Auteurs, date et publication :
Auteurs Ciaran Laverty , Kyle D. Green , Jaimie T. A. Dick , Daniel Barrios-O’Neill , Paul J. Mensink , Vincent Médoc , Thierry Spataro , Joe M. Caffrey , Frances E. Lucy , Pieter Boets , J. Robert Britton , Josephine Pegg , Cathal Gallagher
Publication : Biological Invasions
Date : 2025
Volume : 19
Issue : 5
Pages : 1653-1665
Catégorie(s)
#CNRS #ENS #PLANAQUARésumé
Insights into past marine carbon cycling and water mass properties can be obtained by means of geochemical proxies calibrated through controlled laboratory experiments with accurate seawater carbonate system (C-system) manipulations. Here, we explored the use of strontium/calcium ratio (Sr/Ca) of the calcite shells of benthic foraminifera as a potential seawater C-system proxy through a controlled growth experiment with two deep-sea species (Bulimina marginata and Cassidulina laevigata) and one intertidal species (Ammonia T6). To this aim, we used two experimental set-ups to decouple as much as possible the individual components of the carbonate system, i.e., changing pH at constant dissolved inorganic carbon (DIC) and changing DIC at constant pH. Four climatic chambers were used with different controlled concentrations of atmospheric pCO2 (180 ppm, 410 ppm, 1000 ppm, 1500 ppm). Our results demonstrated that pH did not influence the survival and growth of the three species. However, low DIC conditions (879 μmol kg−1) negatively affected B. marginata and C. laevigata through reduced growth, whereas no effect was observed for Ammonia T6. Our results also showed that Sr/Ca was positively correlated with total Alkalinity (TA), DIC and bicarbonate ion concentration ([HCO3−]) for Ammonia T6 and B. marginata; i.e., DIC and/or [HCO3−] were the main controlling factors. For these two species, the regression models were coherent with published data (existing so far only for Ammonia T6) and showed overall similar slopes but different intercepts, implying species-specific effects. Furthermore, the Sr/Ca - C-system relationship was not impacted by ontogenetic trends between chamber stages, which is a considerable advantage for paleo-applications. This applied particularly to Ammonia T6 that calcified many chambers compared to the two other species. However, no correlation with any of the C-system parameters was observed for Sr/Ca in C. laevigata. This might imply either a strong species-specific effect and/or a low tolerance to laboratory conditions leading to a physiological stress, thereby impacting the Sr incorporation into the calcite lattice of C. laevigata.
Auteurs, date et publication :
Auteurs M. Mojtahid , P. Depuydt , A. Mouret , S. Le Houedec , S. Fiorini , S. Chollet , F. Massol , F. Dohou , H. L. Filipsson , W. Boer , G. -J. Reichart , C. Barras
Publication : Chemical Geology
Date : 2023
Pages : 121396
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
Geometric morphometry has evolved as a powerful tool to unravel species delimitations within the genus Aristolochia. A survey conducted on the variation of Aristolochia trilabiata flowers and leaves revealed an overlooked entity in its affinity, which is newly described herein as Aristolochia franzii. The new species differs from its relative A. trilabiata by various floral characters, notably the presence of papillae on both the upper and lower limb zones, the presence of a well defined medial upper limb zone, the number of veins on the lateral upper limb zone, a considerably shorter tube, and the relative position of upper and lower limb zones. Furthermore, the leaf shape of A. franzii is cordiform-elongate to hastate, compared to the consistently more compact and shorter cordiform leaves of A. trilabiata. So far, A. franzii has been recorded from Northern Brazil (Amazonas) and French Guiana. An illustration of the diagnostic characters and comparison with A. trilabiata is provided, as well as the geographic distribution and a preliminary assessment of the conservation status.
Auteurs, date et publication :
Auteurs Dominik Frank
Publication : Brittonia
Date : 2025
Volume : 75
Issue : 4
Pages : 358-368
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Territoriality has been widely described across many animal taxa, where the acquisition and defence of a territory are critical for the fitness of an individual. Extensive evidence suggests that androgens are involved in the modulation of territorial behaviours in male vertebrates. Short-term increase of androgen following a territorial encounter appears to favour the outcome of a challenge. The “Challenge Hypothesis” proposed by Wingfield and colleagues outlines the existence of a positive feedback relationship between androgen and social challenges (e.g., territorial intrusions) in male vertebrates. Here we tested the challenge hypothesis in the highly territorial poison frog, Allobates femoralis, in its natural habitat by exposing males to simulated territorial intrusions in the form of acoustic playbacks. We quantified repeatedly androgen concentrations of individual males via a non-invasive water-borne sampling approach. Our results show that A. femoralis males exhibited a positive behavioural and androgenic response after being confronted to simulated territorial intrusions, providing support for the Challenge Hypothesis in a territorial frog.
Auteurs, date et publication :
Auteurs Camilo Rodríguez , Leonida Fusani , Gaëlle Raboisson , Walter Hödl , Eva Ringler , Virginie Canoine
Publication : General and Comparative Endocrinology
Date : 2022
Volume : 326
Pages : 114046
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Contribution of the collections of the Muséum national d’Histoire naturelle and Didier Morin to the knowledge of the Batrachideinae and Lophotettiginae (Orthoptera, Tetrigidae) of French Guiana. Two important collections of Tetrigidae Rambur, 1838 containing more than 1000 individuals from French Guiana were consulted and revised in order to complete the knowledge of this group in this area. Given the large number of specimens to be treated, the analyses focussed in a first time on two subfamilies, Batrachideinae Bolívar, 1887 and Lophotettiginae Hancock, 1909, representing 489 individuals of which 456 were identified to species level. The results show the presence of 14 taxa, of which 11 are new to the department and four are new to science and described in this article: Paurotarsus pennatulus n. sp., Scaria guyanensis Doucet & Itrac-Bruneau, n. sp., Scaria macromaculata Doucet & Itrac-Bruneau, n. sp. and Scaria madeleinae n. sp. In addition, the female of Phelene maroon Cadena-Castañeda & Tumbrinck, 2021 and the male of Tettigidea pulchella Rehn, 1904, unknown until now, are described thanks to this material. As a result of these numerous contributions, a new identification key for the two studied subfamilies is proposed.
Auteurs, date et publication :
Auteurs Raphaëlle Itrac-Bruneau , Guillaume Doucet
Publication : Zoosystema
Date : 2023
Volume : 45
Issue : 20
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Forest dynamic models predict the current and future states of ecosystems and are a nexus between physiological processes and empirical data, forest plot inventories and remote-sensing information. The problem of biodiversity representation in these models has long been an impediment to a detailed understanding of ecosystem processes. This challenge is amplified in species-rich and high-carbon tropical forests. Here we describe an individual-based and spatially explicit forest growth simulator, TROLL, that integrates recent advances in plant physiology. Processes (carbon assimilation, allocation, reproduction, and mortality) are linked to species-specific functional traits, and the model was parameterized for an Amazonian tropical rainforest. We simulated a forest regeneration experiment from bare soil, and we validated it against observations at our sites. Simulated forest regeneration compared well with observations for stem densities, gross primary productivity, aboveground biomass, and floristic composition. After 500years of regrowth, the simulated forest displayed structural characteristics similar to observations (e.g., leaf area index and trunk diameter distribution). We then assessed the model's sensitivity to a number of key model parameters: light extinction coefficient and carbon quantum yield, and to a lesser extent mortality rate, and carbon allocation, all influenced ecosystem features. To illustrate the potential of the approach, we tested whether variation in species richness and composition influenced ecosystem properties. Overall, species richness had a positive effect on ecosystem processes, but this effect was controlled by the identity of species rather by richness per se. Also, functional trait community means had a stronger effect than functional diversity on ecosystem processes. TROLL should be applicable to many tropical forests sites, and data requirement is tailored to ongoing trait collection efforts. Such a model should foster the dialogue between ecology and the vegetation modeling community, help improve the predictive power of models, and eventually better inform policy choices.
Auteurs, date et publication :
Auteurs Isabelle Marechaux , Jerome Chave
Publication : ECOLOGICAL MONOGRAPHS
Date : 2017
Volume : 87
Issue : 4
Pages : 632-664
Catégorie(s)
#ANR-Citation #CIRAD #CNRS #FORET NouraguesRésumé
Baseline error correction is critical for airborne SAR tomography as the actual flight trajectory often deviates from the designed one due to turbulence, which may lead to large sidelobes or even complete defocusing in the tomograms. Current baseline error correction methods, however, are susceptible to heavy decorrelation noise. To mitigate the adverse effect of decorrelation noise, in this paper, a novel method for airborne SAR tomography baseline errors correction driven by small baseline interferometric phase is proposed. In this method, a novel mathematical model that relates interferometric phase to the baseline error differences is first derived, then a small baseline interferometric pairs selection strategy is employed to estimate the baseline error differences through an alternate iterative algorithm, and finally the baseline errors are obtained through accumulating summation of the baseline error differences. The use of small baseline interferograms can avoid the phase linking processing and thereby greatly alleviate the heavy decorrelation effect. Both simulated and real airborne P-band SAR tomography experiments have demonstrated that the proposed method can achieve more accurate and robust estimation of baseline errors and is more tolerant to decorrelation noise than the well-known phase center double localization (PCDL) method.
Auteurs, date et publication :
Auteurs Guobing Zeng , Huaping Xu , Wei Liu , Aifang Liu , Yuan Wang
Publication : IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date : 2025
Volume : 16
Pages : 10007-10021
Catégorie(s)
#CNRS #FORET NouraguesRésumé
The intensification of summer drought expected with climate change can induce metabolism modifications in plants to face such constraints. In this experiment, we used both a targeted approach focused on flavonoids, as well as an untargeted approach, to study a broader fraction of the leaf metabolome of Quercus pubescens exposed to amplified drought. A forest site equipped with a rainfall exclusion device allowed reduction of natural rainfall by ~30% over the tree canopy. Leaves of natural drought (ND) and amplified drought (AD) plots were collected over three seasonal cycles (spring, summer, and autumn) in 2013 (the second year of rain exclusion), 2014, and 2015. As expected, Q. pubescens metabolome followed a seasonal course. In the summer of 2015, the leaf metabolome presented a shifted and early autumnal pattern because of harsher conditions during this year. Despite low metabolic modification at the global scale, our results demonstrated that 75% of Quercus metabolites were upregulated in springs when trees were exposed to AD, whereas 60 to 73% of metabolites (93% in summer 2015), such as kaempferols and quercetins, were downregulated in summers/autumns. Juglanin, a kaempferol pentoside, as well as rhododendrin derivatives, were upregulated throughout the year, suggesting an antioxidant ability of these metabolites. Those changes in terms of phenology and leaf chemistry could, in the end, affect the ecosystem functioning.
Auteurs, date et publication :
Auteurs Amélie Saunier , Stéphane Greff , James D. Blande , Caroline Lecareux , Virginie Baldy , Catherine Fernandez , Elena Ormeño
Publication : Metabolites
Date : 2022
Volume : 12
Issue : 4
Pages : 307
Catégorie(s)
#CNRS #FORET O3HPRésumé
Threadsnakes are known for their conserved external morphology and historically controversial systematics, challenging taxonomic, biogeographic and evolutionary researches in these fields. Recent morphological studies—mostly based on µCT data of the skull and lower jaw—have resolved systematic issues within the group, for instance leading to the description of new taxa or re-positioning little-known scolecophidian taxa in the tree of life. Herein we describe a new polymorphic species of the genus Siagonodon from Amazonia based on morphological (external, osteology and hemipenis) and molecular data, and provide the first hemipenial description for the genus. We also reassign Siagonodon acutirostris to the genus Trilepida based on osteological data in combination with molecular evidence. The new species described represents an evolutionary paradox for scolecophidians because the species displays a remarkable variation in the shape of the snout region that is otherwise always highly conserved in this clade. Finally, this study reinforces the importance of protected areas as essential in maintaining vertebrate populations, including those that are not yet formally described.
Auteurs, date et publication :
Auteurs Angele Martins , Manuella Folly , Guilherme Nunes Ferreira , Antônio Samuel Garcia Da Silva , Claudia Koch , Antoine Fouquet , Alessandra Machado , Ricardo Tadeu Lopes , Roberta Pinto , Miguel Trefaut Rodrigues , Paulo Passos
Publication : Vertebrate Zoology
Date : 2023
Volume : 73
Pages : 345-366
Catégorie(s)
#CNRS #FORET NouraguesRésumé
In Mediterranean ecosystems, the projected rainfall reduction of up to 30% may alter plant–soil interactions, particularly litter decomposition and Home Field Advantage (HFA). We set up a litter transplant experiment in the three main forests encountered in the northern part of the Medi-terranean Basin (dominated by either Quercus ilex, Quercus pubescens, or Pinus halepensis) equipped with a rain exclusion device, allowing an increase in drought either throughout the year or concentrated in spring and summer. Senescent leaves and needles were collected under two precipitation treatments (natural and amplified drought plots) at their “home” forest and were left to decompose in the forest of origin and in other forests under both drought conditions. MS-based metabolomic analysis of litter extracts combined with multivariate data analysis enabled us to detect modifications in the composition of litter specialized metabolites, following amplified drought treatment. Amplified drought altered litter quality and metabolomes, directly slowed down litter decomposition, and induced a loss of home field (dis)advantage. No indirect effect mediated by a change in litter quality on decomposition was observed. These results may suggest major alterations of plant–soil interactions in Mediterranean forests under amplified drought conditions.
Auteurs, date et publication :
Auteurs Elodie Quer , Susana Pereira , Thomas Michel , Mathieu Santonja , Thierry Gauquelin , Guillaume Simioni , Jean-Marc Ourcival , Richard Joffre , Jean-Marc Limousin , Adriane Aupic-Samain , Caroline Lecareux , Sylvie Dupouyet , Jean-Philippe Orts , Anne Bousquet-Mélou , Raphaël Gros , Marketa Sagova-Mareckova , Jan Kopecky , Catherine Fernandez , Virginie Baldy
Publication : Plants
Date : 2025
Volume : 11
Issue : 19
Pages : 2582