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Plant litter decomposition is a significant ecosystem function that regulates nutrient cycling, soil fertility, and biomass production. It is heavily regulated by nutrient intake. The effects of exogenous nutrients on litter decomposition are not yet fully understood. To determine how Eriobotrya japonica litter decomposition responds to adding nutrients, we used the decomposition litter bag method in the laboratory for 180 days. There were five different nutrient treatment levels were used: control (no addition), low nitrogen addition (LN; 100 kg N·ha−1·year−1), high nitrogen addition (HN; 200 kg N·ha−1·year−1), phosphorus addition (P; 50 kg P·ha−1·year−1), and micronutrient addition (M; 50 kg M·ha−1·year−1). According to a repeated-measures analysis of variance, adding N reduced the remaining mass (p < 0.01) by 4.1% compared to the CK group. In contrast, adding M increased the remaining mass (p < 0.01) by 6.8% compared to the CK group. Adding P had no significant effect on the remaining mass. Although the amount of residual carbon (C) was unaffected, adding N increased the level of residual N in the litter. Litter C content, K content, N concentration, and C/N ratio were linearly correlated to the remaining litter (p < 0.01). Although adding nutrients decreased soil enzyme activity later in the decomposition process, no significant correlation was detected between enzyme activity and the remaining mass. N fertilization treatments decreased the soil microbial diversity index. The addition of nitrogen and micronutrients reduced the abundance of Acidobacteria, while HN addition increased the abundance of Actinobacteria. The addition of micronutrients increased the abundance of Proteobacteria. These results imply that N-induced alterations in the element content of the litter regulated the effects of nutrient inputs on litter decomposition. This study can be a reference for the fertilization-induced decomposition of agricultural waste litter.

Long-term observations of the volume mixing ratio (VMR) profiles and total columns of key atmospheric constituents are significant for understanding climate change and the impact of the carbon budget in China. This study provides an overview of the first ground-based high-resolution Fourier-transform spectrometry (FTS) observation station in China, which is located in Hefei, east China. The FTS observation station can observe the total columns and VMR profiles of more than 30 atmospheric constituents. Time series of some key atmospheric constituents observed at the Hefei station since 2014 have been released to the public. The major scientific achievements obtained to date at this station include spectral retrieval characterization and harmonization, investigation of the overall characteristics of key atmospheric constituents, emission estimates, satellite and chemical transport model (CTM) evaluations, and a summary of pollutant sources and transport patterns. An outlook is also presented of the envisaged plan for observations, scientific studies, and data usage at the Hefei station. China has explicitly proposed reaching a peak in its CO2 emissions by 2030 and realizing carbon neutrality by 2060. The Hefei station will provide scientific assistance to the Chinese Government for developing green economy policies and achieving carbon neutrality and the goals of the Paris Agreement.

Artemisia frigida, as an important indicator species of grassland degradation, holds significant guidance significance for understanding grassland degradation status and conducting grassland restoration. Therefore, conducting rapid surveys and monitoring it is crucial. In this study, to address the issue of insufficient identification accuracy due to the large density and small size of Artemisia frigida in UAV images, we improved the YOLOv7 object detection algorithm to enhance the performance of the YOLOv7 model in Artemisia frigida detection. We applied the improved model to the detection of Artemisia frigida across the entire experimental area, achieving spatial mapping of Artemisia frigida distribution. The results indicate: In comparison across different models, the improved YOLOv7 + Biformer + wise-iou model exhibited the most notable enhancement in precision metrics compared to the original YOLOv7, showing a 6% increase. The mean average precision at intersection over union (IoU) threshold of 0.5 (mAP@.5) also increased by 3%. In terms of inference speed, it ranked second among the four models, only trailing behind YOLOv7 + biformer. The YOLOv7 + biformer + wise-iou model achieved an overall detection precision of 96% and a recall of 94% across 10 plots. The model demonstrated superior overall detection performance. The enhanced YOLOv7 exhibited superior performance in Artemisia frigida detection, meeting the need for rapid mapping of Artemisia frigida distribution based on UAV images. This improvement is expected to contribute to enhancing the efficiency of UAV-based surveys and monitoring of grassland degradation. These findings emphasize the effectiveness of the improved YOLOv7 + Biformer + wise-iou model in enhancing precision metrics, overall detection performance, and its applicability to efficiently map the distribution of Artemisia frigida in UAV imagery for grassland degradation surveys and monitoring.

The decline of ecological connectivity poses a challenge for China as it faces a continuous loss of biodiversity. However, this phenomenon also increases the country’s natural reserves and afforestation area. With the approval of the national plan for combating climate change and the implementation of the “ecological redline” policy, there is an opportunity to improve China’s eco-connectivity with significant investments available for a continuous ecological restoration. However, little research has been conducted with respect to ecological connectivity, thus preventing policy makers from allocating a central investment between provinces for ecological restoration. This study modelled the resistance map against connectivity conservation by quantifying indicators of human disturbance and subsequently derived the national eco-corridor network by using least-cost path methods. A total of 2790 potential eco-corridors, connecting 97% of the protected areas in continental China were extracted. The paper ranked the importance of each eco-corridor for maintaining national ecological connectivity and identified the pinch points with high resistance. Based on the national eco-corridor framework, this paper proposed a two-dimensional coded table to help policy makers conduct effective management. The table also develops scenarios to aid decision makers in allocating central investments in provinces. By prioritizing ecological restoration to enhance ecological connectivity, the established eco-corridor network and scenario analysis will contribute to biodiversity conservation in China. This paper gives policy suggestions on cross-border management and plan implementation of eco-corridors, which helps decision makers in working towards ecological protection in China.

The large tectonic lake is one of the most important water bodies in the source area of the Yellow River (SAYR), northeastern Qinghai-Tibet Plateau (QTP). It plays a key role in decelerating climatic change and regulating regional climate patterns. In this study, we used Landsat images (MSS, TM, ETM+ and OLI) of Lake Gyaring and Lake Ngoring (the Two Sisters Lakes), which are the two largest tectonic lakes in the SAYR, to determine annual lake area fluctuations from 1986 to 2020. The results show that lake area increases were generally consistent with a warming trend in the SAYR. The temperature signals were separated from the lake area changes by using a detrending analysis and found that the processed data are closely correlated with variations of precipitation and streamflow in the SAYR, and the previously reported paleoclimate records, which include the δ18O record from stalagmite, A/C (Artemisia/Chenopodiaceae) ratio from lake sediment and scPDSI (self-calibrating Palmer Drought Severity Index) from the tree ring on the northeastern margin of the QTP. The phase of relatively large lake areas typically coincides with a negative excursion in δ18O, a high A/C ratio, and elevated scPDSI values, while the opposite is true for smaller lake areas. It is suggested that the total area of the Two Sisters Lakes is closely associated with hydroclimatic conditions in the SAYR. Furthermore, an association of high TSI anomalies with the water area expansion of the Two Sisters Lakes is also observed, implying that solar activity is the key driving factor for the hydrologic variability in the SAYR on decadal timescales. The findings of our study highlight the validity of previous paleoclimate archives in the northeastern QTP and demonstrate the potential of using remote sensing techniques to investigate paleoclimate.

Due to the fragmentation of protected areas (PA), it is important to build ecological corridors in order to connect scattered PA and form protection networks for biodiversity conservation. We take the Chinese ecological conservation redline (ECR) as an example to study the construction of ecological corridors. China has defined ECR to improve the system of PA in key ecological functional zones, nature reserves, and areas of sensitive and fragile ecological environment. In this study, 187 core areas of ECR were identified using ArcGIS masking and dissolving technology to build corridors, covering 95% of the total ECR areas. Using the Linkage Mapper tool and the Pinchpoint Mapper, we identified 454 ecological corridors 68,794 km long. The results of the line density analysis showed that there are 9 key regional biological corridors connected to the ECR at the national scale, which must focus on protecting and strengthening ecological construction during the implementation of ecological conservation redline policy. Our study will provide references for developing a regional pattern of ecological security, territorial spatial planning, and will promote the implementation of biodiversity conservation policies.

To reveal the characteristics of climate change and the controlling factors for vegetation dynamics in the Ordos, Inner Mongolia, China, 34 years (1982-2015) of regional climate variables and vegetation dynamics were investigated. The results show that: Annual mean air temperature (TMP) significantly increased with a linear slope of 0.473°C/10yr. Annual precipitation (PRE) had a non-significant positive trend nearly 5 times lower than the trend of potential evapotranspiration (PET). The average Normalized Difference Vegetation Index (NDVI) computed for the region was found to show a significant positive trend (6.131×10-4/yr). However, all climate variables displayed non-significant correlations with NDVI at annual scale. The reduction of desert and the increase of grassland over the past decades were accountable for the increased NDVI. Principal components analysis revealed that the regional climate change can be characterized as changes in temperature, humidity and the availability of radiant energy. Based on principal components regression coefficients, NDVI was mostly sensitive to humidity component, followed by growing season warmth (WMI). Spatially, 93.1% of the pixels displayed positive trend and 61.8% of the pixels displayed significant change over the past decades. Both principal regression analysis and partial correlation analysis revealed that NDVI in eastern part of Ordos was sensitive to TMP, whereas, NDVI in southern and western areas of Ordos displayed the high sensitivity to combined effects of PRE and cloud coverage (CLD). Partial correlation analyses also revealed that TMX was a surrogate for aridity, TMN was a representative of humidity, and temperature variations below the threshold of 5°C (CDI) were less important than WMI. We conclude that regional climate change can be characterized by warming and increased aridity. The significant positive trend of regional NDVI and the non-significant correlations between NDVI and climate variables at annual scale suggests the hidden role of the human activities.

In the quantification model of emission intensity of emission sources, the estimation of the background concentration of greenhouse gases near an emission source is an important problem. The traditional method of estimating the background concentration of greenhouse gases through statistical information often results in a certain deviation. In order to solve this problem, we propose an adaptive estimation method of CO2 background concentrations near emission sources in this work, which takes full advantage of robust local regression and a Gaussian mixture model to achieve accurate estimations of greenhouse gas background concentrations. It is proved by experiments that when the measurement error is 0.2 ppm, the background concentration estimation error is only 0.08 mg/m3, and even when the measurement error is 1.2 ppm, the background concentration estimation error is less than 0.4 mg/m3. The CO2 concentration measurement data all show a good background concentration assessment effect, and the accuracy of top-down carbon emission quantification based on actual measurements should be effectively improved in the future.

Magnolia officinalis subsp. officinalis and M. officinalis subsp. biloba are important medicinal plants in China. The bark of these two subspecies is commonly used in the production of a widely-used Chinese traditional medicine named ‘Houpu’. In recent years, M. o. subsp. officinalis and M. o. subsp. biloba have become increasingly threatened owing to the over-harvesting of their bark and the fragmentation of their habitats. In this study, we aimed to support the conservation and cultivation of these two subspecies in China by: (1) assessing the relationship between numerous environmental variables and the geographical distributions of the subspecies; (2) analysing the environmental characteristics of suitable habitats for both subspecies and predicting the spatial distribution of these habitats in China; and (3) identifying conservation areas of both subspecies in China via overlay analysis. We also assessed the degree of human disturbance within suitable habitats. We found that temperature was a major determinant for the distribution of M. o. subsp. officinalis. Conversely, the distribution of M. o. subsp. biloba was primarily dependent on precipitation rather than temperature. Distinct habitat preferences were observed between M. o. subsp. officinalis and M. o. subsp. biloba. Suitable habitats of M. o. subsp. officinalis were primarily distributed in the northern subtropical areas of China, with greater fluctuations in ambient temperature, lower extreme temperatures, less precipitation and greater fluctuations in precipitation. Habitats suitable for M. o. subsp. biloba were highly fragmented and were distributed in the central subtropical areas of China. We found that a large proportion of suitable habitats were not in the protected areas and that they were significantly disturbed by human activity. This analysis could provide useful information for the conservation of both M. o. subsp. officinalis and M. o. subsp. biloba and could aid in the selection of cultivation sites.

Policies directly affect land-use change, which in turn, affects ecosystem services. In parallel with the implementation of a full-scale development program for the western region, the Chinese government has introduced a series of ecological protection and restoration strategies for development and construction. This study conducted a quantitative spatial evaluation of the ecosystem service value (ESV) of national nature reserves in the western region under this dual policy of development and protection. On the basis of land-use data and related evaluation parameters, fluctuations in the valuation of ecosystem services during 2000–2010 were analyzed in response to land-use changes under the comprehensive policy. Results showed that the increases in the areas of forestland and water bodies led to an increase of CNY 74.1 billion in the ESV from 2000 to 2010, equivalent to 2.02%. Grassland with increased production capacity and water bodies were the main factors driving the total ESV dynamics. Values of all ES increased significantly. Therefore, the ecological conservation and restoration policy, along with the development policy, had a positive influence on ecosystem services in the nature reserves in western China.

Deep learning-based semantic segmentation technology is widely applied in remote sensing and has achieved excellent performance in remote sensing image target extraction. Greenhouses play an important role in the development of agriculture in China. However, the rapid expansion of greenhouses has had a series of impacts on the environment. Therefore, the extraction of large-scale greenhouses is crucial for the sustainable development of agriculture and environmental governance. It is difficult for existing methods to acquire precise boundaries. Therefore, we propose a spatial convolutional long short-term memory structure, which can fully consider the spatial continuity of ground objects. We use multitask learning to improve the network’s ability to extract image boundaries and promote convergence through auxiliary loss. We propose a superpixel optimization module to optimize the main-branch results of network semantic segmentation using more precise boundaries obtained by advanced superpixel segmentation techniques. Compared with other mainstream methods, our proposed structure can better consider spatial information and obtain more accurate results. We chose Shandong Province, China, as the study area and used Gaofen-1 satellite remote sensing images to create a new greenhouse dataset. Our method achieved an F1 score of 77%, a significant improvement over mainstream semantic segmentation networks, and it could extract greenhouse results with more precise boundaries. We also completed large-scale greenhouse mapping for Shandong Province, and the results show that our proposed modules have great potential in greenhouse extraction.

Climate change and land use management were competing explanations for vegetation dynamics in cold and semi-arid region of north-eastern Inner Mongolia, China. In order to reveal the role of human disturbance and clarify the regional climate-vegetation relationship, long-term (1982–2013) datasets of climate variables and vegetation dynamics in a forest-steppe transition zone of north-eastern Inner Mongolia, China were collected. Partial correlation analyses, principal components regression (PCR), and residual analyses were conducted to reveal the vegetation sensitivities to different climate variables and the impact of anthropogenic activities on climate-vegetation relationship. The results showed that.(1) Annual mean air temperature (TMP) significantly increased at a linear slope of 0.08 °C per decade, annual precipitation (PRE) had an insignificantly linear slope of −16.42 mm per decade (p = 0.15). The average Normalized Difference Vegetation Index (NDVI) had a significantly negative trend over the past decades. A change point around the year 1998, coincided with the occurrence of an intense global El Niño event was also identified.(2) Regional climate change can be represented by changes in temperature, humidity and radiation. NDVI in the steppes display high sensitivity to moisture availability. Whereas, forests was influenced by the warmth index (WMI), accumulation of monthly temperature above a threshold of 5 °C. Partial correlation analyses showed that pixels of positive correlation with PRE (controlling TMP) overlap with the pixels of high partial correlation with minimum temperature (controlling maximum temperature), which suggests a hidden link between minimum temperature and PRE in this region.(3) The spatial distribution of significantly decreased NDVI overlap with cropland expansion, as well as the low residual square (R2) from PCR analysis. The NDVI decline in these expanded croplands suggests human disturbance on vegetation dynamics. Following climate warming, NDVI of forested land displayed positive trend. Whereas, most of steppe displayed negative trend, possibly resulting from combined effects of climate drying and human disturbance.We conclude that the regional climate change can be characterized as warming and drying. Steppe areas were sensitive to humidity changes while forested land was mostly influenced by growing season warmth. Overall, the regional NDVI displayed significantly negative trend over the past decades. Beyond climate drying, cropland expansion in the transition area between grassland and forested land is also an important driver for decreased NDVI. Further studies on the ecological and hydrological consequences of crop land expansion is necessary.

The expansion of protected area (PA) networks is necessary for countries and territories worldwide to conserve biodiversity, protect natural ecosystems and achieve sustainable development. However, challenges remain in expanding the PA network effectively, especially in regard to addressing priority conservation areas and balancing social development and ecological conservation. These problems are addressed in the “Ecological Conservation Redline” (ECR), an ambitious program launched in China to establish a comprehensive and large-scale conservation network. In this study, we presented a framework based on the ECR to guide PA network expansion, which identifies the areas requiring priority conservation and incorporates coordinated ecological conservation and social development. The framework consists of three steps: (1) design the network by identifying the hotspots of ecological function, ecological fragility and biodiversity, (2) transform the network from theory to practice through boundary verification, and (3) define a management policy with consideration of the livelihood of local communities. This framework was applied in Sichuan Province, China to demonstrate its effectiveness on expanding the PA network and improving conservation efforts. The framework provides important references for planning of PA networks and contributes to global expectations of effective environmental management.

Increasing light is widely recognised to be harmful to the wilderness of protected areas (PAs). However, minimal studies revealed the spatiotemporal distribution and variation of nighttime lights (NTLs) at the regional and single protected area levels on a continuous time. We assessed the extent and intensity of NTLs within and around the PAs during 1992–2012 in mainland China. Lighted area index (LAI), lighted intensity index (LII), potential LAI (PLAI) and potential LII (PLII) were developed as indicators to represent the total quantity and the intensity in a PA and in a 5-km buffer zone around the PA on the basis of the Defense Meteorological Program Operational Line-Scan System NTL data. NTL in PAs covered 7192 km2 in 2012, accounting for 0.73% of the total area of PAs. The highest values of LAI and LII were observed in Northeast and South Central China among the six geographical divisions. The LAI and LII increased by 3.22 and 3.51 times from 1992 to 2012, which showed that the area and intensity of NTL in PAs experienced simultaneous growth. We identified a significant increase of NTL within 36% of PAs and outside 60% of PAs, indicating the persistent increase in the intensity of human disturbance in and around these PAs. The NTL growth rates in marine and coastal and wild plant PAs were the greatest and lowest among different types of PAs, with values of 76.47% and 15.79%, respectively. We suggested that development of targeted countermeasures for each PA should comprehensively consider the conservation objectives, the type of PA, and the lighting conditions inside and outside the PA. The findings can provide useful information for targeting management strategies to alleviate light pollution and human disturbance.

Vegetation is a crucial and intuitive index that can be used to evaluate the ecological status. Since the 20th century, land use has changed significantly in Yellow River Basin (YRB), along with great changes of vegetation, serious soil erosion, and gradual ecological deterioration. To improve the ecological environment in the YRB, China has carried out a series of ecological protection projects since the 1970s. Therefore, long-term sequence monitoring of vegetation in YRB is necessary to show the conservation effect and better support the further protection and restoration. This study analysed vegetation changes from 2000 to 2019 based on an annual mean fractional vegetation cover (FVC) dataset. The Theil–Sen median trend analysis method was used to analyse trends in FVC. The results showed that the vegetation in the YRB has improved significantly, with an average annual growth rate of 0.65%, and the ‘green line’ of vegetation has moved approximately 300 km westward. The influence of climate on vegetation is essential; therefore, this study also analysed the influence of temperature and precipitation on vegetation over time and space. Ecological control and afforestation are important anthropogenic factors that affect vegetation. The growth trend (0.6%/a) in key ecological function regions (KEFRs) was the fastest, and even though the protection measures are not strict, they provide space for afforestation. The China Ecological Conservation Red Line (CECRL) and the national nature reserves (NNRs) showed relatively flat trends. Ecological afforestation projects were closely correlated with the growth trend of the FVC. The correlation between FVC and the intensity of ecological engineering was significant in typical areas.

Climate change and air pollution pose multiple health threats to humans through complex and interacting pathways, whereas urban vegetation can improve air quality by influencing pollutant deposition and dispersion. This study estimated the amount of PM2.5 removal by the urban forest in the city of Shanghai by using remote sensing data of vegetation and a model approach. We also identified its potential contribution of urban forest presence in relation to human population and particulate matter concentration. Results show that the urban forest in Shanghai reached 46,161 ha in 2017, and could capture 874 t of PM2.5 with an average of 18.94 kg/ha. There are significant spatial heterogeneities in the role of different forest communities and administrative districts in removing PM2.5. Although PM2.5 removal was relatively harmonized with the human population distribution in terms of space, approximately 57.41% of the urban forest presented low coupling between removal capacity and PM2.5 concentration. Therefore, we propose to plant more trees with high removal capacity of PM2.5 in the western areas of Shanghai, and increase vertical planting in bridge pillars and building walls to compensate the insufficient amount of urban forest in the center area.

Understanding rainfall anomalies and their relationship with floods in the Yangtze River Basin (YRB) is essential for evaluating flood disasters, which have a great impact on the development of agriculture and the economy. On the basis of daily rainfall data from 1961 to 2010 from 178 meteorological stations, the temporal and spatial characteristics of rainfall anomalies in the YRB were studied on an annual scale, seasonal scale, and monthly scale. The annual rainfall of the YRB showed a generally increasing trend from 1961 to 2010 (14.22 mm/10 a). By means of the Bernaola–Galvan abrupt change test and Redfit spectrum analysis, it was found that the annual average rainfall increased abruptly after 1979 and had a cycle of 2–3 years. On the seasonal scale, the rainfall in spring and autumn showed a gradually decreasing trend, especially in September, while it showed a significant increasing trend in summer and winter in the YRB. As for the monthly scale, the rainfall in the rainy season from June to July presented a clear increasing trend during the study period, which greatly enhanced the probability of floods in the YRB. Additionally, through the analysis of the spatial distribution characteristics of rainfall in the entire YRB from 1961 to 2010, it was observed that the annual rainfall amount in the YRB presented an “increase–decrease–increase” tendency from east to west, accompanied by a rain belt that continuously moved from west to east. Moreover, the rainfall characteristics in flood years were summarized, and the results revealed that the years with rainfall anomalies were more likely to have flood disasters. However, anomalies alone would not result in big floods; the spatially and temporally inhomogeneous rainfall distribution might be the primary reason for flood disasters in the entire YRB.

Global water shortage is becoming increasingly severe, so the identification and protection of potential areas for harvesting water play important roles in alleviating drought. Suitable sites for potential water harvesting require a high runoff potential. Avoiding soil erosion caused by high surface runoff, however, is also necessary. We therefore developed a procedure for the continuous accounting of runoff potential based on the Soil Conservation Service curve number and potential risks of water and soil loss based on the universal soil loss equation to evaluate the potential for water harvesting. Suitable sites for rainwater harvesting covered 24.90% of the semi-arid area of Chifeng, southeastern Inner Mongolia, China. The best areas accounted for 8.4% of the study area. The southern part of the Greater Hinggnan Mountains in northern Chifeng had a large rainwater harvesting area, and the western and eastern parts of the Chifeng area belonging to Horqin Sandy Land and Hunshandake Sandy Land, respectively, had smaller rainwater-harvesting areas. The eight reservoirs in the Xilamulun River Basin were further analyzed as an example. Derived sites investigated by ground-truth field verification indicated a method accuracy of 87.5%. This methodology could be effective in other areas with similar requirements due to the increasing demand for water resources and requirements for the protection of soil-water resources.

Water transparency represented by the Secchi disk depth (Zsd) plays an important role in understanding water ecology environment variations, especially for optically complex and shallow lake waters. In this study, using in situ measured remote sensing reflectance (Rrs), diffuse attenuation coefficient (Kd), and Zsd data collected in Lake Taihu (China), a regional algorithm for estimating Kd from Rrs was designed, and the semi-analytical model proposed by Lee et al. (2015) (hereafter called Lee_2015 model) was refined using a linear scaling correction for remote sensing of Zsd. The results showed that a good agreement between the derived Kd and in situ measured data (mean absolute percentage error (MAPE) = 26% for Kd(490); MAPE < 5% for Kd at 443, 555, and 660 nm). The in situ Rrs-derived Zsd results using the refined Lee_2015 model compared well with the in situ measured Zsd (R2 = 0.72 and MAPE = 36%), which was an obvious improvement over the Lee_2015 model in our study region. Subsequently, the refined Lee_2015 model was applied to the geostationary ocean color imager (GOCI) observations between 2012 and 2018 to yield the spatial and temporal variations of water transparency in the Lake Taihu waters. The long-term mean distribution of Zsd revealed that water transparency values in the northeastern Lake Taihu were generally higher than those in the southwest part. Monthly climatological Zsd patterns suggested that the Zsd distributions had large temporal variability, and distinct monthly patterns of Zsd existed in different subregions of Lake Taihu. The significant interannual variations of Zsd in Lake Taihu are probably affected by a combination of the water column stability mainly caused by wind, water temperature, human activity, and riverine discharge. The present study can provide a new approach for quantifying water visibility and serve for water-color remote sensing of optically complex and highly turbid waters.

Drought and shortages of soil water are becoming extremely severe due to global climate change. A better understanding of the relationship between vegetation type and soil-moisture conditions is crucial for conserving soil water in forests and for maintaining a favorable hydrological balance in semiarid areas, such as the Saihanwula National Nature Reserve in Inner Mongolia, China. We investigated the temporal dynamics of soil moisture in this reserve to a depth of 40 cm under three types of vegetation during a period of rainwater recharge. Rainwater from most rainfalls recharged the soil water poorly below 40 cm, and the rainfall threshold for increasing the moisture content of surface soil for the three vegetations was in the order: artificial Larix spp. (AL) > Quercus mongolica (QM) > unused grassland (UG). QM had the highest mean soil moisture content (21.13%) during the monitoring period, followed by UG (16.52%) and AL (14.55%); and the lowest coefficient of variation (CV 9.6-12.5%), followed by UG (CV 10.9-18.7%) and AL (CV 13.9-21.0%). QM soil had a higher nutrient content and higher soil porosities, which were likely responsible for the higher ability of this cover to retain soil water. The relatively smaller QM trees were able to maintain soil moisture better in the study area.

Changes in land use can cause significant changes in the ecosystem structure and process variation of ecosystem services. This study presents a detailed spatial, quantitative assessment of the variation in the value of ecosystem services based on land use change in national nature reserves of the Ningxia autonomous region in China. We used areas of land use types calculated from the remote sensing data and the adjusted value coefficients to assess the value of ecosystem services for the years 2000, 2005, and 2010, analyzing the fluctuations in the valuation of ecosystem services in response to land use change. With increases in the areas of forest land and water bodies, the value of ecosystem services increased from 182.3×10(7) to 223.8×10(7) US$ during 2000-2010. Grassland and forest land accounted for 90% of this increase. The values of all ecosystem services increased during this period, especially the value of ecosystem services for biodiversity protection and soil formation and protection. Ecological restoration in the reserves had a positive effect on the value of ecosystem services during 2000-2010.

Environmental risk assessment is an essential step in the development of solutions for pollution problems and new environmental regulations. An assessment system for environmental risks has been developed in China in recent decades. However, many of the Chinese technical guidelines, standards, and regulations were directly adapted from those of developed countries, and were not based on the Chinese environmental and socioeconomic context. Although existing environmental regulations for pollutants are usually obtained by extrapolations from high-dose toxicological data to low-dose scenarios using linear-non-threshold (LNT) models, toxicologists have argued that J-shaped or inverse J-shaped curves may dominate the dose–response relationships for environmental pollutants at low doses because low exposures stimulate biological protective mechanisms that are ineffective at higher doses. The costs of regulations based on LNT and J-shaped models could therefore be dramatically different. Since economic factors strongly affect the decision-making process, particularly for developing countries, it is time to strengthen basic research to provide more scientific support for Chinese environmental regulations. In this paper, we summarize current Chinese environmental policies and standards and the application of environmental risk assessment in China, and recommend a more scientific approach to the development of Chinese regulations.

Western China is vast, expansive, sparsely populated, and economically underdeveloped, but it plays an important role in economic and social development in China. While the west is a crucial base of power resources, it is also rich in fauna and flora resources and the major habitat for China's many rare wildlife species. Therefore, protecting its ecological environment is vitally significant not only to the west itself, but also to social and economic development of the whole country. However, because of the fragility of the ecological environment of the west, plus improper human activities in the long past, the ecological environment of western China has been seriously damaged. This article describes the following 10 issues regarding damages to western China's ecological environment: (1) Crisis of Water Resources; (2) River Dry-Up; (3) Lake Shrinkage; (4) Retreating Glacier and Rising Snowline; (5) Aggravation of Marsh Closure for Farming and Damages Caused Thereby; (6) Serious River and Lake Pollution and Deteriorating Water Quality; (7) Degradation of Ecological Function of Forests; (8) Degradation of Grassland; (9) Land Desertification; and (10) Drastic Reduction in the Number of Wildlife Animals and Plants, and Threat of Extinction for Certain Species. The author offers several suggestions to address these issues.