Résumé
Rare species are crucial components of the highly diverse soil microbial pool and over-proportionally contribute to the soil functions. However, much remains unknown about their assembling rules. The biogeographic patterns and species aggregations of the rare bacterial biosphere were assessed using 140 soil samples from a gradient of 2000 km across the main tea-producing areas in China. About 96% OTUs with ~40% sequences were classified as rare taxa. The rare bacterial communities were significantly affected by geographical regions and showed distance-decay effects, indicating that the rare bacteria are not cosmopolitan, they displayed a pattern of limited dispersal and were restricted to certain sites. Variation partitioning analysis (VPA) revealed that environmental variation and spatial factors explained 12.5% and 6.4%, respectively, of the variance in rare bacterial community. The Mantel and partial Mantel tests also showed that the environmental factors had stronger (~3 times) impacts than spatial factors. The null model showed that deterministic processes contributed more than stochastic processes in rare bacterial assembly (75% vs. 25%). There is likely an enrichment in ecological functions within the rare biosphere, considering this high contribution of deterministic processes in the assembly. In addition, the assembly of rare taxa was found to be mainly driven by soil pH. Overall, this study revealed that rare bacteria were not cosmopolitan, and their assembly was more driven by deterministic processes. These findings provided a new comprehensive understanding of rare bacterial biogeographic patterns and assembly rules.
Auteurs, date et publication :
Auteurs Qicheng Xu , Ning Ling , Achim Quaiser , Junjie Guo , Jianyun Ruan , Shiwei Guo , Qirong Shen , Philippe Vandenkoornhuyse
Publication : Microbial Ecology
Date : 2021
Catégorie(s)
#CNRS #EcoGenO #Université de RennesRésumé
The most unusual, and thus irreplaceable, functions performed by species in three different species-rich ecosystems are fulfilled by only the rare species in these ecosystems.
Auteurs, date et publication :
Auteurs David Mouillot , David R. Bellwood , Christopher Baraloto , Jerome Chave , Rene Galzin , Mireille Harmelin-Vivien , Michel Kulbicki , Sebastien Lavergne , Sandra Lavorel , Nicolas Mouquet , C. E. Timothy Paine , Julien Renaud , Wilfried Thuiller , Georgina M. Mace
Publication : PLoS Biology
Date : 2013
Volume : 11
Issue : 5
Pages : e1001569
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
A central challenge in ecology is understanding the emergence of patterns as the result of interactions among individuals. Dynamic forest models can provide a fine-scale description of the ecological, physiological and environmental processes that explain the demography of coexisting tree species. This in turn helps predict changes under future scenarios. However, model accessibility is a major obstacle to a wide use and communication across scientific disciplines and for educational purposes. Here, we present the R package rcontroll, which provides access to the TROLL forest simulator in the R environment. TROLL is individual-based and spatially explicit and leverages knowledge of ecology, biogeochemistry and tree ecophysiology through a trait-based parameterisation. TROLL has been used to simulate carbon fluxes and tree diversity in tropical and subtropical forests and to explore forest resilience to disturbance and environmental changes more generally. rcontroll provides a user-friendly environment to set up and analyse TROLL simulations with varying community compositions, ecological parameters and climate conditions. We show how to test parameter sensitivity in TROLL using the rcontroll R package. We also demonstrate the flexibility and ease of use of rcontroll by replicating a previously published study based on the TROLL simulator. Both examples are included with reproducible code documents. Complex forest simulators are important scientific tools for science and education, and wide access to these tools is an important condition for their adoption. TROLL is designed to address a wide range of ecological and environmental questions, and the new R package rcontroll is designed to be an entry point for TROLL model users.
Auteurs, date et publication :
Auteurs Sylvain Schmitt , Guillaume Salzet , Fabian Jörg Fischer , Isabelle Maréchaux , Jerome Chave
Publication : Methods in Ecology and Evolution
Date : 2025
Volume : 14
Issue : 11
Pages : 2749-2757
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plantderived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.
Auteurs, date et publication :
Auteurs Judith M. Sarneel , Mariet M. Hefting , Taru Sandén , Johan Van Den Hoogen , Devin Routh , Bhupendra S. Adhikari , Juha M. Alatalo , Alla Aleksanyan , Inge H. J. Althuizen , Mohammed H. S. A. Alsafran , Jeff W. Atkins , Laurent Augusto , Mika Aurela , Aleksej V. Azarov , Isabel C. Barrio , Claus Beier , María D. Bejarano , Sue E. Benham , Björn Berg , Nadezhda V. Bezler
Publication : Ecology Letters
Date : 2025
Volume : 27
Issue : 5
Pages : e14415
Catégorie(s)
#CNRS #FORET PuechabonAuteurs, date et publication :
Auteurs Clément Lermyte , Pierre-Michel Forget
Publication : Tropical Conservation Science
Date : 2025
Volume : 2
Issue : 4
Pages : 374-387
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Olivier Boissier , Axelle Bouiges , Irene Mendoza , François Feer , Pierre‐Michel Forget
Publication : Biotropica
Date : 2025
Volume : 46
Issue : 5
Pages : 633-641
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Changes in rainfall amounts and patterns have been observed and are expected to continue in the near future with potentially significant ecological and societal consequences. Modelling vegetation responses to changes in rainfall is thus crucial to project water and carbon cycles in the future. In this study, we present the results of a new model-data intercomparison project, where we tested the ability of 10 terrestrial biosphere models to reproduce the observed sensitivity of ecosystem productivity to rainfall changes at 10 sites across the globe, in nine of which, rainfall exclusion and/or irrigation experiments had been performed. The key results are as follows: (a) Intermodel variation is generally large and model agreement varies with timescales. In severely water-limited sites, models only agree on the interannual variability of evapotranspiration and to a smaller extent on gross primary productivity. In more mesic sites, model agreement for both water and carbon fluxes is typically higher on fine (daily–monthly) timescales and reduces on longer (seasonal–annual) scales. (b) Models on average overestimate the relationship between ecosystem productivity and mean rainfall amounts across sites (in space) and have a low capacity in reproducing the temporal (interannual) sensitivity of vegetation productivity to annual rainfall at a given site, even though observation uncertainty is comparable to inter-model variability. (c) Most models reproduced the sign of the observed patterns in productivity changes in rainfall manipulation experiments but had a low capacity in reproducing the observed magnitude of productivity changes. Models better reproduced the observed productivity responses due to rainfall exclusion than addition. (d) All models attribute ecosystem productivity changes to the intensity of vegetation stress and peak leaf area, whereas the impact of the change in growing season length is negligible. The relative contribution of the peak leaf area and vegetation stress intensity was highly variable among models.
Auteurs, date et publication :
Auteurs Athanasios Paschalis , Simone Fatichi , Jakob Zscheischler , Philippe Ciais , Michael Bahn , Lena Boysen , Jinfeng Chang , Martin De Kauwe , Marc Estiarte , Daniel Goll , Paul J Hanson , Anna B Harper , Enqing Hou , Jaime Kigel , Alan K Knapp , Klaus S Larsen , Wei Li , Sebastian Lienert , Yiqi Luo , Patrick Meir
Publication : Global Change Biology
Date : 2025
Volume : 26
Pages : 3336-3355
Catégorie(s)
#CNRS #FORET PuechabonAuteurs, date et publication :
Auteurs Terry L Erwin
Publication : ZooKeys
Date : 2025
Issue : 145
Pages : 79
Catégorie(s)
#⛔ No DOI found #CNRS #FORET NouraguesRésumé
Dispersal, i.e. movements potentially leading to gene flow, is central in evolutionary ecology. Many factors can trigger dispersal, all linked to the social and/or the environmental context. Moreover, it is now widely demonstrated that phenotypes with contrasted dispersal abilities coexist within populations of a same species. The current challenge is to elucidate how social and environmental factors will influence the dispersal decision of individuals with distinct phenotypes. We have used the Metatron, a unique experimental mesocosm dedicated to the study of dispersal within fragmented landscapes, to analyze the relative and interactive roles played by ten potential dispersal triggers in experimental two-patch metapopulations of butterflies. We demonstrate in our model species that some factors (flight performance and wing length) have direct effects on emigration decision, others act only through interactive effects (sex ratio), while a third class of factors presents both direct and interactive effects (weather conditions, habitat quality and sex). We also show that disperser and resident individuals have distinct behavioral and morphological attributes, revealing the existence of a dispersal syndrome. Finally, our results also suggest that the environmental context, and especially weather conditions and habitat quality, prevails over social factors and individual phenotypes in butterflies' decision to disperse. Our approach is applicable to many species facing medium to strong environmental fluctuations, and constitutes a new way to master the idiosyncrasy of the dispersal process. Our framework should also help prioritize the factors responsible for populations' spatial distribution, which is obviously crucial in the current era of global changes.
Auteurs, date et publication :
Auteurs Delphine Legrand , Audrey Trochet , Sylvain Moulherat , Olivier Calvez , Virginie M. Stevens , Simon Ducatez , Jean Clobert , Michel Baguette
Publication : Ecography
Date : 2025
Volume : 38
Issue : 8
Pages : 822-831
Catégorie(s)
#CNRS #Metatron terrestreRésumé
There is a growing interest in understanding and forecasting the responses of plant communities to projected changes of environmental conditions. Multi-stage demographic approaches, where plant recruitment is explored across multiple and consecutive stages, are essential to obtain a whole overview of the consequences of increasing aridity on tree recruitment and forest dynamics, but they are still rarely used. In this study, we present the results of an experimental rainfall exclusion aimed to evaluate the impact of projected increasing drought on multiple stage-specific probabilities of recruitment in a key tree species typical of late-successional Mediterranean woodlands (Quercus ilex L.). We calibrated linear and nonlinear likelihood models for the different demographic processes and calculated overall probabilities of recruitment along a wide range of microhabitat conditions. Rainfall exclusion altered Q. ilex recruitment throughout ontogeny. Seed maturation, seedling emergence and survival and, to a lesser extent, post-dispersal seed survival were the most sensitive demographic processes to decreased rainfall. Interestingly, both the identity of the most critical stages for recruitment and their specific sensitivity to rainfall manipulation depended largely on the yearly pattern of precipitation. The microhabitat heterogeneity strongly determined the success of recruitment in the study species. The experimental increase in drought displaced the peak of maximum overall recruitment towards the low end of the light gradient, suggesting that the dependence on shrubs for an effective recruitment in Q. ilex could be intensified under future environmental scenarios. In terms of phenotypic plasticity, Q. ilex seedlings responded more strongly to light availability than to experimentally increased drought, which could reduce its ability to persist under on-going environmental conditions due to climate change. Results from this study provide a full picture of the ecological and functional consequences of the projected rainfall reduction on tree recruitment and forest dynamics in two years of contrasting precipitation.
Auteurs, date et publication :
Auteurs Ignacio M. Pérez-Ramos , Jesús Rodríguez-Calcerrada , Jean M. Ourcival , Serge Rambal
Publication : Perspectives in Plant Ecology, Evolution and Systematics
Date : 2013
Volume : 15
Issue : 2
Pages : 106-117