Résumé
Abstract
As the global climate warms, the fate of lacustrine fish is of huge concern, especially given their sensitivity as ectotherms to changes in water temperature. The Arctic charr (
Salvelinus alpinus
L.) is a salmonid with a Holarctic distribution, with peripheral populations persisting at temperate latitudes, where it is found only in sufficiently cold, deep lakes. Thus, warmer temperatures in these habitats particularly during early life stages could have catastrophic consequences on population dynamics. Here, we combined lake temperature observations, a 1-D hydrodynamic model, and a multi-decadal climate reanalysis to show coherence in warming winter water temperatures in four European charr lakes near the southernmost limit of the species’ distribution. Current maximum and mean winter temperatures are on average ~ 1 °C warmer compared to early the 1980s, and temperatures of 8.5 °C, adverse for high charr egg survival, have frequently been exceeded in recent winters. Simulations of winter lake temperatures toward century-end showed that these warming trends will continue, with further increases of 3–4 °C projected. An additional 324 total accumulated degree-days during winter is projected on average across lakes, which could impair egg quality and viability. We suggest that the perpetuating winter warming trends shown here will imperil the future status of these lakes as charr refugia and generally do not augur well for the fate of coldwater-adapted lake fish in a warming climate.
Auteurs, date et publication :
Auteurs Seán Kelly , Tadhg N. Moore , Elvira de Eyto , Mary Dillane , Chloé Goulon , Jean Guillard , Emilien Lasne , Phil McGinnity , Russell Poole , Ian J. Winfield , R. Iestyn Woolway , Eleanor Jennings
Publication : Climatic Change
Date : 2025
Volume : 163
Issue : 1
Pages : 599-618
Catégorie(s)
#INRAE #OLARésumé
Lake surface water temperatures (LSWTs) are sensitive to atmospheric warming and have previously been shown to respond to regional changes in the climate. Using a combination of in situ and simulated surface temperatures from 20 Central European lakes, with data spanning between 50 and ∼100 years, we investigate the long-term increase in annually averaged LSWT. We demonstrate that Central European lakes are warming most in spring and experience a seasonal variation in LSWT trends. We calculate significant LSWT warming during the past few decades and illustrate, using a sequential t test analysis of regime shifts, a substantial increase in annually averaged LSWT during the late 1980s, in response to an abrupt shift in the climate. Surface air temperature measurements from 122 meteorological stations situated throughout Central Europe demonstrate similar increases at this time. Climatic modification of LSWT has numerous consequences for water quality and lake ecosystems. Quantifying the response of LSWT increase to large-scale and abrupt climatic shifts is essential to understand how lakes will respond in the future.
Auteurs, date et publication :
Auteurs R. Iestyn Woolway , Martin T. Dokulil , Wlodzimierz Marszelewski , Martin Schmid , Damien Bouffard , Christopher J. Merchant
Publication : Climatic Change
Date : 2025
Volume : 142
Issue : 3-4
Pages : 505-520
Catégorie(s)
#INRAE #OLARésumé
It is widely agreed that competition is an important factor that regulates plant populations and shapes communities in agricultural landscapes. Many studies have suggested that crop and grassland competition can be used for cost-effective sustainable weed control. However, effective weed management requires a precise knowledge of the effects of agronomic practices and there is a lack of quantitative indicators to compare and predict the success of weed control by competition. Here, we studied weed abundance dynamics over a 12-year period in crop-grassland rotations (rotation treatments consisted of maize, wheat and barley crops, alternating with temporary grassland maintained for three or six years in the rotation and fertilised with ∼30 or ∼230 kg ha−1 year−1 of nitrogen). In addition to classical statistical analysis of the different rotation treatments, we modelled weed abundance as a function of the crop and grassland competition, expressed here by biomasses harvested in the preceding years. We show that weed abundance decreases over the years in grassland and subsequent crops only if the grassland receives sufficient nitrogen fertiliser. Our model had a greater explanatory power than the rotation treatments. This model estimates a critical biomass level above which weeds are suppressed in subsequent years, and below which they tend to thrive. This critical biomass level was 24.3 and 4.7 tonnes ha−1 of dry matter for crops and grassland, respectively, highlighting the greater competitiveness of grasslands than of crops. Several clear differences between weed functional groups emerged. This new modelling approach directly links the interannual dynamics of weed populations to current and previous biomass production levels. This approach facilitates the development of environment-friendly weed management strategies and paves the way for comparisons of the competitiveness against weeds of crops and grassland under various pedoclimatic conditions and agronomic practices.
Auteurs, date et publication :
Auteurs Mauricio Z. Schuster , François Gastal , Diana Doisy , Xavier Charrier , Anibal de Moraes , Safia Médiène , Corentin M. Barbu
Publication : European Journal of Agronomy
Date : 2025
Volume : 113
Pages : 125963
Catégorie(s)
#ACBB #ACBB Lusignan #INRAEAuteurs, date et publication :
Auteurs Nathalie Lécrivain , Bernard Clément , Aymeric Dabrin , Juliette Seigle-Ferrand , Damien Bouffard , Emmanuel Naffrechoux , Victor Frossard
Publication : Chemosphere
Date : 2025
Volume : 264
Pages : 128451
Catégorie(s)
#INRAE #OLARésumé
A better understanding of the links between dissolved organic matter and biogeochemical processes in soil could help in evaluating global soil dynamics. To assess the effects of land cover and parental material on soil biogeochemistry, we studied 120 soil samples collected from various ecosystems in Burgundy, France. The potential solubility and aromaticity of dissolved organic matter was characterised by pressurised hot-water extraction of organic carbon (PH-WEOC). Soil physico-chemical characteristics (pH, texture, soil carbon and nitrogen) were measured, as was the δ13C signature both in soils and in PH-WEOC. We also determined bacterial and fungal abundance and the genetic structure of bacterial communities. Our results show that the potential solubility of soil organic carbon is correlated to carbon and clay content in the soil. The aromaticity of PH-WEOC and its δ13C signature reflect differences in the decomposition pathways of soil organic matter and in the production of water-extractable organic compounds, in relation to land cover. The genetic structure of bacterial communities is related to soil texture and pH, and to PH-WEOC, revealing that water-extractable organic matter is closely related to the dynamics of bacterial communities. This comprehensive study, at the regional scale, thus provides better definition of the relationships between water-extractable organic matter and soil biogeochemical properties.
Auteurs, date et publication :
Auteurs J. Guigue , J. Lévêque , O. Mathieu , P. Schmitt-Kopplin , M. Lucio , D. Arrouays , C. Jolivet , S. Dequiedt , N. Chemidlin Prévost-Bouré , L. Ranjard
Publication : Soil Biology and Biochemistry
Date : 2025
Volume : 84
Pages : 158-167
Catégorie(s)
#ANR-Citation #Genosol #INRAERésumé
Abstract. The implementation of agroecological practices often leads to additional soil organic carbon storage, and we have sought to assess the biogeochemical stability of this additional carbon. To achieve this, we implemented a multi-method approach using particle size and density fractionation, Rock-Eval® (RE) thermal analyses and long-term incubation (484 d), which we applied to topsoil samples (0–30 cm) from temperate Luvisols that had been subjected in >20-year-long experiments in France to conservation agriculture (CA), organic agriculture (ORG) and conventional agriculture (CON-LC) in the La Cage experiment and to organic waste product (OWP) applications in the QualiAgro experiment, including biowaste compost (BIOW), residual municipal solid waste compost (MSW), farmyard manure (FYM) and conventional agriculture without organic inputs (CON-QA). The additional carbon resulting from agroecological practices is the difference between the carbon stock of the bulk soil and physical fractions or carbon pools in the soil affected by agroecological practices and that of the same soil affected by a conventional practice used as control. The incubations provided information on the additional carbon stability in the short term (i.e. mean residence time, MRT, of <2 years) and showed that the additional soil organic carbon mineralized faster than the carbon in the conventional control at La Cage but slower at QualiAgro. In OWP-treated plots at QualiAgro, 60 %–66 % of the additional carbon was stored as mineral-associated organic matter (MAOM-C) and 34 %–40 % as particulate organic matter (POM-C). In CA and ORG systems at La Cage, 77 %–84 % of the additional carbon was stored as MAOM-C, whereas 16 %–23 % was stored as POM-C. Management practices hence influenced the distribution of additional carbon in physical fractions. Utilizing the PARTYSOC model with Rock-Eval® thermal analysis parameters, we found that most, if not all, of the additional carbon belonged to the active carbon pool (MRT∼30–40 years). In summary, our comprehensive multi-method evaluation indicates that the additional soil organic carbon is less stable over decadal and pluri-decadal timescales compared to soil carbon under conventional control conditions. Our results show that particle size and density fractions can be heterogenous in their biogeochemical stability. On the other hand, although the additional carbon is mainly associated with MAOM, the high proportion of this carbon in the active pool suggests that it has a mean residence time which does not exceed ∼50 years. Furthermore, agroecological practices with equivalent additional carbon stocks (MSW, FYM and CA) exhibited a higher proportion of additional carbon in POM-C under MSW (40 %) and FYM (34 %) compared to CA (16 %), which suggests a high chemical recalcitrance of POM-C under OWP management relative to conservation agriculture. Additional soil organic carbon derived from organic waste, i.e. biomass that has partially decomposed and has been transformed through its processing prior to its incorporation in soil, would be more biogeochemically stable in soil than that derived directly from plant biomass. The apparent contradictions observed between methods can be explained by the fact that they address different kinetic pools of organic carbon. Care must be taken to specify which range of residence times is considered when using any method with the intent to evaluate the biogeochemical stability of soil organic matter, as well as when using the terms stable or labile. In conclusion, the contrasting biogeochemical stabilities observed in the different management options highlight the need to maintain agroecological practices to keep these carbon stocks at a high level over time, given that the additional carbon is stable on a pluri-decadal scale.
Auteurs, date et publication :
Auteurs Tchodjowiè P. I. Kpemoua , Pierre Barré , Sabine Houot , François Baudin , Cédric Plessis , Claire Chenu
Publication : SOIL
Date : 2024
Volume : 10
Issue : 2
Pages : 533-549
Catégorie(s)
#INRAE #PRO #PRO QualiAgroAuteurs, date et publication :
Auteurs Victor Frossard , Dominique Fontvieille
Publication : Hydrobiologia
Date : 2025
Volume : 814
Issue : 1
Pages : 219-232
Catégorie(s)
#INRAE #OLARésumé
The use of herbicides for weed control is very common, but some of them represent a threat to human health, are environmentally detrimental and stimulate herbicide resistance. Therefore, using microorganisms as natural herbicides appears as a promising alternative. The mycoflorae colonizing different species of symptomatic and asymptomatic weeds were compared to characterize the possible mycoherbicidal candidates associated with symptomatic weeds. A collection of 475 symptomatic and asymptomatic plants belonging to 23 weed species was established. A metabarcoding approach based on amplification of the internal transcribed spacer (ITS) region combined with high-throughput amplicon sequencing revealed the diversity of fungal communities hosted by these weeds: 542 fungal genera were identified. The variability of the composition of fungal communities revealed a dispersed distribution of taxa governed neither by geographical location nor by the botanical species, suggesting a common core displaying non-specific interactions with host plants. Beyond this core, specific taxa were more particularly associated with symptomatic plants. Some of these, such as Alternaria, Blumeria, Cercospora, Puccinia, are known pathogens, while others such as Sphaerellopsis, Vishniacozyma and Filobasidium are not, at least on crops, and constitute new tracks to be followed in the search for mycoherbicidal candidates. IMPORTANCE: This approach is original because the diversity of weed-colonizing fungi has rarely been studied before. Furthermore, targeting both the ITS1 and ITS2 regions to characterize the fungal communities i) highlighted the complementarity of these two regions, ii) revealed a great diversity of weed-colonizing fungi, and iii) allowed for the identification of potential mycoherbicides, among which unexpected genera.
Auteurs, date et publication :
Auteurs Marion Triolet , Véronique Edel-Hermann , Nadine Gautheron , Samuel Mondy , Carole Reibel , Olivier André , Jean-Philippe Guillemin , Christian Steinberg
Publication : Applied and Environmental Microbiology
Date : 2022
Pages : aem0217721
Catégorie(s)
#ANR-Citation #Genosol #INRAERésumé
The current challenge in agriculture is to move from intensively managed to multifunctional agricultural landscapes that can simultaneously provide multiple ecological functions (multifunctionality), thus ensuring the delivery of ecosystem services important for human well-being. There is evidence that biodiversity is the main driver of multiple ecosystem functions. However, how biodiversity, and which components of biodiversity are the sources of multifunctionality, remain elusive. In the present study, we explore the role of weed richness and weed abundance as possible sources of ecosystem multifunctionality of an intensive agricultural landscape. Weeds are a key component of the arable field ecosystem trophic network by supporting various ecological functions while being a possible threat for production. We combine empirical data on ten ecosystem functions related to pollination, pest control and soil fertility, and measured across 184 fields cultivated with winter cereal, oilseed rape or hays in the Long Term Socio-Ecological Research site Zone Atelier Plaine & Val de Sèvre. We found that weed diversity was a strong contributor to multifunctionality in all crop types, especially when using the threshold-based approach. The effects of weed diversity were less pronounced for individual ecological functions except for weed seed predation and urease activity. As weeds may have dual effects on yields, we also explored the relationship between ecosystem multifunctionality and yield considering weed abundance. We however found a neutral relationship between yield and ecosystem multifunctionality. These results suggest that field management that maintains high levels of weed diversity can enhance multifunctionality and most ecological functions. Understanding how to maintain weed diversity in agricultural landscapes can therefore help to design sustainable management favoring the delivery of multiple services while maintaining food production. The next challenge will therefore be to assess the relative contribution of management practices, landscape features and weed diversity on ecosystem multifunctionality and yield.
Auteurs, date et publication :
Auteurs Sabrina Gaba , Nathalie Cheviron , Thomas Perrot , Séverine Piutti , Jean-Luc Gautier , Vincent Bretagnolle
Publication : Frontiers in Sustainable Food Systems
Date : 2020
Volume : 4
Pages : 71
Catégorie(s)
#ANR-Citation #BiochemEnv #INRAEAuteurs, date et publication :
Auteurs N. Colbach , C. Tschudy , D. Meunier , S. Houot , B. Nicolardot
Publication : European Journal of Agronomy
Date : 2025
Volume : 45
Pages : 7-19