Hengduan Mountain alpine flora history shown to be longest on Earth

July 30, 2020

The alpine biome harbors distinctive communities adapted to stressful environmental conditions. For plants, the world's most species-rich temperate alpine biota occurs in the Qinghai-Tibet Plateau (QTP), Himalaya, and the Hengduan Mountains (THH).

Threatened by global warming, alpine species are vulnerable. To understand how alpine biotas formed in response to historical environmental change may improve our ability to predict and mitigate threats.

In a study published in Science, researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences showed that the alpine flora of the Hengduan Mountains has continuously existed far longer than any other alpine flora on Earth. They also illustrated how modern biotas have been shaped by past geological and climatic events.

The researchers from XTBG and the Field Museum of the U.S. connected the dynamic tectonic and climatological history of the THH region to the biological processes that have driven the development of its alpine biota. The scientists especially focused on whether phylogenetic estimates of alpine ancestry are temporally and spatially consistent with geological evidence of alpine habitat availability.

By using a joint model of biome occupation, evolution of geographic range, and lineage diversification, they analyzed time-calibrated phylogenies of 18 groups of flowering plants.

"Our historical reconstructions indicate that an alpine flora had emerged in the THH region by the early Oligocene. This is much earlier than estimated origins of other extant alpine floras," said Prof. XING Yaowu from XTBG.

In addition, the researchers tested whether major tectonic events in the QTP, Himalaya, and Hengduan Mountains left discernible imprints on the tempo and mode of alpine biotic assembly.

They found that overall rates of in situ alpine speciation began to increase from the early Miocene and were jointly driven by the uplift of Himalaya and the Hengduan Mountains as well as intensification of the Asian monsoon.

"Our results, derived from analyses of time-scaled molecular phylogenies and not in situ fossil evidence of alpine ancestry, are nevertheless temporally consistent with the latest geological evidence that active orogeny associated with widespread crustal shortening and thickening established highlands from eastern Tibet to the Hengduan Mountains by the end of the Eocene," said DING Wenna, first author of the study.

"The rich alpine flora of the THH region has been shaped by a long and complex history of colonization, local recruitment and in situ diversification driven by mountain building and climate change. The Hengduan Mountains are not only the cradle of alpine plants. They are also the primary source of alpine lineages colonizing the Himalaya and QTP, which need urgent conservation in this temperate biodiversity hotspot," said Prof. XING.

Chinese Academy of Sciences Headquarters

Related Himalaya Articles from Brightsurf:

Tracking the Himalayan history from the evolution of hundreds of frogs, lizards and snakes
We examined two hypotheses about the uplift of the Himalaya based on biotic assembly through time of the herpetofauna.

How rain can move mountains
Scientists have long thought that rainfall has a dramatic effect on the evolution of mountainous landscapes, but the reasons for how and why have been elusive.

Ground-breaking discovery finally proves rain really can move mountains
A pioneering technique which captures precisely how mountains bend to the will of raindrops has helped solve a long-standing scientific enigma.

Seismic data explains continental collision beneath Tibet
New imagery reveals the causes of seismic activity deep beneath the Himalaya region, contributing to an ongoing debate over the continental collision process when two tectonic plates crash into each other.

Plate tectonics goes global
A research team led by Dr. WAN Bo from the Institute of Geology and Geophysics (IGG) of the Chinese Academy of Sciences has revealed that plate tectonics went global 2 billion years ago.

Hengduan Mountain alpine flora history shown to be longest on Earth
Researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences showed that the alpine flora of the Hengduan Mountains has continuously existed far longer than any other flora on Earth.

Ancient mountain formation and monsoons helped create a modern biodiversity hotspot
In a new study in Science, researchers examined the plant life in the China's Hengduan Mountains, the Himalaya Mountains, and the Qinghai-Tibet Plateau.

New scenario for the India-Asia collision dynamics
The India-Asia collision is an outstanding smoking gun in the study of continental collision dynamics.

Caves tell us that Australia's mountains are still growing
Research shows Buchan Caves to be about 3.5 million years old and that Victoria's East Gippsland has remained tectonically active for long times, even into the present-day, which is why residents occasionally report earthquakes.

Why the 'uplift of the Tibetan plateau' is a myth
Spicer and colleagues combine stable isotope and fossil paleoaltimetry to chart the growth of Tibet, the Himalaya and the Hengduan mountains through time and show the plateau is young, less that 15 million years old, and evolved not just by the collision of India with Eurasia but through multiple earlier mountain-building events and the infilling of deep ancient lowlands hosting subtropical monsoon-adapted biotas.

Read More: Himalaya News and Himalaya Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.