Around the world, tropical forests are disappearing at alarming rates. As conservations race against time to protect these ecosystems, it’s crucial to know where it would be most fruitful to focus their efforts. Key to that is data. While it has long been understood that Latin America is richer in plant species than tropical Africa, scientists lacked concrete numbers to illustrate that fact. A paper recently published in Science, featuring four Missouri Botanical Garden scientists among its coauthors, provides exactly that.
The paper, “The distribution of biodiversity richness in the tropics,” found Latin America is more than twice as rich in plant species as tropical Africa and is home to a third of the world’s biodiversity. Missouri Botanical Garden Researchers Roy Gereau, Peter Phillipson, and Carmen Ulloa coauthored the paper.
The researchers determined distribution of biodiversity by comparing the numbers of vascular plant species in the Afrotropical Region (Africa south of the Sahara plus Madagascar) and Latin America using the Vascular Plants of Americas website developed by the Garden, the African Plant Database, a collaboration among the South African National Biodiversity Institute, the Geneva Botanical Garden and the Missouri Botanical Garden, and the Catalogue of the Plants of Madagascar developed at the Garden and housed on its Tropicos database. They also found that based on more approximate but still reliable numbers, Tropical Asia is as rich per area in plant species as Latin America, but considerably smaller.
Comparing the databases confirmed that Latin America is more than twice as rich in plant species, in a smaller area, than tropical Africa and that new species are being discovered in Latin America much more rapidly.
“This information is very important in accurately understanding the distribution of biodiversity worldwide, since, combined with the best available information from relatively well-known groups of animals, it becomes clear that Latin America is home to at least a third of the world’s total biodiversity,” Raven says. “This enables us to know that research concentrated there will certainly yield far more new species than that conducted in any other part of the globe.”
Gereau comments that plant species numbers may not be strictly comparable between major tropical regions because the species concepts used in one region may be predominantly broader or narrower than those used in another region, comparison of regional floras at the level of families and genera can give some insight into the comparative richness of these regions in terms of major evolutionary lines. This can provide some productive lines for future research.
Ulloa noted that Ecuador, where she conducts her research, is a hotspot for new discoveries. Although it is one of the smaller countries in the Americas, similar in size to the state of Colorado, scientists have named about 100 new species from Ecuador each year of the past five years. This year alone, 120 new species were named for the Mesoamerican flora in the Piperaceae, or black pepper family, by Garden collaborator Dr. Ricardo Callejas and published in the most recent volume of Flora Mesoamericana edited and published at the Garden.
“Naming species takes time, patience, and dedication,” Ulloa explains. “Several unnamed species have long shelf-lives stocked away in herbaria and may never be named, thus the importance to curate and maintain active herbarium collections.”
Going forward, Ulloa said keeping the Vascular Plants of the Americas, VPA, website up-to-date is a top priority, given the findings of the paper. Already, she has three other collaborative papers in the works using data from the VPA.
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