Advances in Earth Science ›› 2008, Vol. 23 ›› Issue (8): 830-839. doi: 10.11867/j.issn.1001-8166.2008.08.0830

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Distribution Patterns of Genera of Yunnan Seed Plants with References to Their Biogeographical Significances

Zhu Hua   

  1. Xishuangbanna Tropical Botanical Garden, the Chinese Academy of Sciences, Kunming 650223,China
  • Received:2007-12-04 Revised:2008-06-06 Online:2008-08-10 Published:2008-08-10

Zhu Hua. Distribution Patterns of Genera of Yunnan Seed Plants with References to Their Biogeographical Significances[J]. Advances in Earth Science, 2008, 23(8): 830-839.

A total of 31 regional floras that covered whole Yunnan province were used for making frequency maps of distribution types at generic level by Arcview software. The following results were given: 1. Tropical genera account for 29.6% to 94.1% of the total genera in regional floras with the highest proportion in the areas of southern Yunnan, while temperate genera account for 6% to 70.4% of the total genera with the highest proportion from the area of northwestern Yunnan. 2. Among tropical elements, the genera of Pantropical distribution contribute from 13.64% to 46% of the total genera in regional floras with the highest proportion in dry and hot valleys in western and southeastern Yunnan, and the genera of Tropical Asian distribution contribute from 3.33% to 42.26% with the highest proportion in southern Yunnan. 3. Among temperate elements, the genera of North temperate distribution contribute from 2% to 30.39% of the total genera in regional floras with the highest proportion in northwestern Yunnan, and the ones of East Asian distribution contribute from 2% to 14.57% with the highest proportion in Hengduan Mountains in northwestern Yunnan. 4. In relationship with vegetations of Yunnan, the genera of Tropical Asia, Old world tropics and Tropical Asia to Australia distributions occur mainly in the tropical forests in southern Yunnan; the genera of Pantropical and Tropical Asia to Tropical Africa distributions occur mainly in the vegetations on dry and hot valleys; the genera of North temperate distribution occur mainly in forests on mountains with a cold and wet climate, while the genera of East Asian, East Asian and North America disjunct, and Old world temperate distributions occur mainly in the vegetations of the area with a warm climate. 5. In biogeography, the frequent patterns of the genera of seed plants imply that the “Tanaka line” could also act as a demarcation line between the tropical Asia flora (Indo-Malaysia flora) and East Asia flora in Yunnan; the semi-savanna vegetation in the dry and hot valleys in Yunnan could have floristic affinity to savanna of Africa; the Yunnan geo-plate could have clock-wise movement by bumping of India plate during the uplift of Himalayas. It is supported that Yunnan should be a region with tropical areas as the horizontal base because almost all areas of lower elevation are tropical in nature regardless of their latitudinal location.

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