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In responding to global ecosystem conservation and sustainable social development, numerous ecological restoration projects have been performed in ecologically vulnerable areas around the world, especially in semi-arid areas. Affected by local hydrothermal conditions, whether ecological restoration projects can achieve goals of balanced water-carbon enhancement as well as sustainable development in semi-arid areas is controversial. It is uncertain that to what extent the land use change caused by ecological restoration projects will affect the water-carbon imbalance. This research takes the Bashang Plateau Protection Zone (BPZ), a typical semi-arid area in Hebei Province of China, as a porotype to discover the spatial water-carbon changes and their contributing factors under ecological projects during 2000 to 2020 through root mean square deviation and random forest analysis. Results show: (1) In the past two decades, carbon sequestration in BPZ continued to improve while water conservation decreased significantly. The water-carbon imbalance regions in BPZ increased nearly 6.80 folds, from 338.60 km2 to 2642.38 km2. (2) Precipitation and temperature exerted the most significant impact on the formation of water-carbon imbalance regions, whereas the contribution of land use change could reach 40%, demonstrating that human activities were also strongly responsible for water-carbon imbalance. (3) Ecological restoration pattern of limiting afforestation and agricultural land expansion with priority restoration of grassland is beneficial to achieving water-carbon balance and sustainable goals of ecological restoration in semi-arid regions. [ABSTRACT FROM AUTHOR]

The ecological security of urban surface water is subject to significant risk due to rapid urbanization. Pollutant discharge and accumulation are among the most critical stressors endangering urban surface water and affecting the normal operation of urban aquatic ecosystem services. In this study, we assessed how pollutant accumulation stresses water purification systems, which perform important urban ecosystem services. First, we applied a water environmental capacity model to calculate thresholds of urban surface water environmental capacity under a given water quality target. Second, based on a stepwise regression method, an equation was used to describe the relationship between stressor factors (pollutant accumulation) and measurable socioeconomic indicators. Third, an ecological risk index was used as an assessment endpoint indicator to assess the negative ecological effect of pollutant accumulation. Finally, risk level was classified according to the risk quotient method. Taking Xiamen City as an example, we analyzed the contribution of different sources of pollutants and evaluated the urban ecological risk posed by two major contaminants present in the environment by measuring chemical oxygen demand (COD) and ammonium nitrogen (NH4+-N). The results show that the ecological risk indexes of both COD and NH4+-N are expected to decrease from 2020 to 2030; that of COD is expected to fall from medium to low, whereas that of NH4+-N is expected to fall from high to medium. These findings demonstrate that the ecological risk posed to the surface water in Xiamen City can be reduced by controlling population growth, optimizing industrial structure, and promoting economic development. [ABSTRACT FROM AUTHOR]

Power generation determines coal resource utilization in China. However, the development and construction of coal-fired power plants (CFPPs) are bringing new challenges to coal resource utilization efficiency, coal exploiting and utilizing technology, and ecosystem and environmental protection. To better resolve these challenges, various governmental agencies and industrial organizations have sponsored a series of research projects for top research institutions in China. In this special issue, based on a series of research in Xilingol, Inner Mongolia, we focus on the impacts of CFPP construction on ecosystems from the aspects of ecological carrying capacity, ecological sensitivity, and ecological compensation. The articles published in this special issue support a general conclusion that CFPP construction is a double-edge sword to eco-environmental protection. Therefore, it is especially important to take the countermeasures of ecosystem and environmental protection while developing CFPPs. [ABSTRACT FROM PUBLISHER]

Water quality is one of the most serious problems of environment and national sustainable development strategy now facing China. After hard work over the last several decades, urban-sewage treatment in China is now relatively well developed. It now affords mainly higher levels of sewage collection and treatment, as well as pollution-load control. The characteristic rapid urbanization now occurring in China is still increasing and developing dramatically, and involves large numbers of people. However, in towns, sewage treatment infrastructure is inadequate, and a high percentage of the sewage generated there is not effectively collected and treated. The sewage and pollution load of such towns have become the most important reason for environmental water problems in China. To understand the priorities of sewage treatment in such towns, and their spatial distribution in China, we conducted two nationwide investigations of water use and sewage discharge in towns. Based on the integrated analytic hierarchy process (AHP), assessment indices and a framework of town-sewage treatment priorities in China were constructed. Then, we assessed and analyzed the priorities of towns regarding three aspects of sewage treatment: environmental stress, economic capability, and infrastructure. The results showed that the southeast coastal areas and north China had higher demand for sewage treatment than other areas. The demand in eastern and western areas had obvious differences in spatial distribution, but had nearly no differences within those areas. The towns having the greatest demand for high-priority sewage treatment were concentrated in regions with high economic capability and intense water resource utilization. [ABSTRACT FROM AUTHOR]