Man searches for traces of life in space and hopes to one day make contact with extraterrestrials. He doesn’t even know which creatures live with him on planet earth. Even with the trees, which can hardly be overlooked and should therefore be relatively easy to identify, scientists have so far only been able to get a rough overview. Even less is known about insects, many of which are tiny and can only be distinguished under a microscope – let alone microorganisms that are invisible to the naked eye.
In the case of trees, at least it now seems clear how many different species there are on earth, which does not mean that you know them all. According to a recent study published in the science journal PNAS was published, there are 73,300. That is 14 percent more than previously thought, the authors write. 9200 of them are still unknown and have to be discovered first. To arrive at these numbers, the researchers evaluated databases in which a total of around 64,100 different tree species were registered. The result was then extrapolated using a statistical method.
But why is it important to know how many and which animals and plants live on earth? The answer is simple: you can’t protect what you don’t know. The less you know about other species, the greater the risk of accidentally destroying something, so to speak. And the more species disappear, the more fragile the natural cycles on which humans depend. Trees are a good example of this. They slow down climate change because they bind the greenhouse gas carbon dioxide and they produce oxygen, which we also need to breathe.
The new findings show where it would be most effective to invest in protecting trees
The current study also shows that most of the different tree species grow in South America: 43 percent of all tree species that exist worldwide are found there. In Eurasia it is 22 percent, in Africa 16 percent, in North America 15 percent and in Oceania 11 percent. As theoretical as that sounds, it could be of practical use. In combination with the phenomenon that has been known for a long time that the biodiversity of trees increases continuously from the poles towards the equator, the new findings show, for example, where it would be most effective to invest in tree protection: in the tropical regions of South America. More species would benefit from a single new nature reserve there than anywhere else in the world. Which is not to say that the approximately 90 tree species in Germany are not worthy of protection.
The protection of animals also works better the more you know about them. There are many examples of well-intentioned but unsuccessful species protection projects. In 2018, for example, eleven endangered black rhinos in Kenya were relocated from one national park to another at great expense. The rhinos should find better conditions there and be protected from poachers. What the “rescuers” had not considered: The rhinos could not tolerate the high salt content of the water in their new home. Before long they were all dead.