Acta Geographica Sinica ›› 2005, Vol. 60 ›› Issue (3): 433-444.doi: 10.11821/xb200503010

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Study on the Characteristics and the Cause of Sandy Desertified Land in the West of Hainan Island

LI Sen1,2, SUN Wu3, LI Fan1, LIN Peisong1, ZHENG Yinghua1,3, NIE Lei1   

  1. 1. The Resources and Environmental Science Research Institute, Foshan Uiniversity, Foshan 528000, China;
    2. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS, Xi'an 710075, China;
    3. Department of Geography, South China Normal University, Guangzhou 510631, China
  • Received:2004-12-21 Revised:2005-04-07 Online:2005-05-25 Published:2005-05-25
  • Supported by:

    National Natural Science Foundation of China, No.40271012; Key project of Science and Technology of Hainan (2003)

Abstract:

The west of Hainan Island is the only sandy desertified area of the tropical dry grasslands with sparse trees in China, and it is a very typical sandy desertified land type and course. The sandy desertified land, which is on the sandy coastal plain, the river delta and the sandy mesa, is distributed in the long and narrow area. The sandy desertified lands have the tropical coastal dene characteristics in the district, the shape, the xerophyte and the rapid evolvement of land use. Under the influence of tropical monsoon climate, the foehn effect of the rain shadow field of the Changshan Mountains and the Wuzhishan Mountains and the cold ocean current in the Beibu Gulf, it is developed into the semi-arid climate and the environment of dry grasslands with sparse trees. So that it comes into being for the driving force, the space and the material base of the desertification. The sandy desertified land in the west of Hainan Island in history is due to many factors such as the climate change, the excessive reclamation and excessive firewood, but the factor of human leads the first. The present-day sandy desertified land in the west of Hainan Island can be divided into five stages of increase, renewal, re-increase, reversion and fluctuation in the 20th century, its process is not only controlled by the climate change in several years or decades scale, but also the unreasonable human activities. The area of sandy desertified land increased from 201.45 km2 to 251.61 km2 from the end of the 1950s to the 1970s with an increasing rate of 3.53 km2/a. It has decreased to 122.57 km2 since the 1990s with a decrease rate of -7.72 to -3.20 km2/a. The temperature in the west of Hainan Island appeared to go up by 0.24 oC/10a and the precipitation descended by -23.93 mm/10a for the past 50 years. The land resources are being excessively exploited because of continuous increase in population and domestic animals in recent decades. The results show that the human activities are greatly associated with desertification degree, and the present-day sand desertification in the west of Hainan Island has evolved into the desertification process which is mainly affected by the human activities.

Key words: Hainan Island, sandy desertification, tropical semi-arid climate