The Lühe Basin is located in central Yunnan Province. High-quality geochronological studies and numerous well-preserved plant fossils in the Lühe Basin indicate a Paleogene modernization of the flora on the southeastern margin of Tibet. However, it remains unclear when the modern topography was established in Yunnan and what the relationship was between regional topographic development and the evolution of Yunnan's exceptionally rich biodiversity. 

In a study published in Global and Planetary Change, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) identify the Lühe plant fossils in detail to understand the floristic structure, and reconstruct both paleoclimate and paleoelevation of the Lühe Basin during the early Oligocene. Combined with more regional data, they explore the driving factors for modernization of the Yunnan flora in terms of diversity and relative composition. 

Ther new early Oligocene paleoelevation estimate of 1.7 ± 0.9 km for the Lühe Basin, combined with previous studies, show that the southeastern margin of the Tibetan Plateau had already attained close to its present topographic form at ~33 Ma. 

The reconstructed mean annual temperature was similar to that of today, but the seasonal range in temperature was greater. The cold winters led to a high proportion of deciduous plant components and the fossil flora is dominated by Betulaceae and Fagaceae. 

The researchers thus concluded that the appearance of the modern flora across the southeastern margin of the Tibetan Plateau had started by the early Oligocene, corresponding with the establishment of modern topography at that time. 

Contact 

SU Tao Ph.D Principal Investigator         

Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China                

E-mail: sutao@xtbg.org.cn