›› 2018, Vol. 35 ›› Issue (3): 615-623.doi: 10.13866/j.azr.2018.03.14

Previous Articles     Next Articles

Spatiotemporal Variation of Vegetation Cover in the Pastoral Area in Northwestern China during the Period of 1981-2015

MOU Le, LU Yi-xiao, YANG Hui-min, FENG Qi-sheng   

  1. (State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, Gansu, China)
  • Received:2017-08-25 Revised:2017-12-13 Online:2018-05-15 Published:2018-06-01

Abstract: he major parts of pastoral area in northwest China are generally the arid and semiarid regions, and the vegetation in this area is extremely sensitive to environmental change and susceptible to human activities. In recent years, the vegetation in the arid pastoral area is changed obviously, which is affected by the production of agriculture and animal husbandry and the ecological construction. Therefore, it is vital to further understand the vegetation variation in the pastoral area in northwest China, where the national ecological projects and planting structure adjustment of agriculture are implemented, and the theoretical supports are provided for the production of agriculture and animal husbandry and the ecological construction. In this study, the GIMMS 3g NDVI product with a spatial resolution of 8 km × 8 km during the period from 1981 to 2015 was used to reveal the spatiotemporal characteristics of vegetation change in the study area with the Theil-Sen Median trend analysis, Mann-Kendall test and Hurst index. The results showed that the typical vegetation in the arid pastoral area was changed significantly during the period from 1981 to 2015, and the improved area accounted for 41.9% of the total area. The improvement of vegetation was the most obvious from 2006 to 2015, and the improved area occupied 63.7% of the total. All the 11 vegetation types were in a regenerating trend, in which the largest share came from cultivated vegetation, the improved area occupied more than 80% of the total, and the improved areas of pasture and hassock were over 60%. In the past 35 years, the vegetation coverage in the arid pastoral area was tended to a sustainable and positive development, and the proportion of continuously regenerating area was higher than 70% of the total. During the period of 2006-2015, the regeneration and stability occurred in 63.8% of the total area. National ecological projects and planting structure adjustment of agriculture affect significantly the vegetation cover in the arid pastoral areas in northwest China. In the future, the vegetation coverage is supposed to be continuously restored.

Key words: NDVI, vegetation cover, spatiotemporal variation, trend analysis, Hurst index, pastoral area, northwest China