title: Exploring the floristic diversity of tropical Africa.
abstract: Understanding the patterns of biodiversity distribution and what influences them is a fundamental pre-requisite for effective conservation and sustainable utilisation of biodiversity. Such knowledge is increasingly urgent as biodiversity responds to the ongoing effects of global climate change. Nowhere is this more acute than in species-rich tropical Africa, where so little is known about plant diversity and its distribution. In this paper, we use RAINBIO - one of the largest mega-databases of tropical African vascular plant species distributions ever compiled - to address questions about plant and growth form diversity across tropical Africa.
  
  
  
  The filtered RAINBIO dataset contains 609,776 georeferenced records representing 22,577 species. Growth form data are recorded for 97% of all species. Records are well distributed, but heterogeneous across the continent. Overall, tropical Africa remains poorly sampled. When using sampling units (SU) of 0.5°, just 21 reach appropriate collection density and sampling completeness, and the average number of records per species per SU is only 1.84. Species richness (observed and estimated) and endemism figures per country are provided. Benin, Cameroon, Gabon, Ivory Coast and Liberia appear as the botanically best-explored countries, but none are optimally explored. Forests in the region contain 15,387 vascular plant species, of which 3013 are trees, representing 5-7% of the estimated world's tropical tree flora. The central African forests have the highest endemism rate across Africa, with approximately 30% of species being endemic.
  
  
  
  The botanical exploration of tropical Africa is far from complete, underlining the need for intensified inventories and digitization. We propose priority target areas for future sampling efforts, mainly focused on Tanzania, Atlantic Central Africa and West Africa. The observed number of tree species for African forests is smaller than those estimated from global tree data, suggesting that a significant number of species are yet to be discovered. Our data provide a solid basis for a more sustainable management and improved conservation of tropical Africa's unique flora, and is important for achieving Objective 1 of the Global Strategy for Plant Conservation 2011-2020. In turn, RAINBIO provides a solid basis for a more sustainable management and improved conservation of tropical Africa's unique flora.
authors.affiliation: Botanic Garden Meise, Nieuwelaan 38, BE-1860, Meise, Belgium. marc.sosef@botanicgardenmeise.be.
authors.forename: Marc S M
authors.initials: MS
authors.lastname: Sosef
authors.affiliation: DIADE, Université Montpellier, IRD, Montpellier, France.|Laboratoire d'Évolution biologique et Écologie, Faculté des Sciences, Université Libre de Bruxelles, Brussels, Belgium.|CESAB/FRB, Domaine du Petit Arbois, Av. Louis Philibert, Aix-en-Provence, 13100, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Dauby
authors.affiliation: Section for Ecoinformatics & Biodiversity, Department of Bioscience, Aarhus University, Ny Munkegade 114, DK-8000, Aarhus C, Denmark.
authors.forename: Anne
authors.initials: A
authors.lastname: Blach-Overgaard
authors.affiliation: Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK.
authors.forename: Xander
authors.initials: X
authors.lastname: van der Burgt
authors.affiliation: Centre for Ecology, Evolution and Environmental Changes (CE3C), Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016, Lisbon, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Catarino
authors.affiliation: Wageningen University, Biosystematics Group, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
authors.forename: Theo
authors.initials: T
authors.lastname: Damen
authors.affiliation: DIADE, Université Montpellier, IRD, Montpellier, France.|Herbarium et Bibliothèque de Botanique Africaine, Université Libre de Bruxelles, Boulevard du Triomphe, B-1050, Bruxelles, Belgium.|Laboratoire de Botanique systématique et d'Écologie, Département des Sciences Biologiques, École Normale Supérieure, Université de Yaoundé I, Yaoundé, Cameroon.|Center for Tropical Research, Institute of the Environment and Sustainability, University of California, Los Angeles, Box 951496, Los Angeles, CA, 90095, USA.|International Institute of Tropical Agriculture, BP 2008 (Messa), Yaounde, Cameroon.
authors.forename: Vincent
authors.initials: V
authors.lastname: Deblauwe
authors.affiliation: Botanic Garden Meise, Nieuwelaan 38, BE-1860, Meise, Belgium.
authors.forename: Steven
authors.initials: S
authors.lastname: Dessein
authors.affiliation: Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK.
authors.forename: John
authors.initials: J
authors.lastname: Dransfield
authors.affiliation: Herbarium et Bibliothèque de Botanique Africaine, Université Libre de Bruxelles, Boulevard du Triomphe, B-1050, Bruxelles, Belgium.|Missouri Botanical Garden, Africa & Madagascar Department, P.O. Box 299, St. Louis, Missouri, 63166-0299, USA.|AMAP, CNRS, INRA, IRD, Université Montpellier, Montpellier, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Droissart
authors.affiliation: Centre for Ecology, Evolution and Environmental Changes (CE3C), Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016, Lisbon, Portugal.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Duarte
authors.affiliation: Botanic Garden Meise, Nieuwelaan 38, BE-1860, Meise, Belgium.
authors.forename: Henry
authors.initials: H
authors.lastname: Engledow
authors.affiliation: Herbarium et Bibliothèque de Botanique Africaine, Université Libre de Bruxelles, Boulevard du Triomphe, B-1050, Bruxelles, Belgium.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Fadeur
authors.affiliation: CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal.|CEABN/InBio, Centro de Ecologia Aplicada "Professor Baeta Neves", Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Lisboa, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Figueira
authors.affiliation: Missouri Botanical Garden, Africa & Madagascar Department, P.O. Box 299, St. Louis, Missouri, 63166-0299, USA.
authors.forename: Roy E
authors.initials: RE
authors.lastname: Gereau
authors.affiliation: Laboratoire d'Évolution biologique et Écologie, Faculté des Sciences, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Olivier J
authors.initials: OJ
authors.lastname: Hardy
authors.affiliation: Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Harris
authors.affiliation: Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden, The Netherlands.|Picturae, De Droogmakerij 12, 1851LX, Heiloo, The Netherlands.
authors.forename: Janneke
authors.initials: J
authors.lastname: de Heij
authors.affiliation: Botanic Garden Meise, Nieuwelaan 38, BE-1860, Meise, Belgium.
authors.forename: Steven
authors.initials: S
authors.lastname: Janssens
authors.affiliation: Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden, The Netherlands.|Department of Ecology, Faculty of Science, Charles University, Vinicna 7, 128 44, Prague 2, Czech Republic.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Klomberg
authors.affiliation: Institut für Geobotanik und Botanischer Garten, Im Neuwerk 21, University Halle-Wittenberg, 06108, Halle (Saale), Germany.
authors.forename: Alexandra C
authors.initials: AC
authors.lastname: Ley
authors.affiliation: Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK.|Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, UK.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Mackinder
authors.affiliation: Herbarium et Bibliothèque de Botanique Africaine, Université Libre de Bruxelles, Boulevard du Triomphe, B-1050, Bruxelles, Belgium.|Laboratoire d'Ecologie végétale et Biogéochimie, Université Libre de Bruxelles, Boulevard du Triomphe, B-1050, Bruxelles, Belgium.
authors.forename: Pierre
authors.initials: P
authors.lastname: Meerts
authors.affiliation: Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden, The Netherlands.
authors.forename: Jeike L
authors.initials: JL
authors.lastname: van de Poel
authors.affiliation: Laboratoire de Botanique systématique et d'Écologie, Département des Sciences Biologiques, École Normale Supérieure, Université de Yaoundé I, Yaoundé, Cameroon.
authors.forename: Bonaventure
authors.initials: B
authors.lastname: Sonké
authors.affiliation: Botanic Garden Meise, Nieuwelaan 38, BE-1860, Meise, Belgium.|Herbarium et Bibliothèque de Botanique Africaine, Université Libre de Bruxelles, Boulevard du Triomphe, B-1050, Bruxelles, Belgium.|Missouri Botanical Garden, Africa & Madagascar Department, P.O. Box 299, St. Louis, Missouri, 63166-0299, USA.
authors.forename: Tariq
authors.initials: T
authors.lastname: Stévart
authors.affiliation: Botanic Garden Meise, Nieuwelaan 38, BE-1860, Meise, Belgium.
authors.forename: Piet
authors.initials: P
authors.lastname: Stoffelen
authors.affiliation: Section for Ecoinformatics & Biodiversity, Department of Bioscience, Aarhus University, Ny Munkegade 114, DK-8000, Aarhus C, Denmark.
authors.forename: Jens-Christian
authors.initials: JC
authors.lastname: Svenning
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Sepulchre
authors.affiliation: AMAP, CNRS, INRA, IRD, Université Montpellier, Montpellier, France.
authors.forename: Rainer
authors.initials: R
authors.lastname: Zaiss
authors.affiliation: Wageningen University, Biosystematics Group, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.|Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden, The Netherlands.
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Wieringa
authors.affiliation: DIADE, Université Montpellier, IRD, Montpellier, France. thomas.couvreur@ird.fr.|Laboratoire de Botanique systématique et d'Écologie, Département des Sciences Biologiques, École Normale Supérieure, Université de Yaoundé I, Yaoundé, Cameroon. thomas.couvreur@ird.fr.|Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden, The Netherlands. thomas.couvreur@ird.fr.
authors.forename: Thomas L P
authors.initials: TL
authors.lastname: Couvreur
mesh_terms: D000349:Africa; D044822:Biodiversity; D019992:Databases as Topic; D035264:Flowers / Q000502:physiology*; D065928:Forests; D005843:Geography; D013045:Species Specificity; D013997:Time Factors; D014197:Trees / Q000254:growth & development; D014329:Tropical Climate
keywords: Botanical exploration; Digitization; Floristic patterns; Herbarium specimens; Plant growth form; Species richness; Tropical forests