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309 results on '"Pélissier, Raphaël"'

1. LiDAR-based reference aboveground biomass maps for tropical forests of South Asia and Central Africa

Author

Rodda, Suraj Reddy, Fararoda, Rakesh, Gopalakrishnan, Rajashekar, Jha, Nidhi, Réjou-Méchain, Maxime, Couteron, Pierre, Barbier, Nicolas, Alfonso, Alonso, Bako, Ousmane, Bassama, Patrick, Behera, Debabrata, Bissiengou, Pulcherie, Biyiha, Hervé, Brockelman, Warren Y., Chanthorn, Wirong, Chauhan, Prakash, Dadhwal, Vinay Kumar, Dauby, Gilles, Deblauwe, Vincent, Dongmo, Narcis, Droissart, Vincent, Jeyakumar, Selvaraj, Jha, Chandra Shekar, Kandem, Narcisse G., Katembo, John, Kougue, Ronald, Leblanc, Hugo, Lewis, Simon, Libalah, Moses, Manikandan, Maya, Martin-Ducup, Olivier, Mbock, Germain, Memiaghe, Hervé, Mofack, Gislain, Mutyala, Praveen, Narayanan, Ayyappan, Nathalang, Anuttara, Ndjock, Gilbert Oum, Ngoula, Fernandez, Nidamanuri, Rama Rao, Pélissier, Raphaël, Saatchi, Sassan, Sagang, Le Bienfaiteur, Salla, Patrick, Simo-Droissart, Murielle, Smith, Thomas B., Sonké, Bonaventure, Stevart, Tariq, Tjomb, Danièle, Zebaze, Donatien, Zemagho, Lise, and Ploton, Pierre

Published
2024
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3. Evolutionary diversity impacts tropical forest biomass and productivity through disturbance‐mediated ecological pathways.

Author

Borges, Erica Rievrs, Réjou‐Méchain, Maxime, Gourlet‐Fleury, Sylvie, Vincent, Grégoire, Mortier, Frédéric, Bry, Xaxier, Cornu, Guillaume, Baya, Fidèle, Allah‐Barem, Félix, and Pélissier, Raphaël

Subjects
FOREST biomass, WOOD density, TROPICAL forests, FOREST dynamics, FOREST biodiversity, FOREST productivity, BIOMASS conversion
Abstract

Significant research efforts have been made to uncover links between biodiversity and biomass productivity in forest ecosystems. However, the causal link between these two ecosystem components, and the underlying mediation role of disturbance, are yet poorly understood for hyper‐diverse tropical forests, because multiple ecological mechanisms are sequentially or simultaneously in play, leading to contradictory results in observational studies.Here, we introduce a novel framework for inferring the expected effects of evolutionary diversity on biomass stocks and productivity within forest ecosystems using observational field data. This framework involves an analytical decomposition of stand biomass into three key components: the number of trees, the mean size of trees and the mean wood density. Through this approach, we can distinguish structure‐ and compositional‐based diversity effects, which likely have distinct ecological origins. We tested this framework in one of the oldest tropical forest experiments, where different levels of silvicultural disturbances were applied in the 1980s, with regular monitoring since then.Our results revealed that disturbance history mediates the effect of evolutionary diversity on forest biomass dynamics and that several Biodiversity Ecosystem Function (BEF) relationships may be hidden behind the composite biomass variable. We specifically found an overall significant negative relationship between evolutionary diversity and biomass productivity soon after disturbances (~5–8 years), mostly via mean tree size, despite a positive evolutionary diversity effect on mean wood density. This result reflects that the productivity of disturbed forests is driven by a few dominant and disturbance‐prone species with low wood density and large potential stature, and not by niche complementarity among species. However, these effects rapidly vanished with time, with non‐significant overall effect of evolutionary diversity on productivity both ~30 years after disturbance and in the undisturbed plots.Synthesis. By disentangling the effects of evolutionary diversity on the different components of forest biomass, our framework unveiled how evolutionary diversity impacts forest productivity through different ecological mechanisms, and suggests that it plays a major role, albeit mainly negative, only soon after a disturbance. [ABSTRACT FROM AUTHOR]

Published
2024
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4. The puzzling ecology of African Marantaceae forests

Author

Pouteau, Robin, primary, Picard, Juliette, additional, Doumenge, Charles, additional, Brncic, Terry, additional, Gillet, Jean‐François, additional, Doucet, Jean‐Louis, additional, Gourlet‐Fleury, Sylvie, additional, Kimpouni, Victor, additional, Loumeto, Jean‐Joël, additional, Pélissier, Raphaël, additional, and Réjou‐Méchain, Maxime, additional

Published
2024
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5. Beyond variance: Simple random distributions are not a good proxy for intraspecific variability in systems with environmental structure

Author

Girard-Tercieux, Camille, Vieilledent, Ghislain, Clark, Adam T., Courbaud, Benoît, Fortunel, Claire, Kunstler, Georges, Pélissier, Raphaël, Rüger, Nadja, Marechaux, Isabelle, Girard-Tercieux, Camille, Vieilledent, Ghislain, Clark, Adam T., Courbaud, Benoît, Fortunel, Claire, Kunstler, Georges, Pélissier, Raphaël, Rüger, Nadja, and Marechaux, Isabelle

Abstract

The role of intraspecific variability (IV) in shaping community dynamics and species coexistence has been intensively discussed over the past decade and modelling studies have played an important role in that respect. However, these studies often implicitly assume that IV can be represented by independent random draws around species-specific mean parameters. This major assumption has largely remained undiscussed, although a great part of observed IV is structured in space or time, in particular when environmental dimensions that influence individual performance are imperfectly characterised or unobserved in the field. To test the impact of this strong assumption on the outcome of community dynamics models, we designed a simulation experiment where we varied the level of knowledge of the environment in virtual communities, resulting in different relative importance of explained vs unexplained spatial individual variation in performance. We used a community dynamics simulator to generate communities where the unexplained individual variation is, or is not, added as an unstructured random noise. Communities simulated with unstructured IV never reached the community diversity and composition of those where all the variation was explained and structured (perfect knowledge model). This highlights that incorporating unstructured IV (i.e. a random noise) to account for unexplained (but structured) variation can lead to incorrect simulations of community dynamics. In addition, the effects of unstructured IV on community diversity and composition depended on the relative importance of structured vs unstructured IV, i.e. on the level of knowledge of the environment, which may partly explain the contrasting results of previous studies on the effect of IV on species coexistence. In particular, the effect of unstructured IV on community diversity was positive when the proportion of structured IV vs unstructured IV in the model was low, but negative when this proportion was high.

Published
2024

6. Unveiling African rainforest composition and vulnerability to global change

Author

Réjou-Méchain, Maxime, Mortier, Frédéric, Bastin, Jean-François, Cornu, Guillaume, Barbier, Nicolas, Bayol, Nicolas, Bénédet, Fabrice, Bry, Xavier, Dauby, Gilles, Deblauwe, Vincent, Doucet, Jean-Louis, Doumenge, Charles, Fayolle, Adeline, Garcia, Claude, Kibambe Lubamba, Jean-Paul, Loumeto, Jean-Joël, Ngomanda, Alfred, Ploton, Pierre, Sonké, Bonaventure, Trottier, Catherine, Vimal, Ruppert, Yongo, Olga, Pélissier, Raphaël, and Gourlet-Fleury, Sylvie

Published
2021
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7. Pan-tropical prediction of forest structure from the largest trees

Author

Bastin, Jean-François, Rutishauser, Ervan, Kellner, James R., Saatchi, Sassan, Pélissier, Raphael, Hérault, Bruno, Slik, Ferry, Bogaert, Jan, De Cannière, Charles, Marshall, Andrew R., Poulsen, John, Alvarez-Loyayza, Patricia, Andrade, Ana, Angbonga-Basia, Albert, Araujo-Murakami, Alejandro, Arroyo, Luzmila, Ayyappan, Narayanan, de Azevedo, Celso Paulo, Banki, Olaf, Barbier, Nicolas, Barroso, Jorcely G., Beeckman, Hans, Bitariho, Robert, Boeckx, Pascal, Boehning-Gaese, Katrin, Brandão, Hilandia, Brearley, Francis Q., Hockemba, Mireille Breuer Ndoundou, Brienen, Roel, Camargo, Jose Luis C., Campos-Arceiz, Ahimsa, Cassart, Benoit, Chave, Jérôme, Chazdon, Robin, Chuyong, Georges, Clark, David B., Clark, Connie J., Condit, Richard, Coronado, Euridice N. Honorio, Davidar, Priya, de Haulleville, Thalès, Descroix, Laurent, Doucet, Jean-Louis, Dourdain, Aurelie, Droissart, Vincent, Duncan, Thomas, Espejo, Javier Silva, Espinosa, Santiago, Farwig, Nina, Fayolle, Adeline, Feldpausch, Ted R., Ferraz, Antonio, Fletcher, Christine, Gajapersad, Krisna, Gillet, Jean-François, do Amaral, Iêda Leão, Gonmadje, Christelle, Grogan, James, Harris, David, Herzog, Sebastian K., Homeier, Jürgen, Hubau, Wannes, Hubbell, Stephen P., Hufkens, Koen, Hurtado, Johanna, Kamdem, Narcisse G., Kearsley, Elizabeth, Kenfack, David, Kessler, Michael, Labrière, Nicolas, Laumonier, Yves, Laurance, Susan, Laurance, William F., Lewis, Simon L., Libalah, Moses B., Ligot, Gauthier, Lloyd, Jon, Lovejoy, Thomas E., Malhi, Yadvinder, Marimon, Beatriz S., Junior, Ben Hur Marimon, Martin, Emmanuel H., Matius, Paulus, Meyer, Victoria, Bautista, Casimero Mendoza, Monteagudo-Mendoza, Abel, Mtui, Arafat, Neill, David, Gutierrez, Germaine Alexander Parada, Pardo, Guido, Parren, Marc, Parthasarathy, N., Phillips, Oliver L., Pitman, Nigel C. A., Ploton, Pierre, Ponette, Quentin, Ramesh, B. R., Razafimahaimodison, Jean-Claude, Réjou-Méchain, Maxime, Rolim, Samir Gonçalves, Saltos, Hugo Romero, Rossi, Luiz Marcelo Brum, Spironello, Wilson Roberto, Rovero, Francesco, Saner, Philippe, Sasaki, Denise, Schulze, Mark, Silveira, Marcos, Singh, James, Sist, Plinio, Sonke, Bonaventure, Soto, J. Daniel, de Souza, Cintia Rodrigues, Stropp, Juliana, Sullivan, Martin J. P., Swanepoel, Ben, ter Steege, Hans, Terborgh, John, Texier, Nicolas, Toma, Takeshi, Valencia, Renato, Valenzuela, Luis, Ferreira, Leandro Valle, Valverde, Fernando Cornejo, Van Andel, Tinde R., Vasque, Rodolfo, Verbeeck, Hans, Vivek, Pandi, Vleminckx, Jason, Vos, Vincent A., Wagner, Fabien H., Papi Puspa, Warsudi, Wortel, Verginia, Zagt, Roderick J., and Zebaze, Donatien

Published
2018

8. BioTIME: A database of biodiversity time series for the Anthropocene

Author

Dornelas, Maria, Antão, Laura H., Moyes, Faye, Bates, Amanda E., Magurran, Anne E., Adam, Dušan, Akhmetzhanova, Asem A., Appeltans, Ward, Arcos, José Manuel, Arnold, Haley, Ayyappan, Narayanan, Badihi, Gal, Baird, Andrew H., Barbosa, Miguel, Barreto, Tiago Egydio, Bässler, Claus, Bellgrove, Alecia, Belmaker, Jonathan, Benedetti-Cecchi, Lisandro, Bett, Brian J., Bjorkman, Anne D., Błazewicz, Magdalena, Blowes, Shane A., Bloch, Christopher P., Bonebrake, Timothy C., Boyd, Susan, Bradford, Matt, Brooks, Andrew J., Brown, James H., Bruelheide, Helge, Budy, Phaedra, Carvalho, Fernando, Castañeda-Moya, Edward, Chen, Chaolun Allen, Chamblee, John F., Chase, Tory J., Collier, Laura Siegwart, Collinge, Sharon K., Condit, Richard, Cooper, Elisabeth J., Cornelissen, J. Hans C., Cotano, Unai, Crow, Shannan Kyle, Damasceno, Gabriella, Davies, Claire H., Davis, Robert A., Day, Frank P., Degraer, Steven, Doherty, Tim S., Dunn, Timothy E., Durigan, Giselda, Duffy, J. Emmett, Edelist, Dor, Edgar, Graham J., Elahi, Robin, Elmendorf, Sarah C., Enemar, Anders, Ernest, S. K. Morgan, Escribano, Rubén, Estiarte, Marc, Evans, Brian S., Fan, Tung-Yung, Farah, Fabiano Turini, Fernandes, Luiz Loureiro, Farneda, Fábio Z., Fidelis, Alessandra, Fitt, Robert, Fosaa, Anna Maria, Franco, Geraldo Antonio Daher Correa, Frank, Grace E., Fraser, William R., García, Hernando, Gatti, Roberto Cazzolla, Givan, Or, Gorgone-Barbosa, Elizabeth, Gould, William A., Gries, Corinna, Grossman, Gary D., Gutierréz, Julio R., Hale, Stephen, Harmon, Mark E., Harte, John, Haskins, Gary, Henshaw, Donald L., Hermanutz, Luise, Hidalgo, Pamela, Higuchi, Pedro, Hoey, Andrew, Van Hoey, Gert, Hofgaard, Annika, Holeck, Kristen, Hollister, Robert D., Holmes, Richard, Hoogenboom, Mia, Hsieh, Chih-hao, Hubbell, Stephen P., Huettmann, Falk, Huffard, Christine L., Hurlbert, Allen H., Ivanauskas, Natália Macedo, Janík, David, Jandt, Ute, Jazdzewska, Anna, Johannessen, Tore, Johnstone, Jill, Jones, Julia, Jones, Faith A. M., Kang, Jungwon, Kartawijaya, Tasrif, Keeley, Erin C., Kelt, Douglas A., Kinnear, Rebecca, Klanderud, Kari, Knutsen, Halvor, Koenig, Christopher C., Kortz, Alessandra R., Král, Kamil, Kuhnz, Linda A., Kuo, Chao-Yang, Kushner, David J., Laguionie-Marchais, Claire, Lancaster, Lesley T., Lee, Cheol Min, Lefcheck, Jonathan S., Lévesque, Esther, Lightfoot, David, Lloret, Francisco, Lloyd, John D., López-Baucells, Adrià, Louzao, Maite, Madin, Joshua S., Magnússon, Borgþór, Malamud, Shahar, Matthews, Iain, McFarland, Kent P., McGill, Brian, McKnight, Diane, McLarney, William O., Meador, Jason, Meserve, Peter L., Metcalfe, Daniel J., Meyer, Christoph F. J., Michelsen, Anders, Milchakova, Nataliya, Moens, Tom, Moland, Even, Moore, Jon, Moreira, Carolina Mathias, Müller, Jörg, Murphy, Grace, Myers-Smith, Isla H., Myster, Randall W., Naumov, Andrew, Neat, Francis, Nelson, James A., Nelson, Michael Paul, Newton, Stephen F., Norden, Natalia, Oliver, Jeffrey C., Olsen, Esben M., Onipchenko, Vladimir G., Pabis, Krzysztof, Pabst, Robert J., Paquette, Alain, Pardede, Sinta, Paterson, David M., Pélissier, Raphaël, Peñuelas, Josep, Pérez-Matus, Alejandro, Pizarro, Oscar, Pomati, Francesco, Post, Eric, Prins, Herbert H. T., Priscu, John C., Provoost, Pieter, Prudic, Kathleen L., Pulliainen, Erkki, Ramesh, B. R., Ramos, Olivia Mendivil, Rassweiler, Andrew, Remillard, Suzanne M., Richardson, Anthony J., Richardson, J. Paul, van Rijn, Itai, Rocha, Ricardo, Rivera-Monroy, Victor H., Rixen, Christian, Robinson, Kevin P., Rodrigues, Ricardo Ribeiro, de Cerqueira Rossa-Feres, Denise, Rudstam, Lars, Ruhl, Henry, Ruz, Catalina S., Sampaio, Erica M., Rybicki, Nancy, Rypel, Andrew, Sal, Sofia, Salgado, Beatriz, Santos, Flavio A. M., Savassi-Coutinho, Ana Paula, Scanga, Sara, Schmidt, Jochen, Schooley, Robert, Setiawan, Fakhrizal, Shao, Kwang-Tsao, Shaver, Gaius R., Sherman, Sally, Sherry, Thomas W., Siciński, Jacek, Sievers, Caya, da Silva, Ana Carolina, da Silva, Fernando Rodrigues, Silveira, Fabio L., Slingsby, Jasper, Smart, Tracey, Snell, Sara J., Soudzilovskaia, Nadejda A., Souza, Gabriel B. G., Souza, Flaviana Maluf, Souza, Vinícius Castro, Stallings, Christopher D., Stanforth, Rowan, Stanley, Emily H., Sterza, José Mauro, Stevens, Maarten, Stuart-Smith, Rick, Suarez, Yzel Rondon, Supp, Sarah, Tamashiro, Jorge Yoshio, Tarigan, Sukmaraharja, Thiede, Gary P., Thorn, Simon, Tolvanen, Anne, Toniato, Maria Teresa Zugliani, Totland, Ørjan, Twilley, Robert R., Vaitkus, Gediminas, Valdivia, Nelson, Vallejo, Martha Isabel, Valone, Thomas J., Van Colen, Carl, Vanaverbeke, Jan, Venturoli, Fabio, Verheye, Hans M., Vianna, Marcelo, Vieira, Rui P., Vrška, Tomáš, Vu, Con Quang, Van Vu, Lien, Waide, Robert B., Waldock, Conor, Watts, Dave, Webb, Sara, Wesołowski, Tomasz, White, Ethan P., Widdicombe, Claire E., Wilgers, Dustin, Williams, Richard, Williams, Stefan B., Williamson, Mark, Willig, Michael R., Willis, Trevor J., Wipf, Sonja, Woods, Kerry D., Woehler, Eric J., Zawada, Kyle, and Zettler, Michael L.

Published
2018

10. A map of African humid tropical forest aboveground biomass derived from management inventories

Author

Ploton, Pierre, Mortier, Frédéric, Barbier, Nicolas, Cornu, Guillaume, Réjou-Méchain, Maxime, Rossi, Vivien, Alonso, Alfonso, Bastin, Jean-François, Bayol, Nicolas, Bénédet, Fabrice, Bissiengou, Pulchérie, Chuyong, Georges, Demarquez, Benoît, Doucet, Jean-Louis, Droissart, Vincent, Kamdem, Narcisse Guy, Kenfack, David, Memiaghe, Hervé, Moses, Libalah, Sonké, Bonaventure, Texier, Nicolas, Thomas, Duncan, Zebaze, Donatien, Pélissier, Raphaël, and Gourlet-Fleury, Sylvie

Published
2020
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20. Rethinking the nature of intraspecific variability and its consequences on species coexistence

Author

Girard‐Tercieux, Camille, primary, Maréchaux, Isabelle, additional, Clark, Adam T., additional, Clark, James S., additional, Courbaud, Benoît, additional, Fortunel, Claire, additional, Guillemot, Joannès, additional, Künstler, Georges, additional, le Maire, Guerric, additional, Pélissier, Raphaël, additional, Rüger, Nadja, additional, and Vieilledent, Ghislain, additional

Published
2023
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21. Rethinking the nature of intraspecific variability and its consequences on species coexistence

Author

Girard-Tercieux, Camille, Marechaux, Isabelle, Clark, Adam T., Clark, James S., Courbaud, Benoît, Fortunel, Claire, Guillemot, Joannès, Kunstler, Georges, Le Maire, Guerric, Pélissier, Raphaël, Rüger, Nadja, Vieilledent, Ghislain, Girard-Tercieux, Camille, Marechaux, Isabelle, Clark, Adam T., Clark, James S., Courbaud, Benoît, Fortunel, Claire, Guillemot, Joannès, Kunstler, Georges, Le Maire, Guerric, Pélissier, Raphaël, Rüger, Nadja, and Vieilledent, Ghislain

Abstract

Intraspecific variability (IV) has been proposed to explain species coexistence in diverse communities. Assuming, sometimes implicitly, that conspecific individuals can perform differently in the same environment and that IV increases niche overlap, previous studies have found contrasting results regarding the effect of IV on species coexistence. We aim at showing that the large IV observed in data does not mean that conspecific individuals are necessarily different in their response to the environment and that the role of high-dimensional environmental variation in determining IV has largely remained unexplored in forest plant communities. We first used a simulation experiment where an individual attribute is derived from a high-dimensional model, representing “perfect knowledge” of individual response to the environment, to illustrate how large observed IV can result from “imperfect knowledge” of the environment. Second, using growth data from clonal Eucalyptus plantations in Brazil, we estimated a major contribution of the environment in determining individual growth. Third, using tree growth data from long-term tropical forest inventories in French Guiana, Panama and India, we showed that tree growth in tropical forests is structured spatially and that despite a large observed IV at the population level, conspecific individuals perform more similarly locally than compared with heterospecific individuals. As the number of environmental dimensions that are well quantified at fine scale is generally lower than the actual number of dimensions influencing individual attributes, a great part of observed IV might be represented as random variation across individuals when in fact it is environmentally driven. This mis-representation has important consequences for inference about community dynamics. We emphasize that observed IV does not necessarily impact species coexistence per se but can reveal species response to high-dimensional environment, which is consistent with

Published
2023

24. Exploring the link between spectral variance and upper canopy taxonomic diversity in a tropical forest: influence of spectral processing and feature selection

Author

Badourdine, Colette, Féret, Jean‐baptiste, Pélissier, Raphaël, Vincent, Grégoire, 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), Territoires, Environnement, Télédétection et Information Spatiale (UMR TETIS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), ANR-17-CE32-0001,BioCop,Suivi de la biodiversité tropicale avec les satellites Sentinel-2 du programme Copernicus(2017), and ANR-10-LABX-0025,CEBA,CEnter of the study of Biodiversity in Amazonia(2010)

Subjects
forest canopy, tropical forest biodiversity, Biodiversity mapping, imaging spectroscopy, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, features selection, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, spectral diversity
Abstract

International audience; The rapid loss of biodiversity in tropical rainforests calls for new remote sensing approaches capable of providing rapid estimates of biodiversity over large areas. Imaging spectroscopy has shown potential for the estimation of taxonomic diversity, but the link with spectral diversity has not been investigated extensively with experimental data so far. We explored the relationship between taxonomic diversity and visible to near infrared spectral variance derived from various spectral processing techniques by means of a labeled dataset comprising 2000 individual tree crowns from 200 species from an experimental tropical forest station in French Guiana. We generated a set of artificially assembled communities covering a broad range of taxonomic diversity from this experimental dataset. We analyzed the impact of various processing steps: spectral normalization, spectral transformation through principal component analysis, and feature selection. Correlation between taxonomic diversity and inter-specific spectral variance was strong. Correlation was lower with total spectral variance, with or without normalization and transformation. Dimensionality reduction through feature selection resulted in dramatic improvement of the correlation between Shannon index and spectral variance. While airborne diversity mapping of tropical forest may not be at hand yet, our results confirm that spectral diversity metrics, when computed on properly preprocessed and selected spectral information can predict taxonomic diversity in tropical ecosystems.

Published
2023

29. Beyond variance: simple random distributions are not a good proxy for intraspecific variability in systems with environmental structure

Author

Girard-Tercieux, Camille, primary, Vieilledent, Ghislain, additional, Clark, Adam, additional, Clark, James S., additional, Courbaud, Benoit, additional, Fortunel, Claire, additional, Kunstler, Georges, additional, Pélissier, Raphaël, additional, Rüger, Nadja, additional, and Maréchaux, Isabelle, additional

Published
2022
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30. Rethinking the nature of intraspecific variability and its consequences on species coexistence

Author

Girard-Tercieux, Camille, primary, Maréchaux, Isabelle, additional, Clark, Adam, additional, Clark, James, additional, Courbaud, Benoît, additional, Fortunel, Claire, additional, Guillemot, Joannes, additional, Kunster, Georges, additional, Maire, Guerric Le, additional, Pélissier, Raphaël, additional, Rüger, Nadja, additional, and Vieilledent, Ghislain, additional

Published
2022
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31. Mapping tree mortality rate in a tropical moist forest using multi-temporal LiDAR

Author

Huertas, Claude, Sabatier, Daniel, Derroire, Géraldine, Ferry, Bruno, Jackson, Toby D., Pélissier, Raphaël, Vincent, Grégoire, Huertas, Claude, Sabatier, Daniel, Derroire, Géraldine, Ferry, Bruno, Jackson, Toby D., Pélissier, Raphaël, and Vincent, Grégoire

Abstract

Background and aims: Several studies have shown an increase in tree mortality in intact tropical forests in recent decades. However, most studies are based on networks of field plots whose representativeness is debated. We examine the potential of repeated Airborne LiDAR Scanning data to map forest structure change over large areas with high spatial resolution and to detect tree mortality patterns at landscape level. Methods: The study site is a complex forested landscape in French Guiana with varied topographic positions, vegetation structures and disturbance history. We computed a Gap Dynamics Index from Canopy Height Models derived from successive LiDAR data sets (2009, 2015 and 2019) that we compared to field-measured mortality rates (in stem number and basal area loss) obtained from regular monitoring of 74 1.56-ha permanent plots. Results: At the plot level, the relation between gap dynamics and absolute basal area loss rate (combining fallen and standing dead trees) was overall highly significant (R2 = 0.60) and especially tight for the 59 ha of unlogged forest (R2 = 0.72). Basal area loss rate was better predicted from gap dynamics than stem loss rate. In particular, in previously logged plots, intense self-thinning of small stems did not translate into detectable gaps, leading to poor predictability of stem mortality by LiDAR in those forests severely disturbed 30 years before. At the landscape scale, LiDAR data revealed spatial patterns of gap creation that persisted over the successive analysis periods. Those spatial patterns were related to local topography and canopy height. High canopy forests and bottomlands were more dynamic, with a higher fraction of canopy affected by gaps per unit time indicating higher basal area loss rates. Conclusion: Gap detection and mapping via multitemporal LiDAR data is poised to become instrumental in characterizing landscape-scale forest response to current global change. Meaningful comparison of gap dynamics across time

Published
2022

32. Biodiversity and multifunctionality: insights from rice varietal mixtures in the highlands of Madagascar [00349]

Author

Rahajaharilaza, Koloina, Muller, Bertrand, Vom Brocke, Kirsten, Morel, Jean-Benoit, Pélissier, Raphaël, Ramavovololona, Perle, Fort, Florian, Violle, Cyrille, Rahajaharilaza, Koloina, Muller, Bertrand, Vom Brocke, Kirsten, Morel, Jean-Benoit, Pélissier, Raphaël, Ramavovololona, Perle, Fort, Florian, and Violle, Cyrille

Abstract

The role of biodiversity on ecosystem functioning is increasingly discussed in a multifunctionality context. However, assessing multiple performances in natura is complex and applied perspectives remain scarce. Interestingly, the growing interest for varietal mixtures in agronomy represents a unique opportunity to challenge the role of intraspecific diversity for the regulation of multiple outcomes at the same time. This is the case for rice production in Madagascar. Especially, as the highlands region is increasingly impacted by climate change and by the socio-economic burden resulting from these environmental changes. Pests and pathogens are placing undue pressure on rice crops while disease resistance is also being affected by climate change. The effect of varietal diversity on upland-rice multifunctionality, as well as yield components and resistance to Pyricularia were assessed and quantified during a two-year trial in the highlands of Madagascar. In the first year of the trial, binary mixtures of ten phenotypically contrasted varieties were established. Based on these first-year results, the four most contrasting varieties were selected to repeat the field trial the following season, this time with the inclusion of two levels of fertilization (high and low). First-year results showed that the crop susceptibility to blast disease was reduced by 6.5% in the mixed plots compared to plots with pure stand. Furthermore, varietal mixture generated a yield gain of 13% compared to pure crops in the first year and a yield gain of 17% in the second year under low fertilization. In the highly fertilized treatment, however, the gain was reduced to 4%. In order to identify the multifunctional variety combinations, a functional classification using a combinatorial model was used. Our results suggest that varietal association composed of different functional groups promotes the multifunctionality of cropping systems, when cultivated in suboptimal conditions for plant growth.

Published
2022

37. Leveraging Signatures of Plant Functional Strategies in Wood Density Profiles of African Trees to Correct Mass Estimations From Terrestrial Laser Data

Author

Momo, S. T., Ploton, Pierre, Martin-Ducup, O., Lehnebach, R., Fortunel, Claire, Sagang, L. T., Boyemba, F., Couteron, Pierre, Fayolle, A., Libalah, M., Loumeto, J., Medjibe, V., Ngomanda, A., Obiang, D., Pélissier, Raphaël, Rossi, V., Yongo, O., Sonke, B., Barbier, Nicolas, and PREREDD Collaborators

Subjects
lcsh:R, lcsh:Medicine, lcsh:Q, lcsh:Science
Abstract

Wood density (WD) relates to important tree functions such as stem mechanics and resistance against pathogens. This functional trait can exhibit high intraindividual variability both radially and vertically. With the rise of LiDAR-based methodologies allowing nondestructive tree volume estimations, failing to account for WD variations related to tree function and biomass investment strategies may lead to large systematic bias in AGB estimations. Here, we use a unique destructive dataset from 822 trees belonging to 51 phylogenetically dispersed tree species harvested across forest types in Central Africa to determine vertical gradients in WD from the stump to the branch tips, how these gradients relate to regeneration guilds and their implications for AGB estimations. We find that decreasing WD from the tree base to the branch tips is characteristic of shade-tolerant species, while light-demanding and pioneer species exhibit stationary or increasing vertical trends. Across all species, the WD range is narrower in tree crowns than at the tree base, reflecting more similar physiological and mechanical constraints in the canopy. Vertical gradients in WD induce significant bias (10%) in AGB estimates when using database-derived species-average WD data. However, the correlation between the vertical gradients and basal WD allows the derivation of general correction models. With the ongoing development of remote sensing products providing 3D information for entire trees and forest stands, our findings indicate promising ways to improve greenhouse gas accounting in tropical countries and advance our understanding of adaptive strategies allowing trees to grow and survive in dense rainforests.

Published
2020

42. Quels besoins de connaissances pour construire le futur des forêts en France ? Au-delà du plan de relance

Author

Leroy, Maya, primary, Bontemps, Jean-Daniel, additional, Brahic, Elodie, additional, Dupouey, Jean-Luc, additional, Forget, Pierre-Michel, additional, Garcia, Serge, additional, Gond, Valéry, additional, Kleinschmit von Lengefeld, Andreas Nikolaus, additional, Landmann, Guy, additional, Morin, Xavier, additional, Pélissier, Raphaël, additional, Picard, Nicolas, additional, and Marty, Pascal, additional

Published
2021
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46. Identifying uncertainties in scenarios and models of socio-ecological systems in support of decision-making

Author

Rounsevell, Mark D.A., primary, Arneth, Almut, additional, Brown, Calum, additional, Cheung, William W.L., additional, Gimenez, Olivier, additional, Holman, Ian, additional, Leadley, Paul, additional, Luján, Criscely, additional, Mahevas, Stéphanie, additional, Maréchaux, Isabelle, additional, Pélissier, Raphaël, additional, Verburg, Peter H., additional, Vieilledent, Ghislain, additional, Wintle, Brendan A., additional, and Shin, Yunne-Jai, additional

Published
2021
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47. The real potential of current passive satellite data to map aboveground biomass in tropical forests

Author

Jha, Nidhi, Tripathi, Nitin Kumar, Barbier, Nicolas, Virdis, Salvatore, Chanthorn, Wirong, Viennois, Gaëlle, Brockelman, Warren, Nathalang, Anuttara, Tongsima, Sissades, Sasaki, Nophea, Pélissier, Raphaël, Réjou-Méchain, Maxime, Asian Institute of Technology [Pathumthani] (AIT), 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), National Science and Technology Development Agency [Bangkok] (NSTDA), Kasetsart University (KU), CarboShareAsia project, and European Project: 3DForMod

Subjects
Biomass mapping, Passive satellite sensor, Technology, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Ecology, forest carbon, Sensor saturation limit, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, QH540-549.5, random forest
Abstract

International audience; Forest biomass estimation at large scale is challenging and generally entails large uncertainty in tropical regions. With their wall-to-wall coverage ability, passive remote sensing signals are frequently used to extrapolate field estimates of forest aboveground biomass (AGB). However, studies often use limited reference data and/or flawed validation schemes and thus report unreliable extrapolation error estimates. Here, we compared the ability of three medium- to high-resolution passive satellite sensors, Landsat-8 (L8), Sentinel-2B (S2) and Worldview-3 (WV3), to map AGB in a forest landscape of Thailand. We used a large airborne LiDAR-derived AGB dataset as a reference to train and validate a random forest algorithm and conducted robust error assessments and variable selection using spatialized cross-validations. Our results indicate that the selected predictors strongly varied among the three sensors and between analyses were restricted to low (≤200 Mg ha−1) and high (>200 Mg ha−1) AGB areas. WV3 and S2 data outperformed L8 data to extrapolate AGB (RMSE of 68 and 72 against 84 Mg ha−1, respectively) due to the inclusion of the red-edge band and, probably, to their higher spatial and spectral resolution. Sensitivity to large AGB values was higher for WV3 than for S2 and L8 with saturation point of 247 Mg ha−1 against 204 and 192 Mg ha−1. AGB values above these saturation points remained poorly predictable, especially for L8, indicating that several tropical forest AGB maps should be interpreted with extreme caution. However, predicted gradients of lower AGB values (≤200 Mg ha−1), i.e., in early forest successional stages, were fairly consistent among sensors (r > 0.70), even if the mean absolute difference between estimates was large when AGB predictions were extrapolated out of the calibration area at regional level (34%). We finally showed that calibrating the model only within the sensitivity AGB domain (e.g.

Published
2021

48. Identifying uncertainties in scenarios and models of socio-ecological systems in support of decision-making

Author

Rounsevell, Mark D.a., Arneth, Almut, Brown, Calum, Cheung, William W.l., Gimenez, Olivier, Holman, Ian, Leadley, Paul, Luján, Criscely, Mahevas, Stephanie, Maréchaux, Isabelle, Pélissier, Raphaël, Verburg, Peter H., Vieilledent, Ghislain, Wintle, Brendan A., Shin, Yunne-jai, Rounsevell, Mark D.a., Arneth, Almut, Brown, Calum, Cheung, William W.l., Gimenez, Olivier, Holman, Ian, Leadley, Paul, Luján, Criscely, Mahevas, Stephanie, Maréchaux, Isabelle, Pélissier, Raphaël, Verburg, Peter H., Vieilledent, Ghislain, Wintle, Brendan A., and Shin, Yunne-jai

Abstract

There are many sources of uncertainty in scenarios and models of socio-ecological systems, and understanding these uncertainties is critical in supporting informed decision-making about the management of natural resources. Here, we review uncertainty across the steps needed to create socio-ecological scenarios, from narrative storylines to the representation of human and biological processes in models and the estimation of scenario and model parameters. We find that socio-ecological scenarios and models would benefit from moving away from “stylized” approaches that do not consider a wide range of direct drivers and their dependency on indirect drivers. Indeed, a greater focus on the social phenomena is fundamental in understanding the functioning of nature on a human-dominated planet. There is no panacea for dealing with uncertainty, but several approaches to evaluating uncertainty are still not routinely applied in scenario modeling, and this is becoming increasingly unacceptable. However, it is important to avoid uncertainties becoming an excuse for inaction in decision-making when facing environmental challenges.

Published
2021
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49. Pantropical variability in tree crown allometry

Author

Loubota Panzou, Grace Jopaul, Fayolle, Adeline, Jucker, Tommaso, Phillips, Oliver L., Bohlman, Stephanie, Banin, Lindsay F., Lewis, Simon L., Affum-Baffoe, Kofi, Alves, Luciana F., Antin, Cécile C.M., Arets, Eric, Arroyo, Luzmila, Baker, Timothy R., Barbier, Nicolas Serge, Beeckman, Hans, Berger, Uta, Bocko, Yannick Enock, Bongers, Frans, Bowers, Samuel S.J., Brade, Thom, Brondizio, Eduardo S., Chantrain, Arthur, Chave, Jérôme, Compaore, Halidou, Coomes, David, Diallo, Adama, Dias, Arildo S., Dimobe, Kangbéni, Djagbletey, Gloria Djaney, Domingues, Tomas, Doucet, Jean-Louis, Drouet, Thomas, Forni, Eric, Godlee, John L., Goodman, Rosa C., Gourlet-Fleury, Sylvie, Hien, Fidele, Iida, Yoshiko, Angoboy Ilondea, Bhely, Ilunga Muledi, Jonathan, Jacques, Pierre, Kuyah, Shem, López-Portillo, Jorge, Loumeto, Jean Joël, Marimon‐Junior, Ben Hur, Marimon, Beatriz Schwantes, Mensah, Sylvanus, Mitchard, Edward T. A., Moncrieff, Glenn, Narayanan, Ayyappan, O’Brien, Sean T., Ouedraogo, Korotimi, Palace, Michael W., Pélissier, Raphaël, Ploton, Pierre, Poorter, Lourens, Ryan, Casey C.M., Saiz, Gustavo, Santos, Karin, Schlund, Michael, Sellan, Giacomo, Sonke, Bonaventure, Sterck, Frank, Thibaut, Quentin, Van Hoef, Yorick, Veenendaal, Elmar, Vovides, Alejandra A.G., Xu, Yaozhan, Yao, Tze Leong, Feldpausch, Ted R., Loubota Panzou, Grace Jopaul, Fayolle, Adeline, Jucker, Tommaso, Phillips, Oliver L., Bohlman, Stephanie, Banin, Lindsay F., Lewis, Simon L., Affum-Baffoe, Kofi, Alves, Luciana F., Antin, Cécile C.M., Arets, Eric, Arroyo, Luzmila, Baker, Timothy R., Barbier, Nicolas Serge, Beeckman, Hans, Berger, Uta, Bocko, Yannick Enock, Bongers, Frans, Bowers, Samuel S.J., Brade, Thom, Brondizio, Eduardo S., Chantrain, Arthur, Chave, Jérôme, Compaore, Halidou, Coomes, David, Diallo, Adama, Dias, Arildo S., Dimobe, Kangbéni, Djagbletey, Gloria Djaney, Domingues, Tomas, Doucet, Jean-Louis, Drouet, Thomas, Forni, Eric, Godlee, John L., Goodman, Rosa C., Gourlet-Fleury, Sylvie, Hien, Fidele, Iida, Yoshiko, Angoboy Ilondea, Bhely, Ilunga Muledi, Jonathan, Jacques, Pierre, Kuyah, Shem, López-Portillo, Jorge, Loumeto, Jean Joël, Marimon‐Junior, Ben Hur, Marimon, Beatriz Schwantes, Mensah, Sylvanus, Mitchard, Edward T. A., Moncrieff, Glenn, Narayanan, Ayyappan, O’Brien, Sean T., Ouedraogo, Korotimi, Palace, Michael W., Pélissier, Raphaël, Ploton, Pierre, Poorter, Lourens, Ryan, Casey C.M., Saiz, Gustavo, Santos, Karin, Schlund, Michael, Sellan, Giacomo, Sonke, Bonaventure, Sterck, Frank, Thibaut, Quentin, Van Hoef, Yorick, Veenendaal, Elmar, Vovides, Alejandra A.G., Xu, Yaozhan, Yao, Tze Leong, and Feldpausch, Ted R.

Abstract

Aim: Tree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about large-scale variation and determinants in tropical tree crown allometry. In this study, we explored the continental variation in scaling exponents of site-specific crown allometry and assessed their relationships with environmental and stand-level variables in the tropics. Location: Global tropics. Time period: Early 21st century. Major taxa studied: Woody plants. Methods: Using a dataset of 87,737 trees distributed among 245 forest and savanna sites across the tropics, we fitted site-specific allometric relationships between crown dimensions (crown depth, diameter and volume) and stem diameter using power-law models. Stand-level and environmental drivers of crown allometric relationships were assessed at pantropical and continental scales. Results: The scaling exponents of allometric relationships between stem diameter and crown dimensions were higher in savannas than in forests. We identified that continental crown models were better than pantropical crown models and that continental differences in crown allometric relationships were driven by both stand-level (wood density) and environmental (precipitation, cation exchange capacity and soil texture) variables for both tropical biomes. For a given diameter, forest trees from Asia and savanna trees from Australia had smaller crown dimensions than trees in Africa and America, with crown volumes for some Asian forest trees being smaller than those of trees in African forests. Main conclusions: Our results provide new insight into geographical variability, with large continental differences in tropical tree crown allometry that were driven by stand-level and environmental variables. They have implic, SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2021

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