Arid Zone Research ›› 2021, Vol. 38 ›› Issue (4): 1104-1110.doi: 10.13866/j.azr.2021.04.22

• Plant and Plant Physiology • Previous Articles     Next Articles

Spatiotemporal evolution of vegetation coverage in Alhagi sparsifolia Reserve in Turpan Basin, Xinjiang

LI Ziyu(),CHENG Qihui,HUANG Feng(),GUO Zhentian   

  1. College of Hydrology and Water Resources, Hohai University, Nanjing 210098, Jiangsu, China
  • Received:2021-01-26 Revised:2021-03-15 Online:2021-07-15 Published:2021-08-03
  • Contact: Feng HUANG E-mail:1034677728@qq.com;huangfeng1987@hhu.edu.cn

Abstract:

It is of substantial significance for ecological and environmental protection to restore vegetation coverage by returning grazing land to grassland. In this study, the regional normalized difference vegetation index (NDVI) data were extracted from Landsat Thematic Mapper (TM)/ Enhanced Thematic Mapper Plus (ETM+)/Operational Land Imager multi-phase remote sensing images, which were selected from July to September of each year from 1996 to 2020. Meanwhile, Fractional Vegetation Coverage (FVC) was calculated by computing the equation of Excess Green minus Excess Red (ExG-ExR). Additionally, the variables in the equation were based on Unmanned Aerial Vehicle images in the early part of August 2019. The best-fit curve between NDVI and FVC was first established based on the above NDVI and FVC data in the same period. Then, two parameters of the pixel binary model were calculated through the fitted curve between NDVI and FVC: NDVI for the pure bare soil pixels and NDVI for the pure vegetation cover pixels. Then, the pixel binary model was used to retrieve the vegetation coverage of the Alhagi sparsifolia reserve in the Turpan Basin from 1996 to 2020. Finally, linear regression analysis was used to investigate the evolution of vegetation coverage in the A.sparsifolia Reserve in the Turpan Basin throughout the study period. The results showed that vegetation coverage increased in the A.sparsifolia Reserve in the Turpan Basin over the past 25 years. The area of the significant improvement area accounted for 20.14% of the total area of the A. sparsifolia Reserve in the Turpan Basin, and the vegetation coverage of the significant improvement area increased from 3.09% to 18.30% over the past 25 years. A.sparsifolia was primarily distributed from western to central regions in the significant improvement area along the tail of the Baiyang River, which empties into the Aiding Lake, its terminal lake, at the lowest altitude of the A.sparsifolia Reserve. The areas in the west and northeast of the A.sparsifolia Reserve, which were close to residential land located in the south of the Flaming Mountains and east of Tuokesun County, also belonged to the significant improvement area. The results of this research provide a scientific reference for selecting the two parameters of the pixel binary model and a scientific basis for ecological environment management and protection of the Turpan Basin in Xinjiang.

Key words: the pixel binary model, normalized difference vegetation index, fractional vegetation coverage, unmanned aerial vehicle remote sensing, Alhagi sparsifolia Reserve, Turpan, Xinjiang