| Records |
| Author |
Ntawuhiganayo, E.B.; Uwizeye, F.K.; Zibera, E.; Dusenge, M.E.; Ziegler, C.; Ntirugulirwa, B.; Nsabimana, D.; Wallin, G.; Uddling, J. |
| Title |
Traits controlling shade tolerance in tropical montane trees |
Type |
Journal Article |
| Year |
2020 |
Publication |
Tree physiology |
Abbreviated Journal |
Tree Physiol. |
| Volume |
40 |
Issue |
2 |
Pages |
183-197 |
| Keywords |
biomass allocation; leaf temperature; plant traits; Rwanda; shade intolerance; shade tolerance; tropical montane forest; article; biomass allocation; breathing; canopy; carbon balance; compensation; photosynthesis; plant leaf; plant stem; rain forest; Rwanda; shade tolerance; species difference; sweating |
Abstract  |
Tropical canopies are complex, with multiple canopy layers and pronounced gap dynamics contributing to their high species diversity and productivity. An important reason for this complexity is the large variation in shade tolerance among different tree species. At present, we lack a clear understanding of which plant traits control this variation, e.g., regarding the relative contributions of whole-plant versus leaf traits or structural versus physiological traits. We investigated a broad range of traits in six tropical montane rainforest tree species with different degrees of shade tolerance, grown under three different radiation regimes (under the open sky or beneath sparse or dense canopies). The two distinct shade-tolerant species had higher fractional biomass in leaves and branches while shade-intolerant species invested more into stems, and these differences were greater under low radiation. Leaf respiration and photosynthetic light compensation point did not vary with species shade tolerance, regardless of radiation regime. Leaf temperatures in open plots were markedly higher in shade-tolerant species due to their low transpiration rates and large leaf sizes. Our results suggest that interspecific variation in shade tolerance of tropical montane trees is controlled by species differences in whole-plant biomass allocation strategy rather than by difference in physiological leaf traits determining leaf carbon balance at low radiation. © The Author(s) 2019. Published by Oxford University Press. |
| Address |
Rwanda Agriculture and Animal Resources Development, PO Box 5016Kigali, Rwanda |
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| Publisher |
NLM (Medline) |
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| ISSN |
17584469 (Issn) |
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| Notes |
Export Date: 16 March 2020 |
Approved |
no |
| Call Number |
EcoFoG @ webmaster @ |
Serial |
922 |
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| Author |
Laybros, A.; Aubry-Kientz, M.; Féret, J.-B.; Bedeau, C.; Brunaux, O.; Derroire, G.; Vincent, G. |
| Title |
Quantitative airborne inventories in dense tropical forest using imaging spectroscopy |
Type |
Journal Article |
| Year |
2020 |
Publication |
Remote Sensing |
Abbreviated Journal |
Remote Sens. |
| Volume |
12 |
Issue |
10 |
Pages |
1577 |
| Keywords |
Hyperspectral; LiDAR; Species diversity; Tropical forest; Cost effectiveness; Discriminant analysis; Infrared devices; Infrared radiation; Logistic regression; Remote sensing; Tropics; Classification accuracy; Classification performance; Linear discriminant analysis; Operational applications; Regularized discriminant analysis; Remote sensing technology; Short wave infrared bands; Visible and near infrared; Forestry |
| Abstract |
Tropical forests have exceptional floristic diversity, but their characterization remains incomplete, in part due to the resource intensity of in-situ assessments. Remote sensing technologies can provide valuable, cost-effective, large-scale insights. This study investigates the combined use of airborne LiDAR and imaging spectroscopy to map tree species at landscape scale in French Guiana. Binary classifiers were developed for each of 20 species using linear discriminant analysis (LDA), regularized discriminant analysis (RDA) and logistic regression (LR). Complementing visible and near infrared (VNIR) spectral bands with short wave infrared (SWIR) bands improved the mean average classification accuracy of the target species from 56.1% to 79.6%. Increasing the number of non-focal species decreased the success rate of target species identification. Classification performance was not significantly affected by impurity rates (confusion between assigned classes) in the non-focal class (up to 5% of bias), provided that an adequate criterion was used for adjusting threshold probability assignment. A limited number of crowns (30 crowns) in each species class was sufficient to retrieve correct labels effectively. Overall canopy area of target species was strongly correlated to their basal area over 118 ha at 1.5 ha resolution, indicating that operational application of the method is a realistic prospect (R2 = 0.75 for six major commercial tree species). © 2020 by the authors. |
| Address |
Cirad, UMR EcoFoG (AgroParistech, CNRS, INRAE, Université des Antilles, Université de la Guyane), Kourou, French Guiana, 97379, France |
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| Publisher |
Mdpi Ag |
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20724292 (Issn) |
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no |
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EcoFoG @ webmaster @ |
Serial |
969 |
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| Author |
Schmitt, S.; Hérault, B.; Ducouret, É.; Baranger, A.; Tysklind, N.; Heuertz, M.; Marcon, É.; Cazal, S.O.; Derroire, G. |
| Title |
Topography consistently drives intra- and inter-specific leaf trait variation within tree species complexes in a Neotropical forest |
Type |
Journal Article |
| Year |
2020 |
Publication |
Oikos |
Abbreviated Journal |
Oikos |
| Volume |
129 |
Issue |
10 |
Pages |
1521-1530 |
| Keywords |
intraspecific variability; leaf traits; Paracou; species complex; syngameon; tropical forests; Bayesian analysis; coexistence; divergence; genetic variation; hierarchical system; leaf area; local adaptation; niche overlap; species diversity; topography; tropical forest; Guyana Shield |
| Abstract |
Tropical forests shelter the highest species diversity worldwide, although genus diversity is lower than expected. In the species-rich genera, species complexes are composed of closely-related species that share large amounts of genetic variation. Despite the key role of species complexes in diversification, evolution and functioning of ecological communities, little is known on why species complexes arise and how they are maintained in Neotropical forests. Examining how individual phenotypes vary along environmental gradients, within and among closely-related species within species complexes, can reveal processes allowing species coexistence within species complexes. We examined leaf functional trait variation with topography in a hyperdiverse tropical forest of the Guiana Shield. We collected leaf functional traits from 766 trees belonging to five species in two species complexes in permanent plots encompassing a diversity of topographic positions. We tested the role of topography on leaf functional trait variation with a hierarchical Bayesian model, controlling for individual tree diameter effect. We show that, mirroring what has been previously observed among species and communities, individual leaf traits covary from acquisitive to conservative strategy within species. Moreover, decreasing wetness from bottomlands to plateaus was associated with a shift of leaf traits from an acquisitive to a conservative strategy both across and within closely-related species. Our results suggest that intraspecific trait variability widens species’ niches and converges at species’ margins where niches overlap, potentially implying local neutral processes. Intraspecific trait variability favors local adaptation and divergence of closely-related species within species complexes. It is potentially maintained through interspecific sharing of genetic variation through hybridization. © 2020 Nordic Society Oikos. Published by John Wiley & Sons Ltd |
| Address |
INRAE, UMR EcoFoG (Agroparistech, CNRS, Cirad, Université des Antilles, Univ. de la Guyane), Kourou, French Guiana |
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| Publisher |
Blackwell Publishing Ltd |
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00301299 (Issn) |
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no |
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EcoFoG @ webmaster @ |
Serial |
950 |
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Gargallo-Garriga, A.; Sardans, J.; Granda, V.; Llusià, J.; Peguero, G.; Asensio, D.; Ogaya, R.; Urbina, I.; Van Langenhove, L.; Verryckt, L.T.; Chave, J.; Courtois, E.A.; Stahl, C.; Grau, O.; Klem, K.; Urban, O.; Janssens, I.A.; Peñuelas, J. |
| Title |
Different “metabolomic niches” of the highly diverse tree species of the French Guiana rainforests |
Type |
Journal Article |
| Year |
2020 |
Publication |
Scientific Reports |
Abbreviated Journal |
Sci. Rep. |
| Volume |
10 |
Issue |
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Pages |
6937 |
| Keywords |
article; ecological niche; French Guiana; metabolome; plant leaf; rainy season; reproduction; stress; tropical rain forest |
| Abstract |
Tropical rainforests harbor a particularly high plant diversity. We hypothesize that potential causes underlying this high diversity should be linked to distinct overall functionality (defense and growth allocation, anti-stress mechanisms, reproduction) among the different sympatric taxa. In this study we tested the hypothesis of the existence of a metabolomic niche related to a species-specific differential use and allocation of metabolites. We tested this hypothesis by comparing leaf metabolomic profiles of 54 species in two rainforests of French Guiana. Species identity explained most of the variation in the metabolome, with a species-specific metabolomic profile across dry and wet seasons. In addition to this “homeostatic” species-specific metabolomic profile significantly linked to phylogenetic distances, also part of the variance (flexibility) of the metabolomic profile was explained by season within a single species. Our results support the hypothesis of the high diversity in tropical forest being related to a species-specific metabolomic niche and highlight ecometabolomics as a tool to identify this species functional diversity related and consistent with the ecological niche theory. © 2020, The Author(s). |
| Address |
INRA, UMR EcoFoG, CNRS, Cirad, AgroParisTech, Université des Antilles, Université de Guyane, Kourou, 97310, France |
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Thesis |
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| Publisher |
Nature Research |
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20452322 (Issn) |
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no |
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EcoFoG @ webmaster @ |
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930 |
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Céréghino, R.; Corbara, B.; Leroy, C.; Carrias, J.-F. |
| Title |
Ecological determinants of community structure across the trophic levels of freshwater food webs: a test using bromeliad phytotelmata |
Type |
Journal Article |
| Year |
2020 |
Publication |
Hydrobiologia |
Abbreviated Journal |
Hydrobiologia |
| Volume |
847 |
Issue |
2 |
Pages |
391-402 |
| Keywords |
Environmental filtering; Functional group; Neotropical; Niche; Trophic interactions; alga; assembly rule; bacterium; community structure; ecological modeling; environmental conditions; food web; freshwater ecosystem; functional group; Neotropic Ecozone; niche; protozoan; taxonomy; trophic interaction; trophic level; algae; Invertebrata; Protozoa |
| Abstract |
Understanding the relative importance of habitat and biotic drivers on community assembly across food web components is an important step towards predicting the consequences of environmental changes. Because documenting entire food webs is often impractical, this question has been only partially investigated. Here, we partitioned variation in species assemblages of the major components of tank bromeliad food webs (bacteria, algae, protozoans, detritivorous and predatory invertebrates) into habitat and biotic determinants and examined the influence of habitat variables and predator or prey abundance on all taxonomic assemblages. Ecological determinism of assemblage structure ranged from weak in bacteria (< 10% of the explained variance) to strong in predatory invertebrates (90%). Habitat features and canopy openness significantly influenced species assemblages; however, prey or predator density had far and away the most significant structuring effects. If biotic forces are at least as important as the abiotic forces while the importance of stochasticity declines towards upper trophic levels, then trophic levels could respond differently to natural or anthropogenic disturbance and to shifts in species distributions. The effects of such differential responses on food web reconfiguration, however, remain to be elucidated. © 2019, Springer Nature Switzerland AG. |
| Address |
UMR EcoFoG (AgroParisTech, CIRAD, CNRS, INRA, Université de Guyane, Université des Antilles), Kourou, 97310, France |
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Springer |
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00188158 (Issn) |
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no |
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EcoFoG @ webmaster @ |
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996 |
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Touchard, A.; Aili, S.R.; Téné, N.; Barassé, V.; Klopp, C.; Dejean, A.; Kini, R.M.; Mrinalini; Coquet, L.; Jouenne, T.; Lefranc, B.; Leprince, J.; Escoubas, P.; Nicholson, G.M.; Treilhou, M.; Bonnafé, E. |
| Title |
Venom Peptide Repertoire of the European Myrmicine Ant Manica rubida: Identification of Insecticidal Toxins |
Type |
Journal Article |
| Year |
2020 |
Publication |
Journal of proteome research |
Abbreviated Journal |
J. Proteome Res. |
| Volume |
19 |
Issue |
4 |
Pages |
1800-1811 |
| Keywords |
glycosylated toxin; peptidome; polycationic α-helix; predation; pyroglutamate; reversible neurotoxicity |
| Abstract |
Using an integrated transcriptomic and proteomic approach, we characterized the venom peptidome of the European red ant, Manica rubida. We identified 13 “myrmicitoxins” that share sequence similarities with previously identified ant venom peptides, one of them being identified as an EGF-like toxin likely resulting from a threonine residue modified by O-fucosylation. Furthermore, we conducted insecticidal assays of reversed-phase HPLC venom fractions on the blowfly Lucilia caesar, permitting us to identify six myrmicitoxins (i.e., U3-, U10-, U13-, U20-MYRTX-Mri1a, U10-MYRTX-Mri1b, and U10-MYRTX-Mri1c) with an insecticidal activity. Chemically synthesized U10-MYRTX-Mri1a, -Mri1b, -Mri1c, and U20-MYRTX-Mri1a irreversibly paralyzed blowflies at the highest doses tested (30-125 nmol·g-1). U13-MYRTX-Mri1a, the most potent neurotoxic peptide at 1 h, had reversible effects after 24 h (150 nmol·g-1). Finally, U3-MYRTX-Mri1a has no insecticidal activity, even at up to 55 nmol·g-1. Thus, M. rubida employs a paralytic venom rich in linear insecticidal peptides, which likely act by disrupting cell membranes. |
| Address |
VenomeTech, 473 Route des Dolines – Villa 3, Valbonne, 06560, France |
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NLM (Medline) |
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15353907 (Issn) |
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Export Date: 20 April 2020 |
Approved |
no |
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EcoFoG @ webmaster @ |
Serial |
927 |
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Soong, J.L.; Janssens, I.A.; Grau, O.; Margalef, O.; Stahl, C.; Van Langenhove, L.; Urbina, I.; Chave, J.; Dourdain, A.; Ferry, B.; Freycon, V.; Herault, B.; Sardans, J.; Peñuelas, J.; Verbruggen, E. |
| Title |
Soil properties explain tree growth and mortality, but not biomass, across phosphorus-depleted tropical forests |
Type |
Journal Article |
| Year |
2020 |
Publication |
Scientific reports |
Abbreviated Journal |
Sci Rep |
| Volume |
10 |
Issue |
2302 |
Pages |
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| Abstract |
We observed strong positive relationships between soil properties and forest dynamics of growth and mortality across twelve primary lowland tropical forests in a phosphorus-poor region of the Guiana Shield. Average tree growth (diameter at breast height) increased from 0.81 to 2.1 mm yr-1 along a soil texture gradient from 0 to 67% clay, and increasing metal-oxide content. Soil organic carbon stocks in the top 30 cm ranged from 30 to 118 tons C ha-1, phosphorus content ranged from 7 to 600 mg kg-1 soil, and the relative abundance of arbuscular mycorrhizal fungi ranged from 0 to 50%, all positively correlating with soil clay, and iron and aluminum oxide and hydroxide content. In contrast, already low extractable phosphorus (Bray P) content decreased from 4.4 to <0.02 mg kg-1 in soil with increasing clay content. A greater prevalence of arbuscular mycorrhizal fungi in more clayey forests that had higher tree growth and mortality, but not biomass, indicates that despite the greater investment in nutrient uptake required, soils with higher clay content may actually serve to sustain high tree growth in tropical forests by avoiding phosphorus losses from the ecosystem. Our study demonstrates how variation in soil properties that retain carbon and nutrients can help to explain variation in tropical forest growth and mortality, but not biomass, by requiring niche specialization and contributing to biogeochemical diversification across this region. |
| Address |
Institut National Polytechnique Félix Houphouët-Boigny, Ivory CoastYamoussoukro, Cote d'Ivoire |
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NLM (Medline) |
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Edition |
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20452322 (Issn) |
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no |
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EcoFoG @ webmaster @ |
Serial |
916 |
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