Format: ORAL

Laura Matas-Granados1,2, Claire Fortunel3, Luis Cayuela4, Julia G. de Aledo1,2,4, Celina Ben Saadi1, Nathan J. B. Kraft5, Christopher Baraloto6, S. Joseph Wright7, Jason Vleminckx8, Nancy C. Garwood9, Peter Hietz10, Margaret R. Metz11, Frederick C. Draper12, Timothy R. Baker13, Oliver L. Phillips13, Eurdice N. Honorio Coronado14, Kalle Ruokolainen15, Roosevelt Garca-Villacorta16,17, Katherine H. Roucoux14, Maximilien Guze18, Elvis Valderrama Sandoval19, Paul V.A. Fine20, Carlos A. Amasifuen Guerra21, Ricardo Zarate Gomez22, Pablo R. Stevenson Diaz23, Abel Monteagudo-Mendoza24, Rodolfo Vasquez Martinez25, John Terborgh26, Mathias Disney27, Roel Brienen13, Percy Nez Vargas24, Jhon del Aguila Pasquel22,28, Yadvinder Malhi29, Jacob B. Socolar30, Fernando Cornejo-Valverde31, Gerardo Flores Llampazo22, Jim Vega Arenas19, Darcy Galiano Cabrera24, Javier Silva Espejo24, Joey Talbot13, Barbara Vinceti32, Jos Reyna Huaymacari22, Nallaret Davila Cardozo22, Cecilia Balln Falcn33, Ted R. Feldpausch34, Varun Swamy35, Julio M. Grandez Rios22, Manuel J. Maca1,2

1Departamento de Biología, Área de Botánica, Universidad Autónoma de Madrid, Madrid, Spain. 2Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, Madrid, Spain. 3AMAP, University of Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France. 4Departamento de Biología y Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, Móstoles, Madrid, Spain. 5Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA. 6International Center for Tropical Botany at the Kampong, Institute of Environment, Florida International University, Miami, Florida, USA. 7Smithsonian Tropical Research Institute, Panama City, Panama. 8Yale Institute for Biospheric Studies (YIBS), Yale University, New Haven, Connecticut, USA. 9School of Biological Sciences, LifeScience II, Southern Illinois University, Carbondale, Illinois, USA. 10Institute of Botany, University of Natural Resources and Life Sciences, 1180, Vienna, Austria. 11Department of Biology, Lewis & Clark College, Portland, Oregon, USA. 12School of Geography and Planning, University of Liverpool, UK. 13School of Geography, University of Leeds, UK. 14School of Geography & Sustainable Development, University of St Andrews, St Andrews, UK. 15Department of Biology, University of Turku, Turku, Finland. 16Programa Restauración de Ecosistemas (PRE), Centro de Innovación Científica Amazónica (CINCIA), Tambopata, Madre de Dios, Perú. 17Peruvian Center for Biodiversity and Conservation (PCBC), Iquitos, Loreto, Perú. 18Man and Biosphere Programme, UNESCO, Paris, Île-de-France, France. 19Facultad de Ciencias Biológicas, Universidad Nacional de la Amazonía Peruana, Iquitos, Perú. 20Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA. 21Escuela de Ingeniería Forestal, Facultad de Ingeniería y Ciencias Agrarias, Universidad Nacional Toribio Rodríguez de Mendoza de Amazonas (UNTRM), Chachapoyas, Perú. 22Instituto de Investigaciones de la Amazonía Peruana, Iquitos, Perú. 23Departamento de Ciencias Biológicas, Universidad de los Andes (Colombia), Bogotá, Colombia. 24Universidad Nacional de San Antonio Abad del Cusco, Cusco, Perú. 25Estación Biológica del Jardín Botánico de Missouri, Oxapampa, Perú. 26Department of Biology and Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA. 27Department of Geography, University College London, London, UK. 28Universidad Nacional de la Amazonia Peruana, Iquitos, Perú. 29Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK. 30NCX, 2443 Fillmore St. #380-1418 San Francisco, CA 94115. 31Andes to Amazon Biodiversity Program, Madre de Dios, Madre de Dios, Peru. 32Bioversity International, Rome, Italy. 33Univerdiad Nacional Agraria La Molina, La Molina, Perú. 34Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK. 35San Diego Zoo Institute for Conservation Research, Escondido, California, USA.

Many studies have documented dominance by few species in Amazonian forests, but the underlying mechanisms of tree species dominance remain unclear. Given the key role that these dominant species play in crucial ecosystem processes, clarifying the causes of dominance is essential to understand how Amazonian forests will respond to global change drivers. Here, we used an extent plot network encompassing contrasting habitats in Amazonia to study the ecological processes underpinning dominance through the study of their functional traits. We asked whether: 1) dominant species have a different functional profile than non-dominant species and 2) functional traits capture species differences in dominance patterns. We considered six plant functional traits through the compilation of trait information from different projects: specific leaf area (SLA), leaf area (LA), N content per unit leaf mass (LN), maximum diameter at breast height (DBHmax), wood density (WD), and seed mass (SM). We found that dominant species can reach greater maximum size than non-dominant species and that trait combinations of dominant species varied between habitat type. Additionally, we found that larger dominant species had higher regional frequency, associated with higher dispersal ability, and lower local abundance, likely due to negative density dependence. Greater SM allowed higher regional frequency of dominant species via greater dispersion and seedling survival. Finally, traits related to resource conservative strategies favored higher local densities, whereas the opposite pattern was linked to higher regional frequency. Our study reveals the potential of trait-based approaches in the study of the ecological mechanisms underlying dominance in tropical forests. Our findings highlight the importance of forest habitat conditions in shaping species dominance. Accounting for both local abundance and regional frequency when studying dominance can improve our understanding and forecasting of species responses to global change drivers and help us to effectively direct new conservation policies in Amazonia.