Biodiv Sci ›› 2016, Vol. 24 ›› Issue (4): 367-377.  DOI: 10.17520/biods.2015240

Special Issue: 中国西南干旱河谷的植物多样性

• Original Papers • Previous Articles     Next Articles

Flora compositions and spatial differentiations of vegetation in dry valleys of Southwest China

Ye Liu1, Xinxin Zhu2, Zehao Shen3,*(), Hang Sun4,*()   

  1. 1 School of Urban Planning and Design, Shenzhen Graduate School, Peking University, Shenzhen 518055.
    2 College of Life Science, Xinyang Normal University, Xinyang, Henan 464000.
    3 Department of Ecology, College of Urban and Environmental Sciences, the Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871.
    4 Key Laboratory of Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204
  • Received:2015-09-11 Accepted:2016-02-02 Online:2016-04-20 Published:2016-05-11
  • Contact: Shen Zehao,Sun Hang


Based on plant community data collected from dry valleys of nine major rivers in Gansu, Sichuan and Yunnan provinces of Southwest China, we divided the families and genera of the vascular plants into geographic elements of Chinese flora, and analyzed the spatial patterns. We found the flora of dry valleys of Southwest China revealed a complex composition of geographic elements with wide floristic connections, including 11 family area-types and 15 genera area-types. The ratio of tropical versus temperate floristic elements was 3.06 at the family level, and 1.77 at the genus level, showing a distinctive affinity for tropical floras, and later imprints of temperate floras. A clear floristic linkage existed between the dry valley floras and the Mediterranean, Western- and Central-Asian floras. The percentages of East Asian elements and endemic Chinese elements were below the average value in the flora found for the subtropical region in China. The Sino-Himalayan element had a value higher than that for the Sino-Japan element in the dry valley floras. The floristic affinity to the tropics weakened while affinity to temperate flora intensified moving in the region from the southwest to northeast. Linkages with the Mediterranean-Central Asian floras, and also the percentage of East Asian elements and endemic Chinese elements increased in the same direction. A boundary between the Sino-Japan type and Sino-Himalayan type was detected between the dry valley floras of Nanpanjiang River and Yuanjiang River. With respect to the genus level floristic composition of geographic elements, Nujiang River, Lancangjiang River and Yuanjiang River were separated from the other rivers, which are all upper branches of the Yangtze River. This departure indicated the impacts of the evolution of the Yangtze River, which were characterized by headward erosion, river confluences, on the characteristics of modern flora in dry valleys.

Key words: dry valleys of Southwest China, vascular plants, floristic elements, similarity, spatial differentiation