Résumé
Tropical rainforests host exceptional biodiversity and provide important ecosystem services, but they are facing anthropogenic and climatic threats. Preserving the genetic diversity of forest tree populations is essential for their capacity to adapt and exhibit resilience to environmental changes and anthropogenic pressures. Here, we collected conservation genetic baseline information for the heavily exploited timber tree Dicorynia guianensis Amshoff (Fabaceae) at the regional and local levels in French Guiana. Based on genotyping at five microsatellite loci in 1566 individuals collected in 23 forest locations, we documented the genetic differentiation of locations from the West of French Guiana and identified distinctive genetic diversity patterns with higher genetic diversity and some bottlenecked sites in the East and inland. The regional population genetic structure is likely the result of past population isolation in distinct Pleistocene refuges and different demographic histories potentially influenced by Holocene drought periods or palaeofires. Assessment of spatial genetic structure (Sp from 0 to 0.028) in five intensively sampled locations yielded estimates of Wright’s neighborhood size of 35 to 313, indicative of restricted dispersal and local metapopulation dynamics, and useful as baseline information to assess the effects of selective logging for conservation management. These results support the current management strategies with low impact extraction of D. guianensis in three zones of the French Guiana permanent forest domain and allow us to make recommendations for further research and management to best preserve its genetic diversity and adaptive potential.
Auteurs, date et publication :
Auteurs Julien Bonnier , Niklas Tysklind , Valérie Troispoux , Ivan Scotti , Stéphanie Barthe , Olivier Brunaux , Stéphane Guitet , Stéphane Traissac , Myriam Heuertz
Publication : Tree Genetics & Genomes
Date : 2025
Volume : 20
Issue : 1
Pages : 2
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
* Sex-biased dispersal, that is, the difference in dispersal between males and females, is thought to be the consequence of any divergent evolutionary responses between sexes. In anisogamous species, asymmetry in parental investment may lead to sexual conflict, which entails male–male competition (for sexual partner access), female–female competition (for feeding or egg-laying habitat patches) and/or male–female competition (antagonistic co-evolution). * As competition is one of the main causes of dispersal evolution, intra- and intersexual competition should have strong consequences on sex-biased dispersal. However, very few experimental studies, if any, have simultaneously addressed the effect of biased sex ratio on (i) each dispersal stage (emigration, transience, immigration), (ii) the dispersal phenotype and (iii) the colonization success of new habitat in order to fully separate the effects of varying male and female density. * Here, we used the Metatron, a unique experimental system composed of 48 interconnected enclosed patches dedicated to the study of dispersal in meta-ecosystems, to investigate the effect of sex ratio on dispersal in a butterfly. We created six populations with three different sex ratios in pairs of patches and recorded individual movements in these simple metapopulations. * Emigration was higher when the proportion of males was higher, and individuals reached the empty patch at a higher rate when the sex ratio in the departure patch was balanced. Males had a better dispersal success than females, which had a lower survival rate during dispersal and after colonization. We also showed that sex and wing size are major components of the dispersal response. * We did not observe sex-biased dispersal; our results thus suggest that female harassment by males and male–male competition might be more important mechanisms for the dispersal of females and males, than the search for a mating partner. Furthermore, the demonstration of a differential mortality between males and females during dispersal provides causal hypotheses of the evolution of sex-biased dispersal.
Auteurs, date et publication :
Auteurs Audrey Trochet , Delphine Legrand , Nicolas Larranaga , Simon Ducatez , Olivier Calvez , Julien Cote , Jean Clobert , Michel Baguette
Publication : Journal of Animal Ecology
Date : 2025
Volume : 82
Issue : 5
Pages : 946-955
Catégorie(s)
#CNRS #Metatron terrestreAuteurs, date et publication :
Auteurs Max Ringler , Walter Hödl , Eva Ringler
Publication : Behavioral Ecology
Date : 2025
Volume : 26
Issue : 2
Pages : 340-349
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous persistent organic pollutants that accumulate in soils because of their high affinity for soil organic matter (SOM). As these pollutants are toxic to humans and the environment, a better understanding of their fate in the environment is required. This study aimed to assess the PAH distribution within soils according to different soil fractions: the free particulate organic matter (fPOM), the occluded particulate organic matter (oPOM) and the mineral-associated organic matter (MaOM). PAH contents were measured in bulk soils and SOM fractions of alpine soils along an elevation gradient in the French Alps (Lautaret) from 1920 m to 2840 m a.s.l. A specific PAH distribution was identified, with highest PAH contents in the oPOM, followed by the fPOM, then the MaOM. Organic matter (OM) contents of each fraction can partly explain this distribution, but results of nuclear magnetic resonance (NMR) spectroscopy on fPOM and oPOM also highlighted a correlation between the PAH contents and the degree of decomposition of SOM. This indicates that the PAH distribution may be linked to the formation and transformation of fractions: (i) PAHs in the fPOM correspond to relatively recent deposits and mainly reflect the background contamination, (ii) in the oPOM are the PAHs that resist biodegradation during the transformation of fPOM into oPOM and accumulate in the oPOM; this accumulation may be further enhanced by the formation of aggregates. Finally, (iii) in the MaOM, the lower PAH contents can be explained by the different formation pathway of this fraction and its high degree of decomposition. As the PAH distribution may have an impact on their dynamics in soils, it should be taken into consideration in future research.
Auteurs, date et publication :
Auteurs Lise Marchal , Noelia Garcia-Franco , David Gateuille , Luis Carlos Colocho Hurtarte , Christopher Just , Emmanuel Naffrechoux , Martin Wiesmeier , Jérôme Poulenard
Publication : European Journal of Soil Science
Date : 2026
Volume : 76
Issue : 1
Pages : e70059
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Many species of Neotropical frogs have evolved to deposit their tadpoles in small water bodies inside plant structures called phytotelmata. These pools are small enough to exclude large predators but have limited nutrients and high desiccation risk. Here, we explore phytotelm use by three common Neotropical species: Osteocephalus oophagus, an arboreal frog that periodically feeds eggs to its tadpoles; Dendrobates tinctorius, a tadpole-transporting poison frog with cannibalistic tadpoles; and Allobates femoralis, a terrestrial tadpole-transporting poison frog with omnivorous tadpoles. We found that D. tinctorius occupies pools across the chemical and vertical gradient, whereas A. femoralis and O. oophagus appear to have narrower deposition options that are restricted primarily by pool height, water capacity, alkalinity, and salinity. Dendrobates tinctorius tadpoles are particularly flexible and can survive in a wide range of chemical, physical, and biological conditions, whereas O. oophagus seems to prefer small, clear pools and A. femoralis occupies medium-sized pools with abundant leaf litter and low salinity. Together, these results show the possible niche partitioning of phytotelmata among frogs and provide insight into stressors and resilience of phytotelm breeders.
Auteurs, date et publication :
Auteurs Chloe A. Fouilloux , Shirley Jennifer Serrano-Rojas , Juan David Carvajal-Castro , Janne K. Valkonen , Philippe Gaucher , Marie-Therese Fischer , Andrius Pasukonis , Bibiana Rojas
Publication : ECOLOGY AND EVOLUTION
Date : 2021
Volume : 11
Issue : 13
Pages : 9021-9038
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
Abstract Aim To determine the interplay between climate and land use changes in driving population dynamics in a butterfly species, Coenonympha hero, at the southern limit of its distribution. Location French Jura massif and Europe. Methods We analysed patterns of genetic diversity distribution at 817 loci in 136 butterflies from 31 sites using NGS to infer the genetic structure and population size changes over time, using two methods of demographic inference (SNP frequency spectrum analyses and coalescent ABC inferences). We then characterized the climate and land use descriptors of C. hero geographic distribution using species distribution modelling (SDM) and ordination method and compared demographic changes to changes in climatically suitable areas. Results Coenonympha hero persists in the Jura massif as three core populations that share a common history of decline in two steps: an old decline and a more recent decline that resulted in population fragmentation, the southernmost sites being the most threatened (lowest genetic diversity). Climate change during the Würm glaciation is presumably the main factor explaining the first demographic decline. The second decline started 2000 years ago possibly under increased human pressure as suggested by recent extinctions in several sites nowadays characterized by urban and agricultural surfaces. Both climate and land use variables are important descriptors of C. hero distribution, as SDM predictions were improved by adding aridity index, altitude and land use to bioclimatic predictors. Its habitats include forests in north-eastern Europe and grasslands in the Jura massif. Main conclusions Using SDM and genetic demographic inferences, we identified a persistent glacial refuge for the species in Europe. We show that although this relictual population has declined and fragmented under the combined effects of climate warming and anthropization, the metapopulation is still functional but requires particular conservation attention to maintain its connectivity, and to favour the local persistence of this highly endangered butterfly species.
Auteurs, date et publication :
Auteurs Stéphanie Sherpa , Caroline Kebaïli , Delphine Rioux , Maya Guéguen , Julien Renaud , Laurence Després
Publication : Diversity and Distributions
Date : 2025
Volume : 28
Issue : 2
Pages : 271–290
Catégorie(s)
#CNRS #eDNAAuteurs, date et publication :
Auteurs Marc Gibernau , Vignola–Route des Sanguinaires
Publication : Aroideana
Date : 2025
Volume : 38
Issue : EN2
Pages : 38-66
Catégorie(s)
#⛔ No DOI found #CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs B Vlasáková , J Pinc , F Jůna , Z Kotyková Varadínová
Publication : Plant Biology
Date : 2025
Volume : 21
Issue : 4
Pages : 753-761
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Katerina Dontsova , Zsuzsanna Balogh-Brunstad , Jon chorover
Date : 2020
Pages : 33-58
Catégorie(s)
#ANR-Citation #CNRS #Ecotron IleDeFrance #ENSRésumé
Facing warming environments, species can exhibit plastic or microevolutionary changes in their thermal physiology to adapt to novel climates. Here, using semi-natural mesocosms, we experimentally investigated over two successive years whether a 2°C-warmer climate produces selective and inter- and intragenerational plastic changes in the thermal traits (preferred temperature and dorsal coloration) of the lizard Zootoca vivipara. In a warmer climate, the dorsal darkness, dorsal contrast, and preferred temperature of adults plastically decreased and covariances between these traits were disrupted. While selection gradients were overall weak, selection gradients for darkness were slightly different between climates and in the opposite direction to plastic changes. Contrary to adults, male juveniles were darker in warmer climates either through plasticity or selection and this effect was strengthened by intergenerational plasticity when juveniles’ mothers also experienced warmer climates. While the plastic changes in adult thermal traits alleviate the immediate overheating costs of warming, its opposite direction to selective gradients and to juveniles’ phenotypic responses may slow down evolutionary shifts toward phenotypes that are better adapted to future climates. Our study demonstrates the importance of considering inter- and intragenerational plasticity along with selective processes to better understand adaptation and population dynamics in light of climate change.
Auteurs, date et publication :
Auteurs Elvire Bestion , Luis M San-Jose , Lucie Di Gesu , Murielle Richard , Barry Sinervo , Jessica Côte , Olivier Calvez , Olivier Guillaume , Julien Cote
Publication : Evolution
Date : 2023
Volume : 77
Issue : 7
Pages : 1634-1646