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Droughts resulting from global warming severely hamper the healthy development of terrestrial vegetation ecosystems. This paper defines a terrestrial vegetation ecological drought index, i.e., the Standardized Water Supply–Demand Index (SSDI), based on the water balance method using the same calculation model as the SPEI. The theory of run is used to analyze the spatial and temporal distribution of the drought characteristics in the Yangtze River Basin (YRB). The results show that (1) the drought events monitored by the SSDI were in good agreement with historical drought events, and the correlation coefficient between SSDI and NDVI (0.94) was significantly higher than that between SPEI and NDVI (0.88). (2) About 55.4% of the regions in the YRB experienced more than 13 droughts, and about 41.4% of the regions had an average drought duration of more than 3.1 months. In the northern part of the YRB, droughts tend to develop in a short-term high frequency, while in the southern part of the YRB, there is a long-term low-frequency development trend. Nearly 24.5% of the regions have an average drought intensity of more than 1.4, and most of them are located in the lower reaches of the Yangtze River. (3) Over the last 18 years, about 79.5% of the regions in the YRB showed an increasing trend in SSDI, of which 36.8% showed an increasing trend of more than 0.04/yr. In addition, 40.4% of the regions showed a significant upward trend. Precisely analyzing the spatiotemporal variation of drought characteristics in the YRB is critical for drought risk assessment and sustainable development of water resources and could provide a theoretical basis for effective water resource allocation and drought relief. • A new drought monitoring index, i.e., the Standardized Water Supply–Demand Index (SSDI) was defined. • SSDI can effectively monitor drought events. • SSDI is more suitable for monitoring ecological drought. • Drought of vegetation ecosystem in the Yangtze River Basin was assessed and analyzed with the SSDI. • It provides a theoretical basis for drought management and water allocation in the Yangtze River Basin. [ABSTRACT FROM AUTHOR]

Coupled human and natural system research is an urgent issue in the Anthropocene. However, this has not yet been conducted from the perspective of multiplex networks, which are a powerful tool to elucidate the interactions in human-natural systems. This paper establishes a framework of human-water multiplex networks (HWMNs) to explain the combined effects of human-water interactions in the Yangtze River basin. The spatial linkages and the status of each province in the Yangtze River basin can be characterized through the index of network flow and topology. Research demonstrated that the highest import flow of the virtual water environment capacity flow in the Yangtze River Basin is to Jiangsu Province, at 16.2 thousand t. The highest export flow in the Yangtze River Basin is from Shanghai city, at 33.2 thousand t. The control power of Shanghai city over Sichuan Province accounts for 56.59% of the water resources, which is the highest value and can be recognized as one type of telecoupling of water resources. The provinces in the delta of the Yangtze River basin, including Shanghai city, Jiangsu Province and Zhejiang Province, benefit the most from economic trade. The community structure of the virtual water environment capacity flow is highly consistent with the geographical distribution of the Yangtze River basin. Comprehensive research methods combined with network flow analysis and network topology analysis provide more general results. The microenvironmental effect of indirect pollutant discharge is uncovered through HWMNs. This research can provide a more connected view of integrated water management. Image 1 • A framework of HWMN is established to reveal the combined environmental effects. • The key provinces are revealed through the network flow analysis and topology analysis. • The provinces in the Yangtze river delta obtains most of the water environment benefits. • The environmental effect of the indirect pollutant discharge through HWMN is revealed. [ABSTRACT FROM AUTHOR]