The number of tree species on Earth.


Type
Article
Change log
Authors
Cazzolla Gatti, Roberto  ORCID logo  https://orcid.org/0000-0001-5130-8492
Gamarra, Javier GP 
Crowther, Tom 
Abstract

One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground-sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness.

Description
Keywords
biodiversity, forests, hyperdominance, rarity, richness
Journal Title
Proc Natl Acad Sci U S A
Conference Name
Journal ISSN
0027-8424
1091-6490
Volume Title
119
Publisher
Proceedings of the National Academy of Sciences