PROGRESS IN GEOGRAPHY ›› 2016, Vol. 35 ›› Issue (6): 768-778.doi: 10.18306/dlkxjz.2016.06.010

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Forest and grassland coverage change in the Yellow River-Huangshui River Valley in northeast Qinghai-Tibet Plateau during the Qing Dynasty

Zhilei WU1(), Fenggui LIU1,2,3,*(), Yili ZHANG3,4, Qiong CHEN1, Qiang ZHOU1, Dengxing YANG1   

  1. 1. College of Biologic and Geographic Sciences, Qinghai Normal University, Xining 810008, China
    2. Key Laboratory of Qinghai-Tibet Plateau Resources and Environment, Xining 810008, China
    3. Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
    4. Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China
  • Online:2016-06-23 Published:2016-06-23
  • Contact: Fenggui LIU E-mail:wuzl32@163.com;lfg_918@163.com
  • Supported by:
    National Natural Science Foundation of China, No.41271123, No.41261010, No.41371120;Strategic Priority Research Program of the Chinese Academy of Sciences, No.XDB03030500

Abstract:

The Yellow River-Huangshui River Valley(YHV) located in the northeast edge of the Qinghai-Tibet Plateau is a typical farming-pastoral area. Since the Qing Dynasty, the expansion of cultivated land has led to a significant change in forest and grassland cover in this region. Base on the current vegetation map, soil and topographic factors, and historical data in literature, this study reconstructed the potential forest and grassland spatial distribution in the YHV. Combined with the reconstructed farmland change in the Qing Dynasty, we calculated the change of forest and grassland coverage in the YHV in the Qing Dynasty. The results show that: (1) The spatial distribution of forest and grassland before cropland expansion in the Qing Dynasty was consistent with present day vegetation distribution. The forest area was slightly larger, the shrub area was spatially more contiguous, and the distribution of grassland was wider. (2) The estimated area of forestland was 0.28×104 km2, the area of shrub was 0.93×104 km2, and the area of grassland was 2.1618×104 km2 before reclamation in the Qing Dynasty. Because of farmland reclamation activities, it is estimated that the areas of grassland, shrub, and forest have decreased by 5180.41 km2, 1330.35 km2, and 441.31 km2 in the YHV region at the end of the Qing Dynasty. The area of reclaimed grassland was the largest (52% of potential grid of grassland became cultivated cropland) and the intensity of conversion was high (the average reclamation index of grassland grids was 10%). The reduced areas mainly concentrated in the LeDu Basin, Xining Basin in the middle of the Huangshui Valley, Jianzha Basin in the Yellow River Valley, and the Hualong Basin. The target vegetation types that have been reclaimed by humans in the YHV in the Qing Dynasty were not only influenced by factors of natural environment but also social policies.

Key words: Qing Dynasty, Qinghai-Tibet Plateau, forest and grassland, coverage change, Yellow River-Huangshui River Valley