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Author Mirabel, Ariane ; Marcon, Eric ; Hérault, Bruno doi  openurl
  Title 30 Years of postdisturbance recruitment in a Neotropical forest Type Journal Article
  Year 2021 Publication Ecology and Evolution Abbreviated Journal  
  Volume 11 Issue 21 Pages (down) 14448-14458  
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  Address  
  Corporate Author Thesis  
  Publisher John Wiley & Sons, Ltd (10.1111) Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1043  
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Author Schmitt, Sylvain ; Raevel, Valérie ; Réjou-Méchain, Maxime ; Ayyappan, Narayanan ; Balachandran, Natesan ; Barathan, Narayanan ; Rajashekar, Gopalakrishnan ; Munoz, François doi  openurl
  Title Canopy and understorey tree guilds respond differently to the environment in an Indian rain forest Type Journal Article
  Year 2021 Publication Journal of Végétation Science Abbreviated Journal  
  Volume 32 Issue 5 Pages (down) e13075  
  Keywords  
  Abstract Questions Changes in the functional composition of tree communities along resource availability gradients have received attention, but it is unclear whether understorey and canopy guilds respond similarly to different light, biomechanical, and hydraulic constraints. Location An anthropically undisturbed, old-growth wet evergreen dipterocarp forest plot located in Karnataka State, India. Methods We measured leaf and wood traits of 89 tree species representing 99% of all individuals in a 10-ha permanent plot with varying topographic and canopy conditions inferred from Light Detection And Ranging (LiDAR) data. We assigned tree species to guilds of canopy and understorey species and assessed the variation of the guild-weighted means of functional-trait values with canopy height and topography. Results The functional-trait space did not differ between canopy and understorey tree species. However, environmental filtering led to significantly different functional composition of canopy and understorey guild assemblages. Furthermore, they responded differently along environmental gradients related to water, nutrients, light, and wind exposure. For example, the canopy guild responded to wind exposure while the understorey guild did not. Conclusions The pools of understorey and canopy species are functionally similar. However, fine-scale environmental heterogeneity impacts differently on these two guilds, generating striking differences in functional composition between understorey and canopy guild assemblages. Accounting for vertical guilds improves our understanding of forest communities' assembly processes.  
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  Corporate Author Thesis  
  Publisher International Association for Vegetation Science Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1038  
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Author Urbina, Ifigenia ; Grau, Oriol ; Sardans, Jordi ; Margalef, Olga ; Peguero, Guillermo ; Asensio, Dolores ; Llusia, Joan ; Ogaya, Roma ; Gargallo-Garriga, Albert ; Van Langenhove, Leandro ; Verryckt, Lore T. ; Courtois, Elodie A. ; Stahl, Clement ; Soong, Jennifer L. ; Chave, Jérome ; Hérault, Bruno ; Janssens, Ivan A. ; Sayer, Emma ; Penuelas, Josep doi  openurl
  Title High foliar K and P resorption efficiencies in old-growth tropical forests growing on nutrient-poor soils Type Journal Article
  Year 2021 Publication Ecology and Evolution Abbreviated Journal  
  Volume 11 Issue 13 Pages (down) 8969-8982  
  Keywords  
  Abstract Resorption is the active withdrawal of nutrients before leaf abscission. This mechanism represents an important strategy to maintain efficient nutrient cycling; however, resorption is poorly characterized in old-growth tropical forests growing in nutrient-poor soils. We investigated nutrient resorption from leaves in 39 tree species in two tropical forests on the Guiana Shield, French Guiana, to investigate whether resorption efficiencies varied with soil nutrient, seasonality, and species traits. The stocks of P in leaves, litter, and soil were low at both sites, indicating potential P limitation of the forests. Accordingly, mean resorption efficiencies were higher for P (35.9%) and potassium (K; 44.6%) than for nitrogen (N; 10.3%). K resorption was higher in the wet (70.2%) than in the dry (41.7%) season. P resorption increased slightly with decreasing total soil P; and N and P resorptions were positively related to their foliar concentrations. We conclude that nutrient resorption is a key plant nutrition strategy in these old-growth tropical forests, that trees with high foliar nutrient concentration reabsorb more nutrient, and that nutrients resorption in leaves, except P, are quite decoupled from nutrients in the soil. Seasonality and biochemical limitation played a role in the resorption of nutrients in leaves, but species-specific requirements obscured general tendencies at stand and ecosystem level.  
  Address  
  Corporate Author Thesis  
  Publisher Wiley Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1011  
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Author Levionnois, Sébastien ; Salmon, Camille ; Alméras, Tancrède ; Clair, Bruno ; Ziegler, Camille ; Coste, Sabrina ; Stahl, Clement ; Gonzalez-Melo, Andrés ; Heinz, Christine ; Heuret, Patrick doi  openurl
  Title Anatomies, vascular architectures, and mechanics underlying the leaf size-stem size spectrum in 42 Neotropical tree species Type Journal Article
  Year 2021 Publication Journal of Experimental Botany Abbreviated Journal  
  Volume 72 Issue 22 Pages (down) 7957–7969  
  Keywords  
  Abstract The leaf size-stem size spectrum is one of the main dimensions of plant ecological strategies. Yet the anatomical, mechanical, and hydraulic implications of small vs. large shoots are still poorly understood. We investigated 42 tropical rainforest tree species in French Guiana, with a wide range of leaf areas at the shoot level. We quantified the scaling of hydraulic and mechanical constraints with shoot size estimated as the water potential difference ΔΨ and the bending angle ΔΦ, respectively. We investigated how anatomical tissue area, flexural stiffness and xylem vascular architecture affect such scaling by deviating (or not) from theoretical isometry with shoot size variation. Vessel diameter and conductive path length were found to be allometrically related to shoot size, thereby explaining the independence between ΔΨ and shoot size. Leaf mass per area, stem length, and the modulus of elasticity were allometrically related with shoot size, explaining the independence between ΔΦ and shoot size. Our study also shows that the maintenance of both water supply and mechanical stability across the shoot size range are not in conflict.  
  Address  
  Corporate Author Thesis  
  Publisher Oxford University Press Place of Publication Editor  
  Language Summary Language Original Title  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1050  
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Author Schmitt, Sylvain ; Tysklind, Niklas ; Hérault, Bruno ; Heuertz, Myriam doi  openurl
  Title Topography drives microgeographic adaptations of closely related species in two tropical tree species complexes Type Journal Article
  Year 2021 Publication Molecular Ecology Abbreviated Journal  
  Volume 30 Issue 20 Pages (down) 5080-5093  
  Keywords  
  Abstract Closely related tree species that grow in sympatry are abundant in rainforests. However, little is known of the ecoevolutionary processes that govern their niches and local coexistence. We assessed genetic species delimitation in closely related sympatric species belonging to two Neotropical tree species complexes and investigated their genomic adaptation to a fine-scale topographic gradient with associated edaphic and hydrologic features. Combining LiDAR-derived topography, tree inventories, and single nucleotide polymorphisms (SNPs) from gene capture experiments, we explored genome-wide population genetic structure, covariation of environmental variables, and genotype-environment association to assess microgeographic adaptations to topography within the species complexes Symphonia (Clusiaceae), and Eschweilera (Lecythidaceae) with three species per complex and 385 and 257 individuals genotyped, respectively. Within species complexes, closely related tree species had different realized optima for topographic niches defined through the topographic wetness index or the relative elevation, and species displayed genetic signatures of adaptations to these niches. Symphonia species were genetically differentiated along water and nutrient distribution particularly in genes responding to water deprivation, whereas Eschweilera species were genetically differentiated according to soil chemistry. Our results suggest that varied topography represents a powerful driver of processes modulating tropical forest biodiversity with differential adaptations that stabilize local coexistence of closely related tree species.  
  Address  
  Corporate Author Thesis  
  Publisher Wiley Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1045  
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Author Aubry-Kientz, Mélaine ; Laybros, Anthony ; Weinstein, Ben ; Ball, James G. C. ; Jackson, Toby ; Coomes, David ; Vincent, Grégoire doi  openurl
  Title Multisensor data fusion for improved segmentation of individual tree crowns in dense tropical forests Type Journal Article
  Year 2021 Publication IEEE Journal of Selected topics in Applied Earth Observations and Remote Sensing Abbreviated Journal  
  Volume 14 Issue Pages (down) 3927-3936  
  Keywords  
  Abstract Automatic tree crown segmentation from remote sensing data is especially challenging in dense, diverse, and multilayered tropical forest canopies, and tracking mortality by this approach is even more difficult. Here, we examine the potential for combining airborne laser scanning (ALS) with multispectral and hyperspectral data to improve the accuracy of tree crown segmentation at a study site in French Guiana. We combined an ALS point cloud clustering method with a spectral deep learning model to achieve 83% accuracy at recognizing manually segmented reference crowns (with congruence >0.5). This method outperformed a two-step process that involved clustering the ALS point cloud and then using the logistic regression of hyperspectral distances to correct oversegmentation. We used this approach to map tree mortality from repeat surveys and show that the number of crowns identified in the first that intersected with height loss clusters was a good estimator of the number of dead trees in these areas. Our results demonstrate that multisensor data fusion improves the automatic segmentation of individual tree crowns and presents a promising avenue to study forest demography with repeated remote sensing acquisitions.  
  Address  
  Corporate Author Thesis  
  Publisher IEEE Place of Publication Editor  
  Language Summary Language Original Title  
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  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1008  
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Author Peguero, Guille ; Ferrin, Miquel ; Sardans, Jordi ; Verbruggen, Erik ; Ramirez-Rojas , Irène ; Van Langenhove, Leandro ; Verryckt, Lore T. ; Murienne, Jérôme ; Iribar, Amaia ; Zinger, Lucie ; Grau, Oriol ; Orivel, Jérome ; Stahl, Clement ; Courtois, Elodie A. ; Asensio, Dolores ; Gargallo-Garriga, Albert ; Llusia, Joan ; Margalef, Olga ; Ogaya, Roma ; Richter, Andreas ; Janssens, Ivan A. ; Penuelas, Josep doi  openurl
  Title Decay of similitary across tropical forest communities: integrating spatial distance with soil nutrients Type Journal Article
  Year 2021 Publication Ecology Abbreviated Journal  
  Volume 103 Issue 2 Pages (down) e03599  
  Keywords  
  Abstract Understanding the mechanisms that drive the change of biotic assemblages over space and time is the main quest of community ecology. Assessing the relative importance of dispersal and environmental species selection in a range of organismic sizes and motilities has been a fruitful strategy. A consensus for whether spatial and environmental distances operate similarly across spatial scales and taxa, however, has yet to emerge. We used censuses of four major groups of organisms (soil bacteria, fungi, ground insects, and trees) at two observation scales (1-m2 sampling point vs. 2,500-m2 plots) in a topographically standardized sampling design replicated in two tropical rainforests with contrasting relationships between spatial distance and nutrient availability. We modeled the decay of assemblage similarity for each taxon set and site to assess the relative contributions of spatial distance and nutrient availability distance. Then, we evaluated the potentially structuring effect of tree composition over all other taxa. The similarity of nutrient content in the litter and topsoil had a stronger and more consistent selective effect than did dispersal limitation, particularly for bacteria, fungi, and trees at the plot level. Ground insects, the only group assessed with the capacity of active dispersal, had the highest species turnover and the flattest nonsignificant distance−decay relationship, suggesting that neither dispersal limitation nor nutrient availability were fundamental drivers of their community assembly at this scale of analysis. Only the fungal communities at one of our study sites were clearly coordinated with tree composition. The spatial distance at the smallest scale was more important than nutrient selection for the bacteria, fungi, and insects. The lower initial similarity and the moderate variation in composition identified by these distance-decay models, however, suggested that the effects of stochastic sampling were important at this smaller spatial scale. Our results highlight the importance of nutrients as one of the main environmental drivers of rainforest communities irrespective of organismic or propagule size and how the overriding effect of the analytical scale influences the interpretation, leading to the perception of greater importance of dispersal limitation and ecological drift over selection associated with environmental niches at decreasing observation scales.  
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  Corporate Author Thesis  
  Publisher Ecological Society of America Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1022  
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Author Harper, Anna B. ; Williams, Karina E. ; McGuire, Patrick ; Duran Rojas, Maria Carolina ; Hemming, Debbie ; Verhoef, Anne ; Huntingford, Chris ; Rowland, Lucy ; Marthews, Toby ; Breder Eller, Cleiton ; Mathison, Camilla ; Nobrega, Rodolfo L.B. ; Gedney, Nicola ; Vidale, Pier Luigi ; Otu-Larbi, Fred ; Pandey, Divya doi  openurl
  Title Improvement of modeling plant responses to low soil moisture in JULESvn4.9 and evaluation against flux tower measurements Type Journal Article
  Year 2021 Publication Geoscientific Model Development Abbreviated Journal  
  Volume 14 Issue 6 Pages (down) 3269-3294  
  Keywords  
  Abstract Drought is predicted to increase in the future due to climate change, bringing with it myriad impacts on ecosystems. Plants respond to drier soils by reducing stomatal conductance in order to conserve water and avoid hydraulic damage. Despite the importance of plant drought responses for the global carbon cycle and local and regional climate feedbacks, land surface models are unable to capture observed plant responses to soil moisture stress. We assessed the impact of soil moisture stress on simulated gross primary productivity (GPP) and latent energy flux (LE) in the Joint UK Land Environment Simulator (JULES) vn4.9 on seasonal and annual timescales and evaluated 10 different representations of soil moisture stress in the model. For the default configuration, GPP was more realistic in temperate biome sites than in the tropics or high-latitude (cold-region) sites, while LE was best simulated in temperate and high-latitude (cold) sites. Errors that were not due to soil moisture stress, possibly linked to phenology, contributed to model biases for GPP in tropical savanna and deciduous forest sites. We found that three alternative approaches to calculating soil moisture stress produced more realistic results than the default parameterization for most biomes and climates. All of these involved increasing the number of soil layers from 4 to 14 and the soil depth from 3.0 to 10.8 m. In addition, we found improvements when soil matric potential replaced volumetric water content in the stress equation (the “soil14psi” experiments), when the critical threshold value for inducing soil moisture stress was reduced (“soil14p0”), and when plants were able to access soil moisture in deeper soil layers (“soil14_dr*2”). For LE, the biases were highest in the default configuration in temperate mixed forests, with overestimation occurring during most of the year. At these sites, reducing soil moisture stress (with the new parameterizations mentioned above) increased LE and increased model biases but improved the simulated seasonal cycle and brought the monthly variance closer to the measured variance of LE. Further evaluation of the reason for the high bias in LE at many of the sites would enable improvements in both carbon and energy fluxes with new parameterizations for soil moisture stress. Increasing the soil depth and plant access to deep soil moisture improved many aspects of the simulations, and we recommend these settings in future work using JULES or as a general way to improve land surface carbon and water fluxes in other models. In addition, using soil matric potential presents the opportunity to include plant functional type-specific parameters to further improve modeled fluxes.  
  Address  
  Corporate Author Thesis  
  Publisher European Geosciences Union Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1057  
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Author Poyatos, Rafael ; Granda, Victor ; Flo, Victor ; Adams, Mark A. ; Adorjan, Balazs ; Aguadé, David ; Aidar, Marcos P.M. ; Allen, Scott ; Alvarado-Barrientos, M.Susana ; Anderson-Teixeira, Kristina J. ; Aparecido, Luiza Maria ; Arain, M. Altaf ; Aranda, Ismael ; Asbjornsen, Heidi ; Baxter, Robert doi  openurl
  Title Global transpiration data from sap flow measurements: the SAPFLUXNET database Type Journal Article
  Year 2021 Publication Earth System Science Data Abbreviated Journal  
  Volume 13 Issue 6 Pages (down) 2607–2649  
  Keywords  
  Abstract Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land–atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The “sapfluxnetr” R package – designed to access, visualize, and process SAPFLUXNET data – is available from CRAN.  
  Address  
  Corporate Author Thesis  
  Publisher COPERNICUS PUBLICATIONS Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1058  
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Author Vergne, Antoine ; Darbot, Vincent ; Bardot, Corinne ; Enault, François ; Le Jeune, Anne-Hélène ; Carrias, Jean-François ; Corbara, Bruno ; Céréghino, Régis ; Leroy, Celine ; Jeanthon, Christian ; Giraud, Eric ; Mary, Isabelle ; Lehours, Anne-Catherine doi  openurl
  Title Assemblages of anoxygenic phototrophic bacteria in tank bromeliads exhibit a host-specific signatureit Type Journal Article
  Year 2021 Publication Journal of Ecology Abbreviated Journal  
  Volume 109 Issue 7 Pages (down) 2550-2565  
  Keywords  
  Abstract Anoxygenic phototrophic bacteria (APB) are a very significant metabolic functional group in the phytotelmata of tank-forming Bromeliaceae plants. Considering the close relationships existing between the bromeliad and its tank microbiota, the dominance of APB raises the question of their role in the ecology and evolution of these plants. Here, using pufM gene sequencing for taxonomic profiling, we investigated the structure of APB communities in the tanks of five bromeliad species exhibiting different habitat characteristics (i.e. physicochemical factors associated with the host), and occurring in different localities of French Guiana.
We found that APB assemblages were specific to plant species and were less dependent on location or on bromeliad habitat characteristics. This convergence suggests that the identity of the bromeliad species per se is more important than habitat filtering or dispersal to control specific assembly rules for APB. The pufM OTUs were affiliated with five orders of Alpha- and Beta-proteobacteria (Rhodobacterales, Sphingomonadales, Rhizobiales, Burkholderiales and Rhodospirillales), and we assume that they may be major components of the core microbiota of plant-held waters. Our findings also revealed that up to 79% of the sequences were affiliated with APB clades possessing nitrogen-fixing genes suggesting that this metabolic capability is widespread within the APB community inhabiting tank bromeliads. We hypothesized that bromeliads may benefit nutritionally from associations with free-living APB capable to fix atmospheric nitrogen. Synthesis. Understanding the dominance of APB in tank bromeliads and determining whether a potential interplay exists between these partners is an intriguing aspect of possible mutualistic and coevolving interactions between the two existing forms of chlorophototrophy (i.e. bacteriochlorophyll-based anoxygenic and chlorophyll-based oxygenic phototrophy). In the present study, we found that bromeliad species was the main factor that explained variance in APB community composition. These findings suggest that APB and tank bromeliads may have a close, mutualistic relationship and we hypothesize according to our genomic analyses that APB may promote the bromeliad growth by provisioning essential nutrients like nitrogen.
 
  Address  
  Corporate Author Thesis  
  Publisher British Ecological Society Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1023  
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