Abstract
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.
Highlights
High-latitude regions are amongst the most sensitive to climate change globally [1,2,3]
We explored the dynamics of drought and vegetation cover across the Damqu River Basin in this study and assessed the impacts of the former on the latter between 1998 and 2015
The results of this study show that both standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) can be used as reliable indicators to characterize hydrological drought conditions within the Damqu River Basin
Summary
High-latitude regions are amongst the most sensitive to climate change globally [1,2,3]. As the “third pole” of the Earth, the water tower of Asia, and the national ecological security shelter zone of China [4,5,6,7,8], the Qinghai-Tibet Plateau faces the dual threats of climate change and human development [8,9]. The Three River Source Region (TRSR) within the hinterland of the Qinghai-Tibet Plateau is one of the largest areas of natural wetland at highest altitudes. The impact of drought on vegetation conditions within the DRB, YRSR, China gov.cn/]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
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