More than 9000 tree species are still waiting for their discovery. This is the result of a new global inventory that Peter Reich from the University of Michigan and his team present in »PNAS«. This would make their diversity again 14 percent larger than previously thought. The total number of all tree species would then be around 73,000 instead of the previously known 60 065.
For the inventory, the working group combined the data sets of the Global Forest Biodiversity Initiative and TREECHANGE, which collect characteristic values of tree surveys in defined spatial units. Each individual tree is identified and measured. This merger already increased the diversity to 64,000 known tree species. With the help of newly developed statistical models, Reich and Co. then calculated how many species can occur uniquely in a biome, such as rainforests, savannahs or boreal coniferous forests.
The researchers are even a conservative estimate, the researchers write. They suspect 40 percent of these unknown species in South America and mainly in the Andes and Amazonia. The continent already has the highest tree diversity and endemism rate; At the same time, he also home to an above -average number of rarities. "That is why the preservation of the forests in South America has top priority, especially in view of the current crisis of the tropical forests, which is due to human influences such as deforestation, fires and climate change," says Reich.
Worldwide, about half to two-thirds of all already known tree species occur in tropical and subtropical moist forests, which are species-rich but at the same time poorly researched by scientists. In tropical and subtropical dry forests, there are probably also a large number of undiscovered tree species.
