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Limiting global warming to within 1.5 °C might require large-scale deployment of premature negative emission technologies with potentially adverse effects on the key sustainable development goals. Biochar has been proposed as an established technology for carbon sequestration with co-benefits in terms of soil quality and crop yield. However, the considerable uncertainties that exist in the potential, cost, and deployment strategies of biochar systems at national level prevent its deployment in China. Here, we conduct a spatially explicit analysis to investigate the negative emission potential, economics, and priority deployment sites of biochar derived from multiple feedstocks in China. Results show that biochar has negative emission potential of up to 0.92 billion tons of CO 2 per year with an average net cost of US$90 per ton of CO 2 in a sustainable manner, which could satisfy the negative emission demands in most mitigation scenarios compatible with China’s target of carbon neutrality by 2060. Authors analyze the potential of biochar in China, revealing it could sequester up to 0.92 billion tons of CO 2 per year with an average net cost of US$90 per ton of CO 2 in a sustainable manner, supporting carbon neutrality goal by 2060.

Climate change has altered global hydrological cycles mainly due to changes in temperature and precipitation, which may exacerbate the global and regional water shortage issues, especially in the countries along the Belt and Road (B&R). In this paper, we assessed water supply, demand, and stress under three climate change scenarios in the major countries along the Belt and Road. We ensembled ten Global Climate Model (GCM) runoff data and downscaled it to a finer resolution of 0.1° × 0.1° by the random forest model. Our results showed that the GCM runoff was highly correlated with the FAO renewable water resources and thus could be used to estimate water supply. Climate change would increase water supply by 4.85%, 5.18%, 8.16% and water demand by 1.45%, 1.68%, 2.36% under RCP 2.6, 4.5, and 8.5 scenarios by 2050s, respectively. As a result, climate change will, in general, have little impact on water stress in the B&R countries as a whole. However, climate change will make future water resources more unevenly distributed among the B&R countries and regions, exacerbating water stress in some countries, especially in Central Asia and West Asia. Our results are informative for water resource managers and policymakers in the B&R countries to make sustainable water management strategies under future climate change.

Water is a limiting factor for plant growth and vegetation dynamics in alpine sandy land of the Tibetan Plateau, especially with the increasing frequency of extreme precipitation events and drought caused by climate change. Therefore, a relatively stable water source from either deeper soil profiles or ground water is necessary for plant growth. Understanding the water use strategy of dominant species in the alpine sandy land ecosystem is important for vegetative rehabilitation and ecological restoration. The stable isotope methodology of δD, δ18O, and δ13C was used to determine main water source and long-term water use efficiency of Salix psammophila and S. cheilophila, two dominant shrubs on interdune of alpine sandy land in northeastern Tibetan Plateau. The root systems of two Salix shrubs were investigated to determine their distribution pattern. The results showed that S. psammophila and S. cheilophila absorbed soil water at different soil depths or ground water in different seasons, depending on water availability and water use strategy. Salix psammophila used ground water during the growing season and relied on shallow soil water recharged by rain in summer. Salix cheilophila used ground water in spring and summer, but relied on shallow soil water recharged by rain in spring and deep soil water recharged by ground water in fall. The two shrubs had dimorphic root systems, which is coincident with their water use strategy. Higher biomass of fine roots in S. psammophila and longer fine roots in S. cheilophila facilitated to absorb water in deeper soil layers. The long-term water use efficiency of two Salix shrubs increased during the dry season in spring. The long-term water use efficiency was higher in S. psammophila than in S. cheilophila, as the former species is better adapted to semiarid climate of alpine sandy land.

Building ecological networks can effectively enhance the quality and stability of ecosystems and better conserve biodiversity. Previous studies mainly determined ecological corridors based on selecting ecological sources at a regional scale (e.g., an administrative area), without considering the bioclimatic heterogeneity within the study area. Here, we propose a novel integrating approach involving bioclimatic zoning and selecting ecological sources from various bioclimatic zones to design ecological corridors. Taking Xi’an City, China, as an example, key bioclimatic variables were first chosen, and we partitioned the study area based on its bioclimatic characteristics through a combination of K-means clustering and variance inflation factor (VIF). Ecological sources were then identified from the combination of ecosystem services and habitats of 36 endangered species. Subsequently, the minimum cumulative resistance (MCR) model was used to build ecological networks within different bioclimatic zones and across the entire region. We found the following: (1) In Xi’an city, a total of 49 source areas and 117 corridors were identified. The identified network can protect 97.77% of species, facilitating connectivity between 30.50% of ecosystems and 35.5% of species-rich areas. (2) The integrating approach protects 12.26% more species richness and 10.95% more ecosystem services than the average value of the regional and bioregional approaches. Compared to regional and bioregional methods, integrating approaches demonstrate greater advantages in preserving species richness and ecosystem services. This study introduces a novel approach to constructing regional ecological networks, which integrates the impact of bioclimatic zoning into the process of network construction to improve ecosystem services and protect species habitats.

Climate change‐induced species range shift may pose severe challenges to species conservation. The Qinghai‐Tibet Plateau is the highest and biggest plateau, and also one of the most sensitive areas to global warming in the world, which provides important shelters for a unique assemblage of species. Here, ecological niche‐based model was employed to project the potential distributions of 59 key rare and endangered species under three climate change scenarios (RCP2.6, RCP4.5 and RCP8.5) in Qinghai Province. I assessed the potential impacts of climate change on these key species (habitats, species richness and turnover) and effectiveness of nature reserves (NRs) in protecting these species. The results revealed that that climate change would shrink the geographic ranges of about a third studied species and expand the habitats for two thirds of these species, which would thus alter the conservation value of some local areas and conservation effectiveness of some NRs in Qinghai Province. Some regions require special attention as they are expected to experience significant changes in species turnover, species richness or newly colonized species in the future, including Haidong, Haibei and Haixi junctions, the southwestern Yushu, Qinghai Nuomuhong Provincial NR, Qinghai Qaidam and Haloxylon Forest NR. The Haidong and the eastern part of Haibei, are projected to have high species richness and conservation value in both current and future, but they are currently not protected, and thus require extra protection in the future. The results could provide the first basis on the high latitude region to formulate biodiversity conservation strategies on climate change adaptation. In this manuscript, species distribution modeling based on ensemble forecasting was employed to project the potential distributions of 59 key rare and endangered species under three climate change scenarios in Qinghai Province. We assessed the potential impacts of climate change on species diversity (species richness and turnover) and effectiveness of NR network in protecting these species. The results could provide the first decision‐making basis on the high latitude region to formulate biodiversity conservation strategies on climate change adaptation.

Quantifying the contribution of natural ecosystems on air quality regulation can help to lay the foundation for ecological construction, and to promote the sustainable development of natural ecosystems. To identify the spatio-temporal dynamic changes of natural vegetation regulation on SO2 absorption and the underlying mechanism of these changes in Qinghai Province, an important ecological barrier and the unique natural ecosystems, the Biome-BGC model was improved to simulate the canopy conductance to SO2 and leaf area index (LAI) on the daily scale, and then the SO2 absorption by vegetation was estimated coupling SO2 concentration from satellite data. Our results showed that the annual average SO2 absorption of the natural ecosystems in Qinghai Province was 4.74 × 104 tons yr−1 from 2005 to 2018, accounting for about 40% of the total emissions. Spatially, the ecosystem service of SO2 absorption gradually decreased from southeast to northwest, and varied from 0 in Haixi state to 14.37 kg SO2 ha−1 yr−1 in Haibei state. The annual average SO2 absorption in unit area was 0.68 kg SO2 ha−1 yr−1, and significantly higher SO2 absorption was observed in summer with 0.45 kg SO2 ha−1 quarterly. The canopy conductance and LAI controlled by climate variables would be the dominant driving factors for the variation of SO2 absorption for natural ecosystems. The sensitivity analysis showed that SO2 concentration contributed more to the uncertainties of SO2 absorption than the conductance in this study. Our results could provide powerful supports for realistic eco-environmental policy and decision making.

Lakes are an important natural source of CH4 to the atmosphere. However, the multi-seasonal CH4 efflux from lakes has been rarely studied. In this study, the CH4 efflux from Poyang Hu, the largest freshwater lake in China, was measured monthly over a 4-year period by using the floating-chamber technique. The mean annual CH4 efflux throughout the 4 years was 0.54 mmol m−2 day−1, ranging from 0.47 to 0.60 mmol m−2 day−1. The CH4 efflux had a high seasonal variation with an average summer (June to August) efflux of 1.34 mmol m−2 day−1 and winter (December to February) efflux of merely 0.18 mmol m−2 day−1. The efflux showed no apparent diel pattern, although most of the peak effluxes appeared in the late morning, from 10:00 to 12:00 CST (GMT + 8). Multivariate stepwise regression on a seasonal scale showed that environmental factors, such as sediment temperature, sediment total nitrogen content, dissolved oxygen, and total phosphorus content in the water, mainly regulated the CH4 efflux. However, the CH4 efflux only showed a strong positive linear correlation with wind speed within 1 day on a bihourly scale in the multivariate regression analyses but almost no correlation with wind speed on diurnal and seasonal scales.

Global biodiversity priorities are primarily addressed through the establishment or expansion of conservation areas (CAs). Spatial prioritization of these CAs can help minimize biodiversity loss by accounting for the uneven distribution of biodiversity and conservation considerations (e.g., accessibility, cost, and biodiversity threats). Furthermore, optimized spatial priorities can help facilitate the judicious use of limited conservation resources by identifying cost effective CA designs. Here, we demonstrate how key species and ecosystems can be incorporated into systematic conservation planning to propose the expansion and addition of new CAs in the biodiversity-unique and data-poor region of Qinghai Plateau, China. We combined species distribution models with a systematic conservation planning tool, MARXAN to identify CAs for biodiversity on Qinghai Plateau. A set of 57 optimal CAs (273,872 km[sup.2], 39.3 % of this Province) were required to achieve the defined conservation targets in Qinghai Province. We also identified 29 new CAs (139,216 km[sup.2], 20% of Qinghai Province) outside the existing nature reserve (NRs) that are necessary to fully achieve the proposed conservation targets. The conservation importance of these 29 new CAs was also indicated, with 10 labeled as high priority, 11 as medium priority, and 8 as low priority. High priority areas were more abundant in the eastern and southeastern parts of this region. Our results suggest that many species remain inadequately protected within the Qinghai Plateau, with conservation gaps in eastern and northwestern regions. The proposed more representative and effective CAs can provide useful information for adjusting the existing NRs and developing the first National Park in China. Keywords: Conservation planning, conservation area, Qinghai Plateau, spatial prioritization, species distribution model

Plant diversity plays a crucial role in maintaining the functionality of a community and providing essential ecosystem services. Studying the plant diversity and its response to environmental factors in the Yellow River Delta, China, as a newly formed coastal land, is beneficial for protecting plant diversity in coastal areas and maintaining ecosystem stability. In this study, 56 sites were sampled to investigate the diversity of shrubs and herbaceous plant community and its response to environmental factors. The results indicate that the plants growing in the Yellow River Delta are predominantly from the Poaceae and Asteraceae families, with dominant communities consisting of species such as Suaeda salsa, Phragmites australis, Setaria viridis, Imperata cylindrica, and Tamarix chinensis. The Shannon–Wiener index, Simpson diversity index, and Pielou’s evenness index exhibit average values of 0.34, 0.21, and 0.25, respectively, within the Yellow River Delta. These values collectively indicate a low diversity in the vegetation community, reflecting a relatively uncomplicated ecological structure in this area. Additionally, there were no significant differences in biodiversity indices under different soil formation times, but under different land cover types, the biodiversity index of cropland was significantly higher than that of impervious land. Soil salinity index exhibited a significant negative correlation with plant diversity (R2 = 0.279, p < 0.001) in the Yellow River Delta. Moreover, elevation (R2 = 0.247, p < 0.001) and temperature (R2 = 0.219, p < 0.001) showed significant positive effects on plant diversity. Regarding the ecological stoichiometry of plant elements, soil organic carbon exhibited a negative effect on the biodiversity index, while litter carbon showed a positive effect. This may be attributed to the unique topographical conditions and soil salinization in the Yellow River Delta. Our findings provide important references for the sustainable management of wetlands in the Yellow River Delta under conditions of soil salinization.

While air quality in China has improved significantly in recent years, the population is becoming increasingly vulnerable to air pollution due to the aging population. In this study, we assessed premature deaths attributable to long- and short-term exposures to PM2.5 and O3, as well as their driving forces in Shandong from 2014 to 2060 based on county-level near-real-time air pollutant concentration datasets and projected concentrations of PM2.5 and O3. We found that the concentrations of PM2.5 and O3 in most districts and counties from Shandong are still higher than the corresponding concentration limit of Grade II. Premature mortality caused by long- and short-term exposures to PM2.5 decreased by 13,045 and 8092 in 2020 compared with those in 2014, respectively. Furthermore, premature mortality attributable to short-term exposure to O3 was 36.08% higher than that due to short-term exposure to PM2.5 in 2020. The results of the driving force analysis indicate that the health benefits brought about by the improvement in air quality have been offset by the changes in population age structure. In the future, the increase in O3 concentration and population aging are the top two driving forces having adverse effects on the health burden. This study provides support for controlling the health risks of PM2.5 and O3 pollution, especially for the development of dual-pollutant concentration targets and synergistic control strategies.