Assessing the large-scale plant-water relations using remote sensing products in the humid subtropical Pearl River Basin in south China

Abstract

Abstract. Vegetation interact closely with water resources. Conventional studies of plant-water relations at the field scale are fundamental for understanding the mechanisms of how plants alter and adapt to environmental changes, while large-scale studies can be more practical for regional land use and water management towards mitigating climate change impacts. In this study, we investigated the changes in total water storage (TWS), aridity index (AI) and vegetation greenness, productivity and their interactions in the Pearl River Basin since 2002. Results show overall increase of TWS especially in the middle reaches where vegetation greenness and productivity also increased. This region dominated by croplands was identified as the hotspot for changes and interactions between water and vegetation in the basin. Vegetation was more strongly affected by TWS than precipitation (P) at both the annual and monthly scales. Further examination showed that the influence of P on vegetation in wet years was stronger than dry years, while the TWS impact was stronger in dry years than wet years; moreover, greenness responded faster and productivity slower to dryness changes in dry years than wet years. The lag effects resulted in nonlinearity between water and vegetation. This study implies that vegetation in the basin uses rainwater prior to water storage until it gets dry, and the degree of water restriction on vegetation was higher than that of water consumption by vegetation even in this rain-abundant region.

Detection and Attribution of Changes in Terrestrial Water Storage across China: Climate Change versus Vegetation Greening

“…Using the GRACE satellite, Zhao et al [11] investigated the impact of ecological restoration on TWS in northern China from 1982 to 2016. Wang et al [20] suggested that vegetation was more strongly affected by TWS than precipitation on both the annual and monthly scales in the Pearl River basin from 2002 to 2015. In addition to the effects of vegetation, climate change and human activities were altering the hydrological cycle with significant consequences for TWS.…”