Journal of Ecology and Rural Environment ›› 2017, Vol. 33 ›› Issue (5): 426-432.doi: 10.11934/j.issn.1673-4831.2017.05.006

Previous Articles     Next Articles

Spatio-Temporal Distribution of Grassland Degradation in Qinghai-Lake Valley

ZHANG Ming1, CUI Jun2, CAO Xue-zhang1   

  1. 1. Research Center for Ecological Protection and Climate Change Response, Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing 210042, China;
    2. Jiangsu Provincial Key Laboratory of Bioresources in Coastal Saline Soils, Yancheng Teachers University, Yancheng 224002, China
  • Received:2016-07-29 Online:2017-05-25 Published:2017-05-25

Abstract:

Grassland degradation is an effective indicator of eco-environment in the Qinghai-Lake Valley, an ecologically vulnerable area of the Qinghai-Tibetan Plateau. Eight sample plots representing different types of grasslands different in degradation degree in different regions in the valley were set up within the key grassland degradation region and based on grading of grassland degradations in the Qinghai-Lake Valley, spatial distribution and temporal dynamics of the degraded grasslands in the valley were obtained by means of remote sensing. Results show that during the period between 1977 and 2000, grassland degradation was very serious in the valley, with the total area of grassland cut by 206.68 km2, most of which turned into farmlands and sand lands. Grassland degradation occurred mainly in three regions, i. e. the south shore of the Qinghai Lake, Heimahe Township of the Gonghe County, and the Bird Island in the estuary of the Buha River. In the years after 2000, grassland degradation altered in trend with grassland beginning to increase in area, which was attributed to the changes in climate. Increased temperature and precipitation was favorable to growth of grasses and development of grassland. Besides, the government promulgated and enforced a series of grassland protection policies. The year of 2004 was a turning point for the valley, where air temperature and precipitation increased significantly, and consequently, the declining tendency of the water table of the lake was somewhat retarded and grassland degradation lost its momentum. Overall, grassland is the important indicator vegetation of the Qinghai-Lake Valley, and normalized difference vegetation index (NDVI) can be used to accurately monitor vegetation dynamics in the valley.

Key words: Qinghai-Lake Valley, grassland degradation, spatial and temporal distribution, NDVI

CLC Number: