Résumé
With a growing demand for hydroelectric energy, the number of reservoirs is dramatically increasing worldwide. These new water bodies also present an opportunity for the development of fishing activities. However, these reservoirs are commonly impounded on uncut forests, resulting in many immersed trees. These trees hinder fish assessments by disrupting both gill-netting and acoustic sampling. Immersed trees can easily be confused with fish schools on echograms. To overcome this issue, we developed a method to discriminate fish schools from immersed trees. A random forest algorithm was used to classify echo-traces at 120 and 200 kHz, recorded by an EK80 (SIMRAD) in narrowband (continuous wave) and in broadband mode (frequency modulated). We obtained a good discrimination rate between trees and schools, especially in broadband (90% ratio of good classification). We demonstrate that it is possible to discriminate fish schools from immersed trees and thus facilitate the use of fisheries acoustics in reservoirs.
Auteurs, date et publication :
Auteurs Arthur Blanluet , Sven Gastauer , Franck Cattanéo , Chloé Goulon , David Grimardias , Jean Guillard
Publication : Canadian Journal of Fisheries and Aquatic Sciences
Date : 2025
Volume : 79
Issue : 5
Pages : 738-748
Catégorie(s)
#INRAE #OLARésumé
Rock weathering and biological cycling hold the development and sustainability of continental ecosystems, yet the interdependence of macro- and micro-nutrients biogeochemical cycles and their implications for ecosystem functioning remains unclear, despite being of particular importance in the context of global changes. This study focuses on the stocks, fluxes and processes constituting the biogeochemical cycle of boron. Vegetation, soils and solutions were monitored for a full year in a temperate beech forest developed on calcareous soil. Despite an overwhelmingly large B pool in soils, this study points to limited influence of weathering emphasizing the importance of vegetation cycling on this site. The biological imprint on the B cycle is marked by (1) a strong 11B enrichment of solutions compared to the mineral source and (2) systematic correlations observed between B and other strongly recycled elements in all water samples. B isotopes are fractionated within the beech stand with higher values in leaves (23.5‰) and lower in fine roots (−11.7‰), suggesting that the light 10B isotope is preferentially assimilated during plant growth. B isotopic data are consistent with a Rayleigh-like behaviour during xylem transfer leading to an 11B enrichment in the higher parts of the trees, putting internal B transfer as the main driver of the large range of isotopic compositions between plant tissues. B apparent isotopic fractionations are observed in the annually produced biomass and total beech stand, albeit with different values: αxylem-biomass = 0.980 ± 0.009 and 0.990 ± 0.002, respectively, suggesting 11B transfer from old to new tissue. The developed model also points to an isotopic fractionation factor during B uptake much higher than previously evaluated (0.979 < αuptake < 0.994). Overall, this study demonstrates that B isotopes appear as a promising tracer of soilplant interactions with particular emphasis on tree adaptation to B bioavailability in soil.
Auteurs, date et publication :
Auteurs P. Roux , D. Lemarchand , P.-O. Redon , M.-P. Turpault
Publication : Science of The Total Environment
Date : 2025
Volume : 806
Pages : 150396
Catégorie(s)
#FORET Montiers #INRAERésumé
Purpose Douglas-fir occupies a growing role in the European timber industries but its effects on soils and the environment are still not well understood. We monitored the biogeochemical cycle of major elements in 11 representative mature stands throughout France over the 2013 to 2020 period to better understand repercussions on soil processes.
Auteurs, date et publication :
Auteurs Alexia Paul , Arnaud Legout , Bernd Zeller , Gregory van der Heijden , Pascal Bonnaud , Arnaud Reichard , Gilles Nourrisson , Jacques Ranger
Publication : Plant and Soil
Date : 2025
Volume : 479
Issue : 1-2
Pages : 207-231
Catégorie(s)
#ANR-Citation #FORET Breuil #INRAERésumé
The European catfish (Silurus glanis) recently colonised large peri-alpine lakes where its exploitation of the different lake habitats (i.e. littoral, pelagic and deep benthic) may be supported by interindividual trophic variations fostering its establishment. We investigated the prey and lake habitats supporting S. glanis diet in the largest French peri-alpine lake (Lake Bourget) based on the contents of 231 stomachs combined with 217 individual stable isotope measurements (δ13C and δ15N). The interindividual diet variations in stomachs and isotopes were quantified to identify individual specialisation within the population. The effects of body size on trophic characteristics were also explored. For most individuals, a major reliance on littoral resources was determined based on both stomach contents (86% of prey items) and stable isotopes using Bayesian mixing models (BMMs; 70.3 ± 9.6% contributions of the littoral resources). However, pelagic and deep benthic prey (e.g. whitefish and burbot) were also identified, and BMMs indicated significant contributions of pelagic and deep benthic resources to S. glanis diets (15.8 ± 5.3% and 13.9 ± 5.2% respectively). Interindividual variations based on stomach contents were much higher than those estimated from stable isotopes, supporting an opportunistic trophic behaviour; although the population strongly relied on crayfish, perch and roach. Body size explained a minor fraction of S. glanis trophic characteristics, suggesting that ontogeny does not strongly structure the current population diet. Our results underscore the feeding plasticity of S. glanis, revealing that besides the littoral habitat, this invader exploits resources from all habitats in large peri-alpine lakes (deep benthic and pelagic). Therefore, its establishment in these ecosystems may represent a growing threat to resident species, especially if the population and individual body size increase in the near future.
Auteurs, date et publication :
Auteurs Chloé Vagnon , Simon Bazin , Franck Cattanéo , Chloé Goulon , Jean Guillard , Victor Frossard
Publication : Ecology of Freshwater Fish
Date : 2025
Volume : 31
Issue : 4
Pages : 650-661
Catégorie(s)
#INRAE #OLARésumé
The recycling of organic waste products (e.g. sewage sludge, SS) is currently being promoted as a substitute for mineral fertilizers for agricultural lands. The spreading of SS allows the recycling of the nutrients and organic matter it contains. SS contains various pollutants such as volatile organic compounds (VOCs) that adversely affect the ecosystem and human health through ozone production and serve as critical precursors of atmospheric secondary organic aerosols. There are very few studies quantifying the gaseous compounds emitted from SS, and those studies primarily address their odorant properties for identifying suitable odour abatement techniques. There is an urgent need for more comprehensive quantitative information on VOCs emitted from SS as aerosol precursors. In this context, an experimental study was performed on SS samples taken from a wastewater treatment plant located in France. Undigested SS (UDSS), digested SS (DSS) and SS with 30% and 60% dryness were collected from different stages of treatment sequence and analyzed using atmospheric simulation chambers coupled to proton-transfer-reaction quadrupole ionguide time-of-flight mass spectrometer. Our study revealed that SS samples emitted a large spectrum of VOCs. 380 compounds were detected, quantified and classified into different chemical groups. The VOC emissions increased with the increase in the dryness of the sample; the highest being in SS 60%, followed by SS 30%, UDSS and DSS. OVOCs were dominant in SS 60%. The statistical analysis showed that the anaerobic digestion and the dewatering to 60% of dryness decreased the emissions of sulphuric compounds. Aromatic compounds and indoles (e.g. skatole) were emitted significantly from the UDSS. Some of these VOCs can serve as precursor gases for atmospheric aerosol formation. The experimental dataset obtained in this study provides an accurate inventory reference for the VOC emissions from SS samples and shows the impacts of the treatment on emission characteristics of VOCs.
Auteurs, date et publication :
Auteurs K.M. Haider , F. Lafouge , Y. Carpentier , S. Houot , D. Petitprez , B. Loubet , C. Focsa , R. Ciuraru
Publication : Science of The Total Environment
Date : 2025
Volume : 838
Pages : 155948
Catégorie(s)
#INRAE #PT-RMSRésumé
The taxonomic identification of organisms based on the amplification of specific genetic markers (metabarcoding) implicitly requires adequate discriminatory information and taxonomic coverage of environmental DNA sequences in taxonomic databases. These requirements were quantitatively examined by comparing the determination of cyanobacteria and microalgae obtained by metabarcoding and light microscopy. We used planktic and biofilm samples collected in 37 lakes and 22 rivers across the Alpine region. We focused on two of the most used and best represented genetic markers in the reference databases, namely the 16S rRNA and 18S rRNA genes. A sequence gap analysis using blastn showed that, in the identity range of 99–100%, approximately 30% (plankton) and 60% (biofilm) of the sequences did not find any close counterpart in the reference databases (NCBI GenBank). Similarly, a taxonomic gap analysis showed that approximately 50% of the cyanobacterial and eukaryotic microalgal species identified by light microscopy were not represented in the reference databases. In both cases, the magnitude of the gaps differed between the major taxonomic groups. Even considering the species determined under the microscope and represented in the reference databases, 22% and 26% were still not included in the results obtained by the blastn at percentage levels of identity ≥95% and ≥97%, respectively. The main causes were the absence of matching sequences due to amplification and/or sequencing failure and potential misidentification in the microscopy step. Our results quantitatively demonstrated that in metabarcoding the main obstacles in the classification of 16S rRNA and 18S rRNA sequences and interpretation of high-throughput sequencing biomonitoring data were due to the existence of important gaps in the taxonomic completeness of the reference databases and the short length of reads. The study focused on the Alpine region, but the extent of the gaps could be much greater in other less investigated geographic areas.
Auteurs, date et publication :
Auteurs Nico Salmaso , Valentin Vasselon , Frédéric Rimet , Marine Vautier , Tina Elersek , Adriano Boscaini , Claudio Donati , Marco Moretto , Massimo Pindo , Giulia Riccioni , Erika Stefani , Camilla Capelli , Fabio Lepori , Rainer Kurmayer , Ute Mischke , Aleksandra Krivograd Klemenčič , Katarina Novak , Claudia Greco , Giorgio Franzini , Giampaolo Fusato
Publication : Science of The Total Environment
Date : 2025
Volume : 834
Pages : 155175
Catégorie(s)
#INRAE #OLARésumé
Abstract
Untangling causal links and feedbacks among biodiversity, ecosystem functioning, and environmental factors is challenging due to their complex and context-dependent interactions (e.g., a nutrient-dependent relationship between diversity and biomass). Consequently, studies that only consider separable, unidirectional effects can produce divergent conclusions and equivocal ecological implications. To address this complexity, we use empirical dynamic modeling to assemble causal networks for 19 natural aquatic ecosystems (N24
◦
~N58
◦
) and quantified strengths of feedbacks among phytoplankton diversity, phytoplankton biomass, and environmental factors. Through a cross-system comparison, we identify macroecological patterns; in more diverse, oligotrophic ecosystems, biodiversity effects are more important than environmental effects (nutrients and temperature) as drivers of biomass. Furthermore, feedback strengths vary with productivity. In warm, productive systems, strong nitrate-mediated feedbacks usually prevail, whereas there are strong, phosphate-mediated feedbacks in cold, less productive systems. Our findings, based on recovered feedbacks, highlight the importance of a network view in future ecosystem management.
Auteurs, date et publication :
Auteurs Chun-Wei Chang , Takeshi Miki , Hao Ye , Sami Souissi , Rita Adrian , Orlane Anneville , Helen Agasild , Syuhei Ban , Yaron Be’eri-Shlevin , Yin-Ru Chiang , Heidrun Feuchtmayr , Gideon Gal , Satoshi Ichise , Maiko Kagami , Michio Kumagai , Xin Liu , Shin-Ichiro S. Matsuzaki , Marina M. Manca , Peeter Nõges , Roberta Piscia
Publication : Nature Communications
Date : 2022
Volume : 13
Issue : 1
Pages : 1140
Catégorie(s)
#INRAE #OLARésumé
While the impacts of forest management options on carbon (C) storage are well documented, the way they affect C distribution among ecosystem components remains poorly investigated. Yet, partitioning of total forest C stocks, particularly between aboveground woody biomass and the soil, greatly impacts the stability of C stocks against disturbances in forest ecosystems. This study assessed the impact of species composition and stand density on C storage in aboveground woody biomass (stem + branches), coarse roots, and soil, and their partitioning in pure and mixed forests in Europe. We used 21 triplets (5 beech-oak, 8 pine-beech, 8 pine-oak mixed stands, and their respective monocultures at the same sites) in seven European countries. We computed biomass C stocks from total stand inventories and species-specific allometric equations, and soil organic C data down to 40 cm depth. On average, the broadleaved species stored more C in aboveground woody biomass than soil, while C storage in pine was equally distributed between both components. Stand density had a strong effect on C storage in tree woody biomass but not in the soil. After controlling for stand basal area, the mixed stands had, on average, similar total C stocks (in aboveground woody biomass + coarse roots + soil) to the most performing monocultures. Although species composition and stand density affect total C stocks and its partitioning between aboveground woody biomass and soil, a large part of variability in soil C storage was unrelated to stand characteristics.
Auteurs, date et publication :
Auteurs Richard Osei , Miren del Río , Ricardo Ruiz-Peinado , Hugues Titeux , Kamil Bielak , Felipe Bravo , Catherine Collet , Corentin Cools , Jean-Thomas Cornelis , Lars Drössler , Michael Heym , Nathalie Korboulewsky , Magnus Löf , Bart Muys , Yasmina Najib , Arne Nothdurft , Hans Pretzsch , Jerzy Skrzyszewski , Quentin Ponette
Publication : European Journal of Forest Research
Date : 2022
Volume : 141
Issue : 3
Pages : 467-480
Catégorie(s)
#FORET OPTMix #INRAERésumé
Zwitterionic, cationic, and anionic per- and polyfluoroalkyl substances (PFAS) are increasingly reported in terrestrial and aquatic environments, but their inputs to agricultural lands are not fully understood. Here, we characterized PFAS in 47 organic waste products (OWP) applied in agricultural fields of France, including historical and recent materials. Overall, 160 PFAS from 42 classes were detected from target screening and homologue-based nontarget screening. Target PFAS were low in agriculture-derived wastes such as pig slurry, poultry manure, or dairy cattle manure (median ∑46PFAS: 0.66 μg/kg dry matter). Higher PFAS levels were reported in urban and industrial wastes, paper mill sludge, sewage sludge, or residual household waste composts (median ∑46PFAS: 220 μg/kg). Historical municipal biosolids and composts (1976−1998) were dominated by perfluorooctanesulfonate (PFOS), N-ethyl perfluorooctanesulfonamido acetic acid (EtFOSAA), and cationic and zwitterionic electrochemical fluorination precursors to PFOS. Contemporaneous urban OWP (2009−2017) were rather dominated by zwitterionic fluorotelomers, which represented on average 55% of ∑160PFAS (max: 97%). The fluorotelomer sulfonamidopropyl betaines (X:2 FTSA-PrB, median: 110 μg/kg, max: 1300 μg/kg) were the emerging class with the highest occurrence and prevalence in contemporary urban OWP. They were also detected as early as 1985. The study informs for the first time that urban sludges and composts can be a significant repository of zwitterionic and cationic PFAS.
Auteurs, date et publication :
Auteurs Gabriel Munoz , Aurélia Marcelline Michaud , Min Liu , Sung Vo Duy , Denis Montenach , Camille Resseguier , Françoise Watteau , Valérie Sappin-Didier , Frédéric Feder , Thierry Morvan , Sabine Houot , Mélanie Desrosiers , Jinxia Liu , Sébastien Sauvé
Publication : Environmental Science & Technology
Date : 2022
Volume : 56
Issue : 10
Pages : 6056-6068
Catégorie(s)
#ANR-Citation #INRAE #PRO #PRO EFELERésumé
The impacts of invasive species on resident communities are driven by a tangle of ecological interactions difficult to quantify empirically. Combining a niche model with a population dynamic model, both allometrically parametrized, may represent a consistent framework to investigate invasive species impacts on resident communities in a food web context when empirical data are scarce. We used this framework to assess the ecological consequences of an invasive apex predator (
Silurus glanis
) in peri-Alpine lake food webs. Both increases and decreases of resident species abundances were highlighted and differed when accounting for different
S. glanis
body sizes. Complementarily, the prominence of indirect effects, such as trophic cascades, suggested that common approaches may only capture a restricted fraction of invasion consequences through direct predation or competition. By leveraging widely available biodiversity data, our approach may provide relevant insights for a comprehensive assessment and management of invasive species impacts on aquatic ecosystems.
Auteurs, date et publication :
Auteurs Chloé Vagnon , Rudolf P. Rohr , Louis-Félix Bersier , Franck Cattanéo , Jean Guillard , Victor Frossard
Publication : Frontiers in Ecology and Evolution
Date : 2022
Volume : 10
Pages : 913954