Based on historical documents, modern survey and statistics, as well as the result of predecessor studies, the trend and main process of forest dynamics are recognized. The forest area and forest coverage rates for each province of China from 1700 to 1949 are es-timated backward by every 50 years. Linking the result with modern National Forest Inventory data, the spatial-temporal dynamics of Chinese forest in recent 300 years (AD 1700–1998) is quantitatively analyzed. The study shows that in recent 300 years, the forest area in current territory of China has declined by 0.95×10⁸ hm² (or 9.2% of the coverage rate) in total, with a trend of decrease and recovery. Before the 1960s, there was a trend of accelerated de-scending. The forest area was reduced by 1.66×10⁸ hm² (or 17% of the coverage rate) in 260 years. While after the 1960s, there has been a rapid increase. The forest area increased by 0.7×10⁸ hm² (or 8% of the coverage rate) in 40 years. The study also shows that there is a significant spatial difference in the dynamics of forest. The amplitudes of increasing and de-creasing in western China are both smaller than the ones in eastern China. During the rapid declining period from 1700 to 1949, the most serious decrease appeared in the Northeast, the Southwest and the Southeast, where the coverage rate in most provinces dropped over 20%. In Heilongjiang Province, the coverage rate dropped by 50%. In Jilin Province, it dropped by 36%. In Sichuan Province and Chongqing Municipality, it dropped by 42%. In Yunnan Prov-ince, it dropped by 35%. During the recovery period 1949–1998, the western provinces, mu-nicipality and autonomous regions, including Ningxia, Gansu, Inner Mongolia, Si-chuan–Chongqing, Yunnan, Tibet, Xinjiang and Qinghai, etc, the increase rates are all below 5%, while the eastern provinces, municipality and autonomous regions (except Heilongjiang, Hubei, Jiangsu–Shanghai) have achieved an increase over 5%, among which the Guang-dong–Hainan, Guangxi, Anhui, Beijing–Tianjin–Hebei, Shandong, Henan, Zhejiang, and Fu-jian have an increase over 10%.

Detailed analysis of Land Use/Land Cover (LULC) using remote sensing data in complex irrigated basins provides complete profile for better water resource management and planning. Using remote sensing data, this study provides detailed land use maps of the Lower Chenab Canal irrigated region of Pakistan from 2005 to 2012 for LULC change detection. Major crop types are demarcated by identifying temporal profiles of NDVI using MODIS 250 m × 250 m spatial resolution data. Wheat and rice are found to be major crops in rabi and kharif seasons, respectively. Accuracy assessment of prepared maps is performed using three different techniques: error matrix approach, comparison with ancillary data and with previous study. Producer and user accuracies for each class are calculated along with kappa coefficients (K). The average overall accuracies for rabi and kharif are 82.83% and 78.21%, respectively. Producer and user accuracies for individual class range respectively between 72.5% to 77% and 70.1% to 84.3% for rabi and 76.6% to 90.2% and 72% to 84.7% for kharif. The K values range between 0.66 to 0.77 for rabi with average of 0.73, and from 0.69 to 0.74 with average of 0.71 for kharif. LULC change detection indicates that wheat and rice have less volatility of change in comparison with both rabi and kharif fodders. Transformation between cotton and rice is less common due to their completely different cropping conditions. Results of spatial and temporal LULC distributions and their seasonal variations provide useful insights for establishing realistic LULC scenarios for hydrological studies.

Ancient Chinese cartography dates back to the Western Jin Dynasty in the third century. Cartography was initiated during this period by Pei Xiu, a minister and cartographic expert, who suggested six principles of cartography. Pei Xiu, who is known as the father of Chinese cartography, oversaw the completion of the “Yu Gong Regional Maps”, along with 18 articles and the “Terrain Fangzhang Map” (AD 224-271). This led to a number of subsequent cartographic initiatives including the “Wooden Fangzhang Map” (an administrative map) which was completed by Xie Zhuang, a minister during the Southern Dynasties (AD 502-557), “Haineihuayi Tu” (Map of China and its neighbouring countries) (AD 730-805), drawn by Jia Dan, a cartographer of the Tang Dynasty, and “Shouling Tu” (an administrative map, AD 1031-1095), drawn by Shen Kuo, a scientist during the Northern Song Dynasty. Throughout the 16th century, ancient Chinese cartography developed continuously and cumulatively, and formed the specific characteristics of China ancient cartography. Although Western latitude-based and longitude-based mapping techniques introduced to China in AD 1460, the theories and methods of Chinese and Western mapping systems co-existed for over 400 years. The cultural heritage of Chinese cartography can be seen in many famous ancient Chinese maps, including astronomical figures and atlases (world, Chinese, regional, military, water conservancy, historical, and educational maps), charts, and maps of scenic spots. These have hitherto been kept in well-known archives and institutions across the world. They form an important part of the global cultural heritage of ancient maps and cartography. Given their high cultural value, these maps remain an important point of study. This paper provides a preliminary discussion on the rarity, application, and the historical, scientific, and artistic value of ancient Chinese maps.

Ecosystem services are substantial elements for human society. The central challenge to meet the human needs from ecosystems while sustain the Earth’s life support systems makes it urgent to enhance efficient natural resource management for sustainable ecological and socioeconomic development. Trade-off analysis of ecosystem services can help to identify optimal decision points to balance the costs and benefits of the diverse human uses of ecosystems. In this sense, the aim of this paper is to provide key insights into ecosystem services trade-off analysis at different scales from a land use perspective, by comprehensively reviewing the trade-offs analysis tools and approaches that addressed in ecology, economics and other fields. The review will significantly contribute to future research on trade-off analysis to avoid inferior management options and offer a win-win solution based on comprehensive and efficient planning for interacting multiple ecosystem services.

In this paper, we compared the concept of agricultural drought and its relationship with other types of droughts and reviewed the progress of research on agricultural drought monitoring indices on the basis of station data and remote sensing. Applicability and limitations of different drought monitoring indices were also compared. Meanwhile, development history and the latest progress in agricultural drought monitoring were evaluated through statistics and document comparison, suggesting a transformation in agricultural drought monitoring from traditional single meteorological monitoring indices to meteorology and remote sensing-integrated monitoring indices. Finally, an analysis of current challenges in agricultural drought monitoring revealed future research prospects for agricultural drought monitoring, such as investigating the mechanism underlying agricultural drought, identifying factors that influence agricultural drought, developing multi-spatiotemporal scales models for agricultural drought monitoring, coupling qualitative and quantitative agricultural drought evaluation models, and improving the application levels of remote sensing data in agricultural drought monitoring.

Urban agglomerations are an inevitable outcome of China’s new national industrialization and urbanization reaching relatively advanced stages of development over the past 30 years. In the early 2000s, urban agglomerations became new geographical units for participating in global competition and the international division of labor, and China has spent the past decade promoting them as the main spaces for pushing forward its new form of urbanization. The convening of the first Central Work Conference on Urbanization and the National New-type Urbanization Plan (2014-2020) further defined the status of urban agglomerations as the main players in promoting China’s new type of national urbanization. Nevertheless, urban agglomerations remain a weak link in Chinese academia and are in urgent need of study. Only 19 articles on the theme of urban agglomerations were published in the journal Acta Geographica Sinica between 1934 and 2013, accounting for only 0.55% of all articles written during that period. Not only are there very few, they have also all been published within a relatively short period of time, with the first having been published only 10 years ago. The studies are also concentrated among only a few authors and institutions, and research is aimed at national requirements but is rather divergent. Even so, some studies on urban agglomerations have played a leading role and made important contributions to dictating the overall formation of urban agglomerations nationwide. Specifically, a proposed spatial pattern for urban agglomerations formed the basic framework for the spatial structure of China’s urban agglomerations and guided the government to make urban agglomerations the main urban pattern when promoting the new type of urbanization; proposed standards and technologies for identifying the spatial dimensions of urban agglomerations played an important role in defining the scope of national urban agglomerations; a series of studies in the area of urban agglomerations spurred more in-depth and practical studies in the field; and studies on issues related to the formation and growth of urban agglomerations provided warnings on the future selection and development of urban agglomerations. Taking the progress and results of these studies as a foundation, the foci of selecting and developing urban agglomerations in China are as follows: to be problem-oriented and profoundly reflect on and review new problems exposed in the selection and development of urban agglomerations; to concentrate on urban agglomerations and lay importance on the formation of a new “5+9+6” spatial structure for China’s urban agglomerations; to rely on urban agglomerations and promote the formation of a new pattern of national urbanization along the main axes highlighted by urban agglomerations; to be guided by national strategic demand and continue to deepen understanding of major scientific issues in the course of the formation and development of urban agglomerations, including studying the resource and environmental effects of high-density urban agglomerations, scientifically examining resource and environmental carrying capacities of high-density urban agglomerations, creating new management systems and government coordination mechanisms for the formation and development of urban agglomerations, studying the establishment of public finance systems and public finance reserve mechanisms for urban agglomerations, and studying and formulating technical specifications for urban agglomeration planning and standards for delineating urban agglomeration boundaries.

Land use/cover change is an important theme on the impacts of human activities on the earth systems and global environmental change. National land-use changes of China during 2010-2015 were acquired by the digital interpretation method using the high-resolution remotely sensed images, e.g. the Landsat 8 OLI, GF-2 remote sensing images. The spatiotemporal characteristics of land-use changes across China during 2010-2015 were revealed by the indexes of dynamic degree model, annual land-use changes ratio etc. The results indicated that the built-up land increased by 24.6×10³ km² while the cropland decreased by 4.9×10³ km², and the total area of woodland and grassland decreased by 16.4×10³ km². The spatial pattern of land-use changes in China during 2010-2015 was concordant with that of the period 2000-2010. Specially, new characteristics of land-use changes emerged in different regions of China in 2010-2015. The built-up land in eastern China expanded continually, and the total area of cropland decreased, both at decreasing rates. The rates of built-up land expansion and cropland shrinkage were accelerated in central China. The rates of built-up land expansion and cropland growth increased in western China, while the decreasing rate of woodland and grassland accelerated. In northeastern China, built-up land expansion slowed continually, and cropland area increased slightly accompanied by the conversions between paddy land and dry land. Besides, woodland and grassland area decreased in northeastern China. The characteristics of land-use changes in eastern China were essentially consistent with the spatial govern and control requirements of the optimal development zones and key development zones according to the Major Function-oriented Zones Planning implemented during the 12th Five-Year Plan (2011-2015). It was a serious challenge for the central government of China to effectively protect the reasonable layout of land use types dominated with the key ecological function zones and agricultural production zones in central and western China. Furthermore, the local governments should take effective measures to strengthen the management of territorial development in future.

Actual evapotranspiration is a key process of hydrological cycle and a sole term that links land surface water balance and land surface energy balance.Evapotranspiration plays a key role in simulating hydrological effect of climate change,and a review of evapotranspiration estimation methods in hydrological models is of vital importance.This paper firstly summarizes the evapotranspiration estimation methods applied in hydrological models and then classifies them into the integrated converting methods and the classification gathering methods by their mechanism.Integrated converting methods are usually used in hydrological models and two differences exist among them:one is in the potential evaporation estimation methods,while the other in the function for defining relationship between potential evaporation and actual evapotranspiration.Due to the higher information requirements of the Penman-Monteith method and the existing data uncertainty,simplified empirical methods for calculating potential and actual evapotranspiration are widely used in hydrological models. Different evapotranspiration calculation methods are used depending on the complexity of the hydrological model,and importance and difficulty in the selection of the most suitable evapotranspiration methods is discussed.Finally,this paper points out the prospective development trends of the evapotranspiration estimating methods in hydrological modeling.

With the environmental deterioration caused by the advance of climate change, soil salinization is a serious and growing global problem. Currently about 7% of the world's land surface is threatened by salinization. China is a country whose soils are severely affected by this problem, which, due to its extensive area, and wide distribution poses a serious threat to regional agricultural development. In this review, we summarize the framework for soil salinization research in China over the past 70 years, assess the weaknesses of existing research in both a domestic and international context, highlight the trends and key findings of global research about saline soils over the past 30 years, and propose six major fields and directions for future research on saline soil.

This study was performed at three eutrophic rivers in Southeast China aiming to determine the magnitude and patterns of dissolved N₂O concentrations and fluxes over a seasonal (in 2009) and diurnal (24 h) temporal scale. The results showed that N₂O concentrations varied from 0.28 to 0.38 (mean 0.32±0.04), 0.29 to 0.46 (mean 0.37±0.07), and 2.07 to 3.47 (mean 2.84±0.63) μg N-N₂O L^-1 in the Fengle, Hangbu and Nanfei rivers, respectively, in the diurnal study performed during the summer of 2008. The study found that mean N₂O concentration and estimated N₂O flux (67.89 ± 6.71 μg N-N₂O m^-2 h^-1) measured from the Nanfei River with serious urban wastewater pollution was significantly higher than those from the Fengle and the Hangbu Rivers with agricultural runoff. In addition, the seasonal study during June and December of 2009 also showed that the mean N₂O concentration (10.59±14.67 μg N-N₂O L^-1) and flux (236.87±449.74 μg N-N₂O m^-2 h^-1) observed from the Nanfei River were significantly higher than those from the other two rivers. Our study demonstrated both N₂O concentrations and fluxes exhibited seasonal and diurnal fluctuations. Over three consecutive days during the summer of 2008, N₂O accumulation rates varied within the range of 3.91-7.21, 2.76-15.71, and 3.23-30.03 μg N-N₂O m^-2 h^-1 for the Fengle, Hangbu and Nanfei Rivers, respectively, and exponentially decreased with time.

Since the 1950s, noteworthy farmland abandonment has been occurring in many developed countries and some developing countries. This global land use phenomenon has fundamentally altered extensive rural landscapes. A review of global farmland abandonment under the headings of “land use change - driving mechanisms - impacts and consequences - policy responses” found the following: (1) Farmland abandonment has occurred primarily in developed countries in Europe and North America, but the extent of abandonment has varied significantly. (2) Changing socio-economic factors were the primary driving forces for the farmland abandonment. And land marginalization was the fundamental cause, which was due to the drastic increase of farming opportunity cost, while the direct factor for abandonment was the shrink of agricultural labor forces. (3) Whether to abandon, to what extent and its spatial distributions were finally dependent on integrated effect from the physical conditions, laborer attributes, farming and regional socio-economic conditions at the village, household and parcel scales. With the exception of Eastern Europe, farmland abandonment was more likely to occur in mountainous and hilly areas, due to their unfavorable farming conditions. (4) A study of farmland abandonment should focus on its ecological and environmental effects, while which is more positive or more negative are still in dispute. (5) Increasing agricultural subsidies will be conductive to slowing the rate of farmland abandonment, but this is not the only measure that needs to be implemented.

Due to China’s rapid urbanization, there is a high probability that the rate of abandonment will increase in the near future. However, very little research has focused on this rapid land-use trend in China, and, as a result, there is an inadequate understanding of the dynamic mechanisms and consequences of this phenomenon. This paper concludes by suggesting some future directions for further research in China. These directions include monitoring regional and national abandonment dynamics, analyzing trends, assessing the risks and socio-economic effects of farmland abandonment, and informing policy making.

Hydrological processes were compared, with and without the influence of precipitation on discharge, to identify the differences between glacierized and non-glacierized catchments in the Urumqi River source region, on the northern slope of the eastern Tianshan Mountains, during the melting season (May-September) in 2011. The study was based on hydrological data observed at 10-min intervals, meteorological data observed at 15-min intervals, and glacier melting and snow observations from the Empty Cirque, Zongkong, and Urumqi Glacier No.1 gauging stations. The results indicated that the discharge differed markedly among the three gauging stations. The daily discharge was more than the nightly discharge at the Glacier No.1 gauging station, which contrasted with the patterns observed at the Zongkong and Empty Cirque gauging stations. There was a clear daily variation in the discharge at the three gauging stations, with differences in the magnitude and duration of the peak discharge. When precipitation was not considered, the time-lags between the maximum discharge and the highest temperature were 1-3 h, 10-16 h, and 5-11 h at the Glacier No.1, Empty Cirque, and Zongkong gauging stations, respectively. When precipitation was taken into consideration, the corresponding time-lags were 0-1 h, 13 h, and 6-7 h, respectively. Therefore, the duration from the generation of discharge to confluence was the shortest in the glacierized catchment and the longest in the catchment where was mainly covered by snow. It was also shown that the hydrological process from the generation of discharge to confluence shortened when precipitation was considered. The factors influencing changes in the discharge among the three gauging stations were different. For Glacier No.1 station, the discharge was mainly controlled by heat conditions in the glacierized region, and the discharge displayed an accelerated growth when the temperature exceeded 5°C in the melt season. It was found that the englacial and subglacial drainage channel of Glacier No.1 had become simpler during the past 20 years. Its weaker retardance and storage of glacier melting water resulted in rapid discharge confluence. It was also shown that the discharge curve and the time-lag between the maximum discharge and the highest temperature could be used to reveal the evolution of the drainage system and the process of glacier and snow melting at different levels of glacier coverage.

Rural tourism has become an important driving force of rural urbanization in China. As the main reception base and important tourism attraction, tourism village is the core element of the tourism destination system. Integrating the method of PRA (Participatory Rural Assessment), GIS technology and high-resolution remote sensing images, this study aims to analyze the spatial morphology evolution of rural settlements induced by tourism through a comparative study of three tourism villages in Yesanpo tourism area. The results suggest the emergence of a “core-periphery” pattern of the spatial evolution of rural settlements. The closer to the core scenic spot, the higher degree of land-use intensity the village shows, as well as the more mature tourism function and greater change in landscape pattern. In particular, Gougezhuang shows an increase of the floor area ratio from 0.17 to 0.44, with the most mature tourism function and the lowest authenticity index of 0.448. Liujiahe has gone through the largest increase in construction land area from 17.3564 ha to 34.1128 ha, with moderately mature tourism function and relatively stable authenticity index of 0.566. Shangzhuang has the lowest construction land scale and intensity, with the poorest tourism function and most well-preserved landscape authenticity index of 0.942. Overall, in terms of the spatial morphology, the three villages show the characteristics of “modern town”, “semi-urbanization” and “traditional village” respectively, in corresponding to three land development types: “intensive reconstruction type”, “enclave extension type” and “in situ utilization type”. The spatial evolution patterns of these three villages imply the spatial characteristics of the touristization of traditional villages in different stages, and also have great representative value for the management of rural settlements in tourism areas in China.

This study analyzed the spatial and temporal variations in the Normalized Difference Vegetation Index (NDVI) on the Mongolian Plateau from 1982-2013 using Global Inventory Modeling and Mapping Studies (GIMMS) NDVI3g data and explored the effects of climate factors and human activities on vegetation. The results indicate that NDVI has slight upward trend in the Mongolian Plateau over the last 32 years. The area in which NDVI increased was much larger than that in which it decreased. Increased NDVI was primarily distributed in the southern part of the plateau, especially in the agro-pastoral ecotone of Inner Mongolia. Improvement in the vegetative cover is predicted for a larger area compared to that in which degradation is predicted based on Hurst exponent analysis. The NDVI-indicated vegetation growth in the Mongolian Plateau is a combined result of climate variations and human activities. Specifically, the precipitation has been the dominant factor and the recent human effort in protecting the ecological environments has left readily detectable imprints in the NDVI data series.

China has been experiencing an unprecedented urbanization process. In 2011, China’s urban population reached 691 million with an urbanization rate of 51.27%. Urbanization level is expected to increase to 70% in China in 2030, reflecting the projection that nearly 300 million people would migrate from rural areas to urban areas over this period. At the same time, the total fertility rate of China’s population is declining due to the combined effect of economic growth, environmental carrying capacity, and modern social consciousness. The Chinese government has loosened its “one-child policy” gradually by allowing childbearing couples to have the second child as long as either of them is from a one-child family. In such rapidly developing country, the natural growth and spatial migration will consistently reshape spatial pattern of population. An accurate prediction of the future spatial pattern of population and its evolution trend are critical to key policy-making processes and spatial planning in China including urbanization, land use development, ecological conservation and environmental protection. In this paper, a top-down method is developed to project the spatial distribution of China’s future population with considerations of both natural population growth at provincial level and the provincial migration from 2010 to 2050. Building on this, the spatial pattern and evolution trend of Chinese provincial population are analyzed. The results suggested that the overall spatial pattern of Chinese population will be unlikely changed in next four decades, with the east area having the highest population density and followed by central area, northeast and west area. Four provinces in the east, Shanghai, Beijing, Tianjin and Jiangsu, will remain the top in terms of population density in China, and Xinjiang, Qinghai and Tibet will continue to have the lowest density of population. We introduced an index system to classify the Chinese provinces into three categories in terms of provincial population densities: Fast Changing Populated Region (FCPR), Low Changing Populated Region (LCPR) and Inactive Populated Region (IPR). In the FCPR, China’s population is projected to continue to concentrate in net immigration leading type (NILT) area where receives nearly 99% of new accumulated floating population. Population densities of Shanghai, Beijing, Zhejiang will peak in 2030, while the population density in Guangdong will keep increasing until 2035. Net emigration leading type (NELT) area will account for 75% of emigration population, including Henan, Anhui, Chongqing and Hubei. Natural growth will play a dominant role in natural growth leading type area, such as Liaoning and Shandong, because there will be few emigration population. Due to the large amount of moving-out labors and gradually declining fertility rates, population density of the LCPR region exhibits a downward trend, except for Fujian and Hainan. The majority of the western provinces will be likely to remain relatively low population density, with an average value of no more than 100 persons per km².

China is distinguished by a prominent monsoonal climate in the east of the country, a continental arid climate in the northwest and a highland cold climate on the Qinghai-Tibet Plateau. Because of the long history of Chinese civilization, there are abundant and well-dated documentary records for climate variation over the whole of the country as well as many natural archives (e.g., tree-rings, ice cores, stalagmites, varved lake sediments and corals) that enable high-resolution paleoclimatic reconstruction. In this paper, we review recent advances in the reconstruction of climate and extreme events over the last 2000 years in China. In the last 10 years, many new reconstructions, based on multi-proxies with wide spatial coverage, have been published in China. These reconstructions enable us to understand the characteristics of climate change across the country as well as the uncertainties of regional reconstructions. Synthesized reconstructed temperature results show that warm intervals over the last 2000 years occurred in AD 1-200, AD 551-760, AD 951-1320, and after AD 1921, and also show that cold intervals were in AD 201-350, AD 441-530, AD 781-950, and AD 1321-1920. Extreme cold winters, seen between 1500 and 1900, were more frequent than those after 1950. The intensity of regional heat waves, in the context of recent global warming, may not in fact exceed natural climate variability seen over the last 2000 years. In the eastern monsoonal region of China, decadal, multi-decadal and centennial oscillations are seen in rainfall variability. While the ensemble mean for drought/flood spatial patterns across all cold periods shows a meridional distribution, there is a tri-pole pattern with respect to droughts south of 25°N, floods between 25° and 30°N, and droughts north of 30°N for all warm periods. Data show that extreme drought events were most frequent in the periods AD 301-400, AD 751-800, AD 1051-1150, AD 1501-1550, and AD 1601-1650, while extreme flood events were frequent in the periods AD 101-150, AD 251-300, AD 951-1000, AD 1701-1750, AD 1801-1850, and AD 1901-1950. Between AD 1551-1600, extreme droughts and flood events occurred frequently. In arid northwest China, climate was characterized by dry conditions in AD 1000-1350, wet conditions in AD 1500-1850, and has tended to be wet over recent decades. On the northeastern Qinghai-Tibet Plateau, centennial-scale oscillations in precipitation have occurred over the last 1000 years, interrupted by several multi- decadal-scale severe drought events. Of these, the most severe were in the 1480s and 1710s. In southwest China, extreme droughts as severe as those seen in Sichuan and Chongqing in 2006 are known to have occurred during historical times.

Based on the data from the Cost-benefit Data of Farm Produce and the China Agricultural Yearbook, this paper divided the intensity of cultivated land use into labor intensity and capital intensity, and then analyzed their temporal and spatial change at both national and provincial levels between 1980 and 2006. The results showed that: (1) At the national level, labor intensity on food produce decreased from 398.5 day/ha in 1980 to 130.25 day/ha in 2006; and a continuous decrease with a steep decline between 1980 and 1986, a slower decline from 1987 to 1996, and another steep decline from 1997 to 2006. On the contrary, capital intensity shows an increasing trend since 1980. As to the internal composition of capital intensity, the proportion of seed, chemical fertilizer and pesticide input decreased from 90.36% to 73.44% and the proportion of machinery increased from 9.64% to 26.56%. The less emphasis on yield-increasing input and more emphasis on labor-saving input are the main reasons for a slow increase of yield per unit area after 1996. (2) At the provincial level, the developed areas have lower labor intensity and higher capital intensity. The less developed ones have higher labor intensity but lower capital intensity. From the viewpoint of the internal composition of capital intensity, labor-saving input accounts for more proportion in the developed areas than that of other areas. The main reason is that in these developed areas, labor input has become a constraint factor in food production as more and more labors engaged in off-farm work. Farmers increase the labor-saving input for higher labor productivity. However, in the less developed areas, the major constraint is the shortage of capital; food production is still depending on labor and yield-increasing inputs.

Struggling for supremacy between great powers and the rise or fall and regime change of great powers are all subject to the Geopolitical Law. Geographers should keep in step with the times, accurately grasp the national interests, and seize the opportunity to contribute to the great rejuvenation of our nation. However, due to lack of criticism on the history and philosophy of geopolitics, we can neither accurately understand the geopolitical theory, nor effectively put the geopolitical theory into practice. This paper introduces the development of critical geopolitics, summarizes the three characteristics of critical geopolitics, and interprets the four classical geopolitical theories accordingly. In order to simplify the interpretation process, this paper firstly presents an analytical framework for interpretation of four classical geopolitical theories; secondly, focuses on interpretation of “The Geographical Pivot of History” put forward by Mackinder according to the analytical framework; finally, critically summarizes the four classical geopolitical theories. Through the critical interpretation, this paper draws a conclusion that there are the scientific, hypothetical and conceptual classical geopolitical theories. The construction of classical geopolitical theories is based on the international geopolitical structure, spatial distribution of national interests and inter-state spatial conflict, in order to show the identity of theoretical constructor, so as to reflect the historicality, sociality, situationality and geographical knowledge - power structure of geopolitical theories.

GIMMS (Global Inventory Modeling and Mapping Studies) NDVI (Normalised Difference Vegetation Index) from 1982 to 2006 and MODIS (Moderate Resolution Imaging Spectroradiometer) NDVI from 2001 to 2010 were blended to extract the grass coverage and analyze its spatial pattern. The response of grass coverage to climatic variations at annual and monthly time scales was analyzed. Grass coverage distribution had increased from northwest to southeast across China. During 1982-2010, the mean nationwide grass coverage was 34% but exhibited apparent spatial heterogeneity, being the highest (61.4%) in slope grasslands and the lowest (17.1%) in desert grasslands. There was a slight increase of the grass coverage with a rate of 0.17% per year. Increase in slope grasslands coverage was as high as 0.27% per year, while in the plain grasslands and meadows the grass coverage increase was the lowest (being 0.11% per year and 0.1% per year, respectively). Across China, the grass coverage with extremely significant increase (P<0.01) and significant increase (P<0.05) accounted for 46.03% and 11% of the total grassland area, respectively, while those with extremely significant and significant decrease accounted for only 4.1% and 3.24%, respectively. At the annual time scale, there are no significant correlations between grass coverage and annual mean temperature and precipitation. However, the grass coverage was somewhat affected by temperature in alpine and sub-alpine grassland, alpine and sub-alpine meadow, slope grassland and meadow, while grass coverage in desert grassland and plain grassland was more affected by precipitation. At the monthly time-scale, there are significant correlations between grass coverage with both temperature and precipitation, indicating that the grass coverage is more affected by seasonal fluctuations of hydrothermal conditions. Additionally, there is one-month time lag-effect between grass coverage and climate factors for each grassland types.

Cyberspace is a new spatial realm of activities involving both humans and data, and it has become a cornerstone of the national security of every country. A scientific understanding of cyberspace is essential for analyzing cyberspace incidents, governing cyberspace and ensuring cybersecurity. Accordingly, cyberspace has become a new field of geographic research in the Information Age. Against the backdrop of fierce international competition over cyberspace, there has been an urgent need to strengthen research between the fields of geography and cybersecurity, leading to theoretical and methodological innovations that have created the sub-discipline of cyberspace geography. Cyberspace geography (CG) extends geographical research from real spaces to virtual spaces, and its theoretical basis is the evolution of the traditional geographic human-land relationship theory into a human-land-network relationship theory. CG research includes constructing mapping relationships between cyberspace and real space, redefining the traditional geographic concepts of distance and regions for cyberspace, creating a language, models and methodologies for visually representing cyberspace, drawing maps of cyberspace, and researching the principles governing the evolution of cyberspace structures and behaviors. The technical methods of CG include collecting and integrating data on elements of cyberspace, visually representing cyberspace and conducting cyberspace situational and behavioral intelligence awareness. Intelligence awareness covers cyberspace situational status assessments, network hotspot event dissemination and traceability analysis, and network event situational simulations and risk predictions. CG offers new perspectives on the scientific understanding of cyberspace, the development of disciplines such as geography and cybersecurity, and the creation of national cybersecurity prevention and control mechanisms as well as a community of common future in cyberspace.

Modern physical geography in China grew from Chinese traditional geography and has been profoundly influenced by the geographical disciplines of Euro-America and Russia. Since the 1950s, integrated studies of physical geography in China have made remarkable progress in the fields of comprehensive physical geographical regionalization, land studies, landscape ecology, and land surface geographical processes. During the past few decades, under the background of global change and rapid socio-economic transformation, a series of environmental and resources problems have boomed in China. To solve these problems and promote the development of integrated studies of physical geography, the following issues were proposed as research priorities: (1) coupling of land surface patterns and processes; (2) integrated research on regional responses and adaptation to global change; (3) analysis of human dimensions of the earth system; (4) ecosystem service research from a geographical perspective; (5) integration of multi-source data and model development; (6) integrated studies on unique geographical units; and (7) important global issues and relevant international programs.

Accompanying the rapid growth of China’s population and economy, energy consumption and carbon emission increased significantly from 1978 to 2012. China is now the largest energy consumer and CO₂ emitter of the world, leading to much interest in researches on the nexus between energy consumption, carbon emissions and low-carbon economy. This article presents the domestic Chinese studies on this hotpot issue, and we obtain the following findings. First, most research fields involve geography, ecology and resource economics, and research contents contained some analysis of current situation, factors decomposition, predictive analysis and the introduction of methods and models. Second, there exists an inverted “U-shaped” curve connection between carbon emission, energy consumption and economic development. Energy consumption in China will be in a low-speed growth after 2035 and it is expected to peak between 6.19-12.13 billion TCE in 2050. China’s carbon emissions are expected to peak in 2035, or during 2020 to 2045, and the optimal range of carbon emissions is between 2.4-3.3 PgC/year (1 PgC=1 billion tons C) in 2050. Third, future research should be focused on global carbon trading, regional carbon flows, reforming the current energy structure, reducing energy consumption and innovating the low-carbon economic theory, as well as establishing a comprehensive theoretical system of energy consumption, carbon emissions and low-carbon economy.

The objective of this study was to investigate the concentration and spatial distribution patterns of 9 potentially toxic heavy metal elements (As, Cd, Co, Cr, Pb, Cu, Zn, Mn, and Ni) in road dust in the Bayan Obo Mining Region in Inner Mongolia, China. Contamination levels were evaluated using the geoaccumulation index and the enrichment factor. Human health risks for each heavy metal element were assessed using a human exposure model. Results showed that the dust contained significantly elevated heavy metal elements concentrations compared with the background soil. The spatial distribution pattern of all tested metals except for As coincided with the locations of industrial areas while the spatial distribution of As was associated with domestic sources. The contamination evaluation indicated that Cd, Pb, and Mn in road dust mainly originated from anthropogenic sources with a rating of “heavily polluted” to “extremely polluted,” whereas the remaining metals originated from both natural and anthropogenic sources with a level of “moderately polluted”. The non-cancer health risk assessment showed that ingestion was the primary exposure route for all metals in the road dust and that Mn, Cr, Pb, and As were the main contributors to non-cancer risks in both children and adults. Higher HI values were calculated for children (HI=1.89), indicating that children will likely experience higher health risks compared with adults (HI=0.23). The cancer risk assessment showed that Cr was the main contributor, with cancer risks which were 2-3 orders of magnitude higher than those for other metals. Taken in concert, the non-cancer risks posed by all studied heavy metal elements and the cancer risks posed by As, Co, Cr, Cd, and Ni to both children and adults in Bayan Obo Mining Region fell within the acceptable range.

China has witnessed unprecedented urbanization over the past decades. The rapid expansion of urban population has been dominantly contributed by the floating population from rural areas, of which the spatiotemporal patterns, driving forces, and multidimensional effects are scrutinized and evaluated in this study by using the latest national censuses conducted in 2000 and 2010. Analysis based on the county-level data comes to conclusions as follows. The spatial pattern of floating population has remained stable over the first decade of the new century. The top 1% cities with the largest floating population received 45.5% of all migrants in China. As the rapid development of mega-city regions, the coastal concentration areas of floating population tended to geographically united as a whole, whereas the spatial distribution of migrants within each region varied significantly. The migrant concentration area in the Yangtze River Delta was the largest and its expansion was also the most salient. However, the floating population has growingly moved into provincial capitals and other big cities in the inland regions and its gravity center has moved northward for around 110 km during the study period. The spatial pattern of floating population has been formed jointly by the state and market forces in transitional China and the impacts of state forces have been surpassed by those of market forces in the country as a whole. The attractiveness of coastal cities and counties to the floating population comes mainly from the nonagricultural employment opportunities and public services, reflecting that long-distance and long-term migrants have moved coastward not only to gain employment but also to enjoy city life. By contrast, in the central and western regions, places with a higher economic development level and at a higher administrative level are more attractive to floating populations, demonstrating that the state remains to play an important role in allocating economic resources and promoting regional development in inland China. As the main body of new urban residents, the floating population has contributed substantially to the elevation of the urbanization levels of migrant-sending and -receiving places, by 20.0% and 49.5% respectively. Compared with extensively investigated interprovincial migrants, intra-provincial migrants have higher intention and ability to permanently live in cities and thus might become the main force of China’s urbanization in the coming decades. The internal migration has also reshaped China’s urban system in terms of its hierarchical organization and spatial structure.

Optimizing rural settlements is an important measure to cope with rural decline, and improve the quality of rural life and attractions. This study introduces the "life quality theory". Based on the mechanisms governing the interactions between rural settlement space and life quality, this study examines how to optimize the spatial organization of rural settlements. Three aspects are evaluated - the integration of rural settlement spatial functions, optimization of spatial structure, and regulation of spatial scale - with the objective of building an optimization mode and framework for the spatial organization of rural settlements with high life quality. Our results suggest the following: (1) The settlement is the spatial carrier of life quality, which is an essential settlement component, and these two aspects influence and improve each other. Therefore, reasonable rural settlement space is an important precondition for higher life quality. (2) The spatial function types of rural settlements can be divided into those that maintain livelihoods, develop industry, and upgrade life quality. Optimizing spatial organization of rural settlements based on life quality requires promoting the maintenance of livelihood, integration of industrial development, and implantation in quality improvement. (3) There are two important components of optimizing the spatial organization of rural settlements. One is promoting the organic concentration of living, agricultural, and industrial spaces, the reasonable distribution of social intercourse, recreational, and services spaces, and the organic balance of living, production, and ecological spaces, so as to reasonably optimize the combination of internal spatial types in settlements. The other is forming a functional structure level of a “comprehensive village-featured village” and building spatial organization settlement modes connected by rural roads by relocating and adjusting the function of villages. These changes would require the destruction of underdeveloped villages, retaining normal villages, enlarging important villages, and constructing new villages. (4) As an ideal mode for optimizing rural settlements space based on life quality, the Rural Road-Oriented Development Model (RROD model) should be built at a rational scale for unit settlement and distance between settlements, leading to a fully functional RROD system with rational structure, auxiliary facility, and well-organized distribution.

Lateral migration of the Bhagirathi River temporally creates unavoidable geomorphic hazards in West Bengal, India. The Bhagirathi River flows SW for ~67.30 km between the confluence point of Ajay and Jalangi rivers in East Burdwan and Nadia districts of West Bengal. The course of Bhagirathi is notably migration prone and cultivates problematic changes along its course over time. In the study, we have looked into its migration tendency and unpredictability for past 238 years and then predicted the lateral shifting of river centerline using temporal satellite imageries - Landsat-5 (TM) of 1987 (8, December), 1995 (28, January), 2005 (7, January) and LISS-IV satellite imagery (2017, 5 January);SOI Toposheet - 1968-1969 (79A/2, 79A/3, 79A/6 and 79A/7) and Rennell’s map of 1779. Other highlights are the quest of fluvial features, oxbow lakes, mid-channel bars, channel migration rate, meander geometry, channel sinuosity in different parts of river course and the parts that experience intensive bank erosion. The entire river course has been subdivided into three segments; viz. reaches A, B and C. Investigation displays that degree of sinuosity decreases from its anterior course (1968) to the existing course (2017). Reach-specific outputs display that reach B is highly sinuous (SI value 1.94 in 2017) and SI increases temporarily, whereas for reaches A and C it decreases with time. The rate of migration is higher in reach B than that in reaches C and A. The study displays a notably decreasing trend of migration in comparison with its previous lateral migration and shows that the migration nature over time is intensively inconsistent and unpredictable except very few portions of the river course. The nature of deposition within the river channel shows an unstable behavior during the entire period of the study. Meander geometry depicts a rapid change of river course innate to meander bends and shows a higher rate of migration by meander loop cut-off rather than lateral migration that reflects the inconsistency, erosion vulnerability and unpredictable nature of migration. The present work offers a valuable source to comprehend channel changes in Bhagirathi River and serve as an efficacious base for river-bank migration and erosion hazard planning and management.

Global warming has been one of the major concerns behind the world’s high-speed economic growth. How to implement the coordinated development of the carbon footprint and the economy will be the core issue of the world’s economic and social development, as well as the heated debate of the research at home and abroad in recent years. Based on the energy consumption, integrated with the “Top-Down” life cycle approach and geographically weighted regression (GWR) model, this paper analyzed the spatial differences and multi-mechanism of carbon footprint in provincial China in 2010. Firstly, this study calculated the amount of carbon footprint of each province using “Top-Down” life cycle approach and found that there were significant differences of carbon footprint and per capita carbon footprint in provincial China. The provinces with higher carbon footprint, mainly located in northern China, have large economic scales; the provinces with higher per capita carbon footprint are mainly distributed in central cities such as Beijing, Shanghai and energy-rich regions and heavy chemical bases. Secondly, with the aid of GIS and spatial analysis model (GWR model), this paper had unfolded that the expansion of economic scale is the main driver of the rapid growth of carbon footprint. The growth of population and urbanization also acted as promoting factors for the increase of the carbon footprint. Energy structure had no considerable promoting effect for the increase of the carbon footprint. Improving energy efficiency is the most important factor to inhibit the growing carbon footprint. Thirdly, developing low-carbon economies and low-carbon industries, as well as advocating low-carbon city construction and improving carbon efficiency would be the primary approaches to inhibit the rapid growth of carbon footprint. Moderately controlling the economic scale and population size would also be required to alleviate carbon footprint. Meanwhile, environmental protection and construction of low-carbon cities would evoke extensive attention in the process of urbanization.

Eddy Covariance technique (EC) achieves the direct measurement on ecosystem carbon, nitrogen and water fluxes, and it provides scientific data for accurately assessing ecosystem functions in mitigating global climate change. This paper briefly reviewed the construction and development of Chinese terrestrial ecosystem flux observation and research network (ChinaFLUX), and systematically introduced the design principle and technology of the terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation system of ChinaFLUX. In addition, this paper summarized the main progress of ChinaFLUX in the ecosystem carbon, nitrogen and water exchange and environmental controlling mechanisms, the spatial pattern of carbon, nitrogen and water fluxes and biogeographical mechanisms, and the regional terrestrial ecosystem carbon budget assessment. Finally, the prospects and emphases of the terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation of ChinaFLUX are put forward to provide theoretical references for the development of flux observation and research in China.

The core objective of rural vitalization is to systemically establish a coupling pattern of various rural development elements including population, land and industry. As one of the prerequisites, land resources is required to be optimally allocated via land consolidation. Consequently, land consolidation contributes greatly to population agglomeration, industrial development and resources support under the context of combating rural decline. Based on the key elements affecting rural development, this paper elaborates the connotation of rural vitalization and land consolidation in the new era as well as their relationships. Furthermore, the paper analyzes the alternative paths for achieving rural vitalization via land consolidation, and discusses the future directions of land consolidation and rural vitalization. The conclusions are drawn as follows: (1) To cope with the loss and decline of the intrinsic elements in rural areas, rural vitalization is a development strategy aimed at realizing economic, political, cultural and ecological rejuvenation in rural area by reshaping socio-economic morphology and spatial pattern in rural territory. (2) From the perspective of rural vitalization, land consolidation is endowed with new connotation, which should not only target at activating the key elements of rural development, but also place emphasis on coordinating material space and spirit core as well as integrating the restructuring of the physical space and the rural governance system. (3) Land consolidation should be compatible with regional natural conditions and the current stage of socio-economic development. According to the principle of regional planning and classification strategy, the appropriate models and paths should be adopted to promote the benign interactions of population, land and industry based on engineering techniques and ecological means. (4) Under the background of national strategy of rural vitalization, it is necessary to reshape the value orientation of land consolidation based on a scientific understanding of urban-rural relations and rural territorial functions, coordinate land consolidation planning and rural vitalization planning under the unified spatial planning system, and explore the new model combining land consolidation and multifunctional agriculture.