Response of tree growth to drought variability in arid areas: Local hydroclimate and large-scale precipitation.

The impact of drought on terrestrial ecosystems is increasing, and the spatiotemporal heterogeneity of drought changes exacerbates the difficulty of determining ecosystem responses, especially in arid regions far from oceans. Tree rings have been widely used to understand how forest ecosystems respond to drought. However, the link between local hydroclimate variations related to tree rings and large-scale climate changes is not clear in the Qilian Mountains. Here, we used the tree ring width index to analyze the trend of Picea crassifolia growth and its relationship with climate in the middle Qilian Mountains. The results showed that the radial growth trend of Picea crassifolia is synchronized in the middle Qilian Mountains by calculating the Gleichläufigkeit index (GLK). Our analyses indicated that tree radial growth is positively correlated with drought during the growing season. Tree growth responds stably to drought (scPDSI and SPEI) and precipitation but unstably to temperature during 1950-2019. We further traced the meteorological factors that cause regional drought changes associated with radial growth. An increased total precipitation and decreased evaporation contribute to drought alleviation, favoring an increased tree radial growth. The increased total precipitation is mainly due to increased large-scale precipitation, which is related to water vapor transport changes. This study attempts to explore the influence of large-scale meteorology on regional drought change and its related tree radial growth response, which helps us to better understand the changes in forest ecosystems under climate change.

Measuring the cross-border spillover effects and telecoupling processes of ecosystem services in Western China.

Ecosystem services provide the basic elements for global economic development. In the context of the deepening global integration process, countries and regions are increasingly connected, resulting in a series of cross-country, cross-regional, multi-scale socio-economic-environmental impacts, these new situations and changes require a multi-site, two-way, and cross-temporal and spatial scale comprehensive study of "the relationship between ecosystem services and humans". Based on this, we apply a telecoupling synthesis framework to explore the socio-economic and eco-environmental interactions of ecosystem service spillover effects. Results show that (1) the spillover effect of ecosystem services in western China is significant. More than 66% of ecosystem services spillover to eastern China provinces, and more than 40% of ecosystem services spillover to countries in Southeast Asia, South Asia, and Central Asia, resulting in a total of 679 million people benefiting from the spillover effect. (2) There are also multiple telecoupling processes between the ecosystem service spillovers in the ecologically fragile areas in western China and the rest of the world. In combination with the scenario simulation of the InVEST model, the services such as water supply, soil retention, flood mitigation, and food supply have significant impacts on sustainable development and human well-being in Asia and even the world. (3) The positive feedback effect of telecoupling is critical to the protection of the ecological environment as well as the improvement of people's livelihood and well-being in Western China's ecologically fragile areas. Therefore, we propose strengthening ecological compensation cooperation between local governments and implementing compensatory transfer payments between upstream and downstream. Simultaneously, international cooperation must be strengthened, and an ecological compensation transfer mechanism with beneficiary countries must be established, while the cross-regional flow of ecosystem services must be maintained. This study provides an example for the "ecosystem services and human relations" in multiple places, two directions and across time and space scales, and also practical reference significance for China implementation of projects such as the "the Belt and Road" initiative and transnational and cross regional resource allocation.

Strong bacterial stochasticity and fast fungal turnover in Taihu Lake sediments, China.

Understanding the assembly and turnover of microbial communities is crucial for gaining insights into the diversity and functioning of lake ecosystems, a fundamental and central issue in microbial ecology. The ecosystem of Taihu Lake has been significantly jeopardized due to urbanization and industrialization. In this study, we examined the diversity, assembly, and turnover of bacterial and fungal communities in Taihu Lake sediment. The results revealed strong bacterial stochasticity and fast fungal turnover in the sediment. Significant heterogeneity was observed among all sediment samples in terms of environmental factors, especially ORP, TOC, and TN, as well as microbial community composition and alpha diversity. For instance, the fungal richness index exhibited an approximate 3-fold variation. Among the environmental factors, TOC, TN, and pH had a more pronounced influence on the bacterial community composition compared to the fungal community composition. Interestingly, species replacement played a dominant role in microbial beta diversity, with fungi exhibiting a stronger pattern. In contrast, stochastic processes governed the community assembly of both bacteria and fungi, but were more pronounced for bacteria (R2 = 0.7 vs. 0.5). These findings deepen the understanding of microbial assembly and turnover in sediments under environmental stress and provide essential insights for maintaining the multifunctionality of lake ecosystems.

Research on the coordinated development of ecosystem services and well-being in agricultural and pastoral areas.

Payment for Ecosystem Services (PES) has been widely accepted as a policy tool for promoting ecological and social progress. However, PES development and implementation in traditional agricultural and pastoral areas are often more challenging than in other areas. The contradiction between ecological protection and people's livelihood development in traditional agricultural and pastoral areas is related to developing country's sustainable development strategy. Based on this, we evaluate the PES (ERCCP: the Ecological Relocation and Capital Compensation Program) program in Tianzhu County, as a case study to investigated the impact of ERCCP on the local natural and social ecosystems on a 20-year scale. The results of indicated that ERCCP has achieved "win-win" gains of restoring environment and promoting socioeconomic development: in the 10 years since ERCCP was implemented, the area of forest land and grassland increased significantly, increasing by 1135.6 ha and 919.62 ha, respectively. 57.5% of farmland was converted to grassland and 30.8% to forest, respectively. In addition, 92.2% and 7.5% of bare land were replaced by grassland and forest, respectively, indicating a gradual recovery of green land during this period. We also analyzed the effects of ERCCP on social systems, and found that the change of agro-pastoralists' attitude towards ERCCP promoted the transfer of labor force from the primary industry to the tertiary industry, accelerated the development of urbanization, and made the poor population completely out of poverty by 2020. In addition, we predict that the income level of households, the PES return on investment of local governments, and the value of regional ecosystem services will increase significantly after 2025. In this context, We establish a theoretical model to explain the win-win plan for the coordinated development of ecosystem services and regional well-being to explore the sustainability of PES and provided a typical case for the similar research area in the world, especially in the areas with the ecological fragility and poverty problems.

The fairness of shared responsibility for embodied carbon emission: a case study of the Yellow River Basin, China.

Under the dual constraints of China's carbon peaking and carbon neutrality goals, as well as ecological protection and high-quality development of the Yellow River Basin, clarifying the embodied carbon emissions and responsibility sharing of inter-provincial trade is crucial to the carbon reduction strategy of the Yellow River Basin. This paper uses the MRIO (multi-regional input-output) model to measure the production-side and consumption-side responsibility sharing of nine provinces in the Yellow River Basin in 2012 and 2017, revealing the amount and direction of the embodied carbon transfer between provinces, and finally introduces the share of provincial value added as the responsibility sharing factor to compare and analyze the differences between the three responsibility sharing methods. The results show the following: (1) The embodied carbon emissions on the production side in most provinces of the Yellow River Basin were larger than that on the consumption side, with the most significant differences in Shanxi, Inner Mongolia, and Shandong, among which local demand carbon emissions and intermediate product transfer out of carbon emissions were the main causes of production-side carbon emissions. (2) In general, all provinces except Shaanxi were net carbon transfer-in regions, and the embodied carbon was mainly transferred to Beijing, Jiangsu, Guangdong, Zhejiang, and Hebei. (3) Shared responsibility for carbon emissions was jointly determined by the volume of embodied carbon trade and the ability to obtain value added, which lay between production and consumption side responsibility shares. (4) The Yellow River Basin had a large responsibility-sharing factor and embodied carbon trade, and thus needs to take more responsibility for emission reduction. This study is expected to provide scientific support for the strategy of differentiated emission reduction in the Yellow River Basin and enrich the regional carbon accounting methods.