It is widely accepted that geological history, evolutionary events and processes, and current climatic conditions are significant factors in the formation of contemporary biogeographic patterns.
Prof. ZHU Hua and his student of Xishuangbanna Tropical Botanical Garden (XTBG) applied this concept to investigate the contemporary pattern of floras and the associated geological events during the collision between India and Eurasia.
The researchers investigated the floristic phylogenetic patterns of three representative regions in southern, central, and northwestern Yunnan. They aimed to examine the significance of key geological events, particularly the plate collision-induced uplift of the Himalaya-Tibetan Plateau and the strike-slip extrusion of Indochina, on contemporary patterns of biogeography .They used a comprehensive method combining floristic geography with phylogenetic information.
They extended traditional species-centric floristic analyses and phylogenetic analyses of certain taxa or local floras to incorporate phylogenetic information and focused on regional floras. They used presence/absence floristic data of regions in southern, central, and northwestern Yunnan to analyze the phylogenetic structure and beta diversity of the three regional floras to quantify how closely related pairs of taxa were within or between floras.
They constructed mega-phylogenies of the regional floras and then analyzed the phylogenetic assemblage structure in each flora, as well as the phylogenetic beta diversity between floras from three taxonomical hierarchies (family, genus and species).
They also conducted phylogenetic analyses among different geographical elements (e.g., pantropic or tropical Asia genus, north temperate or temperate Asia genus) for more detailed phylogenetic investigations of these floras.
The integration of floristic geography with phylogenetic information in their analyses provided clues that revealed the influence of geological events on the biogeographical divergence of regional floras, as well as evidences for biogeographical hypotheses about Yunnan. The uplift of the Himalayas and the extrusion of Indochina fit well with the phylogenetic patterns of regional floras across Yunnan.