Auteurs, date et publication :
Auteurs Roland Lupoli
Publication : Zoosystema
Date : 2025
Volume : 40
Issue : sp1
Pages : 21-29
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Maxime Réjou-Méchain , Nicolas Barbier , Pierre Couteron , Pierre Ploton , Grégoire Vincent , Martin Herold , Stéphane Mermoz , Sassan Saatchi , Jérôme Chave , Florian de Boissieu
Publication : Surveys in Geophysics
Date : 2025
Volume : 40
Issue : 4
Pages : 881-911
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Sruthi M Krishna Moorthy , Yunfei Bao , Kim Calders , Stefan A Schnitzer , Hans Verbeeck
Publication : ISPRS Journal of Photogrammetry and Remote Sensing
Date : 2025
Volume : 154
Pages : 114-126
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Abstract Determining the species compositions of local assemblages is a prerequisite to understanding how anthropogenic disturbances affect biodiversity. However, biodiversity measurements often remain incomplete due to the limited efficiency of sampling methods. This is particularly true in freshwater tropical environments that host rich fish assemblages, for which assessments are uncertain and often rely on destructive methods. Developing an efficient and nondestructive method to assess biodiversity in tropical freshwaters is highly important. In this study, we tested the efficiency of environmental DNA (eDNA) metabarcoding to assess the fish diversity of 39 Guianese sites. We compared the diversity and composition of assemblages obtained using traditional and metabarcoding methods. More than 7,000 individual fish belonging to 203 Guianese fish species were collected by traditional sampling methods, and $sim$17 million reads were produced by metabarcoding, among which $sim$8 million reads were assigned to 148 fish taxonomic units, including 132 fish species. The two methods detected a similar number of species at each site, but the species identities partially matched. The assemblage compositions from the different drainage basins were better discriminated using metabarcoding, revealing that while traditional methods provide a more complete but spatially limited inventory of fish assemblages, metabarcoding provides a more partial but spatially extensive inventory. eDNA metabarcoding can therefore be used for rapid and large-scale biodiversity assessments, while at a local scale, the two approaches are complementary and enable an understanding of realistic fish biodiversity.
Auteurs, date et publication :
Auteurs Kévin Cilleros , Alice Valentini , Luc Allard , Tony Dejean , Roselyne Etienne , Gaël Grenouillet , Amaia Iribar , Pierre Taberlet , Régis Vigouroux , Sébastien Brosse
Publication : Molecular Ecology Resources
Date : 2019
Volume : 19
Issue : 1
Pages : 27–46
Catégorie(s)
#CIRAD #CNRS #eDNA #FORET ParacouRésumé
Measuring in situ soil fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) continuously at high frequency requires appropriate technology. We tested the combination of a commercial automated soil CO2 flux chamber system (LI-8100A) with a CH4 and N2O analyzer (Picarro G2308) in a tropical rainforest for 4 months. A chamber closure time of 2 min was sufficient for a reliable estimation of CO2 and CH4 fluxes (100% and 98.5% of fluxes were above minimum detectable flux - MDF, respectively). This closure time was generally not suitable for a reliable estimation of the low N2O fluxes in this ecosystem but was sufficient for detecting rare major peak events. A closure time of 25 min was more appropriate for reliable estimation of most N2O fluxes (85.6% of measured fluxes are above MDF +/- 0.002 nmol m(-2) s(-1)). Our study highlights the importance of adjusted closure time for each gas.
Auteurs, date et publication :
Auteurs Elodie Alice Courtois , Clement Stahl , Benoit Burban , Joke Van den Berge , Daniel Berveiller , Laetitia Brechet , Jennifer Larned Soong , Nicola Arriga , Josep Penuelas , Ivan August Janssens
Publication : BIOGEOSCIENCES
Date : 2019
Volume : 16
Issue : 3
Pages : 785-796
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
Plant litter decomposition is an essential process of ecosystem functioning, driven by a complex soil food web. The identity and density of the predators, as well as the quality and quantity of litter, could conjointly affect the strength of trophic interactions within a soil food web. Pine and oak are dominant tree species in temperate and Mediterranean forests and, although they exhibit distinct litter characteristics, no previous study attempted to decipher how these two litters can affect a litter-based multi-trophic system with varying predator density. Using a microcosm experiment, we aimed at understanding how different densities of a predatory Acari (Stratiolaelaps scimitus) and two Mediterranean litter species (Quercus pubescens and Pinus halepensis) may impact the demographic parameters of the predatory Acari, its Collembola prey (Folsomia candida) and the fungal biomass associated with litter. We did not observe any interactive effect of litter identity and predator density on both predator and prey demographic parameters. Survival and fecundity rates of the predator and its prey decreased at high predator density. However, demographic parameters of the predator and its prey were differentially affected by litter identity, with greater prey demographic parameters in Quercus litter and, in the opposite, greater predator demographic parameters in Pinus litter, probably due to differences in physical characteristics providing more or less refuge for the prey. We also observed a higher increase in fungal biomass in Pinus compared to Quercus litter, i.e. the litter with the fungivorous Collembola abundance reduced by the predatory Acari. Litter identity could thus strongly regulate these tri-trophic interactions (Fungi – fungivorous Collembola – predatory Acari) in forest ecosystems. Finally, the implications of our findings could be important as the distribution area of oak and pine forests may be altered in response to climate change with then potentially strong cascading effects on soil organisms and the processes they drive.
Auteurs, date et publication :
Auteurs Adriane Aupic-Samain , Virginie Baldy , Caroline Lecareux , Catherine Fernandez , Mathieu Santonja
Publication : Pedobiologia
Date : 2019
Volume : 73
Pages : 1-9
Catégorie(s)
#CNRS #FORET O3HPRésumé
The primary objective of the European Space Agency's 7th Earth Explorer mission, BIOMASS, is to determine the worldwide distribution of forest above-ground biomass (AGB) in order to reduce the major uncertainties in calculations of carbon stocks and fluxes associated with the terrestrial biosphere, including carbon fluxes associated with Land Use Change, forest degradation and forest regrowth. To meet this objective it will carry, for the first time in space, a fully polarimetric P-band synthetic aperture radar (SAR). Three main products will be provided: global maps of both AGB and forest height, with a spatial resolution of 200 m, and maps of severe forest disturbance at 50 m resolution (where “global” is to be understood as subject to Space Object tracking radar restrictions). After launch in 2022, there will be a 3-month commissioning phase, followed by a 14-month phase during which there will be global coverage by SAR tomography. In the succeeding interferometric phase, global polarimetric interferometry Pol-InSAR coverage will be achieved every 7 months up to the end of the 5-year mission. Both Pol-InSAR and TomoSAR will be used to eliminate scattering from the ground (both direct and double bounce backscatter) in forests. In dense tropical forests AGB can then be estimated from the remaining volume scattering using non-linear inversion of a backscattering model. Airborne campaigns in the tropics also indicate that AGB is highly correlated with the backscatter from around 30 m above the ground, as measured by tomography. In contrast, double bounce scattering appears to carry important information about the AGB of boreal forests, so ground cancellation may not be appropriate and the best approach for such forests remains to be finalized. Several methods to exploit these new data in carbon cycle calculations have already been demonstrated. In addition, major mutual gains will be made by combining BIOMASS data with data from other missions that will measure forest biomass, structure, height and change, including the NASA Global Ecosystem Dynamics Investigation lidar deployed on the International Space Station after its launch in December 2018, and the NASA-ISRO NISAR L- and S-band SAR, due for launch in 2022. More generally, space-based measurements of biomass are a core component of a carbon cycle observation and modelling strategy developed by the Group on Earth Observations. Secondary objectives of the mission include imaging of sub-surface geological structures in arid environments, generation of a true Digital Terrain Model without biases caused by forest cover, and measurement of glacier and icesheet velocities. In addition, the operations needed for ionospheric correction of the data will allow very sensitive estimates of ionospheric Total Electron Content and its changes along the dawn-dusk orbit of the mission.
Auteurs, date et publication :
Auteurs Shaun Quegan , Thuy Le Toan , Jerome Chave , Jorgen Dall , Jean-François Exbrayat , Dinh Ho Tong Minh , Mark Lomas , Mauro Mariotti D'Alessandro , Philippe Paillou , Kostas Papathanassiou , Fabio Rocca , Sassan Saatchi , Klaus Scipal , Hank Shugart , T. Luke Smallman , Maciej J. Soja , Stefano Tebaldini , Lars Ulander , Ludovic Villard , Mathew Williams
Publication : Remote Sensing of Environment
Date : 2019
Volume : 227
Pages : 44-60
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
Phenotypic effects of global warming have been documented in many different taxa. However, the importance of transgenerational phenotypic plasticity in these adaptations are seldom studied. In birds, temperature could affect egg characteristics. Higher temperatures during egg-laying may reduce maintenance costs for females and allow a higher investment in reproduction. Yet, females may also use temperatures as a cue for the risk of mismatch latter in the season. Thus, higher temperatures may be correlated to an acceleration of embryonic development (e.g. via hormonal manipulation). We performed an experiment in which night-time temperature was increased in the nestbox by approximately 1 degrees C throughout the entire laying period in great tits (Parus major). We collected one pre-treatment egg (beginning of the laying sequence) and one post-treatment egg (end of the laying sequence). Egg content (yolk androgens and lysozymes in the albumen), eggshell coloration, eggshell mass, egg mass, and shape were not affected by the treatment. However, last-laid eggs in clutches from control nestboxes had a thicker eggshell than last-laid eggs from heated nestboxes, suggesting a putative slight decrease of maternal investment with the experimental increase of temperature. We also observed effects of the laying sequence on egg characteristics. Eggs that were laid late in the laying sequence were heavier, larger, had larger spots and higher yolk androgens than eggs laid earlier. Lysozyme concentration decrease with the laying sequence in late clutches only. Thus, effects of temperature may also change with the laying sequence and it would be interesting in the future to tests the effects on first-laid eggs.
Auteurs, date et publication :
Auteurs Josefa Bleu , Simon Agostini , Frederic Angelier , Clotilde Biard
Publication : GENERAL AND COMPARATIVE ENDOCRINOLOGY
Date : 2019
Volume : 275
Pages : 73-81
Catégorie(s)
#ANR-Citation #CEREEP #CNRS #ENSRésumé
Synthetic aperture radar (SAR) tomography (TomoSAR) is an emerging technology to image the 3D structure of the illuminated media. TomoSAR exploits the key feature of microwaves to penetrate into vegetation, snow, and ice, hence providing the possibility to see features that are hidden to optical and hyper-spectral systems. The research on the use of P-band waves, in particular, has been largely propelled since 2007 in experimental studies supporting the future spaceborne Mission BIOMASS, to be launched in 2022 with the aim of mapping forest aboveground biomass (AGB) accurately and globally. The results obtained in the frame of these studies demonstrated that TomoSAR can be used for accurate retrieval of geophysical variables such as forest height and terrain topography and, especially in the case of dense tropical forests, to provide a more direct link to AGB. This paper aims at providing the reader with a comprehensive understanding of TomoSAR and its application for remote sensing of forested areas, with special attention to the case of tropical forests. We will introduce the basic physical principles behind TomoSAR, present the most relevant experimental results of the last decade, and discuss the potentials of BIOMASS tomography.
Auteurs, date et publication :
Auteurs Stefano Tebaldini , Dinh Ho Tong Minh , Mauro Mariotti d’Alessandro , Ludovic Villard , Thuy Le Toan , Jerome Chave
Publication : Surveys in Geophysics
Date : 2019
Volume : 40
Issue : 4
Pages : 779-801
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
Studying variation in life-history traits and correlated behaviours, such as boldness and foraging (i.e., pace-of-life syndrome), allows us to better understand how these traits evolve in a changing environment. In fish, it is particularly relevant studying the interplay of resource abundance and size-selection. These are two environmental stressors affecting fish in natural conditions, but also associated with human-induced environmental change. For instance, fishing, one of the most important threats for freshwater and marine populations, results in both higher mortality on large-sized fish and reduced population density.
Auteurs, date et publication :
Auteurs Beatriz Diaz Pauli , Sarah Garric , Charlotte Evangelista , L. Asbjørn Vøllestad , Eric Edeline
Publication : BMC Evolutionary Biology
Date : 2019
Volume : 19
Issue : 1
Pages : 127