Water Availability in China's Oases Decreased Between 1987 and 2017

Abstract

Oases are the most dynamic, productive, and vulnerable ecosystems in drylands and are centers of human life and economic development in arid and semi-arid regions (X. Li et al., 2016;S. Zhou et al., 2015). In China, oases support the livelihoods of tens of millions of inhabitants, and maintaining the stability of oasis ecosystems is essential for regional ecological security and sustainable development (P. Chen et al., 2022a). Under climate change and expanded human activity, China's oases have undergone a significant expansion during the past three decades (P. Chen et al., 2022a), which has profoundly affected regional water budgets and ecosystem services (

Spatio‐Temporal Dynamics of Aboveground Biomass in China's Oasis Grasslands Between 1989 and 2021

“…The MCA results suggest that AGB dynamics in oasis grasslands are more strongly coupled to cropland expansion than to climate factors. This strong coupling can mainly be attributed to the rapid expansion of cropland and the spatiotemporal mismatch between water supply and demand (Chen et al., 2023). Compared to other types of water use, agricultural water consumption in oasis regions holds a notably higher proportion, with a more pronounced increase trend (Figure S11 in Supporting Information S1).…”

“…Therefore, the dynamics of agricultural water consumption have a profound impact on the regional water resource balance. Although the warming‐induced increases in glacier meltwater supply and precipitation quantity provide a greater water supply, the increase in agricultural water demand is even greater (Chen et al., 2023; Fu et al., 2022; Yao et al., 2022). The redistribution of water resources between agriculture and natural vegetation led to a closer relationship between cropland expansion and grassland AGB.…”

“…In order to support the rapidly increasing population and ensure food security, cropland in oases has undergone significant expansion over the past three decades, and its growth has often come at the expense of grasslands (Chen et al., 2022). Since oases are located in northwestern China, where precipitation is extremely scarce, rivers formed by glacial meltwater and snowmelt of high mountains serve as the primary source of water supply in the region (Chen et al., 2023). Grain production in the oasis regions necessitates the extraction of substantial amounts of streamflow and groundwater for agricultural irrigation (Fu et al., 2022).…”

Distribution and Growth Drivers of Oases at a Global Scale

“…Surface runoff (SR): SR is crucial for oases as it serves not only as their primary water source but also plays a key role in maintaining ecological balance, supporting agricultural production, regulating climate, and promoting economic and social development (P. Chen et al., 2023).…”

Locating Hydrologically Unsustainable Areas for Supporting Ecological Restoration in China's Drylands

“…Regarding the self‐sufficiency of water resources at the local scale, we developed WSS index to determine whether the water demand (ET) of dryland ecosystems is met by the water supply (precipitation): $$$\begin{array}{c}\text{WSS}=\frac{\text{Water}\,\text{availability}}{P}=\frac{P-ET}{P}\end{array}$$$ where P is precipitation and ET is actual evapotranspiration. The numerator of this indicator is the water availability calculated as the difference between the ecosystem water supply ( P ) and demand ( ET ), and the denominator is the water supply (P. Chen et al., 2023; Z. Chen et al., 2023; F. Zhao et al., 2021). As a water balance indicator, the relative index of the WSS enabled us to compare the water availability across different precipitation levels.…”