title: The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa.
abstract: Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species' range size is a better predictor of the number of times it has been collected than the species' estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites.
authors.affiliation: Naturalis Biodiversity Center, Vondellaan 55, Postbus 9517, 2300 RA Leiden, The Netherlands.|Coordenação de Botânica, Museu Paraense Emílio Goeldi, Av. Magalhães Barata 376, C.P. 399, Belém, PA 66040-170, Brazil.
authors.forename: Hans
authors.initials: H
authors.lastname: Ter Steege
authors.affiliation: Naturalis Biodiversity Center, Vondellaan 55, Postbus 9517, 2300 RA Leiden, The Netherlands.
authors.forename: Rens W
authors.initials: RW
authors.lastname: Vaessen
authors.affiliation: Herbario Amazónico Colombiano, Instituto SINCHI, Calle 20 No 5-44, Bogotá, DF, Colombia.
authors.forename: Dairon
authors.initials: D
authors.lastname: Cárdenas-López
authors.affiliation: Institut de Recherche pour le Développement (IRD, UMR AMAP), TA A-51/PS2, Bd. de la Lironde, 34398 Montpellier cedex 5, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sabatier
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, SE-405 30 Göteborg, Sweden.|Gothenburg Botanical Garden, Carl Skottsbergs gata 22A, SE-413 19, Göteborg, Sweden.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Antonelli
authors.affiliation: Naturalis Biodiversity Center, Vondellaan 55, Postbus 9517, 2300 RA Leiden, The Netherlands.
authors.forename: Sylvia Mota
authors.initials: SM
authors.lastname: de Oliveira
authors.affiliation: Science and Education, The Field Museum, 1400 S. Lake Shore Drive, Chicago, IL 60605-2496, USA.|Nicholas School of the Environment, Duke University, Durham, North Carolina 27705, USA.
authors.forename: Nigel C A
authors.initials: NC
authors.lastname: Pitman
authors.affiliation: Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166-0299, USA.
authors.forename: Peter Møller
authors.initials: PM
authors.lastname: Jørgensen
authors.affiliation: Coordenação de Botânica, Museu Paraense Emílio Goeldi, Av. Magalhães Barata 376, C.P. 399, Belém, PA 66040-170, Brazil.
authors.forename: Rafael P
authors.initials: RP
authors.lastname: Salomão
mesh_terms: D044822:Biodiversity; D057189:Checklist / Q000379:methods*; D003247:Conservation of Natural Resources / Q000379:methods*; D010802:Phylogeny; D065947:Rainforest; D014197:Trees / Q000145:classification*