Résumé
Reconstructions of evolutionary and historical biogeographic processes can improve our understanding of how species assemblages developed and permit inference of ecological drivers affecting coexistence. We explore this approach in Austrolebias, a genus of annual fishes possessing a wide range of body sizes. Regional assemblages composed of different species with similar size distributions are found in four areas of eastern South America. Using phylogenetic trees, species distribution models and size data we show how trait evolution and historical biogeography have affected the composition of species assemblages. We extend age-range correlations to improve estimates of local historical biogeography. We find that size variation principally arose in a single area and infer that ecological interactions drove size divergence. This large-size lineage spread to two other areas. One of these assemblages was likely shaped by adaptation to a new environment, but this was not associated with additional size divergence. We found only weak evidence that environmental filtering has been important in the construction of the remaining assemblage with the smallest range of sizes. The repeated assemblage structures were the result of different evolutionary and historical processes. Our approach sheds light on how species assemblages were built when typical clustering approaches may fall short.
Auteurs, date et publication :
Auteurs Andrew J. Helmstetter , Tom J. M. Van Dooren , Alexander S. T. Papadopulos , Javier Igea , Armand M. Leroi , Vincent Savolainen
Publication : bioRxiv
Date : 2018
Pages : 436808
Catégorie(s)
#CNRS #ENS #PLANAQUARésumé
Glioblastoma (GB) is a highly invasive primary brain tumor that nearly always systematically recurs at the site of resection despite aggressive radio-chemotherapy. Previously, we reported a gene expression signature related to tumor infiltration. Within this signature, the EMX2 gene encodes a homeodomain transcription factor that we found was down regulated in glioblastoma. As EMX2 is reported to play a role in carcinogenesis, we investigated the impact of EMX2 overexpression in glioma-related cell lines.
Auteurs, date et publication :
Auteurs Annabelle Monnier , Rachel Boniface , Régis Bouvet , Amandine Etcheverry , Marc Aubry , Tony Avril , Véronique Quillien , Eric Chevet , Jean Mosser
Publication : BMC Cancer
Date : 2018
Volume : 18
Issue : 1
Pages : 1213
Catégorie(s)
#CNRS #EcoGenO #Université de RennesAuteurs, date et publication :
Auteurs Emily R Naylor , Timothy E Higham
Publication : Integrative and comparative biology
Date : 2025
Volume : 59
Issue : 1
Pages : 168-181
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Gustavo Graciolli , Ricardo Guerrero , Francois Catzeflis
Publication : Biota Neotropica
Date : 2025
Volume : 19
Issue : 4
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, 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 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 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 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