Acta Geographica Sinica ›› 2002, Vol. 57 ›› Issue (2): 174-184.doi: 10.11821/xb200202007

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The Evolution of Mangrove and Its Geographic Background in Tropical China

HUANG Zhen-guo, ZHANG Wei-qiang   

  1. Guangzhou Institute of Geography, Guangzhou 510070, China
  • Received:2001-06-04 Revised:2001-09-26 Online:2002-03-25 Published:2010-09-06
  • Supported by:

    National Natural Science Foundation of China, No. 49771010, 40071011

Abstract:

According to palynological analysis of about thirty samples, the developing process of mangrove since the late Tertiary in the tropical zone of China is discussed. The mangrove can be divided into two types, i.e., the typical and general. The former is represented by Sonneratia, Rhizophora, etc., which only grow in the southern tropical zone. At present the north limit of typical mangrove lies in 19o30'N and that of general mangrove, about 26oN in China. The oldest sporo-pollens of mangrove have been found in the Oligocene stratum in Zhujiang River estuary basin. From Miocene to Pliocene the north limit of mangrove reached Japan. But it was returned to about 22oN, i.e., the northern part of Leizhou Peninsula of Guangdong during Early Pleistocene.It is worth noting that the Last Interglacial Period was a prosperous stage for the evolution of mangrove. The pollens of Sonneratia dated at 42 000~32 696 a BP can be seen in Chenghai of Hanjiang Delta. It shows that the north limit of typical mangrove moved northwards from 19o30'N at present to 23o40'N at that time, showing an amplitude of 2~2.5 oC of rise in temperature than present.The pollens of Sonneratia with datings of 36 230~25 410 aBP have been found also in Shenzhen, Hong Kong, Shuidong and Haikou. The eight palynological profiles from Fuzhou to Beihai indicate that the mangrove disappeared during the Last Glacial Period, which can be seen only in some profiles in South China Sea but the pollens of Sonneratia and Rhizophora were carried by the sea current from southern South China Sea. Up to Early Holocene (9 656~7 912 aBP) the mangrove revived, in which about 7 000 aBP was another prosperous stage corresponding to the Megathermal in Holocene. Sonneratia caseolaris and Bruguiera sexangula have been found from the profiles in Shenzhen and Hong Kong and thus it can be deduced that the typical mangrove developed once again in Middle Holocene and its north limit was moved northwards to 22o20'N, i.e., the estuary of Zhujiang River.It is reported that there are pollens of Acgiceras corniculatum in the Middle Holocene stratum even in Ningbo (29o50'N) of Zhejiang. However they are not developed in situ because about twenty sites of Holocene mangrove pollens are found in the seafloor of East China Sea but they are carried by the Kuroshio or Taiwan Warm Current from south.The north limit of distribution of mangrove at present (26oN) is formed in Middle Holocene. After Middle Holocene the typical mangrove disappeared north of 19o30'N in China's tropical zone but there is Sonneratia alba in Iriomote Island (25oN) of Japan at present. It is also influenced by the Kuroshio, and the cold-resistant Kandelia candel is growing in Kagoshima Bay of Japan, where is the northernmost location of mangrove in the west Pacific Ocean.

Key words: mangrove, tropical zone, China