The impact of drought on vegetation conditions within the Damqu River Basin, Yangtze River Source Region, China

• Published in: PloS one Vol. 13; no. 8; p. e0202966
• Main Authors: Zhao, Zhilong, Zhang, Yili, Liu, Linshan, Hu, Zengzeng
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 24-08-2018; Public Library of Science (PLoS)
• Subjects: Biology and Life Sciences; China; Climate change; Correlation; Correlation analysis; Drought; Drought index; Droughts; Earth science; Earth Sciences; Ecology and Environmental Sciences; Ecosystem; Ecosystems; Environmental impact; Environmental Monitoring; Evapotranspiration; Evapotranspiration-precipitation relationships; Geography; Grasslands; Humidity trends; Hydrology; Influence; Laboratories; Leaf area; Leaf area index; Natural resources; Normalized difference vegetative index; People and Places; Plant climatology; Plant Development; Precipitation; Regression analysis; Remote sensing; River basins; Rivers; Seasons; Simulation; Standardized precipitation index; Summer; Trends; Vegetation; Vegetation effects; Vegetation index; Water conservation; Water shortages; Watersheds; China; Beijing China; Tibetan Plateau; Tibet; Yangtze River
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0202966

Drought and vegetation conditions within the Damqu River Basin, part of the Yangtze River Source Region (YRSR), are assessed here using the standardized precipitation index (SPI), the standardized precipitation evapotranspiration index (SPEI), the normalized difference vegetation index (NDVI), and the leaf area index (LAI). We utilized Sen's method, least squares regression method, linear regression and Pearson's correlation analysis to study variations in drought and vegetation indices and the drought effect on vegetation between 1988 and 2015. Results reveal that droughts occurred at a 25% frequency over this period; SPI and SPEI analyses show that 1994, 1999, 2005, and 2010 were change points and that the basin was characterized by varying drought and humidity trends. Subsequent to 2010, both SPI and SPEI decreased within the basin, while 1995, 2000, 2004, and 2010 were change points for NDVI and LAI while the watershed exhibited variable trends in vegetation reduction and increase. The NDVI-annual values of 63.36% regions and the LAI-summer values of 68.39% areas within the basin were decreased during 1988-2015 and 2000-2015, respectively. Subsequent to 2010, both NDVI and LAI decreased within the basin and significant positive correlations at inter-annual and inter-summer time scales were seen in both drought and vegetation indices; drought has exerted a lag effect on vegetation as shown by significant positive correlations between annual SPI/SPEI values and following year NDVI/LAI values.