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13 results on '"Gilles Dauby"'

1. Impact of end‐of‐century climate change on priority non‐timber forest product species across tropical Africa

Author

Biowa Eldys N. Amoussou, Rodrigue Idohou, Romain Glèlè Kakaï, Gilles Dauby, Thomas L. P. Couvreur, Université d’Abomey-Calavi = University of Abomey Calavi (UAC), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Montpellier (UM), Diversité, adaptation, développement des plantes (UMR DIADE), and Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Université de Montpellier (UM)

Subjects
[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Representative concentration pathways, Species distribution modelling, Dispersal, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, Ecology, Evolution, Behavior and Systematics, NTFP
Abstract

International audience; Plant species providing Non-Timber Forest Products (NTFP) are economically important across Africa. How this heterogeneous and understudied resource will respond to ongoing climate change remains understudied. Here, we modelled the impact of end-of-the-century climate change on the distribution of 40 NTFP plant species distributed across tropical Africa. Occurrence data were extracted from a taxonomically verified database and three different ecological niche modelling algorithms were used. Species distributions were modelled under two end-of-century (2085) climate change models (RCP4.5 and RCP8.5) and two dispersal scenarios (limited and expanded). We show that for the 40 NTFP plant species studied here, different responses are modelled with some species gaining in suitable habitats (47.5%–65% under RCP4.5), whereas others will lose in suitable habitats (35%–52.5% under RCP4.5). Nevertheless, we also show that our results vary between the different methods used, such as modelling algorithms, dispersal scenarios and general circulation models. Overall, our results suggest that the response of NTFP species to climate change depends on their distribution, ecology and dispersal ability.

Published
2022

2. Additive influences of soil and climate gradients drive tree community composition of Central African rain forests

Author

Nicolas Texier, Raphaël Pélissier, Donatien Zebaze, Moses Libalah, Stéphane Takoudjou Momo, Bonaventure Sonké, Narcisse Guy Kamdem, Nicolas Barbier, Gislain Ii Mofack, Claire Fortunel, Pierre Couteron, Simon L. Lewis, Gilles Dauby, Vincent Droissart, Pierre Ploton, Gyslene Kamdem, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), University of Yaoundé [Cameroun], Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire de Botanique et Ecologie, Université de Yaoundé I, Université libre de Bruxelles (ULB), Laboratoire de Botanique systématique et d'Ecologie [ENS Yaoudé], and Université de Yaoundé I-École normale supérieure [ENS] - Yaoundé 1

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Soil gradient, Plant Science, Rainforest, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 010603 evolutionary biology, 01 natural sciences, Climate gradient, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Cameroon, Relative species abundance, 0105 earth and related environmental sciences, 2. Zero hunger, Ecology, Species abundance, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, 15. Life on land, Tropical rain forest, Tree (data structure), Community composition, 13. Climate action, Species occurrence, Environmental science, Tropical rainforests, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; Aim: Examining tree species-environment association can offer insight into the drivers of vegetation patterns and key information of practical relevance to forest management. Here, we aim to quantify the contribution of climate and soil gradients to variation in Central African tree species composition (abundance and occurrence). Location: Tropical rainforests of southern and eastern Cameroon. Methods: We established 82 1-ha permanent plots across seven localities and censused all trees ≥ 10 cm in diameter, representing a total of 37,733 trees and 455 species. In 60 of those plots, we measured ten soil variables describing texture and nutrients levels and extracted ten bioclimatic variables from global-gridded climate databases. We synthesized the main environmental gradients by conducting principal component analyses on climate and soil data respectively. We performed unconstrained and constrained non-symmetric correspondence analyses to account for the individual and joint contributions of climate and soil on species abundance and occurrence. Results: Climate and soil contributed similarly to variances of species abundance and occurrence (12–15 % variance for climate vs. 11–12 % variance for soil). Climate influence mostly concerns some abundant species, while some of the less abundant species were mainly driven by soil. Fractions of species variances accounted for by climate and soil show strong correlation when assessed from species occurrence and abundance data. Conclusion: Variation in occurrence and abundance of tropical forest trees can be partly shaped by both climate and soil gradients in Cameroon, which emphasizes the importance to jointly consider soil and climate in species distribution modeling. Less abundant species may express environmental influence differently than abundant species and convey complementary information about community assemblage. Though showing congruent patterns here, species abundance and occurrence reflect different interacting community processes and both should be examined to better understand vegetation patterns.

Published
2020

3. The ECAT dataset: expert-validated distribution data of endemic and sub-endemic trees of Central Africa (Dem. Rep. Congo, Rwanda, Burundi)

Author

Wesley Tack, Henry Engledow, Nuno Veríssimo Pereira, Christian Amani, Steven P. Bachman, Patricia Barberá, Henk J. Beentje, Gaël U. D. Bouka, Martin Cheek, Ariane Cosiaux, Gilles Dauby, Petra De Block, Corneille E. N. Ewango, Eberhard Fischer, Roy E. Gereau, Serene Hargreaves, Yvette Harvey-Brown, Davy U. Ikabanga, Edouard Ilunga wa Ilunga, James Kalema, Peris Kamau, Olivier Lachenaud, Quentin Luke, Ithe Mwanga Mwanga, Sydney T. Ndolo Ebika, Jacques Nkengurutse, Aimable Nsanzurwimo, Salvator Ntore, Sophie L. Richards, Reddy Shutsha Ehata, Murielle Simo-Droissart, Tariq Stévart, Marc S. M. Sosef, Meise Botanic Garden [Belgium] (Plantentuin), Université officielle de Bukavu, Royal Botanic Gardens [Kew], Missouri Botanical Garden, International Union for Conservation of Nature (IUCN), University of Yaoundé [Cameroun], Université de Montpellier (UM), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Montpellier (UM), Université libre de Bruxelles (ULB), and Université de Yaoundé I

Subjects
flowering plants, endemics, geographic range, conservation, threatened, Plant Science, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, IUCN Red List, data capture, flora, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Africa, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Ecology, Evolution, Behavior and Systematics, data cleaning, herbarium
Abstract

International audience; In this data paper, we present a specimen-based occurrence dataset compiled in the framework of the Conservation of Endemic Central African Trees (ECAT) project with the aim of producing global conservation assessments for the IUCN Red List. The project targets all tree species endemic or sub-endemic to the Central African region comprising the Democratic Republic of the Congo (DR Congo), Rwanda, and Burundi. The dataset contains 6361 plant collection records with occurrences of 8910 specimens from 337 taxa belonging to 153 genera in 52 families. Many of these tree taxa have restricted geographic ranges and are only known from a small number of herbarium specimens. As assessments for such taxa can be compromised by inadequate data, we transcribed and geo-referenced specimen label information to obtain a more accurate and complete locality dataset. All specimen data were manually cleaned and verified by botanical experts, resulting in improved data quality and consistency.

Published
2022

4. An efficient method for defining plant species under High Conservation Value (HCV) criterion 1 based on the IUCN Red List criteria: A case study using species endemic to Gabon

Author

Gilles Dauby, Porter P. Lowry, Nicolas Texier, Tariq Stévart, Ehoarn Bidault, Davy U. Ikabanga, Université libre de Bruxelles (ULB), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Missouri Botanical Garden, Institut de Systématique, Evolution, Biodiversité (ISYEB ), Muséum national d'Histoire naturelle (MNHN)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Université des Sciences et Techniques de Masuku [Franceville, Gabon] (USTM), and Botanic Garden Meise

Subjects
0106 biological sciences, Ecology, Agroforestry, 010604 marine biology & hydrobiology, Sustainable forest management, Logging, Rare species, Endangered species, 15. Life on land, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 010603 evolutionary biology, 01 natural sciences, Geography, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Habitat, Threatened species, IUCN Red List, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Endemism, Nature and Landscape Conservation
Abstract

International audience; The High Conservation Value (HCV) concept, developed by the Forest Stewardship Council to promote sustainable forest management, is widely employed for certification of forestry and agriculture concessions, and has been adopted by many logging and palm oil companies. HCV criterion 1, which deals with “endemic, and rare, threatened or endangered species”, is rarely used in certification, mainly because lists of these species are incomplete, especially for plants, and performing threat assessments is time-consuming. The IUCN Red List Categories are often suggested as a suitable basis to define threatened taxa for the application of HCV1, but this requires the rapid and efficient assessment of large numbers of species. Using the plants endemic to Gabon as a case study, we propose a rapid, two-step procedure to identify HCV1 species. First, based on 3,298 verified and geo-referenced herbarium records, we used GIS layers and an automated computational workflow in the R environment to identify potentially threatened species using an approach aligned with IUCN Red List criteria A, B, and D. Ninety percent of the automated assessments correctly indicated the risk of extinction; errors involved incorrect assessments of species whose habitat is in reality not threatened, or occurred during the calculation of the number of locations (sensu IUCN) when a single threat impacts large areas. In a second step designed to correct these issues and comply with the Red List guidelines, we performed species-by-species verification of the automated assessments, taking into account the ecology and habitat of each species and the nature of the threats it faces. Of the 389 endemic taxa analyzed, 86 % were identified as threatened (83 CR, 171 EN, and 80 VU); of these, only 35 % are recorded from at least one National Park, but most are found in logging/oil palm (72 %) or mining (55 %) concessions, underscoring the need to improve the application of the HCV concept. To strengthen the use of HVC subcriterion 1.2 (rare, threatened or endangered species), we propose an explicit method for identifying rare species based on a quantitative threshold of the Extent of Occurrence (20,000 km²), and we examine the concept of endemicity with respect to the application of HVC subcriterion 1.3 (endemic species). The proposed methodology addresses an urgent need to develop a national interpretation of the HCV concept in Gabon, adopted as a national standard for logging concessions, and offers an efficient, reliable approach for the application of HVC1 elsewhere in Central Africa.

Published
2021

5. Unveiling African rainforest composition and vulnerability to global change

Author

Sylvie Gourlet-Fleury, Maxime Réjou-Méchain, Catherine Trottier, Adeline Fayolle, Olga Diane Yongo, Jean Joël Loumeto, Jean-Paul Kibambe Lubamba, Guillaume Cornu, Fabrice Bénédet, Raphaël Pélissier, Nicolas Bayol, Alfred Ngomanda, Nicolas Barbier, Gilles Dauby, Ruppert Vimal, Pierre Ploton, Jean-Louis Doucet, Vincent Deblauwe, Xavier Bry, Jean-François Bastin, Claude Garcia, Charles Doumenge, Bonaventure Sonké, Frédéric Mortier, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Forêts et Sociétés (UPR Forêts et Sociétés), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Département Environnements et Sociétés (Cirad-ES), Département Systèmes Biologiques (Cirad-BIOS), Gembloux Agro-Bio Tech [Gembloux], Université de Liège, FRM Ingénierie, Institut Montpelliérain Alexander Grothendieck (IMAG), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley], University of California, International Institute of Tropical Agriculture [Nigeria] (IITA), Consultative Group on International Agricultural Research [CGIAR] (CGIAR), Université Libre de Kinshasa (ULK), Université Marien Ngouabi, Institut de Recherche en Ecologie Tropicale (IRET), Centre national de la recherche scientifique et technologique (CENAREST), University of Yaoundé [Cameroun], Géographie de l'environnement (GEODE), Université Toulouse - Jean Jaurès (UT2J)-Centre National de la Recherche Scientifique (CNRS), Université de Bangui, BELSPO, FWF, ANR-12-EBID-0002,CoForTips,Forêts du Bassin du Congo: Biodiversité, Points de Basculement et Résilience des Systèmes Écologiques et Sociaux Forestiers.(2012), ANR-18-CE02-0025,GAMBAS,Nouvelles avancées dans la modélisation de la biodiversité et des services écosystémiques : améliorations statistiques et pertinences écologiques des modèles de distribution multi-espèces(2018), European Project: 3DForMod, University of California [Berkeley] (UC Berkeley), University of California (UC), Université Toulouse - Jean Jaurès (UT2J), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Acclimatization, Vulnerability, Distribution (economics), Datasets as Topic, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 01 natural sciences, Global Warming, Trees, conservation des forêts, Abundance (ecology), K01 - Foresterie - Considérations générales, Human Activities, Forêt tropicale humide, education.field_of_study, Multidisciplinary, type forestier (composition botanique), Ecology, Temperature, Sustainable Development, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, Tropical ecology, Geography, protection de la forêt, P01 - Conservation de la nature et ressources foncières, Seasons, Rainforest, P40 - Météorologie et climatologie, Distribution géographique, Population, Climate change, Flowers, Distribution des populations, 010603 evolutionary biology, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Humans, vulnérabilité, Africa, Central, Community ecology, education, Population Growth, 0105 earth and related environmental sciences, Changement climatique, business.industry, Global change, 15. Life on land, 13. Climate action, Sustainability, Africa, Forest ecology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, business, Climate-change impacts
Abstract

Africa is forecasted to experience large and rapid climate change1 and population growth2 during the twenty-first century, which threatens the world’s second largest rainforest. Protecting and sustainably managing these African forests requires an increased understanding of their compositional heterogeneity, the environmental drivers of forest composition and their vulnerability to ongoing changes. Here, using a very large dataset of 6 million trees in more than 180,000 field plots, we jointly model the distribution in abundance of the most dominant tree taxa in central Africa, and produce continuous maps of the floristic and functional composition of central African forests. Our results show that the uncertainty in taxon-specific distributions averages out at the community level, and reveal highly deterministic assemblages. We uncover contrasting floristic and functional compositions across climates, soil types and anthropogenic gradients, with functional convergence among types of forest that are floristically dissimilar. Combining these spatial predictions with scenarios of climatic and anthropogenic global change suggests a high vulnerability of the northern and southern forest margins, the Atlantic forests and most forests in the Democratic Republic of the Congo, where both climate and anthropogenic threats are expected to increase sharply by 2085. These results constitute key quantitative benchmarks for scientists and policymakers to shape transnational conservation and management strategies that aim to provide a sustainable future for central African forests. A large dataset of 6 million trees from 193 taxa is used to map the floristic and functional composition of central African forests and predict their vulnerability to climate change.

Published
2021

6. A large-scale species level dated angiosperm phylogeny for evolutionary and ecological analyses

Author

Olivier J. Hardy, Brecht Verstraete, Hans Beeckman, Maxime Réjou-Méchain, C.A.M. Marshall, Marc S.M. Sosef, Vincent Droissart, Vincent S. F. T. Merckx, Olivier Maurin, Steven B. Janssens, William D. Hawthorne, Fidèle Baya, Denis Beina, Michelle van der Bank, Thomas L. P. Couvreur, Gilles Dauby, Samuel Vanden Abeele, Arne Mertens, Maurizio Mascarello, Léo-Paul M.J. Dagallier, Filip Vandelook, Botanic Garden Meise, Diversité, adaptation, développement des plantes (UMR DIADE), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), School of Engineering and Science, Jacobs University [Bremen], Ministère Centrafricain des Eaux, Forêts, Chasses et Pêches (MEFCP), Natural History Museum of Denmark, Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Evolution Biologique et Ecologie, Université de Bruxelles, Université libre de Bruxelles (ULB), HERBAXYLAREDD project (BR/143/A3/HERBAXYLAREDD), BELSPO research program AFRIFORD, Couvreur, Thomas LP [0000-0002-8509-6587], Mertens, Arne [0000-0003-3272-9464], Dagallier, Leo-Paul MJ [0000-0002-3270-1544], Vanden Abeele, Samuel [0000-0001-9100-3642], Mascarello, Maurizio [0000-0003-0325-2345], Droissart, Vincent [0000-0001-9798-5616], Marshall, Cicely [0000-0002-7397-6472], Apollo - University of Cambridge Repository, Evolutionary and Population Biology (IBED, FNWI), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Libre de Bruxelles [Bruxelles] (ULB), Meise Botanic Garden [Belgium] (Plantentuin), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Couvreur, Thomas L P [0000-0002-8509-6587], and Dagallier, Leo-Paul M J [0000-0002-3270-1544]

Subjects
0106 biological sciences, FOSSIL EVIDENCE, Angiosperms, Evolution, Biodiversity & Conservation, Biology, phylogeny, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 010603 evolutionary biology, 01 natural sciences, WESTERN INTERIOR, 03 medical and health sciences, GENUS, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Species level, Phylogenetics, evolution, R PACKAGE, lcsh:QH301-705.5, FRUITS, Phylogeny, 030304 developmental biology, NEW-JERSEY, 0303 health sciences, Science & Technology, Phylogenetic tree, Ecology, EARLY EOCENE, NORTH-AMERICA, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, lcsh:Biology (General), Large-scale dating analyses, FOS: Biological sciences, GenBank, large-scale dating analyse, large-scale dating analyses, Biodiversity Conservation, SP-NOV, Research questions, DIVERSIFICATION, ecology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Scale (map), angiosperms, Biologie, Life Sciences & Biomedicine, Research Article
Abstract

Phylogenies are a central and indispensable tool for evolutionary and ecological research. Even though most angiosperm families are well investigated from a phylogenetic point of view, there are far less possibilities to carry out large-scale meta-analyses at order level or higher. Here, we reconstructed a large-scale dated phylogeny including nearly 1/8th of all angiosperm species, based on two plastid barcoding genes, matK (incl. trnK) and rbcL. Novel sequences were generated for several species, while the rest of the data were mined from GenBank. The resulting tree was dated using 56 angiosperm fossils as calibration points. The resulting megaphylogeny is one of the largest dated phylogenetic tree of angiosperms yet, consisting of 36,101 sampled species, representing 8,399 genera, 426 families and all orders. This novel framework will be useful for investigating different broad scale research questions in ecological and evolutionary biology., info:eu-repo/semantics/published

Published
2020

7. Plastome phylogeography in two African rain forest legume trees reveals that Dahomey Gap populations originate from the Cameroon volcanic line

Author

Boris B. Demenou, Myriam Heuertz, Laura Albreht, Dario I. Ojeda, Jérémy Migliore, Jan J. Wieringa, Olivier J. Hardy, Gilles Dauby, Franck K. Monthe, Arthur Boom, Université libre de Bruxelles (ULB), Biodiversité, Gènes & Communautés (BioGeCo), Université de Bordeaux (UB)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Norwegian Institute of Bioeconomy Research (NIBIO), Naturalis Biodiversity Center [Leiden], Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Evolution Biologique et Ecologie, and Université de Bruxelles

Subjects
0106 biological sciences, 0301 basic medicine, Colonization origin, Population fragmentation, Rainforest, Cameroon volcanic line, Pleistocene, Seed dispersal, Lineage (evolution), Biology, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 010603 evolutionary biology, 01 natural sciences, 03 medical and health sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Genetics, Benin, Dahomey gap, Cameroon, Plastids, Glacial period, Molecular Biology, Phylogeny, Ecology, Evolution, Behavior and Systematics, Ecology, Plastid genome sequencing, Genetic Variation, Fabaceae, Last Glacial Maximum, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, 15. Life on land, Biosystematiek, Phylogeography, 030104 developmental biology, African rain forest, Haplotypes, 13. Climate action, Biosystematics, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Biologie
Abstract

Paleo-environmental data show that the distribution of African rain forests was affected by Quaternary climate changes. In particular, the Dahomey Gap (DG) – a 200 km wide savanna corridor currently separating the West African and Central African rain forest blocks and containing relict rain forest fragments – was forested during the mid-Holocene and possibly during previous interglacial periods, whereas it was dominated by open vegetation (savanna) during glacial periods. Genetic signatures of past population fragmentation and demographic changes have been found in some African forest plant species using nuclear markers, but such events appear not to have been synchronous or shared across species. To better understand the colonization history of the DG by rain forest trees through seed dispersal, the plastid genomes of two widespread African forest legume trees, Anthonotha macrophylla and Distemonanthus benthamianus, were sequenced in 47 individuals for each species, providing unprecedented phylogenetic resolution of their maternal lineages (857 and 115 SNPs, respectively). Both species exhibit distinct lineages separating three regions: 1. Upper Guinea (UG, i.e. the West African forest block), 2. the area ranging from the DG to the Cameroon volcanic line (CVL), and 3. Lower Guinea (LG, the western part of the Central African forest block) where three lineages co-occur. In both species, the DG populations (including southern Nigeria west of Cross River) exhibit much lower genetic diversity than UG and LG populations, and their plastid lineages originate from the CVL, confirming the role of the CVL as an ancient forest refuge. Despite the similar phylogeographic structures displayed by A. macrophylla and D. benthamianus, molecular dating indicates very contrasting ages of lineage divergence (UG diverged from LG since c. 7 Ma and 0.7 Ma, respectively) and DG colonization (probably following the Mid Pleistocene Transition and the Last Glacial Maximum, respectively). The stability of forest refuge areas and repeated similar forest shrinking/expanding events during successive glacial periods might explain why similar phylogeographic patterns can be generated over contrasting timescales.

Published
2020

8. Beyond trees: Biogeographical regionalization of tropical Africa

Author

Tariq Stévart, Anne Blach-Overgaard, Jens-Christian Svenning, Olivier J. Hardy, Thomas L. P. Couvreur, Steven Janssens, Bonaventure Sonké, Barbara A. Mackinder, Vincent Droissart, David Harris, Vincent Deblauwe, Gilles Dauby, Marc S.M. Sosef, Jan J. Wieringa, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), Diversité, adaptation, développement des plantes (UMR DIADE), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Evolutionary Biology and Ecology, Department of Organism Biology, Université libre de Bruxelles (ULB), Department of Ecology and Evolutionary Biology, Center for Tropical Research, Institute of the Environment and Sustainability, University of California [Los Angeles] (UCLA), University of California-University of California, Royal Botanical Garden Edinburgh, Royal Botanical Garden, Botanic Garden Meise, Royal Botanic Garden Edinburgh, Aarhus University [Aarhus], University of Yaoundé [Cameroun], Herbarieum et Bibliothèque de Botanique africaine, Section for Ecoinformatics & Biodiversity, Department of Bioscience, Naturalis Biodiversity Center [Leiden], Fondation pour la Recherche sur la Biodiversite Fonds de la Recherche Scientifique - FNRS Villum Fonden 16549 French Foundation for Research on Biodiversity (FRB) Region Provence-Alpes-Cote d'Azur Belgian Fund for Scientific Research, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université Libre de Bruxelles [Bruxelles] (ULB), Aarhus University, and Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])

Subjects
0106 biological sciences, 0301 basic medicine, RAINBIO database, nestedness, CONSERVATION, African bioregions, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, Phytogeography, 010603 evolutionary biology, 01 natural sciences, diversity, 03 medical and health sciences, network clustering, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, growth forms, SPECIES COMPOSITION, Growth form, SUB-SAHARAN AFRICA, Endemism, Ecology, Evolution, Behavior and Systematics, PLANT DIVERSITY, 2. Zero hunger, Diversity, FLORA, Ecology, phytogeography, Species diversity, RAIN-FOREST, ENDEMISM, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, 15. Life on land, REGIONS, 030104 developmental biology, Geography, Liana, Network clustering, PATTERNS, Nestedness, BIODIVERSITY, Ordination, Species richness, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Woody plant
Abstract

Aim: To delineate bioregions in tropical Africa and determine whether different plant growth forms (trees, terrestrial herbs, lianas and shrubs) display the same pattern of regionalization, diversity and endemism as the whole flora.Location: Tropical Africa (excl. Madagascar), from 20 degrees N to 25 degrees S.Taxon: Vascular plants.Methods: Analyses were based on occurrences of 24,719 vascular plant species distributed across tropical Africa extracted from the RAINBIO database. The majority of species (93%) were classified into four growth forms: terrestrial herbs, trees, shrubs and lianas. Biogeographical regions (bioregions) were delimited using a bipartite network clustering approach on the whole dataset and then separately for each growth form. Relationships among bioregions were investigated using non-metric multidimensional scaling ordination, flora nestedness and endemism patterns.Results: Analyses of the whole dataset identified 16 bioregions and 11 transition zones. These were congruent with most of the currently recognized phytogeographical classifications, and also highlighted previously under-recognized bioregions. Bioregion endemism rates were lower and species richness higher when compared to estimates from the White/Association pour l'Etude Taxonomique de la Flore d'Afrique Tropicale (AETFAT) classification. Analysed separately, plant growth forms showed contrasting geographical patterns. Bioregionalization was better resolved for closed forest types using trees and lianas and for open vegetation types using terrestrial herbs, while shrubs showed good discriminative power in all vegetation types.Main conclusions: We show that distribution patterns based on solely trees are not sufficient to define floristic bioregions in tropical Africa. Analyses of spatial patterns using different growth forms are complementary, likely reflecting different evolutionary processes and ecological relationships. The contribution of growth forms to delimit geographical floristic patterns across tropical Africa is of critical importance for land use planning and management, and for selecting priority conservation areas.

Published
2018

9. Species delimitation in the genus Greenwayodendron based on morphological and genetic markers reveals new species

Author

Tariq Stévart, Bertrand M’batchi, Davy Ikabanga, Bonaventure Sonké, Gilles Dauby, Olivier J. Hardy, Christiane Atteke, Thomas L. P. Couvreur, Franck K. Monthe, Rosalía Piñeiro, Brandet‐J. Lissambou, Diversité, adaptation, développement des plantes (UMR DIADE), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Université de Yaoundé I, Herbarieum et Bibliothèque de Botanique africaine, Université libre de Bruxelles (ULB), University of Exeter, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), Laboratoire de Botanique et Ecologie, Université des Sciences et Techniques de Mazuku, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université de Yaoundé I [Yaoundé], Université Libre de Bruxelles [Bruxelles] (ULB), and Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])

Subjects
0106 biological sciences, 0301 basic medicine, Species complex, Allopatric speciation, Population genetics, Annonaceae, Plant Science, Greenwayodendron, Biology, Subspecies, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 010603 evolutionary biology, 01 natural sciences, genetic clustering, 03 medical and health sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, generic recombination, Genus, morphology, Orchidaceae, Ecology, Evolution, Behavior and Systematics, molecular phylogeny, cryptic species, 15. Life on land, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, East Africa, 030104 developmental biology, Herbarium, Genetic marker, Evolutionary biology, Molecular phylogenetics, Africa, Epidendroideae, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Biologie
Abstract

Combining genetic and morphological markers is a powerful approach for species delimitation, much needed in tropical species complexes. Greenwayodendron (Annonaceae) is a widespread genus of trees distributed from West to East African rainforests. Two species and four infra-specific taxa are currently recognized. However, preliminary genetic studies and morphological observations suggested the occurrence of additional species, undescribed to date. We tested species delimitation within Greenwayodendron by combining morphological and population genetics data. First, a visual inspection of about a thousand specimens suggested the existence of seven morphogroups: four of them occur in Central Africa and overlap in Gabon while three others are allopatric, occurring respectively in West Africa, East Africa, and the islands of São Tomé and Príncipe. Their morphological differentiation was confirmed by analysis of 27 morphological characters coded from 233 herbarium specimens. Second, after genotyping 800 samples at eight nuclear microsatellites, Bayesian clustering analyses (STRUCTURE) identified four genetic clusters corresponding to the well-sampled morphogroups but failed to separate the three remaining morphogroups represented by few samples. However, we show that this is an inherent limit of the STRUCTURE algorithm, whereas factorial correspondence analysis (FCA) and pairwise FST and RST measures confirmed the genetic differentiation of all morphogroups. We considered that a clear genetic differentiation occurring between sympatric populations advocates for recognizing distinct species following the biological species concept. Our analyses highlight that the current taxonomic treatment of Greenwayodendron underestimates the total number of species. We identified two new species and support separation at the rank of species of two varieties (G. suaveolens subsp. suaveolens var. gabonica, G. suaveolens subsp. suaveolens var. suaveolens) and one subspecies (G. suaveolens subsp. usambaricum). The taxonomic status of specimens collected in São Tomé and Príncipe remains inconclusive, partly due to the limited fertile material available. Our study highlights the strength of combining morphological and population genetics data for discovering new taxa. Guidelines for using genetic clustering approaches in species delimitation are provided., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2019

10. A third of the tropical African flora is potentially threatened with extinction

Author

Anne Blach-Overgaard, Vincent Droissart, Porter P. Lowry, Gilles Dauby, Jens-Christian Svenning, David Harris, Thomas L. P. Couvreur, Tariq Stévart, George E. Schatz, Bonaventure Sonké, Barbara A. Mackinder, Marc S.M. Sosef, Jan J. Wieringa, Herbarieum et Bibliothèque de Botanique africaine, Université Libre de Bruxelles [Bruxelles] (ULB), Missouri Botanical Garden (USA), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Aarhus University [Aarhus], University of Yaoundé [Cameroun], Diversité, adaptation, développement des plantes (UMR DIADE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université libre de Bruxelles (ULB), Missouri Botanical Garden, Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), and Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)

Subjects
0106 biological sciences, Flora, Conservation of Natural Resources, Databases, Factual, Science Policy, Biodiversity, Endangered species, Extinction, Biological, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 010603 evolutionary biology, 01 natural sciences, Threatened flora, Species extinction, 03 medical and health sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, IUCN Red List, Applied Ecology, Research Articles, 030304 developmental biology, 2. Zero hunger, 0303 health sciences, Multidisciplinary, Extinction, biology, Agroforestry, Physique, Endangered Species, Extinction d'espèce, SciAdv r-articles, 15. Life on land, Plants, Astronomie, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, biology.organism_classification, Geography, Tanzania, 13. Climate action, Threatened species, Africa, Terrestrial ecosystem, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Research Article, Tropical flora
Abstract

Preserving tropical biodiversity is an urgent challenge when faced with the growing needs of countries. Despite their crucial importance for terrestrial ecosystems, most tropical plant species lack extinction risk assessments, limiting our ability to identify conservation priorities. Using a novel approach aligned with IUCN Red List criteria, we conducted a continental-scale preliminary conservation assessment of 22,036 vascular plant species in tropical Africa. Our results underline the high level of extinction risk of the tropical African flora. Thirty-three percent of the species are potentially threatened with extinction, and another third of species are likely rare, potentially becoming threatened in the near future. Four regions are highlighted with a high proportion (>40%) of potentially threatened species: Ethiopia, West Africa, central Tanzania, and southern Democratic Republic of the Congo. Our approach represents a first step toward data-driven conservation assessments applicable at continental scales providing crucial information for sustainable economic development prioritization., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2019

11. Mine versus Wild : a plant conservation checklist of the rich Iron-Ore Ngovayang Massif Area (South Cameroon)

Author

Bonaventure Sonké, Olivier Lachenaud, Hermann Taedoumg, Tariq Stévart, Gyslène Kamdem, Murielle Simo-Droissart, Vincent Droissart, Steven Dessein, Gilles Dauby, K Charlemagne Nguembou, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université Libre de Bruxelles [Bruxelles] (ULB), Botanic Garden Meise, University of Yaoundé [Cameroun], Missouri Botanical Garden (USA), Université libre de Bruxelles (ULB), Meise Botanic Garden [Belgium] (Plantentuin), Missouri Botanical Garden, and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud])

Subjects
0106 biological sciences, IUCN protected area categories, Rare species, Biodiversity, Endangered species, Rubiaceae, Plant Science, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 010603 evolutionary biology, 01 natural sciences, Iron and gold exploitation, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, orchids, Endemism, Submontane forest, iron and gold exploitation, 2. Zero hunger, New records, 010604 marine biology & hydrobiology, new records, Forestry, endangered species, 15. Life on land, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, Ex situ conservation, Orchids, submontane forest, Geography, Herbarium, Important Plant Area, Threatened species, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; Background and aims – The rapid expansion of human activities in South Cameroon, particularly mining in mountainous areas, threatens this region’s exceptional biodiversity. To comprehend the effects of land-use change on plant diversity and identify conservation priorities, we aim at providing a first comprehensive plant checklist of the Ngovayang Massif, focusing on the two richest plant families, Orchidaceae and Rubiaceae.Location – The Ngovayang Massif Area (NMA) is located in the South Region of Cameroon. It is covered by lowland and submontane rainforest (100 to 1110 m elevation).Methods – We compiled a dataset of 6116 georeferenced herbarium specimens, of which 2787 belong to Rubiaceae and Orchidaceae. We used rarefaction methods to explore sampling and diversity patterns, and investigated the altitudinal distribution of rare and/or threatened taxa.Key results – The NMA, which houses about 1500 vascular plant taxa, is the richest documented area for Rubiaceae in Atlantic Central Africa (ACA) and the fifth for Orchidaceae, with respectively 281 and 111 taxa. Among these taxa, 178 (45%) are endemic to ACA and 67 (17%) are considered globally threatened according to IUCN categories and criteria. We show that higher elevation areas (> 750 m), which are also the main areas targeted for mining, are the richest in endangered and/or rare species. Three new records for Cameroon are reported here.Conclusion – The NMA represents an Important Plant Area of Cameroon as confirmed by its exceptional plant diversity (> 20% of the total Flora of Cameroon), by the concentration of many threatened and/or restricted range species (10 taxa are strict endemics of the massif) as well as by the threat on rare habitats (i.e. the submontane vegetation above ~750 m elevation). A management plan involving in situ and ex situ conservation actions is urgently needed to reduce the potential threats of future mining activities.

Published
2019

12. Toward a general tropical forest biomass prediction model from very high resolution optical satellite images

Author

Christophe Proisy, Pierre Couteron, Cécile Antin, David Kenfack, S.T. Momo, Duncan W. Thomas, Gislain Ii Mofack, Nicolas Barbier, Maxime Réjou-Méchain, Jean-Philippe Gastellu-Etchegorry, Jean-François Bastin, N. Barathan, Narcisse Guy Kamdem, P. Petronelli, N. Balachandran, P. Verley, Uta Berger, Gilles Dauby, D. Zebaze Dongmo, Pierre Ploton, S. Pargal, Nicolas Texier, Raphaël Pélissier, Moses Libalah, Vincent Droissart, Georges Chuyong, Bonaventure Sonké, N. Ayyappan, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), AgroParisTech, Institut Français de Pondichéry (IFP), Ministère de l'Europe et des Affaires étrangères (MEAE)-Centre National de la Recherche Scientifique (CNRS), Research Unit of Landscape Ecology and Plant Production Systems, Université libre de Bruxelles (ULB), University of Buéa, Diversité, adaptation, développement des plantes (UMR DIADE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Evolutionary Biology and Ecology [ULB], Herbarium et Bibliothèque de Botanique africain, Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire de Botanique systématique et d'Ecologie [ENS Yaoudé], Université de Yaoundé I-École normale supérieure [ENS] - Yaoundé 1, Smithsonian Tropical Research Institute, Ecologie des forêts de Guyane (UMR ECOFOG), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-AgroParisTech-Université de Guyane (UG)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Washington State University (WSU), Technische Universität Dresden = Dresden University of Technology (TU Dresden), ANR-12-EBID-0002, European Project: 266546,EC:FP7:ENV,FP7-ERANET-2010-RTD,BIODIVERSA2(2010), Institut des sciences et industries du vivant et de l'environnement (ISIVE), Centre National de la Recherche Scientifique (CNRS)-Ministère de l'Europe et des Affaires étrangères (MEAE), Université Libre de Bruxelles [Bruxelles] (ULB), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université de Yaoundé I [Yaoundé]-École normale supérieure [ENS] - Yaoundé 1, Technische Universität Dresden (TUD), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Canopy, 010504 meteorology & atmospheric sciences, Tropical forests, forêt tropicale, Imagerie par satellite, Residual, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 01 natural sciences, Basal area, [SDV.SA.SF]Life Sciences [q-bio]/Agricultural sciences/Silviculture, forestry, Lacunarity, K01 - Foresterie - Considérations générales, Biomasse, Dynamique des populations, Satellite imagery, ComputingMilieux_MISCELLANEOUS, U10 - Informatique, mathématiques et statistiques, Inventaire forestier, Geology, Tropical forest biomass, Forêt, Fourier transform, Ordination, Passive optical imagery, Télédétection, REDD, Soil Science, Structural basin, 010603 evolutionary biology, Texture, Computers in Earth Sciences, Ressource forestière, 0105 earth and related environmental sciences, Remote sensing, model, Méthode statistique, Tropics, Modèle de simulation, 15. Life on land, Forest carbon, Environmental science, U30 - Méthodes de recherche, Canopy structure, satellite images
Abstract

International audience; Very high spatial resolution (VHSR) optical satellite imagery has shown good potential to provide non-saturating proxies of tropical forest aboveground biomass (AGB) from the analysis of canopy texture, for instance through the Fourier Transform Textural Ordination method. Empirical case studies however showed that the relationship between Fourier texture features and forest AGB varies across forest types and regions of the world, limiting model transferability. A better understanding of the biophysical mechanisms on which canopy texture – forest AGB relation relies is a prerequisite to move toward broad scale applications. Here we simulated VHSR optical canopy scenes in identical sun-sensor geometry for 279 1-ha tropical forest inventory plots distributed across the tropics. Our aim was to assess the respective merits and complementarity of two types of texture analysis techniques (i.e. Fourier and lacunarity) on a set of forests with contrasted structure and geographical origin, and develop a general texture-based approach for tropical forest AGB mapping. Across forests, Fourier texture captured a gradient of stands mean crown size reflecting well the progressive changes in stand structure throughout forest aggradation phase (e.g. Pearson's r=−0.42 with basal area) while lacunarity texture captured a gradient of canopy openness (, i.e. Pearson's r=−0.57 with stand gap fraction). Both types of texture indices were highly complementary for predicting forest AGB at the global level (so-called FL-model). The residual error of the FL-model was structured across sites and could be partially captured with a bioclimatic proxy, further improving the performance of the global model (so-called FLE-model) and reducing site-level biases. The FLE model was tested on a set of real Pleiades images covering a mosaic of high-biomass forests in the Congo basin (mean AGB over 49 field plots: 359±98Mgha−1), leading to a significant relationship (R2=0.47 on validation data) with reasonable error levels (

Published
2017

13. Seeing Central African forests through their largest trees

Author

Marc Dufrêne, Terese B. Hart, Corneille E. N. Ewango, Pierre Ploton, T. de Haulleville, Fidèle Baya, Jean-François Gillet, Sylvie Gourlet-Fleury, C De Cannière, Jean-Louis Doucet, Vincent Droissart, Gilles Dauby, Yadvinder Malhi, Duncan W. Thomas, Georges Chuyong, Jean-François Bastin, Adeline Serckx, Tariq Stévart, T. Kavali, David Kenfack, Hans Beeckman, Bonaventure Sonké, Jan Bogaert, Moses Libalah, D. Beina, C. H. Gonmadje, Pierre Couteron, Maxime Réjou-Méchain, Adeline Fayolle, Jean-Remy Makana, Danae Maniatis, Nicolas Barbier, Raphaël Pélissier, Research Unit of Landscape Ecology and Plant Production Systems, Université Libre de Bruxelles [Bruxelles] (ULB)-Université de Liège, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université de Liège - Gembloux, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Oxford University Centre for the Environment (OUCE), University of Oxford [Oxford], Ministère des Eaux, Forêts, Chasse et Pêche, Royal Museum for Central Africa [Tervuren] (RMCA), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), University of Buéa, Diversité, adaptation, développement des plantes (UMR DIADE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Entomologie fonctionnelle et évolutive - Université de Liège, Wildlife Conservation Society, Smithsonian Tropical Research Institute, Laboratoire de Botanique systématique et d'Ecologie [ENS Yaoudé], Université de Yaoundé I [Yaoundé]-École normale supérieure [ENS] - Yaoundé 1, Institut de Mécanique des Fluides de Marseille, Herbarieum et Bibliothèque de Botanique africaine, Université Libre de Bruxelles [Bruxelles] (ULB), Sud Expert Plantes, ANR-12-EBID-0002,CoForTips,Forêts du Bassin du Congo: Biodiversité, Points de Basculement et Résilience des Systèmes Écologiques et Sociaux Forestiers.(2012), Université de Liège-Université libre de Bruxelles (ULB), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), Biens et services des écosystèmes forestiers tropicaux : l'enjeu du changement global (UPR BSEF), Ministère des Eaux, Forêts, Chasse et Pêche [République Centrafricaine], Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Université de Yaoundé I-École normale supérieure [ENS] - Yaoundé 1, Université libre de Bruxelles (ULB), and University of Oxford

Subjects
tropical forest, Tropical and subtropical dry broadleaf forests, F40 - Écologie végétale, distributions, Tropical trees, Biodiversity, Climate change, Forests, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, Models, Biological, size, Article, diversity, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Phénomènes atmosphériques, Forest ecology, K01 - Foresterie - Considérations générales, Bosecologie en Bosbeheer, Stock (geology), Forest floor, Multidisciplinary, biomass, Ecology, Agroforestry, Forestry, dynamics, 15. Life on land, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, PE&RC, Forest Ecology and Forest Management, Climatic change, Geography, Africa, Secondary forest, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, U30 - Méthodes de recherche
Abstract

Large tropical trees and a few dominant species were recently identified as the main structuring elements of tropical forests. However, such result did not translate yet into quantitative approaches which are essential to understand, predict and monitor forest functions and composition over large, often poorly accessible territories. Here we show that the above-ground biomass (AGB) of the whole forest can be predicted from a few large trees and that the relationship is proved strikingly stable in 175 1-ha plots investigated across 8 sites spanning Central Africa. We designed a generic model predicting AGB with an error of 14% when based on only 5% of the stems, which points to universality in forest structural properties. For the first time in Africa, we identified some dominant species that disproportionally contribute to forest AGB with 1.5% of recorded species accounting for over 50% of the stock of AGB. Consequently, focusing on large trees and dominant species provides precise information on the whole forest stand. This offers new perspectives for understanding the functioning of tropical forests and opens new doors for the development of innovative monitoring strategies., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2015

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