Acta Geographica Sinica ›› 2008, Vol. 63 ›› Issue (4): 364-376.doi: 10.11821/xb200804001

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The Spatial and Temporal Characteristics of Grassland Degradation in the Three- River Headwaters Region in Qinghai Province

LIU Jiyuan, XU Xinliang, SHAO Quanqin   

  1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
  • Received:2007-10-23 Revised:2007-12-24 Online:2008-04-25 Published:2010-08-04
  • Supported by:

    The CAS Action-plan for West Development, No.KZCX2-XB2-06-03; National Key Project of Scientific and Technical Supporting Programs, No.2006BAC08B00

Abstract:

Using MSS images in the middle and late 1970s, TM images in the early 1990s and TM/ETM images in 2004, grassland degradation in the Three-River Headwaters Region is interpreted through analysis on RS images in two time series, then the spatial and temporal characteristics of grassland degradation since the 1970s in the Three-River Headwaters Region are analyzed. The results show that grassland degradation in the Three-River Headwaters Region is a continuous changing process which has large area of influence and long time scale, and the drastic intensification phenomenon does not exist in the 1990s as a whole. Grassland degradation pattern in the Three-River Headwaters Region took shape initially in the middle and late 1970s, since the 1970s, this degradation process has taken place continuously, characterizing obviously different rules in different regions. Such as, in humid and sub-humid meadow grassland, grassland firstly fragmentizes, then the degree of vegetation coverage decreases continuously, and finally "black-soil-patch" degraded grassland formed. But in semiarid and arid steppe regions, the degree of grassland vegetation coverage decreases continuously, and finally desertification formed. Because grassland degradation has obvious regional diversity, grassland degradation in the Three-River Headwaters Region could be classified into seven regions, and each region has different characteristics in type, grade, scale and time process of grassland degradation.

Key words: Three-River Headwaters Region, grassland degradation, remote sensing spatial pattern, temporal process, Qinghai