Geographically, the Qinling-Daba Mountains serve as the main body of the north-south transitional zone of China. However, the transitional patterns of their plant species still need to be clarified. This study analyzed latitudinal variations of plant species richness, relative importance values (RIV), and plant species abundance based on plant community field survey data for 163 sample sites along three north-south transect lines in the eastern, middle, and western parts of the study areas. The difference in RIV between subtropical and temperate species (SND-RIV) was selected to reveal the latitudinal interlacing pattern of northern and southern plant species. Along the eastern (Sanmenxia-Yichang), middle (Xi’an-Dazhou), and western (Tianshui-Guangyuan) transects, the richness and RIV of subtropical plant species increased while those of temperate plant species decreased from north to south. In the eastern transect, temperate plant species richness and RIV were the highest at Shennongjia and Funiu Mountain, respectively, because of their high elevations. In the middle transect, subtropical plant species richness and RIV were the highest in the Daba Mountains. In the western transect, richness and RIV were higher for subtropical than temperate plant species from the south of Longnan. The crisscrossing areas of northern and southern plant species were ~180 km, ~100 km, and ~60 km wide for the eastern, middle, and western transects, respectively, showing a narrowing trend from east to west. For the eastern and western transects, decreases in subtropical plant species distribution from south to north could be attributed to a decrease in mean annual precipitation in the same direction. However, for the middle transect, mean annual temperature had a slightly greater influence on plant species’ latitudinal distribution than the moisture index. This study provides a more solid scientific basis for future investigations of this key geographical boundary in China.

Understanding the hydrological effects of the Three Gorges Dam operation in the entire reservoir area is significant to achieving optimal dam regulation. In this paper, a large-scale coupled hydrological-hydrodynamic-dam operation model is developed to comprehensively evaluate the hydrological effects of the river-type Three Gorges Reservoir. The results show that the coupled model is effective for hydrological, hydrodynamic regime and hydropower simulations in the reservoir area. Dam operation could have a notable positive effect on flood control and could reduce the maximum daily flood peak by up to 26.2%. It also contributes a large amount of hydropower, approximately 94.27 TWh/year, and a water supply increase for the downstream area of up to 22% during the dry season. In the flood season, the water level at Cuntan would increase under the condition that the water level of the dam is higher than approximately 158 m due to dam operation. In the dry season, attention should be paid to the low flow velocity near the dam in the reservoir area.

The impacts of climate change on the relationship between fluvial processes and dune landform evolution have been studied. However, the chronology data used to examine this relationship are deficient. The Keriya River has a glacial origin in the Kunlun Mountains on the south margin of the Tarim Basin. The river flows into the Taklimakan Desert, the second largest shifting-dune desert in the world. The dry channels and shifting dunes in this area provide an ideal opportunity to investigate fluvial and aeolian landform evolution processes and their relationship with climate change. We investigated this area during 2008-2011 and obtained 18 fluvial sediment samples from 16 sections for optically stimulated luminescence (OSL) dating. The results show that the ages ranged from 3.4-44.1 ka. Most of the samples (13) were Holocene in age, around 11 ka, 8-9 ka, 5-6.5 ka, 4.6 ka, and 3.4-3.7 ka and were distributed along ancient river channels around sites of Yuansha and Karadun. Two samples close to the Hotan River (38-47 ka) fall within the Marine Isotope Stage 3 (MIS3). Three samples (from one section) were located near ancient channels flowing towards the Yuansha Site and had ages of around 14.5 ka, i.e., during the Last Glacial Maximum (LGM). The analyses of the sediment samples and OSL ages suggest that the Keriya River flooded in the Holocene, the LGM, and MIS3. Fluvial sediments provided the source material for the dunes, and fluvial processes affected the landform evolution in the lower Keriya River. Our results suggest that most of the dunes covered in fluvial sediments in the lower reaches and the area west of the Keriya River developed since the Holocene. This differs from the results of previous studies, which suggested that they developed since the Han (202BC-220AD) and Tang (618-907AD) dynasties. The OSL ages of the fluvial sediments are consistent with the reported deglaciation (after glacial advance) ages in the alpine mountains surrounding the Tarim Basin. This suggests that climate fluctuations may have affected the occurrence of floods and the formation of dunes in the Taklimakan Desert.

Most terrestrial models synchronously calculate net primary productivity (NPP) using the input climate variable, without the consideration of time-lag effects, which may increase the uncertainty of NPP simulation. Based on Normalized Difference Vegetation Index (NDVI) and climate data, we used the time lag cross-correlation method to investigate the time-lag effects of temperature, precipitation, and solar radiation in different seasons on NDVI values. Then, we selected the Carnegie-Ames-Stanford approach (CASA) model to estimate the NPP of China from 2002 to 2017. The results showed that the response of vegetation growth to climate factors had an obvious lag effect, with the longest time lag in solar radiation and the shortest time lag in temperature. The time lag of vegetation to the climate variable showed great tempo-spatial heterogeneities among vegetation types, climate types, and vegetation growth periods. Based on the validation using eddy covariance data, the results showed that the simulation accuracy of the CASA model considering the time-lag effects was effectively improved. By considering the time-lag effects, the average total amount of NPP modeled by CASA during 2001-2017 in China was 3.977 PgC a^-1, which is 11.37% higher than that of the original model. This study highlights the importance of considering the time lag for the simulation of vegetation growth, and provides a useful tool for the improvement of the vegetation productivity model.

Driven by urbanization and industrialization, arable land in hilly and mountainous regions of China is gradually becoming marginalized, with the extent of arable land abandonment rapidly expanding from poor-quality sloping arable land to high-quality terraces. The abandonment of large-scale terraces will lead to a series of socio-economic and ecological effects. A national sample survey was used to investigate the extent and spatial distribution of terrace abandonment in China, and a total of 560 valid village questionnaires from 329 counties were collected in the mountainous areas of China. The main findings are as follows: (1) The phenomenon of terrace abandonment was widespread throughout the country, with 54% of the total surveyed villages exhibiting terrace abandonment, and the area of abandoned terraces accounting for 9.79% of the total. (2) The degree of terrace abandonment is high in the south and low in the north. The most serious region with abandonment was the hilly and mountainous areas in the south, especially in the middle and lower Yangtze River region. (3) The main driving factors of terrace abandonment were rural labor migration, agricultural mechanization level, irrigation conditions, and transportation conditions for cultivation. Targeted measures should be taken based on the specific conditions of each area to alleviate terrace abandonment. Measures such as improving terrace mechanization are universally applicable. Specifically, low-quality terraces can be withdrawn orderly, and for high-quality terraces, multiple measures are needed to consolidate agricultural production, such as adjusting the planting structure, strengthening agricultural infrastructure construction, and encouraging the transfer of land-use rights as well as large-scale operation.

Ecosystem services are the media and channels through which ecological elements, structures, functions, and products benefit human society. Regulating the utilization intensity and protection methods of society on the ecosystem according to the ecosystem service value (ESV) and its influencing mechanism is of great significance for achieving the sustainable development goals. This paper takes the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as the research object and describes the spatiotemporal evolution characteristics of ESV in the GBA from 2000 to 2015. Panel quantile regression is also implemented to increase the understanding of the influencing mechanism of ESV. The main results are as follows: (1) From 2000 to 2015, the total ESV declined with a decreasing rate. The areas of decline were mainly distributed in the central part of the GBA and areas along the Pearl River Estuary. (2) Elasticity index, indicating response of ESV to land use change, reached its peak (1.08). The spatial distribution of elasticity index showed that land use changes brought about more intense ESV variations at the junction of cities. (3) In areas with different ESV levels, the influencing factors have different effects. Land use integrity can only promote ecosystem service capabilities in low-ESV areas. The positive effect of temperature on ecosystem service capacity increases with the increase of ESV, which reflects the self-reinforcement of the ecosystem. Moreover, the negative effect of economic density on ecosystem service capacity decreases with the increase of ESV, which reflects the self-protection of the ecosystem. The combination of such self-reinforcement and self-protection will lead to an ESV gap between the high- and low-ESV areas, and induce the “natural Matthew effect.”

Rapid urbanization has occurred in arid/semiarid China, threatening the sustainability of fragile dryland ecosystems; however, our knowledge of natural environmental constraints on multiscale urban lands in this region is still lacking. To solve this issue, this study retrieved 15-m multiscale urban lands. Results indicated that urban area increased by 68% during 2000-2018, and one-third of the increase was contributed by only three large cities. The coverage of impervious surface area (ISA) and vegetated area (VA) increased by 16.6% and 1.38%, respectively. Such land-cover change may be helpful in suppressing wind erosion and sand storms. We also found that the newly urban lands had relatively lower ISA and higher VA than the old urban lands, indicating an improved human settlement environment. Strong environmental constraints on urban expansion were identified, with cities in oasis urban environments (OUEs) that had water supply expanding 150% faster than cities in desert urban environments (DUEs). Urban development was also constrained by terrain, with 73% of the ISA expansion occurring in relatively flat areas. Overall, the aggregated pattern of urbanization and the increase in ISA and VA in the newly urbanized lands have improved water-use efficiency and ecological services and benefited desert ecosystem protection in arid/semiarid China.

The construction of channel regulation projects, reservoirs, and other human activities have led to significant changes in channel geometry and hydrodynamic conditions in mountainous macrotidal estuaries. However, their impact on the long-term evolution of the turbidity maximum zone (TMZ) in these estuaries is still unclear. Therefore, the Minjiang Estuary (ME) was selected as the study area and using the Gabor filter and surface suspended sediment concentration (SSSC) data retrieved from GF PMS/WFV and Landsat-TM/ETM+/ OLI images in the flood season from 1986 to 2020, the flow direction of Chuanshi Waterway, the spatiotemporal evolution characteristics of TMZ in the ME, and the influence of human activities on these were analyzed. The results indicate that during flood tides in the past 35 years, the TMZ was mainly distributed in sections from the Changmen to the Chuanshi and Meihua waterways. The construction of the Shuikou Reservoir caused the SSSC to decrease by 65 mg/L at the Chuanshi Tidal Gauge Station in the ME. The TMZ in the ME waterway channel notably migrated toward the sea due to the waterway regulation project, with the landward and seaward boundaries moving by 2.5 km and 3 km seaward, respectively. The main distribution area moved from Jinpaimen to the section from Chuanshi Waterway to the mouth of the ME. These variation characteristics were basically consistent with the annual average TMZ in the flood season. Through the interactions between nature and human interventions, the flow regime of the ME tended to converge in the flood season. Therefore, human activities have significantly impacted the long-term evolution of the TMZ in the ME.

Given the challenges of re-creating complex bed load (BL) transport processes in rivers, models are preferred over gathering and examining field data. The highlight of the present research is to develop an approach to determine the ungauged bed load concentration (BLC_u) utilizing the measured suspended sediment concentration (SSC) and hydraulic variables of the last four decades for the Mahanadi River Basin. This technique employs shear stress and SSC equations for turbulent open channel flow. Besides, the predicted BLC_u is correlated with SSC using a power relation to estimate BLC_u on the river and tributaries. Eventually, different BL functions (BLF) efficiency is assessed across stations. The model predicted BLC_u is comparable with the published data for sandy rivers and falls within ± 20%. Outliers in hydraulic and sedimentological statistics significantly influence estimating the BL fraction apart from higher relative ratios and catchment geology. The constants of power functions are physically linked to sediment transport configuration, mechanism, and inflow to the stream. The stream power-based BLF best predicts the BL transport, followed by shear stress and unit discharge approaches. The disparity in the estimation of BLC_u results from station-specific physical factors, sampling data dispersion, and associated uncertainties.

Rust belt cities are largely threatened by a waste of urban space at their core; however, in developing countries where land resources are widely used as instruments for macroeconomic stabilization, urban periphery is also at risk of being underutilized due to land hoarding. Such geographic differences entail new knowledge about how, where, and why underutilized lands are regenerated in the city. Furthermore, rapid urban growth imposes development disparity and mixed underutilization issues on cities in developing countries; therefore, how the geo-information obtained by the regeneration of different underutilized lands differs will be valuable for urban planners and policymakers to make prudent trade-offs. To fill these gaps, we conducted a sequential investigation into the regeneration of underutilized lands in a representative rust belt city - Changchun City in Northeast China, in an attempt to measure the regeneration pattern and analyze the underlying determinants using the Classification and Regression Trees analysis. The results indicated that, of all underutilized lands, increments of vacant lot and remnant cultivated land continued to plague the expanding urban periphery during 2016-2019. In a way, reduced underutilized lands alleviated land use conflicts at the city core. Nearly 23% of the underutilized areas had been regenerated, dominated by realty development, with most converted to residential lands, ecological lands and industrial lands. On the contrary, conversion to transportation lands and parking lots seemed to avoid the rapidly expanding sites. The regeneration rates in a certain area can be increased by a multitude of factors, including denser, simply structured land underutilization, abundant ecosystem services nearby and accessibility to public infrastructures. Site conditions such as residential density and accessibility may have fueled the regeneration associated with residential purposes, while regeneration of industrial development was closely associated with the underutilization density and parcel regularity. This research provides an empirical paradigm for delivering regeneration geo-information across different underutilized lands, particularly for rust belt cities that are caught between a shrinking core and speculative periphery.

The Regional Comprehensive Economic Partnership (RCEP) was formally signed by the Association of Southeast Asian Nations (ASEAN) countries, along with China, Japan, South Korea, Australia, and New Zealand. This was a significant step towards regional integration in the Asia-Pacific region. Analysing the trade structure among member states is crucial in understanding the path to regional integration and policy implications of regional cooperation within the RCEP framework. Based on subdivided commodity data, this study reviews the evolution of merchandise trade in the RCEP region in the past two decades. It investigates the current trade structure of the RCEP, emphasising the relative importance of intra-regional versus extra-regional interdependence and the trade asymmetry of the regional members. The results of the study are as follows: First, the overall extent of regional trade integration in the RCEP region increased modestly from 2001 to 2018, indicating that the RCEP region was export-oriented and there was significant room for further expansion of regional trade. Second, most of the commodities traded in the RCEP region demonstrated much higher extra-regional interdependence than intra-regional in 2018, particularly labor-, capital-, and technology-intensive products such as television and radio apparatus. Third, the trade networks of the top five traded commodities were distinguished by large economic asymmetries, with China, Japan, and South Korea being the dominant regional powers. These findings have significant implications for understanding how to promote regional integration and cooperation. Besides expanding intra-regional trade, outward-oriented factors influenced by the regional powers—including consolidating the global advantages of manufacturing, stabilizing supply chains by including large resource countries, and attracting extra-regional investments—were also the main rationales for the conclusion of the RCEP.

Cropping systems worldwide have been affected by the current trend in global warming and the optimization of cropping systems is an important area of research in the transition of agricultural land. The Loess Plateau is a typical ecologically fragile region with the most serious soil erosion in China. We carried out a field experiment in Yan’an city on the Loess Plateau to explore the effect of sowing date on crop growth and yield. We then analyzed the feasibility of a double-cropping system by considering climatic adaptability, ecological suitability and economic viability. Our results showed that different sowing dates resulted in significant differences in crop growth and that appropriate early sowing can result in higher crop yields for early maturing varieties. We showed that double-cropping systems of sweet maize (Zea mays)-forage rape and feed maize-forage rape are feasible on the Loess Plateau. We discuss the implications for the efficient use of farmland, which is important in guiding agricultural supply-side reform and the development of modern agricultural management.

The semiconductor industry typifies the international division of labor and exhibits significant structural differences in global trade in key product segments. The evolution of cross-border trade flows and dependency relationships, as well as trade organization patterns of manufactured products, equipment and materials for manufacturing, are investigated by constructing a global semiconductor trade relationship matrix and using the Gini coefficient and trade dependency index. It was found that: (1) the global semiconductor trade is highly spatially unbalanced, with materials and equipment trade in particular highly concentrated in a few countries on both the supply and demand sides; (2) China has replaced the US as the largest global semiconductor trade player and has shaped the regionalized system of manufactured goods and materials trade with East and Southeast Asian economies, but its equipment trade is highly dependent on Europe and the US; (3) the semiconductor production model has promoted the regionalization of the east and southeast Asia region in the trade of manufactured products and materials, and developed economies such as the US, the EU, Japan, and South Korea have maintained their monopolistic advantage in the trade of semiconductor equipment by building exclusive innovation networks and establishing trade barriers. The monopolistic nature of the semiconductor equipment trade and the regionalization of manufactured goods and materials have formed the characteristics of the global semiconductor trade and are likely to be further strengthened in future trade.

Scientific field management is an important path to realize ecological production and sustainable development of agriculture. As the main content of field management, nitrogen (N) management is the key to balance the economic and ecological benefits of agricultural production. In the loess hilly-gully region, for the fragile ecological and social system, ecologicalization of agricultural production is an important direction to promote sustainable agricultural development. However, irrational fertilization has been one of the main constraint factors, hindering the ecologicalization of local agriculture. In order to solve the problem and prove the practical significance of field management to ecologicalization of agriculture, this study aimed at evaluating the effects of different N fertilization rates and timing using Root Zone Water Quality Model (RZWQM) and then optimizing the N management. Experiments were conducted from 2018 to 2019 in Yangjuangou watershed, loess hilly-gully region, to calibrate and validate the model. The root mean square error (RMSE) of soil water content, nitrate N concentration, above-ground biomass, leaf area index ranged from 10.5-13.5 mm, 2.96-3.80 mg·kg^–1, 730.3-1273.9 kg·ha^–1 and 0.26-0.38, respectively, with the agreement index (d) between observed and simulated values ranging between 0.88 to 0.98. Simulation results showed that N leaching in semi-arid areas was also quite high due to concentrated rainfall and loose soil, which had previously been neglected. When the fertilization rate decreased by 35% (applying the chemical fertilizer at rate of 245.7 kg N ha^–1) of typical fertilization (applying the chemical fertilizer at rate of 378.0 kg N ha^–1), the leaching and residual N decreased by 72.2%-75.4% and 35.6%-50.9%, respectively, while NUE increased by 41.5%-45.2% with no reduction in maize yield. Additionally, compared with applying additional N at seedling stage in one batch, applying at seedling and jointing stages in two batches further decreased N leaching and improved NUE. Thus, a 35% reduction of typical fertilization rate combined with applying additional N at seedling and jointing stages is recommended. From the perspective of N management, this study demonstrated optimizing field management can play a positive role in the ecologicalization of agriculture, and more field management measures should be explored.

The trend estimate of vegetation change is essential to understand the change rule of the ecosystem. Previous studies were mainly focused on quantifying trends or analyzing their spatial distribution characteristics. Nevertheless, the uncertainties of trend estimates caused by spatiotemporal scale effects have rarely been studied. In response to this challenge, this study aims to investigate spatiotemporal scale effects on trend estimates using Moderate-Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) and Gross Primary Productivity (GPP) products from 2001 to 2019 in the Qinghai-Tibet Plateau (QTP). Moreover, the possible influencing factors on spatiotemporal scale effect, including spatial heterogeneity, topography, and vegetation types, were explored. The results indicate that the spatial scale effect depends more on the dataset with a coarser spatial resolution, and temporal scale effects depend on the time span of datasets. Unexpectedly, the trend estimates on the 8-day and yearly scale are much closer than that on the monthly scale. In addition, in areas with low spatial heterogeneity, low topography variability, and sparse vegetation, the spatiotemporal scale effect can be ignored, and vice versa. The results in this study help deepen the consciousness and understanding of spatiotemporal scale effects on trend detection.

In this paper, we firstly constructed a theoretical framework based on major function-oriented zones (MFOZs). Then taking the Loess Plateau (LP) as the study area, we revealed the spatio-temporal differences and influencing factors of carbon emission equity by using the carbon equity model, Theil index, and Geo-detector. The results showed that: (1) From 2000 to 2017, the carbon equity of the Loess Plateau showed a downward trend, but the ecological carbon equity remained above 2.3, which was significantly higher than the economic carbon equity. (2) The ecological carbon equity in the Loess Plateau increased from the core of urban agglomeration to the periphery. The spatial pattern of economic carbon equity changed from low in the northeast and high in the southwest to low in the north and high in the south. The ecological support coefficient and economic contribution coefficient of provincial capital cities and their surrounding districts remained low since 2000. (3) The equity of carbon emissions in each function-oriented zone in the Loess Plateau was compatible with its orientation. The ecological carbon equity of the key ecological functional zones (KEFZs) was significantly higher than that of the key development zones (KDZs) and the major agricultural production zones (MAPZs), while the economic carbon equity of the KDZs was significantly higher than that of the MAPZs and the KEFZs. (4) The formation and evolution of the spatial differentiation pattern of carbon equity in the Loess Plateau was the result of the long-term interaction effects of geographic location, social economy, science and technology level, and policy system. Among them, eco-environmental protection policy, government financial support, and geographical location are the key driving factors for the spatial pattern of ecological carbon equity. Geographical location, social economic level, and science and technology level are the key factors driving the spatial pattern of economic carbon equity. According to this study, to achieving carbon equity on the Loess Plateau region, what the key approaches are to fully implement the planning of MFOZs, design differentiated regional carbon compensation mechanisms, improve energy efficiency and ecological environment capacity, and build a collaborative regional carbon emission governance system. This research can not only provide an effective framework for analysing the carbon equity, but also offer policy implication for promoting carbon emission reduction and achieving high-quality development goals in the ecologically fragile areas.

Situated in the hinterland of Eurasia, Central Asia is characterized by an arid climate and sparse rainfall. The uneven spatial distribution of water and land resources across the region has pressured economic and social development. An accurate understanding of Central Asia's water resources carrying capacity (WRCC) is vital for enhancing the sustainability of water resources utilization and guiding regional economic and social activities. This study aims to facilitate the sustainability of water resources utilization by evaluating the region's WRCC from the viewpoints of economic and technological conditions and social welfare. A concise yet effective model with relatively fewer parameters was established by adopting water resources data from the Food and Agriculture Organization (FAO) and socioeconomic data from the World Bank. The results indicated that the WRCC of all five Central Asian countries showed an increasing trend with improved water use efficiency from 1995 to 2020. Kazakhstan's WRCC was significantly higher than the other four countries, reaching 54.03 million people in 2020. The water resources carrying index (WRCI) of the five Central Asian countries varied considerably, with the actual population sizes of Turkmenistan and Uzbekistan highly overloaded. Although there has been a decrease in Central Asian countries’ WRCI between 1995 and 2020, water resources utilization problems in the region remain prominent. Based on the water resources carrying capacity evaluation system, to increase available water resources and improve production water use efficiency are key to address these issues. In light of this, this study offers practical and feasible solutions at the policy level: (1) The implementation of signed multilateral agreements on transboundary water resources allocation must proceed through joint governmental efforts. (2) Investments in advancing science and technology need to be increased to improve water use efficiency in irrigation systems. (3) The output of water-intensive crops should be reduced. (4) The industrial structure could be further optimized so that non-agricultural uses are the primary drivers of gross domestic product (GDP) growth.

Snowmelt runoff is a vital source of fresh water in cold regions. Accurate snowmelt runoff forecasting is crucial in supporting the integrated management of water resources in these regions. However, the performances of such forecasts are often very low as they involve many meteorological factors and complex physical processes. Aiming to improve the understanding of these influencing factors on snowmelt runoff forecast, this study investigated the time lag of various meteorological factors before identifying the key factor in snowmelt processes. The results show that solar radiation, followed by temperature, are the two critical influencing factors with time lags being 0 and 2 days, respectively. This study further quantifies the effect of the two factors in terms of their contribution rate using a set of empirical equations developed. Their contribution rates as to yearly snowmelt runoff are found to be 56% and 44%, respectively. A mid-long term snowmelt forecasting model is developed using machine learning techniques and the identified most critical influencing factor with the biggest contribution rate. It is shown that forecasting based on Supporting Vector Regression (SVR) method can meet the requirements of forecast standards.

The agglomeration of the rural e-commerce industry represented by Taobao villages has reshaped the existing urban and rural spatial organization and proposed a new urbanization model. This study identified the spatiotemporal characteristics of Taobao villages in Quanzhou city and built panel regression models to examine the impact of these villages on urbanization level, which is measured via nighttime light (NTL). The results show that (1) while the number of Taobao villages in Quanzhou city has increased rapidly, it has also experienced sporadic growth and monocentric agglomeration, finally forming a polycentric agglomeration pattern; (2) Taobao villages display a significant near-city tendency, and the urbanization level of towns with Taobao villages is higher than that of towns without Taobao villages; (3) the panel regression model highlights that Taobao villages have a significant positive impact on urbanization level. Taobao villages near the city exhibit a greater effect; meanwhile, those that are far away from the city cannot improve their urbanization level unless they reach a considerable degree of agglomeration. Rural e-commerce will become an important direction for the transformation of urban fringe areas, which provides a certain reference for the development of new urbanization in China.

Spatial-temporal scales effects are general among human-nature interactions. However, the laws and mechanisms of the interaction between humans and the environment at different spatial-temporal scales remain to be identified. The Hexi Corridor in Northwest China is located in the eastern section of the Silk Road and is one of the world’s first long-distance cultural exchange centers. Here we present a comprehensive dataset of the Hexi Corridor, including changes in environments, population, wars, famines, settlements, and ancient oases from the Neolithic to the historic period. Results show that humans adapt to climate change on the millennium scale by choosing corresponding production methods. Environmental change, civilization evolution, and dynasty replacement interrelate on the decadal and centennial scales. Social crises are closely linked to extreme weather events on the interannual scale. On the basis of these results, we find similar time scale effects in the world’s major ancient civilizations. We do so by analyzing their processes of civilization evolution.

As a type of urban gentrification oriented by high-quality educational resources, jiaoyufication is a socio-spatial process that refers to the middle-class group that attaches importance to education realizes the agglomeration in famous school districts by purchasing high-price school district houses. Based on the theoretical analysis of jiaoyufication conducted by Chinese and foreign scholars, this paper takes Nanjing as a case city, applies multi-source data like POIs (points of interest), real estate market data, mobile-phone user portraits and questionnaires, and develops a composite measurement of jiaoyufication to identify jiaoyufied school district, jiaoyufied group & its spatial characteristics, and discusses the causal mechanisms and effects of jiaoyufication. With the GIS-entropy-TOPSIS model, this paper evaluates the jiaoyufication level of public primary school districts in the main urban area of Nanjing. The result show that 218 primary school districts are categorized into four types, i.e., high jiaoyufied school district, mid-high jiaoyufied school district, medium jiaoyufied school district, and low jiaoyufied school district. The high jiaoyufied school districts are closely associated with the institutional system. In the high jiaoyufied school districts, many middle-class families have abundant social, economic, and cultural capital. They purchase and move to houses with lower living quality in school districts to pursue high-quality education for their children. The strict school district system, soaring school district housing prices, and intense educational competition continuously solidify the jiaoyufication levels of famous school districts and lock the opportunities for high-quality education in specific school-district spaces and classes or groups. The phenomenon of this socio-spatial reconstruction process, which results from the unequal distribution of high-quality educational resources, tends to aggravate the rich-poor gap and social segregation in cities. It is suggested that equalization of compulsory education services should be effectively carried forward as soon as possible.

Knowledge innovation is a key component of urban innovation function and an important basis for modern urban development. Combining the multidisciplinary research of knowledge innovation, this paper constructs a measurement framework of urban knowledge innovation function from the perspective of urban geography and analyzes its spatial pattern and influencing factors. The conclusions are as follows: (1) The function of urban knowledge innovation refers to the tasks and roles it undertakes in the process of knowledge creation, knowledge dissemination and knowledge application, which is based on the internal knowledge stock and external practice conditions to meet the needs of human survival and development in the new era. The measurement dimensions include functional scale, functional intensity, functional scale, and functional vitality. (2) The development level of knowledge innovation functions in Chinese cities is uneven, and the cities with outstanding knowledge innovation functions are mainly concentrated in the eastern coastal areas and a few developed areas in the central and western regions, forming the diamond-shaped knowledge innovation structure with the Beijing-Tianjin, the Yangtze River Delta, the Pearl River Delta, Shaanxi-Chengdu-Chongqing as the four vertices and central Wuhan and Hefei as the center. According to the Jenks natural breakpoint method, it is divided into national-level, regional-level, local-level and knowledge-innovative development cities. (3) The spatial differentiation characteristics of urban knowledge innovation function are simultaneously affected by various natural and human factors. Among them, economic environment, opening environment, and cultural environment have the strongest interactive explanatory power with other factors, and are the dominant factors affecting the city’s knowledge innovation function. In the future, China should fully considers the status and characteristics of the city’s own knowledge economy development with corresponding policies and measures suitable for the development of the city’s knowledge economy, and strengthen the dominant position of human and social factors in the constructing the city’s knowledge innovation function.

The mass elevation effect (MEE) is a thermal effect, in which heating produced by long wave radiation on a mountain surface generates atmospheric uplift, which has a profound impact on the hydrothermal conditions and natural geographical processes in mountainous areas. Based on multi-source remote sensing data and field observations, a spatial downscaling inversion of temperature in the Tianshan Mountains in China was conducted, and the MEE was estimated and a spatio-temporal analysis was conducted. The GeoDetector model (GDM) and a geographically weighted regression (GWR) model were applied to explore the spatial and temporal heterogeneity of the study area. Four key results can be obtained. (1) The temperature pattern is complex and diverse, and the overall temperature presented a pattern of high in the south and east, but low in the north and west. There were clear zonal features of temperature that were negatively correlated with altitude, and the temperature difference between the internal and external areas of the mountains. (2) The warming effect of mountains was prominent, and the temperature at the same altitude increased in steps from west to east and north to south. Geomorphological units, such as large valleys and intermontane basins, weakened the latitudinal zonality and altitudinal dependence of temperature at the same altitude, with the warming effect of mountains in the southern Tianshan Mountains. (3) The dominant factors affecting the overall pattern of the MEE were topography and location, among which the difference between the internal and external areas of the mountains, and the absolute elevation played a prominent role. The interaction between factors had a greater influence on the spatial differentiation of mountain effects than single factors, and there was a strong interaction between terrain and climate, precipitation, the normalized difference vegetation index (NDVI), and other factors. (4) There was a spatial heterogeneity in the direction and intensity of the spatial variation of the MEE. Absolute elevation was significantly positively correlated with the change of MEE, while precipitation and the NDVI were dominated by negative feedback. In general, topography had the largest effect on the macroscopic control of MEE, and coupled with precipitation, the underlying surface, and other factors to form a unique mountain circulation system and climate characteristics, which in turn enhanced the spatial and temporal heterogeneity of the MEE. The results of this study will be useful in the further analysis of the causes of MEE and its ecological effects.

The coupling of humans and nature differs in terms of distribution and intensity, thus producing a gradient of synthetic geographical environments. Within this variety of gradients, the transitional zone represents a complex space where dynamic processes and unstable conditions are observed. Based on the concepts of ecotone and transitional zone, we propose a conceptual framework for the transitional geospace of coupled human and natural systems and a quantitative identification method for the zone. Taking the Sichuan Basin as an example, this study defined the strength and direction of the coupling of the natural ecosystem and socioeconomic system and divided different types of transitional geospace. The transitional geo- space of the strong coupling type accounted for approximately 16.7% of the study area. Nine of the ten counties with the largest proportion of the type were formerly nationally poor counties in the study area. In the strong coupling type, human and nature jointly explained a high proportion of the variance in transitional stability (e.g., in Shifang city, with an unexplained proportion of 1.7%). The discovery and characterization of the transitional geospace types is crucial for facilitating more effective land use planning and sustainable balance among the population, resources, and environment.

Identifying the spatiotemporal interaction pattern of agricultural product circulation (APC) is crucial for agricultural resource adjustment and food security. Current studies are mostly based on static statistical data over an entire year or a specific period, which cannot describe the spatial pattern of APC and its seasonal variation on a fine spatiotemporal scale. Thus, this study extracts an APC trip chain based on national truck trajectory data and constructs the flow network of the Beijing APC with the city as the spatial unit and the season as the temporal unit. The spatial interaction pattern and seasonal variation in APC are then analyzed from the network spatial form, city node function role, and transportation corridors. The results are as follows: (1) Compared with methods based on static statistical data, the proposed method provides a more complete and refined depiction of the spatiotemporal interaction pattern of APC. (2) The flow network of the Beijing APC involves 316 cities in China, of which 143 cities play a major role with typical seasonal characteristics. These cities can be divided into perennial core cities, perennial major cities, core cities in winter-spring, major cities in winter-spring, core cities in summer-autumn, and major cities in summer-autumn, contributing 2.6%-40.3% to the Beijing APC. (3) There are 6 transportation corridors for the Beijing APC. The Beijing-Tianjin-Hebei corridor and coastal corridor contribute 53.5% and 12.8% of the annual supply, respectively, with a balanced supply in all seasons. The Beijing-Kunming corridor and Beijing-Guangzhou corridor contribute 14.3% and 9.0%, respectively, with much higher supplies in winter and spring. The northeast and northwest corridors contribute 7.3% and 3.3%, respectively, mainly in the summer and autumn. These results help deepen the understanding of agricultural product supply patterns and provide a reference for the design and optimization of agricultural product transportation routes.

As a new mode for Chinese overseas investment and a growth pole for industrialization and urbanization of the host countries, the overseas economic and trade cooperation zone (OETCZ) or overseas free economic zone (OFEZ) of China plays an important role under the Belt and Road Initiative. With the rising attention on OETCZ, studies regarding OETCZ have also increased. However, there is a lack of studies reviewing this topic’s progress, challenges and future directions. This paper employs a systematic review to examine the literature on the OETCZ along the Belt and Road, based on domestic and overseas studies. The results show that domestic studies account for a large proportion of the collected literature, compared to overseas studies. Interdisciplinary research focus includes inductive case studies from a classification perspective, deductive studies based on cultural and institutional perspectives, trade network and bilateral trade relations based on the perspectives of international trade and regional economy, spatial planning studies from urban planning perspective, and overseas comments and earlier studies on Japan’s and Singapore’s overseas parks from the geopolitical and international political perspectives. Despite diverse research contents and dramatic progress, limitations exist in current OETCZ-related studies, including a lack of exploration of the mechanism, questions and concerns from overseas scholars, sustainable development and other problems. Future studies should broaden and deepen research insights, including the “overseas free economic zones (OFEZ)” as a general designation to cover all other types of OETCZs, studies on the primary conditions of host countries, exploration of the theoretical issues behind China’s OETCZ, comparative study of OETCZs such as management structures, profit models, environmental standards and legal systems as well as popular issues questioned internationally.

Transpiration (Tc) is a critical component of the global water cycle. Soil moisture (SM) and vapor pressure deficit (VPD) are key regulators of Tc, and exploring their contributions to changes in Tc can deepen our understanding of the mechanisms of water cycling in terrestrial ecosystems. However, the driving roles of VPD and SM in Tc changes remain debated because of the coupling of SM and VPD through land-atmosphere interactions which restrict the quantification of the independent effects of SM and VPD on Tc. By decoupling the correlations between SM and VPD using a novel binning approach, this study analyzed the dominant drivers of vegetation transpiration in subtropical China from 2003 to 2018 based on multi-source data, including meteorological reanalysis, remotely sensed soil moisture, transpiration, and land cover data. The results show that Tc first increased and then remained stable with an increase in SM across the study area but changed slightly with increasing VPD. Overall, the relative contribution of SM to the change in Tc was approximately five times that of VPD. The sensitivities of Tc to SM and VPD differed among vegetation types. Although the sensitivity of Tc to SM was greater than that of VPD for all four vegetation types, the thresholds of Tc in response to SM were different, with the lowest threshold (approximately 35%) for the other forests and the highest threshold (approximately 55% ) for short wood vegetation. We infer that this is associated with the differences in ecological strategies. To verify the reliability of our conclusions, we used solar- induced chlorophyll fluorescence (SIF) data as a proxy for Tc based on the tight coupling between photosynthesis and transpiration. Consistent results were obtained by repeating the analyses. The results of this study, in which the impacts of SM and VPD on Tc were decoupled, are beneficial for further understanding the critical processes involved in water cycling in terrestrial ecosystems in response to climate change.

We propose a theoretical framework for assessing the ecological benefits provided by key national ecological projects in China over the past 20 years. A dataset consisting of six primary indicators and nine secondary indicators of ecosystem structure, ecosystem quality, and ecosystem services for 2000-2019 was generated using ground survey and remote sensing data. Ecological benefits were quantitatively evaluated following the implementation of these projects in China. Areas with medium, relatively high, and high degrees of ecological restoration accounted for 24.1%, 11.9%, and 1.7% of the national land, respectively. Degrees of ecological restoration were higher in areas with greater numbers of ecological projects. Areas with relatively and absolutely high degrees of ecological restoration were mainly concentrated in the Loess Plateau, the farming-pastoral zone of northern China, the Northeast China Plain, and an area spanning the borders of Sichuan, Yunnan, Guizhou, Chongqing, and Hunan. The relative contributions of climatic factors and ecological projects to changes in vegetation net primary productivity were 85.4% and 14.6%, respectively, and the relative contributions of climatic factors and ecological projects to changes in water erosion modulus were 69.5% and 30.5%, respectively. The restoration potential of national vegetation coverage was 20%, and the restoration potential percentage of forest and grassland vegetation coverage was 6.4% and 23%, respectively. Climatic conditions can inhibit ecological restoration. Areas with relatively high and high degrees of ecological restoration were mainly distributed in areas with an average annual temperature greater than 0°C and annual precipitation greater than 300 mm. Therefore, the limitations associated with climate conditions require consideration during the implementation of national ecological projects. The implementation of combined measures should be emphasized, and the benefits of ecological investment funds should be maximized.

Rural decline is a global issue accompanied by the regional imbalanced development and dysfunction in rural areas. Coordinated interaction among production, living, and ecological functions is essential for the sustainability of rural regional systems. Based on the framework of “element-structure-function”, an indicator system was constructed to explore the evolution characteristics and driving factors of rural regional functions in the farming-pastoral ecotone of northern China (FPENC) using the models of entropy-based TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution), revised vertical and horizontal comparison, and GeoDetector. The results indicated a gradual synergy of rural production, living, and ecological functions during the period 2000-2020. Improvements were observed in production and living functions, and higher ecological function was found in Hebei, Inner Mongolia, Liaoning, and Shaanxi. However, conflicts between ecological function and production and living functions were evident in Shanxi, Gansu, and Ningxia. The spatial structure played a dominant role in determining rural production, living, and ecological functions, with ratios of 38%, 56%, and 84%, respectively. Land and industry emerged as the main driving factors influencing the evolution of rural regional functions. Notably, combined interactions of rural permanent population and primary industry output (0.73), grassland area and tertiary industry output (0.58), and forest area and tertiary industry output (0.72) were responsible for the changes observed in rural production, living, and ecological functions, respectively. The findings suggest that achieving coordinated development of rural regional functions can be accomplished by establishing differentiated rural sustainable development strategies that consider the coupling of population, land, and industry in FPENC.

Urban shrinkage is the process of population loss, industrial and functional decline, and eco-environmental deterioration due to various natural and human factors that occur once a city’s development reaches a certain point. It is an external manifestation of positive or negative changes in an urban economy, society, culture, resource use, and sustainability. Urban shrinkage is a new feature of global urbanization as well as a frontier of international and Chinese research. It has attracted widespread attention from academics in China and overseas, becoming an emerging trend that has spread from developed countries to underdeveloped ones. Research on and responses to urban shrinkage have also become new tasks of China’s new urbanization strategy. Our review of the existing literature reveals that there are significant temporal and spatial differences in research by Chinese and overseas scholars on urban shrinkage. Urban shrinkage studies have paid scant attention to interactions with the eco-environment, with analyses of urban shrinkage mechanisms and factors largely focusing on economic and social development factors; and urban shrinkage index analyses have tended not to include eco-environmental quality and environmental pollution indicators. The key tasks for future urban shrinkage research include the following: to conduct in-depth research on the mechanisms and driving factors of urban shrinkage to reveal the essence of urban shrinkage; to discover the principles behind interactions between urban shrinkage and the eco-environment, as well as to analyze the eco-environmental effects of urban shrinkage; to construct an index system for evaluating the extent, monitoring and providing warnings of, and containing urban shrinkage; and to research urban shrinkage coping strategies under different circumstances and carry out experiments and demonstrations according to local conditions.