With the deepening understanding of the Scientific Outlook on Development, the coupling coordination degree model has become an effective evaluation and research tool for the regional overall balanced development. However, for this model, there are four types of misuses, including writing errors, coefficients loss, weight misuses and model failures, which have significantly affected the scientific nature of academic research. Therefore, this study firstly clarified the normative formula of the traditional coupling coordination degree model. On the basis of discussing the validity of the traditional model in the field of social science research, this study further proposed a modified model of coupling degree. In addition, the coupling coordination degree model has three reliability issues: the subjectivity of index construction, and the volatility and incomparability of coupling results. Taking the ecological and economic system of the Beijing-Tianjin-Hebei region as an example, we proved that the modified coupling coordination degree model has better validity, and the spatial and temporal changes of the research object will affect the reliability of the coupled coordination model.

Ecological environment problems are spreading from some small areas to wide areas across administrative regions due to unreasonable economic development. In this condition, the governments of the connected ecologically regions have to cooperate mutually to alleviate the ecological environment problems. Therefore, the ecological conservation cooperation (ECC) between administrative regions will gradually become usual. However, in the process of making ECC schemes, many significant questions need to be resolved, such as what ECC is, how many parts ECC consists of and how to make a reasonable ECC scheme between cooperators. These questions are all very critical for successful cooperation in resolving ecological environment problems. So far, the term“ecological conservation cooperation (ECC)”still was not defined clearly and accurately, and there is also not a systematical example about researching ECC. Constructing a framework of researching ECC is greatly significant to applied ecology, and will help resolving practically environmental problems. In this paper, based on the review of domestic and abroad researches on ecological cooperation, we gave ECC an accurate definition that is“the joint actions taken by stakeholders according to common agreements, in order to improve and protect ecological environment in a certain spatial scope where there are same ecological environment problems”, explained its connotation, and constructed a framework of ECC, including its compositions, research procedures, main types of cooperation, supervision and evaluations on the implication of ECC. In detail, The composition of ECC consists of the basis and purposes of cooperation, the cooperators, the supervision and evaluation systems; the procedure to construct the cooperation needs ten steps which include diagnosing regionally ecological problem, determining cooperators, finding out the objects of cooperation, clearing relationship between cooperators, mapping out cooperation scheme, consulting opinions about the scheme, implementing the scheme, supervising cooperators to carry out the scheme, evaluating, improving the schemes; there are six types of cooperation, which are labor service cooperation, engineering technology cooperation, industrial development cooperation, economic compensation cooperation, cooperation on ecological environment management, education and talent cooperation. Supervision and evaluation of ecological cooperation also involves four aspects which are supervision and evaluation on scheme implication, evaluation on the rationality of the cooperation scheme, evaluation of the supervision, re-evaluation periodically and eventual evaluation on the ecological environment qualities after implementing the ECC scheme.

Due to the difference of statistic standarda and calculation methods, the results of grain self-sufficiency rate were generally quite different and the assessment of the grain security situation in China varied greatly, which aroused great controversy. In order to accurately analyze the grain security situation of China to avoid misleading the relevant decisions, it is necessary to study the grain statistical data sources and the calculation methods of grain self-sufficiency rate. In this work, three commonly used methods, which were the stint counting method, the flow statistics method and the consumption statistics method, were used to estimate and analyze the grain, cereal grain and edible grain self-sufficiency rate in China during 2000-2016. The results were as follows: (1) The stint counting method would cause distortion in the results, while the results provided by the flow statistics method and the consumption statistics method were more accurate. (2) The cereal grain and edible grain self-sufficiency rates could report the actual grain supply demand relations. (3) The self-sufficiency rate of cereal grain was greater than 98%, and that of edible grain was greater than 100%. However, with the acceleration of industrialization and urbanization, city development demand for more land which would cause serious problems such as embezzlement of cultivated land and soaring grain demand, so grain production still should not be slackened in China. It is suggested that the agricultural structure should be adjusted in the future to stabilize the production of wheat and rice.

Ecosystem service value is the base of decision-making for ecological protection, ecological regionalization and ecological compensation, and it appears the dynamic spatio-temporal changes which are closely connected with the variations of ecological structure and function. However, it is still lack of a universal and integrated dynamic evaluation method for ecosystem service value in China. Based on literature survey, expert knowledge, statistical data and remote sensing data, using model simulations and GIS spatial analysis method, this paper modified and developed the method for evaluating the value equivalent factor in unit area, and proposed an integrated method for dynamic evaluation on Chinese terrestrial ecosystem service value. This method can realize the comprehensive and dynamic assessment of ecosystem service value for 11 service types of 14 different types of terrestrial ecosystem at monthly and provincial scales in China. The preliminary application indicated that the total ecosystem service value was 38.1×10¹² yuan in 2010, in which the value from forest ecosystem was the highest, accounting for about 46%, followed by water body and grassland. Among different ecosystem service types, the contribution from regulation function was the highest, especially the values from hydrological regulation and atmospheric regulation which accounted for about 39.3% and 18.0% of total service value, respectively. Moreover, ecosystem service value presented apparent spatio-temporal patterns in China. Spatially, the ecosystem service value decreased from southeast to northwest and the highest value appeared in southeastern and southwestern regions. Temporally, the ecosystem service value for most of the ecosystems attained the peak in July and reached the trough during December and January except desert, barren and glacier ecosystem. Generally, although this established method still needs to be developed and optimized, it is the first to provide a relatively comprehensive approach for the spatio-temporal dynamic evaluation of ecosystem service value in China, which will be helpful to the scientific decision-making on natural capital rating and ecological compensation.

The paper uses the literature data, spatial analysis and grey correlation analysis to examine the spatial distribution and influencing factors of China's overseas farmland investment activities in Southeast Asia. The results show that: (1) China's overseas farmland investment projects are mostly distributed in the Indo-China Peninsula along the border of China. (2) The spatial distribution of China's overseas farmland investment intention projects and contract projects in this region is similar, while that of the production projects is different from the other two types of projects. (3) China's overseas farmland investment is affected by geo-economy, geo-culture, resource conditions, and geo-politics, and the degree of impact decreases in succession. Indicators such as the average annual total import and export value and the average annual stock of China's foreign direct investment have a significant impact on the choices of Chinese investment companies. Southeast Asia is an important area for China's overseas farmland investment, therefore strengthening economic and cultural exchanges with Southeast Asian countries will play an important role in promoting the smooth development of overseas farmland investment activities carried out by Chinese companies.

Taiwan is a representative region of the land reclamation and the intensive human-environment interaction. The study on the reconstruction of the spatial and temporal change of historical farmland in this province can deepen the understanding of the characteristics, differences and rules of the historical land change process on both Taiwan and the mainland. Based on historical literature and statistical yearbooks, this study uses population data to analyze the characteristics of farmland and population records. Then it comprehensively adopts methods such as citation substitution, linear interpolation, occult coefficient correction method and per capita farmland coefficient method to estimate and correct the spatial and temporal changes of historical farmland in Taiwan province in the past 300 years after verifying the surplus food quantity. The results are shown as follows: (1) The total amount of farmland in Taiwan increased from 0.91×10⁴ hm² in the Dutch occupation period to the current 79.30×10⁴ hm², up nearly 86.60 times. The stage characteristics generally increased first and then continued to decrease. In the middle and early periods of the Qing Dynasty, it showed steady and low-speed growth. During the Japanese occupation period, it showed rapid fluctuations. Then it experienced a slow fluctuation in the middle and early periods of the Republic of China, and gradually declined in the middle and late periods of the Republic of China. (2) On a 100-year scale, there are significant differences in the rules of change between paddy fields and dry fields in Taiwan; the amount of paddy fields increased first and then gradually decreased after volatility. However, the dry farmland increased first and then decreased and then gradually increased. Before 1931, the proportion of dry farmland was higher than that of paddy fields, and its peak period witnessed 3% to 5% higher; then the proportion of paddy fields exceeded that of dry farmland and was in an advantageous position. The average proportion of paddy fields from 1936 to 1965 was 22.23% higher than that of dry fields. (3) The land reclamation process in Taiwan has represented the imbalance between spatial expansion and regional expansion. Land reclamation experienced the development process from one region to the whole area of Taiwan Island, that is, from the south to the north, and from the west to the east. Tainan was the first region to be reclaimed, followed by Taichung and Taipei districts, and the Taitung region was the last one to be reclaimed. The reclamation intensity in Tainan was higher than that in the rest, with a maximum of 36.71%. (4) The HYDE dataset and the results of this study are gradually increasing, but the difference between the farmland area and the change process is significant. The international dataset does not reflect the objective historical facts of the change of farmland in Taiwan in the past 300 years.

Since the 21st century, China's rural social and economic development and infrastructure construction have attained remarkable achievements, but the imbalance between urban and rural development and inadequate rural development are still prominent. In particular, the living environment closely related to rural life is still the short board of rural development. At the beginning of 2018, the central government issued the three-year action plan for rural living environment improvement (RLEI) to focus on improving the rural living environment, building a beautiful and livable village, and pursuing the Rural Revitalization Strategy. This paper analyzes the concept and connotation of RLEI, explains the mechanism of RLEI promoting rural revitalization, combs the mode and mechanism, effect and evaluation of RLEI, and discusses the key areas of strengthening the research of RLEI. The science of rural living environment has developed rapidly in the past 10 years, and has made remarkable progress in basic theory, evolution mechanism, quality evaluation, regulation and control strategy, especially in the research of basic theory, evolution mechanism and quality evaluation. However, there are still obvious deficiencies in the guidance and support of the current research for practice, and there are still some misunderstandings in the practice of local specific RLEI. Facing the strategic needs of rural revitalization, we need to form "eight consensus" in the understanding and practice of RLEI in the new era. In terms of research, we should strengthen the intersection and integration of rural geography and engineering technology science, urban and rural planning science, management science, sociology, etc., and strive to form a systematic research system integrating theoretical research, technological development, mechanism analysis, effectiveness evaluation, and model optimization, which can better support the improvement of rural living environment and realize the function and value enhancement of rural areas, and then effectively contribute to the Rural Revitalization Strategy.

Based on the remote sensing monitoring data of land use change/cover in 1990, 2000, 2010 and 2018, using land use transfer matrix, eco-environmental quality index, and ecological contribution ratio of land use transition, this paper analyzes the spatiotemporal features of "Production-Living-Ecological" space structural transformation and eco-environmental effects of land use/cover change in China from 1990 to 2018. On this basis, we identify the main influencing factors of eco-environmental effects and the spatial heterogeneity by using geographically weighted regression model. The results showed that: (1) The production and living space increased, the ecological space decreased, and the overall situation was insufficient from 1990 to 2018 in the whole country. (2) The high-value areas of eco-environmental quality were concentrated to the east of the Hu Huanyong Line during 1990-2018, and mainly in the south and northeast of China. The low-value areas were mainly distributed to the northwest of Hu Huanyong Line. The squeeze of other ecological space and agricultural production space on grassland and woodland ecological space is an important reason for the deterioration of the eco-environment during the study period. (3) Slope, annual precipitation, land use intensity, elevation, topographic relief, population density, and average annual temperature were the main factors influencing eco-environmental quality pattern in China, and the spatial difference of the effect of each factor was obvious. Chinese policies on economic development should take into account the eco-environmental effect of "Production-Living-Ecological" space transformation and influencing factors in the future, and promote the rational distribution of "Production-Living-Ecological" space and the construction of ecological civilization in China.

Cultivated land abandonment has a profound impact on China's food security. Taking the main grain producing areas in China as an example and based on the identification of the distribution of abandoned land, this paper measured the spatial distribution pattern of abandoned land, established the mediating effect model of cultivated land abandonment, and explored the influence mechanism of cultivated land abandonment on regional grain yield. The results showed that: (1) The area of abandoned cultivated land in the main grain producing areas of China was 4.0553 million hectares, with a rate of 5.85%; the distribution of abandoned land presented a T-shaped pattern, mainly concentrated in the Northeastern Heilongjiang, Northwestern Jilin and Southern Inner Mongolia. (2) Cultivated land abandonment had a significant negative impact on the grain yield of the main grain producing areas. In 2017, these areas lost a farmland production potential of 13.3915 million tons, and the loss of grain output was as high as 22.656 million tons, accounting for 4.69%; Inner Mongolia was the most affected region. (3) Grain sown area, farmland production potential, and agricultural technology input all played an intermediary role, and their regression coefficients were -0.194, -0.025 and 0.006, respectively. (4) We should follow the trend of urban-rural integration and agricultural-rural development, strengthen the input of modern agricultural production factors and policy support in major grain producing areas, and construct the flexible mechanism of spatial transformation between grain production and cultivated land fallow to ensure food security in China.

With unique tourism resources, the Antarctic attracts more and more attention, and the number of tourists to the region is growing rapidly. However, there have been fewer studies on the Antarctic tourism resources, and the research on the classification and evaluation of its tourism resources is almost blank. In this paper, the classification and spatial distribution of the Antarctic tourist resources are studied, and suggestions for the development of Antarctic tourism are put forward, in order to provide a reference for evaluating, developing and conserving these tourism resources. Results show that: (1) In the Antarctic region, substantive tourist activities have been carried out in 558 major tourist resource units, which can be divided into 8 main types, 18 sub-types and 30 basic types according to different attributes. (2) There are diversified natural tourism resources, among which water landscape occupies a large proportion. (3) The tourism resources are unevenly distributed and typically characterized by aggregated distribution, and two high-density clusters are formed in the Antarctic. One is the coastal areas of Graham Land in the northwest of the Antarctic Peninsula and their surrounding islands, and the other is the islands and continent areas near the Ross Sea. (4) Climatic condition and the accessibility of tourism resources are important factors affecting the spatial distribution of Antarctic tourism resources. (5) There are less Antarctic tourism resources related to China, and China's participation and maturity in the development of Antarctic tourism are relatively low. In the future, China should find out the status of Antarctic tourism resources as soon as possible, strengthen the research on the impact of Antarctic tourism, and promote the development of China's tourism to the Antarctic.

China is feeding roughly 20% of the world's population with less than 9% of the world's cultivated land. The food security at national and regional scales has been a major concern. In this study, we took the province-level area as the research unit and utilized GIS spatial analysis and statistical tools to examine the overall characteristics of grain production changes, the evolution characteristics of regional patterns and the impact of these changes on regional grain supply and demand pattern in China during 1999-2018. The results showed that the total national grain output significantly increased with an annual rate of 1.1 million tons. The total grain output of Northern China showed a significant growth trend, while that of Southern China remained stable. The increment of maize yield played a leading role in these changes. The spatio-temporal yield variations of five major food crops (rice, wheat, maize, beans and tubers) were quite different in the past 20 years at provincial-level scale. The change of grain yield had great influence on regional grain supply and demand pattern. Particularly, Guangdong, Zhejiang and Fujian provinces located in the southeast coastal region had changed from supply-oriented provinces of major grains with rice and wheat into demand-oriented provinces. However, the per capita share of grain was 368.0 kg/person in Y 1999-2003 period(the five-year average during 1999-2003) and 461.5 kg/person in Y 2014-2018 period (the five-year average during 2014-2018) at national-level scale, respectively; and the per capita share of the two major grains was 220.3 kg/person and 247.6 kg/person in Y 1999-2003 and Y 2014-2018 periods, respectively. The change of sown area was the direct reason for the change of grain crop yield at national and regional scales. Nevertheless, the fundamental reason was more attributed to the change of attribution, function and quality, which is driven by land use value. Our study classified the reasons for the decrement of cultivated land into "non-agriculture" "non-grain" "wastage" and "ecology" types. Considering the formation causes of each type, the corresponding countermeasures and suggestions for the sustainable use of regional cultivated land were put forward in order to provide reference for the adjustment of regional grain planting pattern and the transformation of demand-oriented provinces of two major types of grain to self-sufficient provinces.

In the context of unprecedented changes of energy geopolitics, China's current energy situation is becoming increasingly complex, and energy security has become a major strategy for national economic development. Under the new situation, not only the scientific issues, research objects, and research methods of the world energy geography and national energy security at the interdisciplinary perspective, but also the global energy governance system and international energy cooperation based on the actual needs of China are worth discussion among experts and scholars. This article uses the form of "question and answer (Q&A)" to provide a panoramic view of the host and nine academic interviewees based on different perspectives. Experts express their opinions in a range of content, including energy security and global energy governance model, the challenges and countermeasures of China's energy security, the new changes of global energy geopolitics, the energy security under the geographical pattern of unequal world energy production and consumption space, the high-quality development of China's energy under the trend of global low-carbon transformation, changes in the global energy supply and demand pattern affected by major public health emergencies, and future research prospects and important research directions of energy geography. We hope that a certain consensus can be reached, so as to better promote the development of the discipline of world energy geography, as well as actively respond to issues such as the unprecedented change of energy geopolitics and national energy security.

The protection of traditional villages and towns is one of the important tasks of new-type urbanization. However, the residential buildings that are tangible cultural heritage and cultural genes are the mainstay of traditional feature in traditional villages and towns, and the traditional villages and towns would have lost the carrier of the inheritance of cultural heritage, if their traditional residential buildings were missing. In this paper, we take the representative architectural landscape characteristic towns and villages as study cases to analyze their regional differentiation of architecture style, and explore the impact mechanism of their regional differentiation of architecture style. The study found that, firstly, there are 12 types of architecture style in Chinese traditional dwellings. The resulting architectural feature areas show that there are obvious differences in spatial distribution between north and south. The northern architectural feature area is divided into two sections with different sizes, and the southern architectural feature area has two "string of pearls" distribution. Secondly, there are obvious regional differentiations in the characteristic of Chinese traditional residential architecture in 5 aspects, namely, settlement environment, spatial layout, modeling style, building materials and detail decoration. Thirdly, from the impact mechanism of architecture style regional differentiation of Chinese traditional residential buildings, the natural environmental factors (including topography, landform, water system, climate, planting material, earth and stone) are the cornerstone of the formation of architecture style regional differentiation of traditional residence. The cultural factors such as the patriarchal ethics, fengshui concept and ethnic culture are the internal impetus of the architecture style regional differentiation of traditional residence. The cultural factors such as population migration, war defense and business economy are the extrapolation forces of architecture style regional differentiation of traditional residence.

It is reported that the basic goal of the “Hongqi River” Project (also known as “Red Flag River” Project) is to improve the ecological and environmental conditions of dry areas in the Northwest China by transfering water from the Yarlung Zangbo River, the Nu River, the Lancang River, the Jinsha River, the Yalong River and the Dadu River in the Qinghai-Xizang (Tibet) Plateau, to Xinjiang and other arid areas. By this way, 200 million mu (around 13.33×10⁴ km²) of farmland and oasis could be developed in the dry areas.“Hongqi River” Project is a grand idea of water diversion across river basins, which has attracted wide attention at home and abroad. However, this grand idea also faces multiple severe challenges in the fields of geology, technology, economy, society and ecology, and there is a great uncertainty.From the perspective of physical geography, natural resources and environment and regional development, 60 billion m³ of water cannot meet the needs of the construction of 200 million mu of farmland, nor can it meet the needs of the ecological green belt of 15×10⁴ km², and the two cannot be realized at the same time. In addition, how much water can reach the receiving area when there is strong leakage and evaporation along the river? The project is planned to be built for 10 years, with investment of 4 trillion yuan. The investment of farmland irrigation per mu is around 2×10⁴ yuan, and the water charge per cubic meter is nearly 66 yuan. Who will pay for the expensive water bill when the project is completed and running?The environmental impacts and ecological consequences caused by water diversion are of great uncertainty and need to be highly concerned. The water diversion project is not only a complex water conservancy project, but also a very complex ecosystem engineering, and a very complicated social and economic project. Environmental effects, ecological consequences and socioeconomic effects involve complex geophysical, chemical and biological processes, as well as the complex process of harmonious balance between human and earth relations. The “Hongqi River” Project involves international rivers at the same time. The potential geopolitical risks need to be drawn attention. At the existing level of understanding, it is necessary to make a thorough and systematic study of these problems.In addition, in the public awareness of “Hongqi River”, there are still several views that are contrary to scientific cognition, such as “changing the climate pattern of China”, “forest causing precipitation”, and breaking the “Hu Huanyong Line”. The analysis and clarification for these misunderstandings are carried out in the paper.

The Karakoram and West Kunlun Mountains in the northwestern part of the Qinghai-Xizang Plateau are a transitional area between the alpine desert and the montane desert.On the bases of recent observations and investigations the structure type of the altitudinal belts, the regional differentiation, and environmental problems in the study area are dealt with in this paper.Characterized by the continental arid type of climate, the altitudinal belts of the Karakoram and West Kunlun Mts. consist chiefly of varions desert and steppe belts. According to the combination pattern of the altitudinal belts, the following four structure-type groups and seven structure types of the altitudinal belts may be identified in the study area:Ⅰ. The arid structure-type group. This structure-type group inclludes three structure types as follows: (1) the xero-mesophilic pattern consisting of the montane forest-steppe belt and the alpine meadow belt; (2) the meso-xerophilic pattern consisting of the montane steppe belt and the alpine meadow belt and (3) the xerophilic pattern possessing the montane steppe belt only.Ⅱ. The extremely arid structure-type group. It includes one structure type. That is the super-xerophilic pattern consisting of the following altitudinal belts: the montane desert belt, the alpine desert belt, the subnival pelt and the nival belt.Ⅲ. The alpine arid structure-type group. It includes two structure types as follows: (1) the super f rigo-xerophilic pattern consisting of the alpine desert belt, the subnival belt, and the nival belt; and (2) the frigo-xerophilic pattern consisting of the alpine desert steppe belt and the alpine desert belt.Ⅳ. The alpine semi-arid structure-type group. It includes one structure type. That is the frigo-meso-xerophilic pattern consisting of the following altitudinal belts: the alpine steppe belt the alpine meadow belt, the subnival belt, and the nival belt.Corresponding to the areal differentiation of the physical geography of the region, the above mentioned four structure-type groups and seven combination patterns of the altitudinal belts vary obviously with the flanks of the Karakoram and West Kunlun Mts. Tte combination of the altitudinal belts and the elevation of each altitudinal belt on the western section are different to a considerable degree from those on the eastern section. The moisture-bearing air masses coming from the west play a significant role in the regional differentiation of the altitudinal belts. They make the desiccation of the southeast more severe than that of the northwest. The broad valleys, basins and plateaus between the Karakorum and the Kunlun Mts. are climatically extremely arid. In these areas the montane desert and the alpine desert are dominant.Owing to the important function of the montane forests in water retention and soil conservation in the arid region, the overlogging and misuse of the forests should be replaced by rational utilization and regeneration. It is suggested that the local government should select proper areas where growing the montane coniferoue forests occur in the West Kunlun Wts. as nature reserves so as to protect a number of endemic and rare species of plants. It is also necessary to establish nature reserves for the conservation of the natural landscape and the wildlife of the Qiangtang Plateau.

Based on the complex network analysis, this paper constructs the global grain trade network of wheat, rice and corn. The study analyzes the overall characteristics and changing trends of the network pattern, and quantitatively evaluates the influencing factors of the network pattern of global grain trade. The result shows that: Firstly, the global food trade network has become a complex, orderly and interdependent network system. The network scale is increasing, and the degree of connectivity and tightness are strengthening continuously. Secondly, the nodes of the global food trade network show the characteristics of disequilibrium structure. And countries with high strength and high node degree play a leading role in the network, showing the characteristics of network structure dominated by exporting countries. Thirdly, economic and social differences, consistency of trade policies, linguistic and cultural proximity have significant effects on food trade networks. Economic and social differences have driven trade networks to become more interconnected and diversified. Consistency in trade policy contributes to a more sustainable and robust trade network. Therefore, it is suggested that China implement a more diversified and multilateralized grain trade policy. China should strengthen and enhance its centrality among nodes of the global food network, fully integrate into the global food trade network, and promote the building of a global community of shared future for food security.

About one-third of land in the world is approximately the basic conditions of waste-land. Wasteland is very wide and has a pivotal position on earth. Meanwhile, it bears very important ecological functions. In recent years, Chinese government and academia paid much attention to the wasteland. Protection and development of wasteland had become an important research topic. Although China has had a lot of provisions on wasteland, and scholars have carried out relevant research on wasteland from different aspects, the definitions and classifi-cations of wasteland are not unified. This hinders the protection and development of wasteland to a certain extent. Firstly, this paper reviews existing definitions of wasteland and clarifies the relationship between wasteland and other related concepts, and then redefines the concept of wasteland: generally wasteland refers to unutilized, idle or abandoned land except for agricultural land and construction land. In the narrow sense wasteland refers only barren state of land, but with appropriate use it could be suitable for agriculture, forest, herd and energy corps. Secondly, this paper systematically analyzes the classification of wastelands in the United States and India, and on the basis of existing land classification system in China, it proposes to add the category of “ecological land”, which plays the main ecological functions, provides ecological services and ecological products of woodland, grassland, wasteland, water and beaches directly or indirectly. At the same time it proposes to divide wasteland into three types: wilderness, unused and abandoned land. Thirdly, this article first recognizes that waste-land has various ecological functions, such as sand-fixation, soil conservation, carbon sequestra-tion and oxygen release, water conservation, biodiversity conservation, etc., which has impor-tant implications for the development and protection of the ecological land and wasteland. Finally, this paper proposes four suggestions on the development and protection of wasteland in China in the future: pay attention to the value of wasteland, establish the property right system of wasteland, prepare the natural resources balance sheet, protect and develop wasteland by categories.

Valuation of global ecosystem services by R Costanza(1997)has attracted attention of the Chinese ecological researchers over the years. And many Chinese scientists have been using the methods to valuate the ecosystem services for forest, grassland and farmland ecosystems. However, it has been turned out that there are several shortcomings in direct adaptation of the methods, for instance, some ecosystem services have been insufficiently valuated or even ignored via using Costanza’s method. To fill this gap, we have, on the basis of Costanza’s method, developed a new method or 'unit value’ based method for assessment of ecosystem services. Expert interviews with structured questionnaire were contacted in 2002 and 2007 respectively, and altogether 700 Chinese ecologists were involved in the interviews for testing the method. It has been found that the values of ecosystem services from expert knowledge based unit value method and biomass based method are comparative. Therefore, expert knowledge based assessment of ecosystem services could be used as a method for assessing ecosystem services with known land use areas, and a good result could be generated within a short period of time. However, for scientifically sound and concrete results, the spatial disparity of ecosystem services should be taken into account.

The Headstreams of the Three Rivers,the Yellow River,Changjiang River and Lan-cangjiang River,are of great ecological significance to Qinghai-Tibet Plateau.They range from31°39'N to36°16'N and89°24'E to102°23'E with elevation s of the headstream regions varying from3450m to6621m.In Qinghai province the headstreams cover an area of0.318million km 2 ,accounting for50.3%of the province total.The largest marshland of China is located here,and these regions are regarded as"China's water tower".There inhabit large quantities of rare wild animals,such as yaks,Tibetan wild donkeys,Tibetan antelopes,and dark-necked cranes etc.On the whole,some 271kinds of wild animals and about 1000species of plants are identi-fied in the headstream regions.In recent two decades,due to global climate change and human activities,the ecosystems of these regions are degrading.The acreage of water and soil erosion reaches34462km 2 ;the areas suffering from rat-caused damages accumulated to6.58million ha,accounting for11%of the whole region;and the desertified area increases to2.53million ha.Some of the glaciers here are shrinking,and the shrinking rate of the glaciers where the Dangqu river originates reach es be-tween8.25m/a and9.9m/a.The lakes here are diminishing with quick water level descending,and the descending level in Zhaling Lake and Eling Lake are over2m.The critical problems urge the authors to seek approaches of ecological alleviation in the three rivers' headstream regions.Thus,the following countermeasures are put forward:to work out scientific plan as quickly as possible to establish natural reserves in the headstream regions;to properly settle the immigrants from responsive regions;to establish scientific research bases for developing and spreading new-high applicable technologies to speed up the environmental re-construction;to lead to restoration of grassland eco-system by eliminating rat-caused damages;and to set up ecological compensative mechanism among areas of upper,middle and lower reaches of a watershed to promote environmental reconstruction.The ultimate intention of this paper is to contribute to ensure the social development towards an ecological sustainability in the three drainage basins.

The spatial pattern evolution of the cities in the historical Yellow River Basin will help us understand the characteristics and development context of human settlements, which plays a key role in ecological protection and urban development in the Yellow River Basin today. This article uses the time series data of cities (BC763-AD1911) in the CHGIS database of Harvard University, the elevation data of STRM, the regional data of nine major basins in China, and the historical population data. It studies the spatio-temporal pattern evolution of cities in the Yellow River Basin, as well as the influencing factors. The results show that: (1) The changes in the number of cities can be divided into five stages. (2) The first level continous stable region includes the high-density urban area in northern Henan with present Anyang as the center, high-density urban area in Guanzhong with present Xi'an as the center, and the secondary high-density area with Jinan, Taiyuan and Luoyang as the center. The second level continuous stable region includes five important city belts, namely, Weihe River city belt, Fenhe River city belt, northern foot city belt of central Shandong mountainous region, eastern foot city belt of Taihang Mountains and Grand Canal city belt. (3) The average distance of city gravity migration is 32 km, and the average distance of population gravity migration is 95.78 km. The distribution of cities and population is closely related. (4) Natural factors such as temperature and precipitation, elevation, distance from the rivers, downstream avulsions of the Yellow River, as well as human factors such as wars, capital transfer and canals, had jointly influenced the spatial and temporal distribution of cities in the Yellow River Basin.

Food waste has become a global problem, which causes widespread concern from the public. The consumption segment is an important part of food waste, and it is increasingly serious. Food waste at the consumer segment is mainly divided into household food waste and food waste outside home. Food waste at the consumer segment has different impacts on national food security, resources and environment, and social and economic development. Food waste at the consumption segment is affected by factors such as economic and social development, cultural background, demographic characteristics, and consumer behavior and awareness. At present, the study of food waste at the consumer segment mostly uses methods such as weighing (or estimating) and measurement model. It still needs to be further explored by developing reasonable quantitative methods, establishing complete theoretical models and proposing concrete research methods. In addition, to reduce food waste at the consumer segment, we should encourage multi-stakeholders to make a joint effort to deal with food waste at the consumer segment from the perspectives of government, society, individuals and other angles.

Taking three large-scale amusement theme parks in the Yangtze River Delta as cases, this paper analyzed the spatial structure of theme parks' tourist market based on mathematical statistics method and GIS spatial analysis. The method of GeoDetector was used to identity the impact factors and their interactions. The results showed that: (1) The spatial distribution of tourist flow in the Yangtze River Delta theme parks presented an overall pattern of "point-axis radiation in the core area (Yangtze River Delta), planar homogeneity in the peripheral area (provinces bordering the Yangtze River Delta), and dotted distribution in the edge area". The main boundary of tourist flow distribution was established in the delta, and the core market boundary was located in the provincial-level regions (except Shanghai). (2) The spatial distribution characteristics of tourist flow varied in time period and three destinations. The curve of tourism space used in amusement theme parks showed a typical basic feature. In normal times tourists were found in the neighboring region, while on holidays tourists were in the distant region. (3) There was some heterogeneity in the main range and form of tourist flow in the three theme parks. The market domain shape of Happy Valley was similar to that of Dinosaur Park. On the whole, Fangte's market domain was pie-shaped. Eighty percent of the three theme parks' market areas overlapped, and there existed a certain spatial competition among the three theme parks. The rank and status of the cities in which the parks were located affected the distribution pattern of tourists. (4) The influencing factors of the theme parks' tourism market varied in spatial degree and intensity. Economic connection intensity, per capita disposable income of residents and the distance were the leading factors affecting tourist flow, but the leading driving factors in different regions differed significantly. Two influencing factors, bilinear and nonlinear, interacted with each other, which could well explain the spatial distribution of tourist sources.

"Three rural issues" (issues concerning agriculture, rural areas, and farmers) is an important mainline of the CPC's centennial course of party building and China's urban-rural development. In order to solve the "three rural issues" in the New Era and promote the implementation of rural revitalization strategy, we hereby invite ten experts in the research field of "three rural issues" and rural revitalization research to conduct interviews. The interview mainly focuses on three perspectives: Historical process and institutional context, urban-rural system and cross scale space, and the integration of policy theory, technical methods, and rural construction practice. It revolves three main lines: The strategic stage and institutional changes of "three rural issues", the essence of "three rural issues" and the ways to solve new "three rural issues", and the rural revitalization mechanism and rural construction practice. The main conclusions are as follows: (1) The essence, key areas, and institutional mechanism innovation of the "three rural issues" in the context of spatio-temporal processes and institutional contexts. It is necessary to grasp the laws of "three rural" (agriculture, rural areas, and farmers) and diagnose the "three rural issues" from the perspective of urban and rural regional systems and even the global perspective space. The "three rural issues" is an optimization decision-making problem for improving the functions of rural regional systems within the overall framework of urban and rural regional systems. The imbalance in urban-rural development and insufficient rural development are the concentrated reflection of the "three rural issues" in the New Era. The crux of the "three rural issues" lies in the uncoordinated development of "human, land, and industry". The core goal of China's "three rural issues" in the new development stage is to move towards the common prosperity of farmers and rural areas. The corresponding development system and working mechanism of "agriculture, rural areas, and farmers" need to grasp the two "bottom lines", do a good job in the two "connections", and promote the two "integrations" in key areas such as national food security, farmers' livelihood development, modern agriculture and rural development, rural revitalization, and urban-rural integration development. (2) The theory of rural revitalization and the rural spatial planning under the requirements of urban-rural system interaction and people's common prosperity. The research and solution of China's "three rural issues" are rooted in the geographical theory of territorial system theory of human-environment interaction and location theory, the sector economy theory and the economic cycle theory, as well as the theory of development economics, sociological function theory and social conflict theories. In the research practice of the "three rural issues", land use transformation theory, rural reconstruction theory, rural development multi-body and multi-pole theory, interface theory, rural attraction theory, and rural sustainability have also been developed. The urban-rural integrated development and the common prosperity of the people should be the result of balanced regional development and Chinese path to modernization. The folk expression of "making rural life attractive" and the strategic goal of "basically realizing rural modernization by 2035" are mutually "exterior-interior" relationship, which can be comprehensively explained from the following three aspects: The spatio-temporal differences and path differentiation of rural settlement evolution and multi-functional transformation, and the phenomenon explanation of rural gentrification and the theoretical application of rural attraction in the context of urban-rural interaction, as well as the theoretical significance and practical path of rural modernization under the guidance of rural sustainability science. Improving local quality is an inherent requirement to meet the people's needs for a better life, and it is an essential requirement and general law of rural revitalization driven by innovation. As the edge of the national urban-rural system, rural areas face constraints such as segmentation, remoteness, low density, and insufficient heterogeneity dividends in improving local quality. Therefore, to improve local quality of rural areas, it is necessary to adapt to and alleviate the relative inefficiency of rural geography, and its important promotion paths include the characteristic development based on endowment, digital transformation and rural agglomeration centered around cities and towns. Guided by spatial planning and taking into account the integrated functional development of production-living-ecological spaces in rural areas, as well as the integration of urban and rural space through spatial planning, through promoting the quality of living space through comprehensive land improvement, assisting in the realization of multifunctional value in agricultural space through refined management, ensuring the sustainable use of ecological space through systematic protection and restoration, which is a solid foundation for rural revitalization and the construction of a new urban-rural relationship. (3) The path mechanism and technical support for the comprehensive rural revitalization and rural construction under the new needs of ecological civilization construction and governance modernization. Comprehensive rural revitalization requires the revitalization of industries, the reform of land, the development of human well-being, and the intelligent updating of technology. First, the essence of operating rural areas is the rational allocation of resources as the object of factors. It is necessary to integrate the high-quality development of agriculture with the high-quality and livable rural areas, promote the interaction and integration of urban and rural systems, actively link natural science, engineering technology innovation, and institutional innovation from the perspective of the big food concept, and implement food safety and important agricultural product supply security. Second, facing the new demand of rural sustainable development and governance modernization, we should innovate the property right governance integration mechanism of rural land system, especially actively build a rural green development mechanism with farmers' participation and an external benefit sharing mechanism of ecological environment governance. Third, it is urgent to break through the barriers that farmers share the gains from the appreciation of rural assets, fill the gap between small farmers and modern agriculture, and establish a concept of county governance that meets the needs of Chinese path to modernization. Fourth, rural construction is an organic combination of the governance of public spaces by the state and the daily life practices of farmers. Through the theory and technology of "computational" rural areas, effective connection and information sharing between the state and rural areas can be achieved, promoting coordinated development from micro to macro, and from local to whole. And we should achieve the aim of building livable, suitable for work, and beautiful rural areas, through multi-level main body co-construction, co-governance, and management. To sum up, the interview views can provide theoretical reference and decision-making reference for the "three rural issues" work innovation and rural revitalization practice towards Chinese path to modernization.