An estimate of the number of tropical tree species.
Slik JWF., Arroyo-Rodríguez V., Aiba S-I., Alvarez-Loayza P., Alves LF., Ashton P., Balvanera P., Bastian ML., Bellingham PJ., van den Berg E., Bernacci L., da Conceição Bispo P., Blanc L., Böhning-Gaese K., Boeckx P., Bongers F., Boyle B., Bradford M., Brearley FQ., Breuer-Ndoundou Hockemba M., Bunyavejchewin S., Calderado Leal Matos D., Castillo-Santiago M., Catharino ELM., Chai S-L., Chen Y., Colwell RK., Chazdon RL., Clark C., Clark DB., Clark DA., Culmsee H., Damas K., Dattaraja HS., Dauby G., Davidar P., DeWalt SJ., Doucet J-L., Duque A., Durigan G., Eichhorn KAO., Eisenlohr PV., Eler E., Ewango C., Farwig N., Feeley KJ., Ferreira L., Field R., de Oliveira Filho AT., Fletcher C., Forshed O., Franco G., Fredriksson G., Gillespie T., Gillet J-F., Amarnath G., Griffith DM., Grogan J., Gunatilleke N., Harris D., Harrison R., Hector A., Homeier J., Imai N., Itoh A., Jansen PA., Joly CA., de Jong BHJ., Kartawinata K., Kearsley E., Kelly DL., Kenfack D., Kessler M., Kitayama K., Kooyman R., Larney E., Laumonier Y., Laurance S., Laurance WF., Lawes MJ., Amaral ILD., Letcher SG., Lindsell J., Lu X., Mansor A., Marjokorpi A., Martin EH., Meilby H., Melo FPL., Metcalfe DJ., Medjibe VP., Metzger JP., Millet J., Mohandass D., Montero JC., de Morisson Valeriano M., Mugerwa B., Nagamasu H., Nilus R., Ochoa-Gaona S., Onrizal None., Page N., Parolin P., Parren M., Parthasarathy N., Paudel E., Permana A., Piedade MTF., Pitman NCA., Poorter L., Poulsen AD., Poulsen J., Powers J., Prasad RC., Puyravaud J-P., Razafimahaimodison J-C., Reitsma J., Dos Santos JR., Roberto Spironello W., Romero-Saltos H., Rovero F., Rozak AH., Ruokolainen K., Rutishauser E., Saiter F., Saner P., Santos BA., Santos F., Sarker SK., Satdichanh M., Schmitt CB., Schöngart J., Schulze M., Suganuma MS., Sheil D., da Silva Pinheiro E., Sist P., Stevart T., Sukumar R., Sun I-F., Sunderland T., Suresh HS., Suzuki E., Tabarelli M., Tang J., Targhetta N., Theilade I., Thomas DW., Tchouto P., Hurtado J., Valencia R., van Valkenburg JLCH., Van Do T., Vasquez R., Verbeeck H., Adekunle V., Vieira SA., Webb CO., Whitfeld T., Wich SA., Williams J., Wittmann F., Wöll H., Yang X., Adou Yao CY., Yap SL., Yoneda T., Zahawi RA., Zakaria R., Zang R., de Assis RL., Garcia Luize B., Venticinque EM.
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.