The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ~40,000 and ~53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ~19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ~4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.

Authors: Silk, J.W.F.; Arroyo-Rodríguez, V.; Aiba, S.-I.; Alvarez-Loayza, P.; Alves, L.F.; Ashton, P.; Balvanera, P.; Bastian, M.L.; Bellingham, P.J.; van den Berg, E.; Bernacci, L.; da Conceição Bispo, P.; Blanc, L.; Böhning-Gaese, K.; Boeckx, P.; Bongers, F.; Boyle, B.; Bradford, M.; Brearley, F.Q.; Hockemba, M.B.; Bunyavejchewin, S.; Matos, D.C.L.; Castillo-Santiago, M.; Catharino, E.L.M.; Chai, S.-L.; Chen, Y.; Colwell, R.K.; Robin, C.L.; Clark, C.; Clark, D.B.; Clark, D.A.; Culmsee, H.; Damas, K.; Dattaraja, H.S.; Dauby, G.; Davidar, P.; DeWalt, S.J.; Doucet, J.-L.; Duque, A.; Durigar, G.; Eichhorn, K.A.O.; Eisenlohr, P.V.; Eler, E.; Ewango, C.; Farwig, N.; Feeley, K.J.; Ferreira, L.; Field, R.; de Oliveira Filho, A.T.; Fletcher, C.; Forshed, O.; Franco, G.; Fredriksson, G.; Gillespie, T.; Gillet, J.-F.; Amarnath, G.; Griffith, D.M.; Grogan, J.; Gunatilleke, N.; Harris, D.; Harrison, R.; Hector, A.; Homeier, J.; Imai, N.; Itoh, A.; Jansen, J.A.; Joly, C.A.; de Jong, B.H.J.; Kartawinata, K.; Kearsley, E.; Kelly, D.L.; Kenfack, D.; Kessler, M.; Kitayama, K.; Kooyman, R.; Larney, E.; Laumonier, Y.; Laurance,S.; Laurance, W.F.; Lawes, M.J.; do Amaral, I.L.; Letcher, S.G.; Lindsell, J.; Lu, X.; Mansor, A.; Marjokorpi, A.; Martin, E.H.; Meilby, H.; Melo, F.P.L.; Metcalfe, D.J.; Medjibe, V.P.; Metzger, J.P.; Millet, J,; Mohandass, D.; Montero, J.C.; de Morisson Valeriano, M.; Mugerwa, B.; Nagamasu, H.; Nilus, R.; Ochoa-Gaona, S.; Onrizal; Page, N.; Parolin, P.; Parren, M.; Parthasarathy, N.; Paudel, E.; Permana, A.; Piedade, M.T.F.; Pitman, N.C.A.; Poorter, L.; Poulsen, A.D.; Poulsen, J.; Powers, J.; Prasad, R.C.; Puyravaud, J.-P.; Razafimahaimodison, J.-C.; Reitsma, J.; dos Santos, J.R.; Spironello, W.R.; Romero-Saltos, H.; Rovero, F.; Rozak, A.H.; Ruokolainen, K.; Rutishauser, E.; Saiter, F.; Saner, P.; Santos, B.A.; Santos, F.; Sarker, S.K.; Satdichanh, M.; Schmitt, C.B.; Schöngart, J.; Schulze, M.; Suganuma, M.S.; Sheil, D.; da Silva Pinheiro, E.; Sist, P.; Stevart, T.; Sukumar, R.; Sun, I.-F.; Sunderland, T.C.H.; Suresh, H.S.; Suzuki, E.; Tabarelli, M.; Tang, J.; Targhetta, N.; Theilade, I.; Thomas, D.W.; Tchouto, P.; Hurtado, J.; Valencia, R.; van Valkenburg, J.L.C.H.; Tran, Van Do; Vasquez, R.; Verbeeck, H.; Adekunle, V.; Vieira, S.A.; Webb, C.O.; Whitfeld, T.; Wich, S.A.; Williams, J.; Wittmann, F.; Wöll, H.; Yang, X.; Yao, C.Y.A.; Yap, S.L.; Yoneda, T.; Zahawi, R.A.; Zakaria, R.; Zang, R.; de Assis, R.L.; Luize, B.G.; Venticinque, E.M.

Subjects: diversity, trees, species, tropical forests, spatial distribution, spatial variation, species richness, species diversity

Publication type: ISI, Journal Article, Publication

Year: 2015

ISSN: 1091-6490

DOI: https://doi.org/10.1073/pnas.1423147112