The distribution of biodiversity richness in the tropics

Abstract

We compare the numbers of vascular plant species in the three major tropical areas. The Afrotropical Region (Africa south of the Sahara Desert plus Madagascar), roughly equal in size to the Latin American Region (Mexico southward), has only 56,451 recorded species (about 170 being added annually), as compared with 118,308 recorded species (about 750 being added annually) in Latin America. Southeast Asia, only a quarter the size of the other two tropical areas, has approximately 50,000 recorded species, with an average of 364 being added annually. Thus, Tropical Asia is likely to be proportionately richest in plant diversity, and for biodiversity in general, for its size. In the animal groups we reviewed, the patterns of species diversity were mostly similar except for mammals and butterflies. Judged from these relationships, Latin America may be home to at least a third of global biodiversity.

Synopsis of EcuadorianPterichis(Orchidaceae)

“…The disadvantage of using a few specimens for the description of new taxa, particularly of new species, is that the intraspecific variation cannot be evaluated. As calculated by Raven et al (2020) an average of 749 new vascular plant species has been described annually from Latin America for the past 25 years and this rate did not decrease with time. According to some estimates (Bebber et al, 2010) about 70,000 species of flowering plants are waiting to be discovered and named.…”

Phylogeny and biogeography of Ceiba Mill. (Malvaceae, Bombacoideae)

“…The Neotropics is the most species-rich region in the world (Antonelli and Sanmartín 2011) and the mechanisms that generated and maintain its biodiversity are constantly debated (Moreau and Bell 2013, Silveira et al 2016, Rangel et al 2018, Schley et al 2018, Sosa et al 2018, Raven et al 2020. Through evolutionary time, the Neotropics have been climatically and geologically dynamic, resulting in a diversity of biomes, from deserts to tropical rain forests (Hughes et al 2013, Rangel et al 2018.…”

The Origins and Drivers of Neotropical Diversity

“…Comprising South America, Central America, tropical Mexico and the Caribbean Islands, the Neotropics are arguably the most biodiverse region on Earth, being home to at least a third of global biodiversity (Raven et al 2020). This region does not only include the largest tropical rainforest, Amazonia, but also eight of the 34 known biodiversity hotspots (Mittermeier et al 2011).…”

“…Based on a comparative phylogenetic dataset containing 150 well-sampled species-level molecular phylogenies and 12,512 extant species, we evaluate the prevalence of the macroevolutionary scenarios 1-4 as general explanations for Neotropical diversification, as well as their variation across clades and geographic settings. This dataset represents ~47-60% of all described tetrapods and ~5-7% of the known plant Neotropical diversity depending on the data source Raven et al 2020), which we use to evaluate the mode, tempo and drivers of Neotropical diversification at the continental scale.…”