Auteurs, date et publication :
Auteurs Ho Tong Minh Dinh , Stefano Tebaldini , Fabio Rocca , Thierry Koleck , Pierre Borderies , Clement Albinet , Ludovic Villard , Alia Hamadi , Thuy Le Toan
Publication : IEEE Transactions on Geoscience and Remote Sensing
Date : 2013
Volume : 51
Issue : 8
Pages : 4460–4472
Catégorie(s)
#CIRAD #FORET ParacouRésumé
Plant phenology characterises the seasonal cyclicity of biological events such as budburst, flowering, fructification, leaf senescence and leaf fall. These biological events are genetically pre-determined but also strongly modulated by climatic conditions, particularly temperature, daylength and water availability. Therefore, the timing of these events is considered as a good indicator of climate change impacts and as a key parameter for understanding and modelling vegetation–climate interactions. In situ observations, empirical or bioclimatic models and remotely sensed time-series data constitute the three possible ways for monitoring the timing of plant phenological events. Remote sensing has the advantage of being the only way of surface sampling at high temporal frequency and, in the case of satellite-based remote sensing, over large regions. Nevertheless, exogenous factors, particularly atmospheric conditions, lead to some uncertainties on the seasonal course of surface reflectance and cause bias in the identification of vegetation phenological events. Since 2005, a network of forest and herbaceous sites has been equipped with laboratory made NDVI sensors to monitor the temporal dynamics of canopy structure and phenology at an intra-daily time step. In this study, we present recent results obtained in several contrasting biomes in France, French Guiana, Belgium and Congo. These sites represent a gradient of vegetation ecosystems: the main evergreen and deciduous forest ecosystems in temperate climate region, an evergreen tropical rain forest in French Guiana, an herbaceous savanna ecosystem in Congo, and a succession of three annual crops in Belgium. In this paper, (1) we provide an accurate description of the seasonal dynamics of vegetation cover in these different ecosystems (2) we identify the most relevant remotely sensed markers from NDVI time-series for determining the dates of the main phenological events that characterize these ecosystems and (3) we discuss the relationships between temporal canopy dynamics and climate factors. In addition to its importance for phenological studies, this ground-based Network of NDVI measurement provides data needed for the calibration and direct validation of satellite observations and products.
Auteurs, date et publication :
Auteurs K. Soudani , G. Hmimina , N. Delpierre , J.-Y. Pontailler , M. Aubinet , D. Bonal , B. Caquet , A. de Grandcourt , B. Burban , C. Flechard , D. Guyon , A. Granier , P. Gross , B. Heinesh , B. Longdoz , D. Loustau , C. Moureaux , J.-M. Ourcival , S. Rambal , L. Saint André
Publication : Remote Sensing of Environment
Date : 2012
Volume : 123
Pages : 234–245
Catégorie(s)
#CIRAD #CNRS #FORET Paracou #FORET PuechabonRésumé
Plant functional traits directly affect ecosystem functions. At the species level, trait combinations depend on trade-offs representing different ecological strategies, but at the community level trait combinations are expected to be decoupled from these trade-offs because different strategies can facilitate co-existence within communities. A key question is to what extent community-level trait composition is globally filtered and how well it is related to global versus local environmental drivers. Here, we perform a global, plot-level analysis of trait–environment relationships, using a database with more than 1.1 million vegetation plots and 26,632 plant species with trait information. Although we found a strong filtering of 17 functional traits, similar climate and soil conditions support communities differing greatly in mean trait values. The two main community trait axes that capture half of the global trait variation (plant stature and resource acquisitiveness) reflect the trade-offs at the species level but are weakly associated with climate and soil conditions at the global scale. Similarly, within-plot trait variation does not vary systematically with macro-environment. Our results indicate that, at fine spatial grain, macro-environmental drivers are much less important for functional trait composition than has been assumed from floristic analyses restricted to co-occurrence in large grid cells. Instead, trait combinations seem to be predominantly filtered by local-scale factors such as disturbance, fine-scale soil conditions, niche partitioning and biotic interactions.
Auteurs, date et publication :
Auteurs Helge Bruelheide , Jürgen Dengler , Oliver Purschke , Jonathan Lenoir , Borja Jiménez-Alfaro , Stephan M Hennekens , Zoltán Botta-Dukát , Milan Chytrý , Richard Field , Florian Jansen , Jens Kattge , Valério D Pillar , Franziska Schrodt , Miguel D Mahecha , Robert K Peet , Brody Sandel , Peter van Bodegom , Jan Altman , Esteban Alvarez-Dávila , Mohammed A S Arfin Khan
Publication : Nature Ecology & Evolution
Date : 2025
Catégorie(s)
#CIRAD #FORET ParacouAuteurs, date et publication :
Auteurs Maarja Öpik , Martin Zobel , Juan J. Cantero , John Davison , José M. Facelli , Inga Hiiesalu , Teele Jairus , Jesse M. Kalwij , Kadri Koorem , Miguel E. Leal , Jaan Liira , Madis Metsis , Valentina Neshataeva , Jaanus Paal , Cherdchai Phosri , Sergei Põlme , Ülle Reier , Ülle Saks , Heidy Schimann , Odile Thiéry
Publication : Mycorrhiza
Date : 2013
Volume : 23
Issue : 5
Pages : 411–430
Catégorie(s)
#CIRAD #FORET ParacouRésumé
The influence of geomorphological features on rain-forest diversity has been reported in different Amazonian regions. Soil filtering is often assumed to underlie the observed geomorphic control on the floristic composition but other hypotheses related to biogeography or long-term forest dynamics are also possible. We tested relationships between geomorphology, soil properties and forest composition in French Guiana rain forest using a recent geomorphological map and a large dataset comprising 3132 0.2-ha plots and 421 soil cores. Soil properties were characterized by laboratory analyses and by field descriptions indicating drainage capacity and classification according to the World Reference Base (WRB). The influence of soils and geomorphology on beta-diversity was tested using variance partitioning and ANOVA-like tests. Our results confirm the hypothesis of a strong relationship between geomorphological landscapes and soil properties. Soil filtering significantly influenced the abundance of more than 40 species or groups of species. However geomorphic control of forest composition involves much more than the effects of the soil, which only explain a minor part of the broad-scale patterns of forest diversity related to geomorphological landscapes. These results reinforce the alternative hypotheses linking geomorphological landscapes to long-term forest change under the control of historical processes that shaped forest diversity.
Auteurs, date et publication :
Auteurs Stéphane Guitet , Vincent Freycon , Olivier Brunaux , Raphaël Pélissier , Daniel Sabatier , Pierre Couteron
Publication : Journal of Tropical Ecology
Date : 2025
Volume : 32
Pages : 22–40
Catégorie(s)
#CIRAD #FORET ParacouAuteurs, date et publication :
Auteurs Christine Le Roux , Félix Muller , Jean-Marc Bouvet , Bernard Dreyfus , Gilles Béna , Antoine Galiana , Amadou M. Bâ
Publication : Microbial Ecology
Date : 2014
Volume : 68
Issue : 2
Pages : 329–338
Catégorie(s)
#CIRAD #FORET ParacouAuteurs, date et publication :
Auteurs Marina Ciminera , Marie-Anne Auger-Rozenberg , Henri Caron , Melfran Herrera , Caroline Scotti-Saintagne , Ivan Scotti , Niklas Tysklind , Alain Roques
Publication : Journal of Medical Entomology
Date : 2018
Catégorie(s)
#CIRAD #FORET ParacouRésumé
Traditional measures of diversity, namely the number of species as well as Simpson's and Shannon's indices, are particular cases of Tsallis entropy. Entropy decomposition, i.e. decomposing gamma entropy into alpha and beta components, has been previously derived in the literature. We propose a generalization of the additive decomposition of Shannon entropy applied to Tsallis entropy. We obtain a self-contained definition of beta entropy as the information gain brought by the knowledge of each community composition. We propose a correction of the estimation bias allowing to estimate alpha, beta and gamma entropy from the data and eventually convert them into true diversity. We advocate additive decomposition in complement of multiplicative partitioning to allow robust estimation of biodiversity.
Auteurs, date et publication :
Auteurs Eric Marcon , Ivan Scotti , Bruno Hérault , Vivien Rossi , Gabriel Lang , Jean Thioulouse
Publication : Plos One
Date : 2014
Volume : 9
Issue : 3
Pages : e90289
Catégorie(s)
#CIRAD #FORET ParacouAuteurs, date et publication :
Auteurs Bruno Hérault , Bénédicte Bachelot , Lourens Poorter , Vivien Rossi , Frans Bongers , Jérôme Chave , C. E. Timothy Paine , Fabien Wagner , Christopher Baraloto
Publication : Journal of Ecology
Date : 2011
Volume : 99
Issue : 6
Pages : 1431–1440
Catégorie(s)
#CIRAD #FORET ParacouRésumé
In Amazonia, the knowledge about Fungi remains patchy and biased towards accessible sites. This is particularly the case in French Guiana where the existing collections have been confined to few coastal localities. Here, we aimed at filling the gaps of knowledge in undersampled areas of this region, particularly focusing on the Basidiomycota. From 2011, we comprehensively collected fruiting-bodies with a stratified and reproducible sampling scheme in 126 plots. Sites of sampling reflected the main forest habitats of French Guiana in terms of soil fertility and topography. The dataset of 5219 specimens gathers 245 genera belonging to 75 families, 642 specimens are barcoded. The dataset is not a checklist as only 27% of the specimens are identified at the species level but 96% are identified at the genus level. We found an extraordinary diversity distributed across forest habitats. The dataset is an unprecedented and original collection of Basidiomycota for the region, making specimens available for taxonomists and ecologists. The database is publicly available in the GBIF repository (https://doi.org/10.15468/ymvlrp).
Auteurs, date et publication :
Auteurs Gaëlle Jaouen , Audrey Sagne , Bart Buyck , Cony Decock , Eliane Louisanna , Sophie Manzi , Christopher Baraloto , Mélanie Roy , Heidy Schimann
Publication : Scientific Data
Date : 2019
Volume : 6
Issue : 1
Pages : 206