| Records |
| Author |
Fortunel, C.; Garnier, E.; Joffre, R.; Kazakou, E.; Quested, H.; Grigulis, K.; Lavorel, S.; Ansquer, P.; Castro, H.; Cruz, P.; Dolezal, J.; Eriksson, O.; Freitas, H.; Golodets, C.; Jouany, C.; Kigel, J.; Kleyer, M.; Lehsten, V.; Leps, J.; Meier, T.; Pakeman, R.; Papadimitriou, M.; Papanastasis, V.P.; Quetier, F.; Robson, M.; Sternberg, M.; Theau, J.P.; Thebault, A.; Zarovali, M. |
| Title |
Leaf traits capture the effects of land use changes and climate on litter decomposability of grasslands across Europe |
Type |
Journal Article |
| Year |
2009 |
Publication |
Ecology |
Abbreviated Journal |
Ecology |
| Volume |
90 |
Issue |
3 |
Pages |
598-611 |
| Keywords |
climate; community functional parameters; disturbance; leaf traits; litter decomposability; litter quality |
Abstract  |
Land use and climate changes induce shifts in plant functional diversity and community structure, thereby modifying ecosystem processes. This is particularly true for litter decomposition, an essential process in the biogeochemical cycles of carbon and nutrients. In this study, we asked whether changes in functional traits of living leaves in response to changes in land use and climate were related to rates of litter potential decomposition, hereafter denoted litter decomposability, across a range of 10 contrasting sites. To disentangle the different control factors on litter decomposition, we conducted a microcosm experiment to determine the decomposability under standard conditions of litters collected in herbaceous communities from Europe and Israel. We tested how environmental factors ( disturbance and climate) affected functional traits of living leaves and how these traits then modified litter quality and subsequent litter decomposability. Litter decomposability appeared proximately linked to initial litter quality, with particularly clear negative correlations with lignin-dependent indices ( litter lignin concentration, lignin : nitrogen ratio, and fiber component). Litter quality was directly related to community-weighted mean traits. Lignin-dependent indices of litter quality were positively correlated with community-weighted mean leaf dry matter content (LDMC), and negatively correlated with community-weighted mean leaf nitrogen concentration (LNC). Consequently, litter decomposability was correlated negatively with community-weighted mean LDMC, and positively with community-weighted mean LNC. Environmental factors ( disturbance and climate) influenced community-weighted mean traits. Plant communities experiencing less frequent or less intense disturbance exhibited higher community-weighted mean LDMC, and therefore higher litter lignin content and slower litter decomposability. LDMC therefore appears as a powerful marker of both changes in land use and of the pace of nutrient cycling across 10 contrasting sites. |
| Address |
[Fortunel, Claire; Garnier, Eric; Joffre, Richard; Kazakou, Elena] CNRS, UMR 5175, Ctr Ecol Fonct & Evolut, F-34293 Montpellier 5, France, Email: claire.fortunel@ecofog.gf |
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ECOLOGICAL SOC AMER |
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Edition |
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0012-9658 |
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| Notes |
ISI:000263776800003 |
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EcoFoG @ eric.marcon @ |
Serial |
121 |
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Quéméré, Erwan ; Aucourt, Marie ; Troispoux, Valérie ; Brosse, Sébastien ; Murienne, Jérôme ; Covain, Raphael ; Le Bail, Pierre-Yves ; Olivier, Jean ; Tysklind, Niklas ; Galan, Maxime |
| Title |
Unraveling the dietary diversity of Neotropical top predators using scat DNA metabarcoding: A case study on the elusive Giant Otter |
Type |
Journal Article |
| Year |
2021 |
Publication |
Environmental DNA |
Abbreviated Journal |
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| Volume |
3 |
Issue |
5 |
Pages |
889-900 |
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| Abstract |
Large carnivores play a pivotal regulating role in maintaining healthy and balanced ecosystems; however, most of them are rare and elusive, and knowledge about their resource consumption is scarce. Traditional methods based on morphological identification of undigested remains are labor intensive and often not sufficiently accurate, leading to errors and biased ecological inferences. Here, we developed a multi-marker DNA metabarcoding approach to analyze the dietary diversity of giant otters (Pteronura brasiliensis) from fecal DNA while controlling predator species identity. We combined two mitochondrial markers, 12S rRNA and cytochrome c oxidase 1 (COI) gene, that target the full range of potential vertebrate and invertebrate prey. We compiled a local reference database of DNA barcodes for most potentially ingested fish, which were used to evaluate the specificity of the metabarcoding primers in silico. Most prey are identified at the species level (>90%) and the dietary profiles provided independently by the two markers are highly similar, whether in terms of list of prey or frequency of occurrences, hence validating the approach. We detected a higher number of rare fish prey with the 12S primers that amplified solely Teleost species while the degenerate COI primers revealed non-fish prey (e.g., amphibians, snakes, birds, and earthworms) and confirmed predator species identity. This study demonstrated that scat DNA metabarcoding is particularly useful to provide in-depth information on elusive carnivorous dietary profile. Our methodology opens up new opportunities to understand how top carnivores diet cope with the effects of anthropogenic alteration of ecosystems and identify conflicts with humans and livestock. |
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| Publisher |
Wiley |
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EcoFoG @ webmaster @ |
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1054 |
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Stahl, C.; Burban, B.; Bompy, F.; Jolin, Z.B.; Sermage, J.; Bonal, D. |
| Title |
Seasonal variation in atmospheric relative humidity contributes to explaining seasonal variation in trunk circumference of tropical rain-forest trees in French Guiana |
Type |
Journal Article |
| Year |
2010 |
Publication |
Journal of Tropical Ecology |
Abbreviated Journal |
J. Trop. Ecol. |
| Volume |
26 |
Issue |
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Pages |
393-405 |
| Keywords |
bark; drought; secondary growth; seasonality; tropical rain forest; water |
| Abstract |
Large seasonal variation in the rate of change in girth of tropical rain-forest tree species has been described, but its origin is still under debate. We tested whether this variation might be related to variation in atmospheric relative humidity through its influence on bark water content and thickness. Variation in trunk circumference of 182 adult trees was measured about twice a month in an undisturbed tropical rain forest over 18 mo using dendrometers. Furthermore, a laboratory experiment was conducted to test the direct influence of relative air humidity on bark water content and thickness. in the field, most trees displayed highly positive rates of change in girth at the onset of the wet season, while a quarter of the trees displayed negative changes during long dry seasons, whatever their total annual growth. This variation was correlated with environmental conditions, particularly with atmospheric relative humidity. Trees with high bark water content and thickness displayed a stronger decrease in girth during the dry season. in the chamber experiment, desiccation induced a decrease in the diameter of the trunk sections in tandem with a decrease in bark water content. As a result, seasonal variation in the rate of change in girth of tropical rain-forest trees reflects variation in trunk biophysical properties, through the influence of relative humidity on bark properties. but not directly variation in secondary growth. |
| Address |
[Stahl, Clement; Burban, Benoit; Bompy, Felix; Jolin, Zachari B.; Sermage, Juliette; Bonal, Damien] INRA, UMR Ecol Forets Guyane 745, Kourou 97387, French Guiana, Email: bonal@nancy.inra.fr |
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CAMBRIDGE UNIV PRESS |
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0266-4674 |
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| Notes |
ISI:000279100600005 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
57 |
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Croft, H.; Chen, J.M.; Wang, R.; Mo, G.; Luo, S.; Luo, X.; He, L.; Gonsamo, A.; Arabian, J.; Zhang, Y.; Simic-Milas, A.; Noland, T.L.; He, Y.; Homolová, L.; Malenovský, Z.; Yi, Q.; Beringer, J.; Amiri, R.; Hutley, L.; Arellano, P.; Stahl, C.; Bonal, D. |
| Title |
The global distribution of leaf chlorophyll content |
Type |
Journal Article |
| Year |
2020 |
Publication |
Remote Sensing of Environment |
Abbreviated Journal |
Remote Sens. Environ. |
| Volume |
236 |
Issue |
111479 |
Pages |
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| Abstract |
Leaf chlorophyll is central to the exchange of carbon, water and energy between the biosphere and the atmosphere, and to the functioning of terrestrial ecosystems. This paper presents the first spatially-continuous view of terrestrial leaf chlorophyll content (ChlLeaf) at the global scale. Weekly maps of ChlLeaf were produced from ENVISAT MERIS full resolution (300 m) satellite data using a two-stage physically-based radiative transfer modelling approach. Firstly, leaf-level reflectance was derived from top-of-canopy satellite reflectance observations using 4-Scale and SAIL canopy radiative transfer models for woody and non-woody vegetation, respectively. Secondly, the modelled leaf-level reflectance was input into the PROSPECT leaf-level radiative transfer model to derive ChlLeaf. The ChlLeaf retrieval algorithm was validated using measured ChlLeaf data from 248 sample measurements at 28 field locations, and covering six plant functional types (PFTs). Modelled results show strong relationships with field measurements, particularly for deciduous broadleaf forests (R2 = 0.67; RMSE = 9.25 microg cm-2; p < 0.001), croplands (R2 = 0.41; RMSE = 13.18 microg cm-2; p < 0.001) and evergreen needleleaf forests (R2 = 0.47; RMSE = 10.63 microg cm-2; p < 0.001). When the modelled results from all PFTs were considered together, the overall relationship with measured ChlLeaf remained good (R2 = 0.47, RMSE = 10.79 microg cm-2; p < 0.001). This result is an improvement on the relationship between measured ChlLeaf and a commonly used chlorophyll-sensitive spectral vegetation index; the MERIS Terrestrial Chlorophyll Index (MTCI; R2 = 0.27, p < 0.001). The global maps show large temporal and spatial variability in ChlLeaf, with evergreen broadleaf forests presenting the highest leaf chlorophyll values, with global annual median values of 54.4 microg cm-2. Distinct seasonal ChlLeaf phenologies are also visible, particularly in deciduous plant forms, associated with budburst and crop growth, and leaf senescence. It is anticipated that this global ChlLeaf product will make an important step towards the explicit consideration of leaf-level biochemistry in terrestrial water, energy and carbon cycle modelling. |
| Address |
UMR EEF, INRA Université de Lorraine, Champenoux54280, France |
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Elsevier Inc. |
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00344257 (Issn) |
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no |
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EcoFoG @ webmaster @ |
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898 |
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| Author |
Coste, S.; Roggy, J.C.; Sonnier, G.; Dreyer, E. |
| Title |
Similar irradiance-elicited plasticity of leaf traits in saplings of 12 tropical rainforest tree species with highly different leaf mass to area ratio |
Type |
Journal Article |
| Year |
2010 |
Publication |
Functional Plant Biology |
Abbreviated Journal |
Funct. Plant Biol. |
| Volume |
37 |
Issue |
4 |
Pages |
342-355 |
| Keywords |
functional diversity; light availability; photosynthetic nitrogen use efficiency; photosynthetic capacity; tropical rainforest |
| Abstract |
Leaf traits of tropical tree species display an important inter-specific diversity, as detected for instance in the large range of values of leaf mass : area ratio (LMA). They also demonstrate a large irradiance-elicited plasticity, but there is still debate whether this plasticity differs among species. To address this question, leaf traits were recorded on saplings from 12 rainforest tree species in French Guiana, grown under approximately 5, 10 and 20% relative irradiance. Fifteen structural and physiological leaf traits related to photosynthesis were measured. The irradiance-elicited plasticity was quantified using a relative distance plasticity index. A large inter-specific diversity was detected for all leaf traits. A principal component analysis opposed species with a large mass-based photosynthesis, respiration, N content and photosynthetic nitrogen use efficiency, to species with a large leaf mass : area ratio, LMA. The two pioneer species used in this study displayed the largest photosynthetic capacity (and lowest LMA) and ranked at one end of the species continuum. Relative irradiance affected almost all traits with the exception of mass-based photosynthesis. A weak interaction was found between species and relative irradiance and the species ranking was maintained among relative irradiance treatments for the majority of the traits. A principal component analysis of the values of relative-distance plasticity index failed to reveal any consistent patterns of traits or species. We concluded that irradiance-elicited plasticity of leaf traits was similar among species irrespective of LMA and successional status, despite the occurrence of a large inter-specific diversity for the investigated traits. |
| Address |
[Dreyer, Erwin] Nancy Univ, INRA, UMR Ecol & Ecophysiol Forestieres 1137, IFR Ecosyst Forestiers Agroressources Biomol & Al, F-54280 Champenoux, France, Email: dreyer@nancy.inra.fr |
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CSIRO PUBLISHING |
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1445-4408 |
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ISI:000275979100009 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
63 |
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Verryckt, L.T.; Ellsworth, D.S.; Vicca, S.; Van Langenhove, L.; Peñuelas, J.; Ciais, P.; Posada, J.M.; Stahl, C.; Coste, S.; Courtois, E.A.; Obersteiner, M.; Chave, J.; Janssens, I.A. |
| Title |
Can light-saturated photosynthesis in lowland tropical forests be estimated by one light level? |
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Journal Article |
| Year |
2020 |
Publication |
Biotropica |
Abbreviated Journal |
Biotropica |
| Volume |
52 |
Issue |
6 |
Pages |
1183-1193 |
| Keywords |
canopy architecture; interspecific variation; light intensity; lowland environment; parameter estimation; photon flux density; photosynthesis; saturation; tropical forest; French Guiana |
| Abstract |
Leaf-level net photosynthesis (An) estimates and associated photosynthetic parameters are crucial for accurately parameterizing photosynthesis models. For tropical forests, such data are poorly available and collected at variable light conditions. To avoid over- or underestimation of modeled photosynthesis, it is critical to know at which photosynthetic photon flux density (PPFD) photosynthesis becomes light-saturated. We studied the dependence of An on PPFD in two tropical forests in French Guiana. We estimated the light saturation range, including the lowest PPFD level at which Asat (An at light saturation) is reached, as well as the PPFD range at which Asat remained unaltered. The light saturation range was derived from photosynthetic light-response curves, and within-canopy and interspecific differences were studied. We observed wide light saturation ranges of An. Light saturation ranges differed among canopy heights, but a PPFD level of 1,000 µmol m−2 s−1 was common across all heights, except for pioneer trees species that did not reach light saturation below 2,000 µmol m−2 s−1. A light intensity of 1,000 µmol m−2 s−1 sufficed for measuring Asat of climax species at our study sites, independent of the species or the canopy height. Because of the wide light saturation ranges, results from studies measuring Asat at higher PPFD levels (for upper canopy leaves up to 1,600 µmol m−2 s−1) are comparable with studies measuring at 1,000 µmol m−2 s−1. © 2020 The Association for Tropical Biology and Conservation |
| Address |
UMR 5174, Laboratoire Evolution et Diversité Biologique, CNRS, Université Paul Sabatier, Toulouse, France |
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Blackwell Publishing Ltd |
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00063606 (Issn) |
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EcoFoG @ webmaster @ |
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948 |
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Levionnois, Sébastien ; Ziegler, Camille ; Heuret, Patrick ; Jansen, Steven ; Stahl, Clément ; Calvet, Emma ; Goret, Jean-Yves ; Bonal, Damien ; Coste, Sabrina |
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Is vulnerability segmentation at the leaf‑stem transition a drought resistance mechanism? A theoretical test with a trait‑based model for Neotropical canopy tree species |
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Journal Article |
| Year |
2021 |
Publication |
Annals of Forest Science |
Abbreviated Journal |
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| Volume |
78 |
Issue |
4 |
Pages |
78-87 |
| Keywords |
Neotropics, bark, canopy, capacitance, drought, drought tolerance, embolism, leaves, models, transpiration, trees, tropical rain forests, xylem |
| Abstract |
Leaf-stem vulnerability segmentation predicts lower xylem embolism resistance in leaves than stem. However, although it has been intensively investigated these past decades, the extent to which vulnerability segmentation promotes drought resistance is not well understood. Based on a trait-based model, this study theoretically supports that vulnerability segmentation enhances shoot desiccation time across 18 Neotropical tree species. CONTEXT: Leaf-stem vulnerability segmentation predicts lower xylem embolism resistance in leaves than stems thereby preserving expensive organs such as branches or the trunk. Although vulnerability segmentation has been intensively investigated these past decades to test its consistency across species, the extent to which vulnerability segmentation promotes drought resistance is not well understood. AIMS: We investigated the theoretical impact of the degree of vulnerability segmentation on shoot desiccation time estimated with a simple trait-based model. METHODS: We combined data from 18 tropical rainforest canopy tree species on embolism resistance of stem xylem (flow-centrifugation technique) and leaves (optical visualisation method). Measured water loss under minimum leaf and bark conductance, leaf and stem capacitance, and leaf-to-bark area ratio allowed us to calculate a theoretical shoot desiccation time (tcᵣᵢₜ). RESULTS: Large degrees of vulnerability segmentation strongly enhanced the theoretical shoot desiccation time, suggesting vulnerability segmentation to be an efficient drought resistance mechanism for half of the studied species. The difference between leaf and bark area, rather than the minimum leaf and bark conductance, determined the drastic reduction of total transpiration by segmentation during severe drought. CONCLUSION: Our study strongly suggests that vulnerability segmentation is an important drought resistance mechanism that should be better taken into account when investigating plant drought resistance and modelling vegetation. We discuss future directions for improving model assumptions with empirical measures, such as changes in total shoot transpiration after leaf xylem embolism. |
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Springer Link |
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EcoFoG @ webmaster @ |
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1034 |
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Barabe, D.; Cuerrier, A.; Quilichini, A. |
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Botanical gardens: Between science and commercialization |
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Journal Article |
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2012 |
Publication |
Natures Sciences Societes |
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20 |
Issue |
3 |
Pages |
334-342 |
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Les jardins botaniques: Entre science et commercialisation. |
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Enseignante-chercheure en Écologie, CNRS, UMR8172 Icologie des Dorêts de Guyane, 97387 Kourou, France |
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Export Date: 3 January 2013; Source: Scopus |
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EcoFoG @ webmaster @ |
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455 |
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Fayad, I.; Baghdadi, N.; Bailly, J.-S.; Barbier, N.; Gond, V.; Herault, B.; El Hajj, M.; Fabre, F.; Perrin, J. |
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Regional scale rain-forest height mapping using regression-kriging of spaceborne and airborne LiDAR data: Application on French Guiana |
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Journal Article |
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2016 |
Publication |
Remote Sensing |
Abbreviated Journal |
Remote Sensing |
| Volume |
8 |
Issue |
3 |
Pages |
240 |
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Airborne LiDAR; Canopy height mapping; Forests; French Guiana; ICESat GLAS |
| Abstract |
LiDAR data has been successfully used to estimate forest parameters such as canopy heights and biomass. Major limitation of LiDAR systems (airborne and spaceborne) arises from their limited spatial coverage. In this study, we present a technique for canopy height mapping using airborne and spaceborne LiDAR data (from the Geoscience Laser Altimeter System (GLAS)). First, canopy heights extracted from both airborne and spaceborne LiDAR were extrapolated from available environmental data. The estimated canopy height maps using Random Forest (RF) regression from airborne or GLAS calibration datasets showed similar precisions (~6 m). To improve the precision of canopy height estimates, regression-kriging was used. Results indicated an improvement in terms of root mean square error (RMSE, from 6.5 to 4.2 m) using the GLAS dataset, and from 5.8 to 1.8 m using the airborne LiDAR dataset. Finally, in order to investigate the impact of the spatial sampling of future LiDAR missions on canopy height estimates precision, six subsets were derived from the initial airborne LiDAR dataset. Results indicated that using the regression-kriging approach a precision of 1.8 m on the canopy height map was achievable with a flight line spacing of 5 km. This precision decreased to 4.8 m for flight line spacing of 50 km. © 2016 by the authors. |
| Address |
BRGM, 3 Avenue Claude Guillemin, Orléans, France |
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Export Date: 22 April 2016 |
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EcoFoG @ webmaster @ |
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675 |
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Biwolé, A.B.; Dainou, K.; Fayolle, A.; Hardy, O.J.; Brostaux, Y.; Coste, S.; Delion, S.; Betti, J.L.; Doucet, J.-L. |
| Title |
Light Response of Seedlings of a Central African Timber Tree Species, Lophira alata (Ochnaceae), and the Definition of Light Requirements |
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Journal Article |
| Year |
2015 |
Publication |
Biotropica |
Abbreviated Journal |
Biotropica |
| Volume |
47 |
Issue |
6 |
Pages |
681-688 |
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biomass allocation; Central Africa; light requirement: Lophira alata; population; relative growth rate; seedling growth; timber species; Afrique centrale; allocation de biomasse; besoins en lumière; croissance des semis; bois d'œuvre; Lophira alata; population; taux de croissance relatif |
| Abstract |
Light is of primary importance in structuring tropical tree communities. Light exposure at seedling and adult stages has been used to characterize the ecological profile of tropical trees, with many implications in forest management and restoration ecology. Most shade-tolerance classification systems have been proposed based on empirical observations in a specific area and thus result in contradictions among categories assigned to a given species. In this study, we aimed to quantify the light requirements for seedling growth of a Central African timber tree, Lophira alata (Ochnaceae), taking into account effects of population origin. In two controlled experiments: a light response experiment and a comparative population experiment, conducted in southwestern Cameroon, using seeds collected from four populations (three from Cameroon and one from Gabon), we examined the quantitative responses to irradiance of seedlings. After 2 years, mortality was very low (<3%), even in extremely low irradiance. Growth and biomass allocation patterns varied in response to light, with intermediate irradiance (24–43%) providing optimal conditions. Light response differed between populations. The Boumba population in the northeastern edge of the species' distribution exhibited the highest light requirements, suggesting a local adaptation. As a result of positive growth at low irradiance and maximum growth at intermediate irradiance, we concluded that L. alata exhibits characteristics of both non-pioneer and pioneer species. Implications of our results to propose an objective way to assign the light requirement for tropical tree species are discussed. |
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1744-7429 |
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EcoFoG @ webmaster @ |
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648 |
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