Résumé
An animal’s behavioral phenotype comprises several traits, which are hierarchically structured in functional units. This is manifested in measured behaviors often being correlated, partly reflecting the need of a coordinated functional response. Unfortunately, we still have limited understanding whether consistent differences in animal behaviors are due to underlying physiological constraints or a result of plastic adaptation to their current environment. Therefore, characterizing the spatial distribution of behaviors can provide important insights into causes and consequences of behavioral variation. In the present study, we quantified behaviors in a wild, free-ranging population of the Neotropical frog Allobates femoralis. We investigated how these behaviors were linked to the frogs’ natural and social environment and quantified the extent to which these behaviors consistently differed among individuals (i.e., animal personality). We assessed levels of aggressiveness, exploration, and boldness by measuring several underlying behaviors expressed in a set of experimental assays, and found evidence for consistent among-individual differences along these axes. Contrary to our expectation, there was no relationship between individual behaviors and their natural environment, but we found a plastic response of males to changes in female density, which might reflect how individuals cope with their socio-ecological environment.
Auteurs, date et publication :
Auteurs Mélissa Peignier , Yimen G. Araya-Ajoy , Lauriane Bégué , Sarah Chaloupka , Katharina Dellefont , Christoph Leeb , Patrick Walsh , Max Ringler , Eva Ringler
Publication : Behavioral Ecology and Sociobiology
Date : 2022
Volume : 76
Issue : 7
Pages : 93
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Two new species of Tovomita Aubl. (Clusiaceae) from the Guiana Shield are described and illustrated. Tovomita maxima Molino & J.Engel, sp. nov., known from French Guiana, Guyana and Brazil, stands out by its large size (up to 30 m high), large leaves with eucamptodromous venation, calyptrate bracteoles and an unusual variation in the number of stamens (74-145). Tovomita saulensis J.Engel & Molino, sp. nov., probably endemic to central French Guiana, is an understory tree with small leaves with brochidodromous venation and flowers with few stamens (9-15). Illustrations, descriptions, photographs in vivo, a preliminary conservation status, distribution map and comments on the morphology of related species are provided.
Auteurs, date et publication :
Auteurs Julien Engel , Jean-François Molino , Lucas C. Marinho
Publication : Adansonia
Date : 2022
Volume : 44
Issue : 16
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Lianas are self-supporting systems that are increasing their dominance in tropical forests due to climate change. As lianas increase tree mortality and reduce tree growth, one key challenge in ecological remote sensing is the separation of a liana and its host tree using remote sensing techniques. This separation can provide essential insights into how tropical forests respond, from the point of view of ecosystem structure to climate and environmental change. Here, we propose a new machine learning method, derived from Random Forest (RF) and eXtreme Gradient Boosting (XGBoosting) algorithms, to separate lianas and trees using Terrestrial Laser Scanning (TLS) point clouds. We test our method on five tropical dry forest trees with different levels of liana infestation. First, we use a multiple radius search method to define the optimal radius of six geometric features. Second, we compare the performance of RF and XGBoosting algorithms on the classification of lianas and trees. Finally, we evaluate our model against independent data collected by other projects. Our results show that the XGBoosting algorithm achieves an overall accuracy of 0.88 (recall of 0.66), and the RF algorithm has an accuracy of 0.85 (recall of 0.56). Our results also show that the optimal radius method is as accurate as the multiple radius method, with F1 scores of 0.49 and 0.48, respectively. The RF algorithm shows the highest recall of 0.88 on the independent data. Our method provides a new flexible approach to extracting lianas from 3D point clouds, facilitating TLS to support new studies aimed to evaluate the impact of lianas on tree and forest structures using point clouds.
Auteurs, date et publication :
Auteurs Tao Han , Gerardo Arturo Sánchez-Azofeifa
Publication : Remote Sensing
Date : 2022
Volume : 14
Issue : 16
Pages : 4039
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Background and aims – The genus Carapichea (Rubiaceae), recently resurrected and separated from Psychotria, currently includes 24 Neotropical species and is morphologically heterogeneous. A revision of the genus in the Guianas is presented here, as part of the authors’ work on the Rubiaceae treatment in the Flora of the Guianas series.
Auteurs, date et publication :
Auteurs Olivier Lachenaud , Piero Delprete
Publication : Plant Ecology and Evolution
Date : 2022
Volume : 155
Issue : 2
Pages : 275-300
Catégorie(s)
#CNRS #FORET NouraguesRésumé
The hologenome concept considers the entity formed by a host and its microbiota, the holobiont, as new level of hierarchical organization subject to neutral and selective forces. We used grafted plants to formally evaluate the hologenome concept. We analyzed the root-endosphere microbiota of two independent watermelon and grapevine plant systems, including ungrafted and reciprocalgrafting combinations. Grafted and ungrafted hosts harbor markedly different microbiota compositions. Furthermore, the results indicate a non-random assembly of bacterial communities inhabiting the root endosphere of chimeric plants with interactive effect of both the rootstock and scion on the recruitment of microorganisms. Because chimeric plants did not have a random microbiota, the null hypothesis that holobionts assemble randomly and hologenome concept is an intellectual construction only can be rejected. The study supports the relevance of hologenome as biological level of organization and opens new avenues for a better fundamental understanding of plants as holobionts.
Auteurs, date et publication :
Auteurs Marine Biget , Tingting Wang , Cendrine Mony , Qicheng Xu , Lucie Lecoq , Véronique Chable , Kevin R. Theis , Ning Ling , Philippe Vandenkoornhuyse
Publication : iScience
Date : 2025
Volume : 26
Issue : 2
Pages : 106031
Catégorie(s)
#CNRS #EcoGenO #Université de RennesRésumé
Plants are widely recognized as chemical factories, with each species producing dozens to hundreds of unique secondary metabolites. These compounds shape the interactions between plants and their natural enemies. We explore the evolutionary patterns and processes by which plants generate chemical diversity, from evolving novel compounds to unique chemical profiles.
Auteurs, date et publication :
Auteurs Dale L. Forrister , María‐José Endara , Abrianna J. Soule , Gordon C. Younkin , Anthony G. Mills , John Lokvam , Kyle G. Dexter , R. Toby Pennington , Catherine A. Kidner , James A. Nicholls , Oriane Loiseau , Thomas A. Kursar , Phyllis D. Coley
Publication : New Phytologist
Date : 2025
Volume : 237
Issue : 2
Pages : 631-642
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Earthworms have a prominent role in supporting soil functioning and thus in providing key services to humanity. Their beneficial role relates to effects on soil structure, carbon and nutrient cycling as well as the soil microbial community. Optimizing the role of earthworms in agricultural systems is therefore crucial for maintaining or improving soil quality and supporting a more sustainable, circular agriculture. Here, we summarize established knowledge on the role of earthworms in agronomy; present novel insights from the past decades; and identify key knowledge gaps to be addressed in the future to fully benefit from earthworms in our agricultural soils. We start by discussing how earthworms affect basic soil processes through their effects on soil structure, microbial communities and biogeochemical cycles. Further, we show how as a result of these changes, earthworms indirectly affect plant growth, the soil greenhouse gas balance and play a role in remediation of contaminated arable soils. We further address one of the paradoxes of earthworm ecology: that they are often not present in the soils where they are most needed. We subsequently discuss potential solutions to this paradox. Finally, we identify 10 key questions that need to be addressed in the near future. In our view, recognizing that earthworms are not a stand-alone solution to improving the sustainability of cropping systems, but an essential piece of the puzzle is crucial for optimizing the benefits they offer in agronomic systems. By managing our earthworm populations well, we manage our soils well.
Auteurs, date et publication :
Auteurs Alix Vidal , Manuel Blouin , Ingrid Lubbers , Yvan Capowiez , Juan C. Sanchez-Hernandez , Tullia Calogiuri , Jan Willem Van Groenigen
Date : 2025
Volume : 181
Pages : 1-78
Catégorie(s)
#CNRS #Ecotron de MontpellierAuteurs, date et publication :
Auteurs Pierre Adrien Reynaud
Publication : Ornitología Neotropical
Date : 2025
Volume : 9
Catégorie(s)
#⛔ No DOI found #CNRS #FORET NouraguesRésumé
Leaf mass per area (LMA) is an important leaf trait but challenging to be accurately estimated. This article proposes a simple leaf radiative transfer model called ISPECT. It explains the difference in optical properties observed on the adaxial (upper) and abaxial (lower) sides of leaves, i.e., their dorsiventrality, with a limited number of structural parameters. The performance of ISPECT in estimating LMA is compared to that of five other leaf radiative transfer models (FASPECT, DLM, PROSPECT-D, PROSPECT-5B, and Leaf-SIP). We tested six experimental datasets with 962 leaf samples and two spectral ranges: the solar domain (0.4–2.5 μm) and the shortwave infrared (1.7–2.4 μm). Results show that PROSPECT-D and PROSPECT-5B accurately estimate LMA using the shortwave infrared spectra, while ISPECT and FASPECT perform well in both spectral ranges. Further analysis demonstrates that leaf dorsiventrality is likely to be an influential factor for LMA estimation: thus ISPECT can accurately estimate LMA in the solar and shortwave infrared domains, with NRMSE of 26.0% and 28.8%, respectively. This motivates further studies on LMA mapping from spaceborne imaging spectrometers (e.g., PRISMA, GaoFen-5, EnMAP) by coupling ISPECT with canopy radiative transfer models.
Auteurs, date et publication :
Auteurs Hanyu Shi , Jingyi Jiang , Stéphane Jacquemoud , Zhiqiang Xiao , Mingguo Ma
Publication : Remote Sensing of Environment
Date : 2025
Volume : 286
Pages : 113444
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Intraspecific variability (IV) has been proposed to explain species coexistence in diverse communities. Assuming, sometimes implicitly, that conspecific individuals can perform differently in the same environment and that IV increases niche overlap, previous studies have found contrasting results regarding the effect of IV on species coexistence. We aim at showing that the large IV observed in data does not mean that conspecific individuals are necessarily different in their response to the environment and that the role of high-dimensional environmental variation in determining IV has largely remained unexplored in forest plant communities. We first used a simulation experiment where an individual attribute is derived from a high-dimensional model, representing “perfect knowledge” of individual response to the environment, to illustrate how large observed IV can result from “imperfect knowledge” of the environment. Second, using growth data from clonal Eucalyptus plantations in Brazil, we estimated a major contribution of the environment in determining individual growth. Third, using tree growth data from long-term tropical forest inventories in French Guiana, Panama and India, we showed that tree growth in tropical forests is structured spatially and that despite a large observed IV at the population level, conspecific individuals perform more similarly locally than compared with heterospecific individuals. As the number of environmental dimensions that are well quantified at fine scale is generally lower than the actual number of dimensions influencing individual attributes, a great part of observed IV might be represented as random variation across individuals when in fact it is environmentally driven. This mis-representation has important consequences for inference about community dynamics. We emphasize that observed IV does not necessarily impact species coexistence per se but can reveal species response to high-dimensional environment, which is consistent with niche theory and the observation of the many differences between species in nature.
Auteurs, date et publication :
Auteurs Camille Girard‐Tercieux , Isabelle Maréchaux , Adam T. Clark , James S. Clark , Benoît Courbaud , Claire Fortunel , Joannès Guillemot , Georges Künstler , Guerric Le Maire , Raphaël Pélissier , Nadja Rüger , Ghislain Vieilledent
Publication : Ecology and Evolution
Date : 2025
Volume : 13
Issue : 3
Pages : e9860