Urban sustainability is a key to achieving the UN sustainable development goals (SDGs). Secure and efficient provision of food, energy, and water (FEW) resources is a critical strategy for urban sustainability. While there has been extensive discussion on the positive effects of the FEW nexus on resource efficiency and climate impacts, measuring the extent to which such synergy can benefit urban sustainability remains challenging. Here, we have developed a systematic and integrated optimization framework to explore the potential of the FEW nexus in reducing urban resource demand and greenhouse gas (GHG) emissions. Demonstrated using the Metropolis Beijing, we have identified that the optimized FEW nexus can reduce resource consumption and GHG emissions by 21.0 and 29.1%, respectively. These reductions come with increased costs compared to the siloed FEW management, but it still achieved a 16.8% reduction in economic cost compared to the business-as-usual scenario. These findings underscore the significant potential of FEW nexus management in enhancing urban resource efficiency and addressing climate impacts, while also identifying strategies to address trade-offs and increase synergies.

In light of the soaring growth of pumped hydro energy storage (PHES) plants in China in recent years, there is an urgent need for a comprehensive understanding of their developmental trajectory and the identification of their multidimensional impacts. This paper reviews the development of PHES in China and highlights its various impacts. Despite the relatively late start of PHES development in China, the country has recently ranked first worldwide with an aggregated installed capacity of 50.94 GW in operation in 2023. These plants are primarily distributed in North China, East China, and South China, contributing to the safe and stable operation of regional power grids. Furthermore, over 300 plants are under construction or in the planning stage across the whole country, aiming to support large-scale renewable energy development and facilitate a sustainable energy transition. However, it is important to recognize that such extensive PHES development requires significant land resources, which can lead to disturbances in local ecosystems and affect nearby residents. Additionally, environmental emissions may arise from a life-cycle perspective. Finally, several countermeasures are proposed to enhance sustainable PHES development in China. They include strengthening the rational planning of new plants to optimize their spatial distribution, refining the engineering design of new plants, and exploring avenues for sharing the benefits of PHES development with a broad spectrum of local residents.

Understanding the mechanisms driving species assembly along elevational gradients in mountains is crucial for biodiversity conservation. However, no consensus has yet been reached on how these mechanisms work. This knowledge gap is particularly pronounced in biodiversity-rich subtropical karst mountains. Integrating multidimensional biodiversity information into research in karst systems will provide new insights into community assembly. Thus, we explored multidimensional forest diversity along an elevational gradient at Jinfo mountain, a karst mountain site, assessing the relative importance of distinct ecological processes in shaping patterns of community diversity and structure. Our results show that different dimensional diversities exhibit similar elevational patterns, with higher diversity observed at low-to-mid elevations than at high elevations. The multidimensional diversity and structure were primarily controlled by climate stress and topographic filtering and were further modulated by soil nutrient limitation and interspecific competition. However, the explanatory weights of these ecological processes were inconsistent among the different dimensions of diversity. The phylogenetic structure was clustered at low and middle elevations, with over-dispersion at high elevations. This indicates that community assembly shifted from being dominated by environmental filtering to being dominated by competitive exclusion as elevation increased. In conclusion, our results demonstrate that combining multidimensional diversity and multiple ecological processes related to community assembly can enhance the understanding of diversity patterns along elevational gradients and the underlying mechanisms maintaining them in subtropical karst mountains.