Marc Paillisson , Tony Dejean , Alice Valentini , Martin A. Schlaepfer , Jean-Marc Roussel , Erika Crispo
Publication : Journal of Applied Ecology
Date : 2014
Volume : 51
Issue : 4
Pages : 871-879
Catégorie(s)
#INRAE #PEARLAuteurs, date et publication :
Auteurs Anthony Bouétard , Jessica Côte , Anne-Laure Besnard , Marc Collinet , Marie-Agnès Coutellec , Christopher Joseph Salice
Publication : Plos One
Date : 2014
Volume : 9
Issue : 9
Pages : e106670
Catégorie(s)
#INRAE #PEARLRésumé
We assembled homogenized long-term time series, up to 19 years, of measurements of net ecosystem exchange of CO2 (NEE) and its partitioning between gross primary production (GPP) and respiration (Reco) for five different ecosystems representing the main plant functional types (PFTs) in France. Part of these data was analyzed to determine the influence of the main environmental variables on carbon fluxes between temperate ecosystems and the atmosphere, and to investigate the temporal patterns of their variations. A multi-temporal statistical analysis of the time series was conducted using random forest (RF) and wavelet coherence approaches. The RF analysis showed that, in all ecosystems, the incident solar radiation was highly correlated with GPP and that GPP was better correlated with the temporal variations of NEE than Reco. The air temperature was the second most important driver in ecosystems with seasonal foliage, i.e., deciduous forest, cropland and grassland; whereas variables related to air or soil drought were prominent in evergreen forest sites. The environmental control on CO2 fluxes was tighter at high frequency suggesting an increased resilience to environmental variations at longer time spans. The spectral analysis performed on three of the five sites selected revealed contrasting temporal patterns of the cross-coherence between CO2 fluxes and climate variables among ecosystems; these were related to the respective PFT, management and soil conditions. In all PFTs, the power spectrum of GPP was well correlated with NEE and clearly different from Reco. The spectral correlation analysis showed that the canopy phenology and disturbance regime condition the spectral correlation patterns of GPP and Reco with the soil moisture and atmospheric vapour deficit.
Auteurs, date et publication :
Auteurs Virginie Moreaux , Bernard Longdoz , Daniel Berveiller , Nicolas Delpierre , Eric Dufrêne , Jean-Marc Bonnefond , Christophe Chipeaux , Jean-Marc Limousin , Jean-Marc Ourcival , Katja Klumpp , Aurore Brut , Tiphaine Tallec , Eric Ceschia , Gérémy Panthou , Denis Loustau , Richard Joffre , Olivier Darsonville
Publication : Tellus B: Chemical and Physical Meteorology
Date : 2020
Volume : 72
Issue : 1
Pages : 1-25
Catégorie(s)
#ACBB #ACBB Theix #INRAERésumé
Performing fish survey protocols with different electrofishing equipment and settings can lead to difficulties in comparing the data obtained. In this study, we captured two fish taxa (i.e. the European eel and salmonids: Atlantic salmon and brown trout) in the field using four models of electrofishers that provided different waveforms: direct current (DC), pulsed direct current (PDC) and pulsed exponential current (PEC). This study aimed to assess effects of using different waveforms and frequencies, while considering environmental variables, on i) attraction, represented by occurrence and catch-per-unit-effort (CPUE) of fishes, and ii) spinal damage, based on ultrasound of the spinal column. For all species, DC and PDC yielded equivalent occurrences and CPUEs, regardless of the frequency. In contrast, PEC induced a significant decrease in occurrences and CPUEs of both eels and salmonids. The percentage of injured fishes increased as the frequency or length of the salmonids increased while waveform had no effect. Ultrasound was determined to be a good non-invasive method to detect injuries in fishes.
Auteurs, date et publication :
Auteurs Gaétan Pottier , Marie Nevoux , Frédéric Marchand
Publication : Knowledge & Management of Aquatic Ecosystems
Date : 2025
Issue : 421
Pages : 42
Catégorie(s)
#ANR-Citation #INRAE #PEARLRésumé
The spatial forest structure that drives the functioning of these ecosystems and their response to global change is closely linked to edaphic conditions. However, the latter properties are particularly difficult to characterize in forest areas developed on karst, where soil is highly rocky and heterogeneous. In this work, we investigated whether geophysics, and more specifically electromagnetic induction (EMI), can provide a better understanding of forest structure. We use EMI (EM31, Geonics Limited, Ontario, Canada) to study the spatial variability of ground properties in two different Mediterranean forests. A naturally post-fire regenerated forest composed of Aleppo pines and Holm oaks and a monospecific plantation of Altlas cedar. To better interpret EMI results, we used electrical resistivity tomography (ERT), soil depth surveys, and field observations. Vegetation was also characterized using hemispherical photographs that allowed to calculate plant area index (PAI). Our results show that the variability of ground properties contribute to explaining the variability in the vegetation cover development (plant area index). Vegetation density is higher in areas where the soil is deeper. We showed a significant correlation between edaphic conditions and tree development in the naturally regenerated forest, but this relationship is clearly weaker in the cedar plantation. We hypothesized that regular planting after subsoiling, as well as sylvicultural practices (thinning and pruning) influenced the expected relationship between vegetation structure and soil conditions measured by EMI. This work opens up new research avenues to better understand the interplay between soil and subsoil variability and forest response to climate change.
Auteurs, date et publication :
Auteurs Simon Damien Carrière , Nicolas K. Martin-StPaul , Claude Doussan , François Courbet , Hendrik Davi , Guillaume Simioni
Publication : Water
Date : 2021
Volume : 13
Issue : 22
Pages : 3218
Catégorie(s)
#FORET FontBlanche #INRAERésumé
The combination of global warming and local stressors can have dramatic consequences on freshwater biota. Sediment deposition is an important pressure that can affect benthic species and benthic ontogenetic stages (eggs and larvae) habitat quality. However, knowledge on the effects of sediment in a warming context is lacking. We used a common garden approach to examine the effects of combined exposure to elevated temperature and deposited sediment on early life history traits in offspring of four wild Arctic char (Salvelinus alpinus) populations, originating from geographically isolated lakes at the southern edge of the species range. We report interactive effects of temperature and sediment, with higher temperature exacerbating the negative effects of sediments on the duration of the incubation period and on the body size – yolk expenditure trade-off during development. Our results highlight that reevaluating the impacts of sediment on organisms under the lens of global warming and at the scale of several wild populations is needed to improve our understanding of how vulnerable species can respond to environmental changes.
Auteurs, date et publication :
Auteurs Lisandrina Mari , Martin Daufresne , Jean Guillard , Guillaume Evanno , Emilien Lasne
Publication : Canadian Journal of Fisheries and Aquatic Sciences
Date : 2021
Catégorie(s)
#INRAE #OLAAuteurs, date et publication :
Auteurs Charles Brun
Date : 2018
Pages : 24