Résumé
This contribution focuses on scientific mediation implemented within scientific tourism initiatives in mountain areas. Three case studies in the French Alps support this research: the Jardin Alpin du Lautaret of the University of Grenoble Alpes, the CREA Mont-Blanc, a private research center organizing participatory science and student travel abroad programs and the scientific hut to hut trekking routes in the Écrins National Park, organized jointly with a scientific research project (Labex ITEM, Reflab). Scientific tourism and mediation are first defined. Next, a quantitative and qualitative approach (with interviews and participant observations) allows us to understand the impact and role of scientific mediation within tourism. Results show a high level of interest of the issue within involved publics and a close connection between experience and knowledge. It appears that it is also a tool for public awareness of the challenges of our modern societies.
Auteurs, date et publication :
Auteurs Yannick Vialette , Pascal Mao , Fabien Bourlon
Publication : Journal of Alpine Research | Revue de géographie alpine
Date : 2021
Issue : 109-2
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Increasing temperature and drought can result in leaf dehydration and defoliation even in drought-adapted tree species such as the Mediterranean evergreen Quercus ilex L. The stomatal regulation of leaf water potential plays a central role in avoiding this phenomenon and is constrained by a suite of leaf traits including hydraulic conductance and vulnerability, hydraulic capacitance, minimum conductance to water vapour, osmotic potential and cell wall elasticity. We investigated whether the plasticity in these traits may improve leaf tolerance to drought in two long-term rainfall exclusion experiments in Mediterranean forests. Osmotic adjustment was observed to lower the water potential at turgor loss in the rainfall-exclusion treatments, thus suggesting a stomatal closure at more negative water potentials and a more anisohydric behaviour in drier conditions. Conversely, leaf hydraulic conductance and vulnerability did not exhibit any plasticity between treatments so the hydraulic safety margins were narrower in the rainfall-exclusion treatments. The sequence of leaf responses to seasonal drought and dehydration was conserved among treatments and sites but trees were more likely to suffer losses of turgor and hydraulic functioning in the rainfall-exclusion treatments. We conclude that leaf plasticity might help the trees to tolerate moderate drought but not to resist severe water stress.
Auteurs, date et publication :
Auteurs Jean-Marc Limousin , Amélie Roussel , Jesús Rodríguez-Calcerrada , José M. Torres-Ruiz , Myriam Moreno , Laura Garcia de Jalon , Jean-Marc Ourcival , Guillaume Simioni , Hervé Cochard , Nicolas Martin-StPaul
Publication : Plant, Cell & Environment
Date : 2025
Volume : 45
Issue : 7
Pages : 1967-1984
Catégorie(s)
#CNRS #FORET PuechabonRésumé
The outstanding diversity of Amazonian forests is predicted to be the result of several processes. While tree lineages have dispersed repeatedly across the Amazon, interactions between plants and insects may be the principal mechanism structuring the communities at local scales. Using metabolomic and phylogenetic approaches, we investigated the patterns of historical assembly of plant communities across the Amazon based on the Neotropical genus of trees Inga (Leguminosae) at four, widely separated sites. Our results show a low degree of phylogenetic structure and a mixing of chemotypes across the whole Amazon basin, suggesting that although biogeography may play a role, the metacommunity for any local community in the Amazon is the entire basin. Yet, local communities are assembled by ecological processes, with the suite of Inga at a given site more divergent in chemical defences than expected by chance Synthesis. To our knowledge, this is the first study to present metabolomic data for nearly 100 species in a diverse Neotropical plant clade across the whole Amazonia. Our results demonstrate a role for plant–herbivore interactions in shaping the clade's community assembly at a local scale, and suggest that the high alpha diversity in Amazonian tree communities must be due in part to the interactions of diverse tree lineages with their natural enemies providing a high number of niche dimensions.
Auteurs, date et publication :
Auteurs María-José Endara , Abrianna J. Soule , Dale L. Forrister , Kyle G. Dexter , R. Toby Pennington , James A. Nicholls , Oriane Loiseau , Thomas A. Kursar , Phyllis D. Coley
Publication : Journal of Ecology
Date : 2025
Volume : 110
Issue : 1
Pages : 34-45
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Relationships between tree size and water use indicate how soil water is partitioned between differently sized individuals, and hence competition for water. These relationships are rarely examined, let alone whether there is consistency in shape across populations. Competition for water among plants is often assumed to be size-symmetric, i.e., exponents (b1) of power functions (water use ∝ biomassb1) equal to 1, with all sizes using the same amount of water proportionally to their size. We tested the hypothesis that b1 actually varies greatly, and based on allometric theory, that b1 is only centered around 1 when size is quantified as basal area or sapwood area (not diameter). We also examined whether b1 varies spatially and temporally in relation to stand structure (height and density) and climate. Tree water use ∝ sizeb1 power functions were fitted for 80 species and 103 sites using the global SAPFLUXNET database. The b1 were centered around 1 when tree size was given as basal area or sapwood area, but not as diameter. The 95% confidence intervals of b1 included the theoretical predictions for the scaling of plant vascular networks. b1 changed through time within a given stand for the species with the longest time series, such that larger trees gained an advantage during warmer and wetter conditions. Spatial comparisons across the entire dataset showed that b1 correlated only weakly (R2 < 12%) with stand structure or climate, suggesting that inter-specific variability in b1 and hence the symmetry of competition for water may be largely related to inter-specific differences in tree architecture or physiology rather than to climate or stand structure. In conclusion, size-symmetric competition for water (b1 ≈ 1) may only be assumed when size is quantified as basal area or sapwood area, and when describing a general pattern across forest types and species. There is substantial deviation in b1 between individual stands and species.
Auteurs, date et publication :
Auteurs David I Forrester , Jean-Marc Limousin , Sebastian Pfautsch
Publication : Tree Physiology
Date : 2025
Volume : 42
Issue : 10
Pages : 1916-1927
Catégorie(s)
#CNRS #FORET PuechabonRésumé
Aim Although soil biodiversity is extremely rich and spatially variable, both in terms of species and trophic groups, we still know little about its main drivers. Here, we contrast four long-standing hypotheses to explain the spatial variation of soil multi-trophic diversity: energy, physiological tolerance, habitat heterogeneity and resource heterogeneity. Location French Alps. Methods We built on a large-scale observatory across the French Alps (Orchamp) made of seventeen elevational gradients ( 90 plots) ranging from low to very high altitude (280–3,160 m), and encompassing large variations in climate, vegetation and pedological conditions. Biodiversity measurements of 36 soil trophic groups were obtained through environmental DNA metabarcoding. Using a machine learning approach, we assessed (1) the relative importance of predictors linked to different ecological hypotheses in explaining overall multi-trophic soil biodiversity and (2) the consistency of the response curves across trophic groups. Results We showed that predictors associated with the four hypotheses had a statistically significant influence on soil multi-trophic diversity, with the strongest support for the energy and physiological tolerance hypotheses. Physiological tolerance explained spatial variation in soil diversity consistently across trophic groups, and was an especially strong predictor for bacteria, protists and microfauna. The effect of energy was more group-specific, with energy input through soil organic matter strongly affecting groups related to the detritus channel. Habitat and resource heterogeneity had overall weaker and more specific impacts on biodiversity with habitat heterogeneity affecting mostly autotrophs, and resource heterogeneity affecting bacterivores, phytophagous insects, enchytraeids and saprotrophic fungi. Main Conclusions Despite the variability of responses to the environmental drivers found across soil trophic groups, major commonalities on the ecological processes structuring soil biodiversity emerged. We conclude that among the major ecological hypotheses traditionally applied to aboveground organisms, some are particularly relevant to predict the spatial variation in soil biodiversity across the major soil trophic groups.
Auteurs, date et publication :
Auteurs Irene Calderón-Sanou , Lucie Zinger , Mickael Hedde , Camille Martinez-Almoyna , Amelie Saillard , Julien Renaud , Ludovic Gielly , Norine Khedim , Clement Lionnet , Marc Ohlmann , Orchamp Consortium , Tamara Münkemüller , Wilfried Thuiller
Publication : Diversity and Distributions
Date : 2025
Volume : 28
Issue : 12
Pages : 2549-2564
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Intraspecific competition at the larval stage is an important ecological factor affecting life-history, adaptation and evolutionary trajectory in holometabolous insects. However, the molecular pathways underpinning these ecological processes are poorly characterized. We reared Drosophila melanogaster at three egg densities (5, 60, and 300 eggs/mL) and sequenced the transcriptomes of pooled third-instar larvae. We also examined emergence time, egg-to-adult viability, adult mass, and adult sex-ratio at each density. Medium crowding had minor detrimental effects on adult phenotypes compared to low density and yielded 24 differentially expressed genes (DEGs), including several chitinase enzymes. In contrast, high crowding had substantial detrimental effects on adult phenotypes and yielded 2107 DEGs. Among these, upregulated gene sets were enriched in sugar, steroid and amino acid metabolism as well as DNA replication pathways, whereas downregulated gene sets were enriched in ABC transporters, taurine, Toll/Imd signaling, and P450 xenobiotics metabolism pathways. Overall, our findings show that larval crowding has a large consistent effect on several molecular pathways (i.e., core responses) with few pathways displaying density-specific regulation (i.e., idiosyncratic responses). This provides important insights into how holometabolous insects respond to intraspecific competition during development.
Auteurs, date et publication :
Auteurs Juliano Morimoto , Marius Wenzel , Davina Derous , Youn Henry , Herve Colinet
Publication : Insect Science
Date : 2025
Volume : n/a
Issue : n/a
Catégorie(s)
#CNRS #EcoGenO #Université de RennesRésumé
Ecological interactions are being affected at unprecedented rates by human activities in tropical forests. Yet, the continuity of ecological functions provided by animals, such as seed dispersal, is crucial for forest regeneration and species resilience to anthropogenic pressures. The construction of new roads in tropical forests is one of the main boosters of habitat destruction as it facilitates human access to previously isolated areas and increases defaunation and loss of ecological functions. It, therefore, becomes increasingly urgent to rapidly assess how recently opened roads and associated anthropogenic activities affect ecological processes in natural habitats, so that appropriate management measures to conserve diversity can be taken. In this study, we aimed to evaluate the effects of anthropogenic pressures on the health status of a mature rainforest crossed by a newly opened road in French Guiana. For this, we combined different methods to conduct a rapid assessment of the forest’s health status. Firstly, we evaluated the activity of frugivores using camera traps deployed in four forest patches located near (<1 km) ecological corridors preserved as canopy bridges over the road during the fruiting periods of four animal-dispersed tree species. Secondly, we analyzed the fate of seeds enclosed in animal-dispersed tropical fruits by calculating the proportions of fruits consumed and seeds removed (either dispersed or predated) by frugivores. Results show that the proportion of fruits opened and consumed was lower in the forest areas located near the road than in the control forest, and this difference was more significant for plant species strictly dependent on large-bodied primates for seed dispersal than for species relying on both primates and birds. Camera traps showed the presence of small primates and kinkajous feeding on Virola fruits in the forest impacted by the road, where large primates were absent. It is thus likely that smaller frugivores exert a compensatory effect that maintains ecological functions near the road. Despite efforts made to preserve forest continuity through ecological corridors, anthropogenic pressures associated with road proximity are affecting wildlife and disrupting associated ecological functions crucial for plant regeneration, contributing to further forest degradation.
Auteurs, date et publication :
Auteurs Opale Coutant , Olivier Boissier , Manon Ducrettet , Aurélie Albert-Daviaud , Axelle Bouiges , Caroline Marques Dracxler , François Feer , Irene Mendoza , Eric Guilbert , Pierre-Michel Forget
Publication : Frontiers in Ecology and Evolution
Date : 2025
Volume : 10
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Current theory predicts that the intensity of biotic interactions, particularly herbivory, decreases with increasing latitude and elevation. However, recent studies have revealed substantial variation in both the latitudinal and elevational patterns of herbivory. This variation is often attributed to differences in study design and the type of data collected by different researchers. Here, we used a similar sampling protocol along elevational gradients in six mountain ranges, located at different latitudes within temperate Eurasia, to uncover the sources of variation in elevational patterns in insect herbivory on woody plant leaves. We discovered a considerable variation in elevational patterns among different mountain ranges; nevertheless, herbivory generally decreased with increasing elevation at both the community-wide and individual plant species levels. This decrease was mostly due to openly living defoliators, whereas no significant association was detected between herbivory and elevation among insects living within plant tissues (i.e., miners and gallers). The elevational decrease in herbivory was significant for deciduous plants but not for evergreen plants, and for tall plants but not for low-stature plants. The community-wide herbivory increased with increases in both specific leaf area and leaf size. The strength of the negative correlation between herbivory and elevation increased from lower to higher latitudes. We conclude that despite the predicted overall decrease with elevation, elevational gradients in herbivory demonstrate considerable variation, and this variation is mostly associated with herbivore feeding habits, some plant traits, and latitude of the mountain range.
Auteurs, date et publication :
Auteurs Mikhail V. Kozlov , Vitali Zverev , Elena L. Zvereva
Publication : Ecology and Evolution
Date : 2025
Volume : 12
Issue : 11
Pages : e9468
Catégorie(s)
#CNRS #Lautaret #UGARésumé
We here establish a new genus in the nymphalid butterfly subtribe Euptychiina, Cisandina Nakahara & Espeland, n. gen. to harbor five species hitherto placed within two polyphyletic genera, namely Magneuptychia Forster, 1964 and Euptychoides Forster, 1964. We compiled data from over 350 specimens in 17 public and private collections, as well as DNA sequence data for all relevant species, to revise the species-level classification of this new genus. According to our multi-locus molecular phylogeny estimated with the maximum likelihood approach, Cisandina lea n. comb., Cisandina philippa n. comb. & reinst. stat., Cisandina fida n. comb., Cisandina sanmarcos n. comb., and Cisandina trinitensis n. comb. are proposed as new taxonomic combinations, since these species are distantly related to the type species of Magneuptychia and Euptychoides and cannot reasonably be accommodated in any other genus. Lectotypes are designated for Papilio lea Cramer, 1777, Papilio junia Cramer, 1780, Euptychia philippa Butler, 1867, and Eupytchia fida Weymer, 1911. Two new species of Cisandina n. gen. are named and described herein, C. esmeralda Nakahara & Barbosa, n. sp. and C. castanya Lamas & Nakahara, n. sp., increasing the described species diversity of the genus to seven. The immature stages of C. castanya n. sp. and C. philippa n. comb. & reinst. stat. are documented along with their natural hostplants, representing the first two species of the genus with known life history information. We describe a new subspecies, Cisandina fida directa Nakahara & Willmott, n. ssp., based on a limited number of specimens from southern Ecuador and central Peru. We were unable to obtain genetic data for the nominate race of C. fida n. comb., and thus, this taxonomic hypothesis is currently based solely on phenotypic characters.
Auteurs, date et publication :
Auteurs Shinichi Nakahara , Maryzender Rodríguez-Melgarejo , Kaylin Kleckner , Thalia Corahua-Espinoza , Rafael Tejeira , Marianne Espeland , Mirna M Casagrande , Eduardo P Barbosa , Joseph See , Geoffrey Gallice , Gerardo Lamas , Keith R Willmott , Marko Mutanen
Publication : Insect Systematics and Diversity
Date : 2022
Volume : 6
Issue : 1
Pages : 2
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Many anuran species remain to be formally named and described in Amazonia, notably in the Guiana Shield, and particularly in megadiverse groups such as Pristimantis. Several species in the Guiana Shield region have been confused with Pristimantis marmoratus and P. ockendeni. Hylodes grandoculis, a taxon previously placed in the synonymy of P. marmoratus, may be available for one of these species. To disentangle this confusing situation, we examined the external morphology and osteology (via µ-CT scans) of the holotype of H. grandoculis, the holotype of Pristimantis marmoratus, and of recently collected material for which we also analyzed molecular, acoustic, and morphological variation. We concluded that some populations from Suriname and northern Pará, Brazil, are distinct from P. marmoratus and correspond to Pristimantis grandoculis. Other populations, from French Guiana, are closely related to P. grandoculis but their status remains ambiguous. Finally, some populations, from French Guiana and Amapá, Brazil, are conspicuously distinct from both P. marmoratus and P. grandoculis and are described herein as P. crepitaculus sp. nov. A third species, belonging to a “trans-amazon complex”, occurs in southern Suriname, Guyana, and Brazil and remains undescribed. Pristimantis grandoculis and related populations from French Guiana lack external tympanum, columella, pharyngeal ostia, vocal slits and do not vocalize. This represents a rare, perhaps unique, example of a deaf and mute species of frogs from the Amazonian lowlands.
Auteurs, date et publication :
Auteurs Antoine Fouquet , Pedro Peloso , Rawien Jairam , Albertina P. Lima , Alexander T. Mônico , Raffael Ernst , Philippe J. R. Kok
Publication : Organisms Diversity & Evolution
Date : 2025
Volume : 22
Issue : 4
Pages : 1065-1098