Carbon emissions are increasing due to human activities related with the energy consumptions for economic development. Thus, attention has been paid to the reduction of the growth of carbon emissions and formulation of policies for addressing climate change. Although most studies have explored the driving forces behind carbon emissions in China, literature lacks studies at the city-level due to a limited availability of statistics on energy consumptions. In this study, based on China's city-level remote sensing carbon emissions from 1992 to 2013, we applied the spatial autocorrelation, spatial Markov-chain transitional matrices, dynamic spatial panel model and Sys-GMM to empirically estimate the key determinants of carbon emissions at the city-level and discuss its spatial spillover effects in consideration of spatiotemporal lag effects and different geographical and economic weighting matrices. Results indicated that the regional inequalities of city-level carbon emissions decreased over time and presented an obvious spatial spillover effect and high-emission "club" agglomeration. In addition, the evolution of the emission pattern has the characteristic of obvious path dependence. Panel data analysis results indicated that there was a significant U-shaped curve that can reflect the relationship between carbon emissions and GDP per capita. In addition, carbon emissions per capita are increasing with economic growth for most cities. High-proportion of secondary industry and extensive growth of investment exerted significantly positive effects on China's city-level carbon emissions. Conversely, rapid population agglomeration, the improvement of technology level, the increase of trade openness and road density play an inhibiting role in carbon emissions. Therefore, in order to reduce carbon emissions, the Chinese government should inhibit the effects of promotion factors and enhance the effects of mitigation factors. Combining with the analysis of results, we argued that optimizing the industrial structure, streamlining the extensive investment, increasing the level of technology and improving the road accessibility are the effective ways to increase energy savings and reduce carbon emissions in China.

Ecosystem services have become one of the major aspects of ecosystem management and evaluation. As a key area of ecosystem services, evaluation of ecosystem changes and implementation effect is important for national key ecological function zones. Such evaluation can help to maintain national ecological security, drive the implementation of the main function zone strategy and advance the construction of an ecological civilization. This article explores the ecological zone of a tropical rainforest region in the central mountain area of Hainan Island, China. Multi-source satellite data and ground observation statistics are analyzed with geo-statistics method and ecological assessment model. The core analysis of this paper includes ecosystem pattern, quality and service. By means of spatial and temporal scale expansion and multi-dimensional space-time correlation analysis, we examine the trend and stability characteristics of ecosystem change, and evaluate the implementation effect. The results showed that, first, the forest area ratio was 84.5% in 2013, which was significantly higher than the average level in Hainan Island. During 1990-2013, settlement gradually increased in ecological zone. After the implementation of the function zone in 2010, human activity intensity was still increasing, with the area ratio rising from 0.5% to 0.8%. The main land use change was urban construction and land reclamation. Second, water conservation in the ecological function zone was better than that outside the zone. During 1990-2013, water conservation increased slightly, and had obvious fluctuation in different periods. Water conservation change decreased first and then increased during both the periods 1990-2000 and 2000-2013. Water conservation quantity was 0.5178 million cubic metres per square kilometer, which was higher than the average outside the zone. Third, soil conservation in the ecological function zone was also better than that outside the zone. Soil conservation showed dramatic fluctuations and relatively poor stability during 1990-2013. Soil conservation quantity was 19500 tons per square kilometer in the ecological function zone. Fourth, the human disturbance index in the ecological function zone was significantly less than that outside the zone and had lower biodiversity threat level. This would be beneficial to biodiversity conservation. In the ecological function zone, average human disturbance index was 0.3664 and 0.1152 lower than that outside the zone. During 1990-2013, human disturbance index variation range outside the zone was 0.0152, about 5.31 times that of the inner zone. Especially in 2010-2013, the increased range of human disturbance index in the ecological function zone was significantly less than that outside value the zone.

Embodied carbon emissions in international trade plays a crucial role in shaping regional commitments towards emission reduction in the context of global climate change and greenhouse gas emission policy. Based on the multi-region input-output analytical framework and the stochastic impacts by regression on population, affluence and technology (STIRPAT) model, this paper analyzes the embodiment of global emissions in trade, so as to explore the characteristics of global carbon emissions under a consumption accounting principle for 39 countries from 1995 to 2011, and investigates the determinants of the embodied emissions in global trade based on an extended STIRPAT model. One finding from this study is that some countries like China and Russia are characterized by the highest net outflow of embodied emissions in trade, while other regions in the world provide strong support for their economic growth through thick trade relationships, and more importantly, comparative advantages are also obtained by their industries associated with trades. Under the production-based accounting principle, these countries like China and Russia have also been accountable for a large volume of emissions embodied in global trade, and thus would face huge pressures to curtail carbon emissions, which, in turn, may also impede the local economic development. Moreover, the lower the net carbon emissions embodied in regional trade, the higher the carbon emissions under a consumption accounting principle. Therefore, the relevant countries should bear greater emissions reduction responsibilities from the perspective of the production-based accounting principle in the context of global climate policy. Additionally, the analysis results show that a larger deal of net carbon emissions embodied in global trade are mainly from Asia and Eastern Europe, while a smaller amount of net carbon emissions embodied in global trade are primarily found in highly economically developed regions like Western Europe and Northern America. Another important finding is that, for environmental impact analysis regarding the corresponding influencing factors, the increase of carbon emissions embodied in global trade would be primarily caused by population and economic development level. For wealthy countries or regions such as the USA and the EU, via trade relations with their main trading partners, their environmental impacts, particularly carbon emissions associated with their consumption, may be transferred to other regions. On that basis, facing severe pressures to curb carbon emissions embodied in international trade in climate policy, these regions should take proactive initiatives like carrying out technology transfer and/or providing financial aid to improve notably other developing countries' production technology. In addition, in order to reduce the impact of trade on the emissions of global economies on global environment, the increase in the overall share of clean energy in the energy consumption structure and energy efficiency improvement should be also an effective policy option.

Abstract: In order to explore the response of influenza A (H1N1) to meteorological factors, we analyzed the spatio-temporal distribution of influenza A (H1N1) in Beijing using global Moran's I and local Getis-Ord G I * . The regression model between influenza A (H1N1) and average wind speed, precipitation, average relative humidity, average temperature was established, based on the geographical weighted regression (GWR) model. The results showed that there was no obvious correlation between influenza A (H1N1) and the precipitation, while a strong positive correlation between influenza A (H1N1) and average wind speed was found. The average temperature and the average relative humidity had a strong negative correlation with the spread of influenza A (H1N1) in Beijing, while the latter presented a more complex impact on the spread of it. In terms of the spatio-temporal variation, the impact of meteorological factors was significant during the period when the number of influenza A (H1N1) infections rose rapidly, while it decreased when the number of infections rose slowly. Regarding the spatial variation, the spatial heterogeneity of the impact of each meteorological factor on the four functional zones of Beijing was obvious, which might be related to regional conditions such as local terrain, wind zone, and local climate.

Cultural sites are relics of human activity and they are also the product of the interactions between human and nature. The size of cultural sites could reflect the population size and grade of the ancient settlements. The study of cultural sites could help us to deepen the understanding of the relationships between human and nature. This paper established the spatial database of the Neolithic cultural sites in the middle reaches of Yangtze River from 9000 a BP to 4000 a BP. by using ArcGIS software. Overlay analysis and statistical method were employed to examine the spatial relationships between the size of archaeological sites and elevation, slope, the distance to the river in different periods. The results showed that, from the early Neolithic period to the late Neolithic period, the number of sites, the size of sites and the spatial distribution range of the sites showed an increasing or expanding trend, and the proportion of overlapping sites increased; Sites with different sizes generally had low altitude, gentle terrain and near river selection tendency. For sites of the late Neolithic Age, while there existed the above-mentioned selection tendency, the selection of altitude, slope and the distance to river tended to show the characteristics of diversification. There were some differences in location selection of Neolithic cultural sites with different sizes in the late Neolithic period. Small sites were mostly located on the gentle slope of 6-15 degrees. The large or medium-sized sites tended to be distributed on the flat land with a slope of 2-6 degrees; From small to large sites, Neolithic sites was dominated by an elevation of 30-50 m. The elevation of super sites was mainly in a range from 50 m to 100 m. The super sites were located in the area less than 1 km far from the river; The Neolithic culture was greatly influenced by the natural factors such as climate, water resources and topography in the early and middle Neolithic Age, and the adaptation ability of culture in the late Neolithic period was gradually enhanced.

Since the late-Cenozoic, the strong uplift of Tibetan Plateau not only formed a large number of tectonic fractures on the southeast edge, but also generated many tectonic rift lakes due to structural stretching and compression. However, in recent years, some of the lakes started to shrink and depicted a reduction in lake depth, which has eventually exerted great influence on local ecological environment and socio-economic development. In this paper the Qionghai Lake, located on the southeast edge of the Tibetan Plateau, is selected as the study area. Based on exploring the debris flow characteristics of Guanba river in the north of Qionghai Lake, the effect of sediment deposition deriving from debris flows on Qionghai Lake is analyzed. The research shows that: (1) The scale and frequency of debris flow occurrence is higher in the Guanba River, and the primary material sources are landslide and non-point source erosion with a movable volume of 428.03×10⁴ m³. (2) The frequent occurrence of floods and debris flows are the primary cause of sediment accumulation in the Qionghai Lake, and the debris flows are controlled by the coupling effect of frequent earthquakes and heavy rainfall. It is predicted that debris flows will still occur frequently, and sedimentation disasters will become more severe in the future. (3) Since 1950, the average deposition rate was about 17.09 mm/a. In terms of current deposition rate, it is inferred that the longevity of the Qionghai Lake will be only about 600 years. (4) The comprehensive governance model with management of administrative law is proposed in the Guanba River. The results can not only provide reference bases for planning management and disaster prevention in Qionghai Lake basin, but also contribute to reveal the reason of lake shrinkage on the southeast edge of Tibetan Plateau.

Establishment of protected areas is one of the most important approaches for biodiversity conservation. Until 2015, China had established 2740 sites for nature reserves with a total area of 1.47 million km², which covering 14.8% of Chinese land surface. Based on remote sensing inversion, model simulation and spatial analysis methods, this study analyzed spatial and temporal variations of habitat from vegetation coverage, net primary production (NPP) and their driving forces in different types and climate zones on the typical nature reserves of China, in the first 15 years of the 21st Century. Results showed that from 2000 to 2015, the vegetation coverage of national nature reserves increased from 36.3% to 37.1%, with all types of nature reserves improved to some extent. The forest ecological nature reserves observed annual growth of 0.1%, grassland meadow type 0.8%, inland wetlands classes 0.2%, desert ecological class 0.1%, wild animal 0.1% and wild plants 0.1%. The NPP of grassland meadow, inland wetlands, desert ecology, wild animal nature reserve had a growth of 2.0 g·m^-2, 1.2 g·m^-2, 0.3 g·m^-2 and 0.4 g·m^-2 respectively. However, the NPP of forest ecological and wild plants nature reserves reduced by a rate of 3.5 g·m^-2 and 2.5 g·m^-2 respectively. In the 15 years, national nature reserves had a weak change from human disturbance, in addition to nature reserves which located in the Qinghai-Tibet Plateau and the south subtropical humid area with a slightly fall, others are increased, especially in the north subtropical and temperate humid zone, the human disturbance increased significantly from 4.7% to 5.4%.

To reveal the impact of rapid urbanization on river system in a river network plain, characteristic indexes of river system, such as grid river density, development coefficient of tributary and fractal dimension, were used to evaluate the temporal and spatial changes of river system in Suzhou City from 1980s to 2010s, based on topographic map in 1:50000 scale and remote sensing image in 30m scale. The results were as following: The length of river system was decreased by 10.55%. From view of each order river, the length of 1st order river was increased by 3.24%, while that of 2nd order river and 3rd order river was decreased by 18.87% and 11.76%, respectively. The grid river density of river system was mainly decreased across most area of this region, and the change trend between main river and tributary was opposite in space, i.e., the grid river density of main river was mostly increased, while that of tributary was mostly decreased. The development coefficient of tributary and fractal dimension of river system respectively changed from 3.36 to 2.78 and 1.70 to 1.63, which indicated that the structure and morphology of river system became simplified. The attenuation of river system became remarkable when the land urbanization rate was greater than 40%. The response to land urbanization for each order river was different. Overall, 1st order river experienced a slight increase, to enhance the capability of flood control and drainage. When the land urbanization rate was less than 40%, some 2nd order rivers were occupied by farmland, and many 3rd order rivers were dug to improve the capacity of drainage and irrigation. When the land urbanization rate was greater than 40%, a lot of tributaries were buried and converted to construction land. And the lower the order river, the more severe the attenuation was.

The Interconnected River System Network (IRSN), which plays a significant role in water resource allocation, water ecological restoration and water quality improvement, has become a key part of the urban lake management. The optimization of IRSN scheme and the evaluation of IRSN effects have a direct influence on the improvement of hydrodynamics and water quality. However, no comprehensive evaluation system has been built up to evaluate the hydrodynamics and water quality of the connected lakes. In this paper, a two-dimensional mathematical hydrodynamics and water quality model was built, and indexes including NH₃-N, TN and TP were chosen as the water quality indexes to simulate the flow field and water quality of the Tangxun Lake group under different IRSN schemes. In addition, a comprehensive evaluation system based on evaluation indexes from the aspects of water hydrodynamics, water quality and socioeconomics was established to evaluate the IRSN effects of the Tangxun Lake group. The results showed that the fluidity of lakes improved greatly after the water diversion. The IRSN project can improve water quality of the lakes in a short time, while the improvement rate decreased gradually as the water diversion time increased. The comparison of these five schemes mentioned in this paper indicated that the fifth scheme (concurrent diversion from Donghu Lake and Liangzi Lake) can achieve the most obvious improvement in both hydrodynamics and water quality and generate the most economic benefits.

The Gaobao lakes refer to a group of lakes to the west bank of the Grand Canal in the central part of Jiangsu Province. They used to be one of the important passages for the Huaihe River draining into the Yangtze River. Under the influence of the changing relationship between the Yellow River and the Huaihe River and land reclamation activities, the shape of the Gaobao lakes has changed dramatically in recent 300 years. This article analyzes three digitized earliest surveyed maps of the Gaobao lakes, discusses related historical literature and investigates some borehole data. In doing so, this article discovers that the evolution of the Gaobao lakes can be divided into three stages. The first stage is from the Kangxi reign to the Qianlong reign (1662-1795), when the Gaobao lakes in recent 300 years reached the top in area - 1606 km2 on the first surveyed map of China complied in 1717. The second stage is after the Qianlong reign, when sandbars began to develop in the Gaobao lakes as the sediments from the Hongze Lake gradually deposited to its northwest. The third stage is after 1851 when the Sanhe River which originated from the southeast part of the Hongze Lake became a main passage for the Huaihe River to empty into the Yangtze River. The Sanhe River brought a large amount of sediments into the Gaobao lakes and formed the Sanhe delta. With the expansion of the Sanhe delta, the Gaobao lakes have been quickly shrinking, from 1606 km² in 1717 to 1494 km2 in 1868, 1072 km² in 1916 and 887 km² in 2011. This article argues that the sediments deposited from the Hongze Lake is a main reason for the shrinkage of the Gaobao lakes. Human reclamation activities expedited the process of sedimentation and changes of the Gaobao lakes.

The Qingyijiang River, which is located in the northern piedmont of Mt. Huangshan, is the longest branch of the lower Yangtze River. Based on the field survey, a well-preserved sequence of one diluvial platform (P) and three river terraces (i.e., T3, T2 and T1) was found, and a corresponding sequence of four gravel beds was also presented, according to two natural sections of Xikou cross section and Chengbei cross section in the Jingxian Basin. In addition to the gravel fabric analysis method, the Electron Spin Resonance dating and palaeomagnetic dating were used to discuss the age, process and cause of river development of the Qingyijiang River. This study concludes that: (1) the results of the gravel fabric analysis show that the T3 terrace is the oldest terrace of the Qingyijiang River, and the T3 gravel bed is the oldest gravel bed of the same river; (2) the dating results show that the formation timing of the Qingyijiang River can be traced back to the period from ~1300 ka BP to ~900 ka BP, and the oldest timing of the river is ~1300 ka BP, whereas the most recent timing is ~900 ka BP; (3) the Qingyijiang River originated from one of the braided rivers on the diluvial fan before 1377 ka BP, and successively experienced three stages of the diluvial fan and braided rivers, the incision by the braided river and the Qingyijiang River formation, that is, the so-called development model of the Qingyijiang River from one braided river on the diluvial fan; and (4) the development of the Qingyijiang River may be a combined result of precipitation increase and tectonic uplift. This study provides a reference for the studies of the small and medium river development in eastern China.

The tradeoffs and optimizations of ecosystem services are the key research fields of ecology and geography. As the most important and complex ecosystem in terrestrial ecosystems, forest ecosystem plays a very important part in the biogeochemical cycle which include terrestrial carbon cycle and water cycle, and also provides numerous ecosystem services that are crucial to human wellbeing. China has the largest plantation area worldwide. Under the background of global warming, there are more and more concerns on timber production and carbon storage of plantations, nevertheless, they have a relationship of restricting each other. Thus, it is necessary to maximize the overall benefit of timber production and carbon storage for forest ecological development in China. We selected the Huitong National Research Station of Forest Ecosystem as our study area, and used permanent sample plot data of plantations and InVEST model to evaluate timber production and carbon storage quantitatively. Then, we constructed a conceptual framework of forest ecosystem service tradeoffs under different management regimes. Lastly, tradeoffs countermeasures for optimizing overall benefits of ecosystem services were put forward. The results showed that: (1) When timber production increased with harvesting intensity over the entire 100 year planning horizon, carbon storage decreased. There were tradeoffs between timber production and carbon storage according to the significant negative relationship. (2) When the overall benefits of timber production and carbon storage increased with harvesting intensity, the value of tradeoffs decreased. T1 and T2 scenarios, with harvesting intensity of 10%-20% every 10 years, were the optimum management regime for timber production and carbon storage to gain more benefits and less tradeoffs. (3) The current harvesting intensity in Huitong County was slightly higher than the optimum harvesting intensity. On practical dimension, these findings suggested that obvious objectives are needed to formulate the corresponding countermeasures of tradeoffs, in order to realize the improvement of ecosystem services and the optimization of ecosystem structures.

For quantitatively explaining the relationship between the vascular plant abundance and habitat factors in the Qinghai-Tibet Plateau, a spatial simulation method has been developed to simulate the distribution of vascular plant species abundance. In this paper, seven datasets covering 37 national nature reserves were used to screen the best correlation equation between the vascular plant abundance and habitat factors in the plateau. These datasets include imformation on the vascular plant type, land cover, mean annual biotemperature, average total annual precipitation, topographic relief, patch connectivity and ecological diversity index. The results show that the multiple correlation coefficient between vascular plant abundance and various of habitat factors is 0.94, the mean error validated with the vascular plant species data of 37 national nature reserves is 2.21 types/km², and the distribution of vascular plant species abundance gradually decreases from southeast to northwest, and reduces with increasing altitude except for the desert area of Qaidam Basin on the Qinghai-Tibet Plateau. Furthermore, the changes of vascular plant species abundance in the plateau during the periods from 1981 to 2010 (T0), from 2011-2040 (T2), from 2041to 2070 (T3) and from 2071 to 2100 (T4) were simulated by combining the land cover change in China and the climatic scenarios of CMIP5 RCP2.6, RCP4.5 and RCP8.5. The results from T0 to T4 show that the vascular plant species abundance in the plateau would decrease in the future, the vascular plant species abundance had the biggest change ranges under RCP8.5 scenario and the smallest change ranges under RCP2.6 scenario. In short, dynamic change and interaction of habitat factors directly affect the spatial distribution of vascular plant species abundance on the Qinghai-Tibet Plateau.

Air pollution is now the most serious environmental problem in China, especially for Beijing-Tianjin-Hebei (Jing-Jin-Ji) urban agglomeration. Under the background of Jing-Jin-Ji integrated development, it is of great importance to study the spatio-temporal distribution and its influencing factors. This paper firstly analyzed the spatio-temporal characteristics of PM_2.5 concentration in 202 counties of Jing-Jin-Ji urban agglomeration using spatial analysis and visualization. Then we quantified the effect degree of different natural and human factors and the spatial spillover effect of these factors using Spatial Durbin Model (SDM). The results are as follows: (1) The PM_2.5 concentration was on the rise as a whole from 2000-2014, and it was high in autumn and winter, while low in spring and summer. Seen from spatial distribution, the PM_2.5 concentration was high in the southeast, while low in the northwest of the study area, and the concentration in urban built-up area was 10-20 μg/m³ higher than that of its surrounding suburban and rural areas. (2) The counties, whose PM_2.5 concentration was below 35 μg/m³, only accounted for 13.9% in 2014. There were significant spatial agglomeration and diffusivity of PM_2.5, and the mean distance interacting among the cities was 200 km. The PM_2.5 of a city increased by more than 0.5% for every 1% increase in the average PM_2.5 of neighboring cities. (3) Socio-economic factors have positive impact on PM_2.5, and most of natural factors have negative impact. (4) Among the influencing factors, contributions to local atmospheric pollution with direct effect are: mean wind speed > annual mean temperature > population density > relief amplitude > the secondary industry share of GDP > energy consumption > vegetation coverage; however, per capita GDP, annual precipitation, and relative humidity have no significant effect on local pollution. (5) Contributions to neighborhood atmospheric pollution with spatial spillover effect are: vegetation coverage > relief amplitude > population density. The findings suggest that we should adopt the adaptation strategies for natural factors and control strategies for human factors. A coordinated and strengthened cooperation between local governments should be established for air pollution control, and environmental planning and legislation should be strengthened in a new round of urban agglomeration planning in China.

High concentration of PM_2.5 has been universally considered as a main cause for haze formation. Therefore, it is important to identify the spatial heterogeneity and influencing factors of PM_2.5 concentration for the purpose of regional air quality control and management. Using PM_2.5 data from 2000 to 2011 that is inversed from NASA atmospheric remote sensing images, and employing the methods in geo-statistics, geographic detectors and geo-spatial analysis, this paper reveals the spatio-temporal evolution patterns and driving factors of PM_2.5 concentration in China. The main findings are as follows: (1) In general, the average concentration of PM_2.5 in China has increased quickly and reached its peak value in the year of 2006; after that, it has been maintained at around 22.47-28.26 μg/m³. (2) PM_2.5 is strikingly uneven in China, with a higher concentration in North and East than in South and West, respectively. In particular, the areas with a relatively high concentration of PM_2.5 are mainly the four regions including the Huang-Huai-Hai Plain, the Lower Yangtze River Delta Plain, the Sichuan Basin, and the Taklimakan Desert. Among them, Beijing-Tianjin-Hebei Region has the highest concentration of PM_2.5. (3) The center of gravity of PM_2.5 has shown an overall eastward movement trend, which indicates an increasingly serious haze in eastern China. Particularly, the center of gravity of high-value PM_2.5 is kept on moving eastward, while that of the low-value PM_2.5 moves westward. (4) The spatial autocorrelation analysis indicates a significantly positive spatial correlation. The "High-High" PM_2.5 agglomeration areas include the Huang-Huai-Hai Plain, Fenhe-Weihe River Basin, Sichuan Basin, and Jianghan plain regions. The "Low-Low" PM_2.5 agglomeration areas include Inner Mongolia and Heilongjiang to the north of the Great Wall, Qinghai-Tibet Plateau, and Taiwan, Hainan and Fujian and other southeast coastal and island areas. (5) Geographic detection analysis indicates that both natural and human factors account for the spatial variations of PM_2.5 concentration. In particular, factors such as natural geographical location, population density, automobile quantity, industrial discharge and straw burning are the main driving forces of PM_2.5 concentration in China.

The research on the interactions among multiple ecosystem services (ES) is a hotspot. Most of the previous studies focused on the qualitative description of ES interactions, however, there have been relatively few studies on spatially explicit and quantitative assessment of ES interactions. In this paper, we mapped the ecosystem service of soil conservation (SC), net primary production (NPP) and water yield (WY) in the upper reaches of Hanjiang River Basin (URHR) based on the land use and land cover (LULC), NDVI, soil properties and observed climate data covering 2000-2013. Moreover, we quantitatively assessed the variation characteristics of interactions among different ES with a spatio-temporal statistical framework by applying the partial correlation analysis at a pixel scale. The results are shown as follows: (1) From 2000 to 2013, the mean annual SC was 434.20 t·hm^-2·yr^-1, and the mean annual WY was 250.34 mm. They also presented a rising tendency at the rate of 16.10 t·hm^-2·yr^-1 and 3.79 mm·yr^-1, respectively. However, the mean annual NPP was 854.11 gC·m^-2·yr^-1, and presented a decreasing tendency at the rate of 8.54 gC·m^-2·yr^-1. (2) Spatially, SC was high in the North-South mountain area, while it was low in the Middle valley region. Similarly, the NPP in the Middle valley region was lower than that of other regions. However, the WY increased from north to south. (3) The three pairwise ES presented different interactions. Both the interaction between SC and NPP and that between SC and WY presented as trade-off, accounting for 62.77% and 71.60% of the total area, respectively. On the contrary, the interaction between NPP and WY was prone to synergies, accounting for 62.89% of the total area. (4) Pairwise ES in different land cover types also presented a different interaction. As for woodland, wetland, cropland, artificial land and bare land, SC and NPP, as well as SC and WY both presented trade-off, while WY and NPP presented synergy. Specially, in grassland, all the three pairwise ES presented a trade-off relationship. Therefore, spatially explicit and quantitative assessment of ES interactions are more helpful for revealing the temporal non-linear evolution, and the spatial heterogeneity of ES interactions. This analysis framework also contributes to the regional sustainable land management and the optimization of multiple ES conservation.

Nowadays, the urban agglomerations in the eastern coastal area of China have been the strategic core regions of national economic development and part of the main regions of the new-type urbanization. However, they suffer a series of eco-environment problems, such as increased consumption of resources, energy and materials. Thus, over the past few years, the eco-environment problem of urban agglomerations has become the forefront subject in the field of geographical research. The paper is unfolded with the definition of the eco-efficiency of urban agglomeration, which is taken as the measurement index of sustainability of urban agglomerations. Subsequently, with the aid of the traditional DEA model and undesirable output model of SBM, the paper carries out a comparative evaluation of the economic efficiency and ecological efficiency of the four major urban agglomerations in eastern China in the three periods of 2005, 2011 and 2014, and analyzes the spatio-temporal characteristics of evolution of urban agglomerations. In conclusion, with an analysis of laxity, the paper proposes corresponding suggestions for the improvement of eco-efficiency of the four major urban agglomerations in coastal China. As is suggested in the results, first and foremost, the overall economic efficiency of urban agglomerations located in Shandong Peninsula, Yangtze River Delta and Pearl River Delta displays a V-shaped pattern of "first decrease and then increase". In contrast, the overall economic efficiency of the Beijing-Tianjin-Hebei urban agglomeration declines from the beginning to the end. Before 2011, a significant impact of pure technical efficiency is displayed, and after 2011, it is greatly affected by scale efficiency. Secondly, the Beijing-Tianjin-Hebei urban agglomeration suffers from a considerable loss of efficiency due to the impact of pollution. In contrast, there is a less severe loss in the efficiency of Shandong Peninsula urban agglomeration. On the whole, the eco-environment efficiency of the four major urban agglomerations was at a descending stage from 2005 to 2011, and at a revival stage from 2011 to 2014. In addition, the spatio-temporal pattern of urban eco-efficiency in the four major urban agglomerations in the coastal areas is possessed with different evolution characteristics. The peri-urban areas of core cities and riverside and seaside areas have a better urban eco-efficiency, and the inland cities have an inferior urban eco-efficiency. Apart from that, it is found that the core cities of the Beijing-Tianjin-Hebei, Yangtze River Delta and Pearl River Delta urban agglomerations have a high resource consumption, economic benefit output and high eco-efficiency. Overall, most cities in the urban agglomerations demonstrate a declining tendency of pollution emissions, together with marked reduction of pollutants and mitigation of environmental problems. Last but not least, the economic eco-efficiency of the four major urban agglomerations is influenced by different factors. The paper conducts a differential analysis from the perspective of urban agglomeration, and proposed the concrete suggestions.

Coastal prograding tidal flats are important wetlands and reserve resources of cropland in China, which provide the services of ecological protection, society security, and economic development. Taking the reclamation zones on the prograding coast of Jiangsu as a case study, this paper analyzed soil quality at the reclamation zones with a duration of 0-40 years to indicate the evolution of cropland quality following reclamation for sustainable use of cropland, by using the method of "space for time substitution". The results show that cropland soils had high salinity but low nutrients. The variation of soil physical and chemical properties is high in the coastal reclamation zones, and the soil particle sizes had obvious gradients of North-South and Land-Sea. The factors such as topography, vegetation status, and the path of tidal flats to cropland had significant impacts on cropland quality evolution following coastal reclamation. The path of tidal flats to cropland were jointly decided by physical condition of reclamation zones, development entity, and development scale in the coastal area of Jiangsu. The cropland trajectories have changed from "halophytes→aquaculture pond→cropland" to "halophytes→cropland" in the central part of the province's coastal area. This change shortened the period of tidal flats to cropland, but led to idle tidal flats after reclamation. The soils of coastal tidal flats have gradually transferred into soils of cropland. The changing trends of soil properties were divided into four types. The first one was the type of increase, such as soil total phosphorous, available phosphorous, and clay content. The second one was the type of decrease, such as sand content. The third one was the type of increase then decrease, such as soil salinity and pH. The fourth one was the type of decrease then increase, such as soil organic matter, total nitrogen, available nitrogen, and capacity of exchange cations. At the initial period of reclamation, soil organic matter showed a declining trend because of the process of mineralization. The soil salinity and pH increased due to transpiration and evaporation. At the middle period of reclamation, soil organic matter and nutrients increased because of the fertilization and organic matter input via human cultivation. Soil salinity and pH decreased as a result of precipitation and water resource facilities. At the later period of reclamation, the factors of soil quality fluctuated under the effect of cultivation management. The quality of cropland at the reclamation zones was fragile and sensible to cultivation management, because of the relatively short history of coastal reclamation.

IImpervious surface (IS) is often recognized as the indicator of regional ecosystems and environmental changes. Its spatio-temporal dynamics and ecological effects have been studied by many researchers, especially for the IS in Beijing municipality. However, most previous relevant studies examined Beijing as a whole without considering the differences and heterogeneity among the functional zones. In this study, the urban expansion in Beijing in some typical years (1991, 2001, 2005, 2011 and 2015) was analyzed by sub-pixel IS that obtained through the simulation of CART and change detection models. Then the spatio-temporal dynamics and variations of IS (1991, 2001, 2011 and 2015) in different functional zones and counties were analyzed based on the method of standard deviation ellipse, Lorenz curve, contribution index (CI) and landscape theory. It is found that the total area of impervious surface in Beijing increased dramatically from 1991 to 2015, increasing about 144.18%. The deflection angle of major axis of standard deviation ellipse decreased from 47.15° to 38.82°, indicating a trend that the major development axis in Beijing moved from the northeast-southwest orientation to the north-south orientation. Moreover, the heterogeneity of IS distribution in different counties weakened gradually but the CI values and landscapes in different zones differed greatly. Urban function extended zone (UFEZ) had the highest CI value, which means it played the most important role in the growth of IS in Beijing, and its lowest CI value was 1.79 during the study period, which is much greater than the highest CI values of other functional zones. Core functional zone (CFZ) contributed less than UFEZ, but it has the highest CONTAG value, showing a more connected IS landscape compared with other zones. The CI values of new urban developed zone (NUDZ) increased rapidly from 1991 to 2015, which increased from negative to positive and multiplied, indicating the NUDZ has become the main source for the growth of IS in Beijing gradually. However, the ecological conservation zone made a negative contribution at all times, and its CI value decreased constantly. In addition, the variations of landscape indices and centroids of impervious surface in different density classes indicate that the high-density impervious surface had a more compact configuration and a greater impact on the ecological environment.