They are very old mountains. How much? Over 30 million years old. No, of course not all flowers come from there. But there is still a great variety to this day. They are the Hengduan Mountains on the Tibetan Plateau of Asia. They have more than 3,000 types of alpine plants. They are the mountains in which the flowers were born.
“It’s a fascinating place,” says Richard Ree, an evolutionary biologist at the Field Museum. “These meadows are similar to the Rocky Mountains in North America, for example. But then you realize that there are ten times more species. ” The Rhododendrons , the Primroses and the Gentians They are particularly diverse.
A long time ago
The plant community is also much, much older. It was created about 30 million years ago. It is the oldest contiguous alpine ecosystem in the world. It had a lot more time to diversify. Evolution has also done its thing. Heavy rains provided essential moisture and promoted the erosion that divided the landscape. It isolated plant populations that eventually decayed into new species.
“We want to understand how species and communities have reacted in the past,” says botanist Pam Soltis. It is from the Florida Museum of Natural History. “We could have a better idea of how fragile they can be in the next century.”
The aim was to find out the age of the plants in the region. DNA sequences were used to create evolution trees from the 18 groups of plants found on the Tibetan plateau. They used plant fossils to calibrate a timeline. The results enabled them to estimate how quickly new species are spreading from one region to another.
The data indicate “a surprising result,” says Ree. Some of the plant groups on the plateau emerged in the Hengduan Mountains about 30 million years ago. Long before what is known for other alpine flora. More new species emerged. Important geological events such as the uplift of mountain ranges isolated plant populations 19 million years ago. Plant speciation accelerated again about 15 million years ago. Geological evidence suggests that the monsoon intensified and the landscape changed.
The diversity of Hengduan’s flora could reflect his happiness. The region avoided the intense icing that wiped out old plant communities in other mountains. The north-south orientation of the mountains could also have helped. Plants had an escape route to warmer climates, with their seeds being transported south by animals, wind or water.
How will the ancient Hengduan flora deal with current human activities? There is an urgent threat. The development of new roads, hydropower plants and the growth of settlements and farms. But the mountains where the flowers were born are still a big attraction. Impressive wild flowers appear on the slopes of the Hengduan Mountains every summer. It is becoming a growing attraction for ecotourism. This prompted the Chinese government to protect parts of this ancient cradle of plant diversity.