中国绿洲及其可持续发展建设

本文以我国干旱区绿洲为对象 ,全面阐述了绿洲对干旱区社会经济发展的贡献 ;研究了干旱区地域系统并进行了绿洲区划 ;系统总结了绿洲的类型并从结构及功能上阐明了绿洲的基本特征 ;文章最后从建立高效可持续发展绿洲体系出发 ,探讨了 2

Ecological environmental quality evaluation and driving factor analysis of the Lijiang River Basin,based on Google Earth Engine

For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region.

天津地区表层土壤多环芳烃类污染物污染源辨析

利用因子分析法及离散点曲面张力样条函数插值法对天津地区表层土壤多环芳烃类污染物污染源的类型及空间分布进行分析.表明研究区不同土地利用类型的污染源大多以混合源(包括燃煤与原油渗漏)为主,其中污灌农田、普通农田、荒地和城市绿地中混合源所占比重依次为61.26%、69.35%、52.86%、64.45%。而各污染源在空间分布上与其所处地理位置、地理条件及该区域内人们的生活习性都比较符合。

The Spatial Differences and Influencing Factors of Tourism Resources in Ningxia,China

The analysis of the spatial distribution of tourism resources and the identification of its influencing factors are crucial for supporting the sustainable development of regional tourism.This study established a comprehensive database of tourism resources in Ningxia Hui Autonomous Region(Ningxia)through a combination of literature review and field research.It examined the quantitative,qualitative,and categorical characteristics of tourism resources in Ningxia,and determined the spatial patterns based on kernel density and spatial association analysis.This study also comprehensively evaluated the societal,economic,and environmental factors influencing the spatial distribution of tourism resources in the entire region by employing the geographical detector model to quantify the influence of each factor.The following results were obtained.(1)There were 29218 individual tourism resources in Ningxia,comprising eight main types,23 subtypes,and 105 fundamental types,and they exhibit a hierarchical pyramidal structure.(2)The tourism resources in Ningxia displayed characteristics of“widespread regional dispersion and limited regional agglomeration”.The spatial distribution of tourism resources was highly imbalanced,and most types of tourism resources exhibit strong positive spatial correlation.(3)The altitude,annual precipitation,population density,distance from urban centers,urbanization rate,and per capita GDP were identified as significant factors influencing the spatial distribution of tourism resources in Ningxia.Based on the results,we recommend that the government should formulate tourism development policies in Ningxia based on local conditions to effectively address the spatial imbalances,enhance the sustainability of tourism development,and continue to promote high-quality tourism development in Ningxia.

The Impacts of Climate Change and Human Activities on Cropland Net Primary Productivity in Bangladesh,India and Myanmar

Under global change and climate variations,determining the impacts of climate change and human activities on cropland net primary productivity(NPP)in Bangladesh,India and Myanmar(BIM)is of great significance for identifying yield-limiting factors,making adaptive agricultural management plans,and improving yields.Based on the GLOPEM-CEVSA model,through an integration of remote sensing data and LAI simulation,we investigated the impacts and spatiotemporal changes of water and human activities on BIM from 1982 to 2015.Three types of cropland NPPs were considered:actual NPP(NPPA),NPP affected by temperature and water(NPPWT),and NPP only affected by temperature(NPPT).Our analysis revealed that the water factor plays a predominant role in determining the NPP level in the BIM.Temperature variability was found to be conducive to NPPT,exhibiting an increasing trend of 10.66 g C m^(-2) yr^(-1).However,this trend was partially offset by precipitation variability,resulting in a net increase of 0.96 g C m^(-2) yr^(-1).In comparing temperature-driven NPP to temperature and water-driven NPP,water stress caused NPPT to decrease by 65.46% compared to NPPWT for the entire region.Cropland NPP in northwestern India and the central Deccan Plateau were significantly affected by water stress.Moreover,the influence of water on NPP in the BIM exhibited a substantial upward trend from 1982 to 2015,with Myanmar experiencing the most significant increase.The gap between NPPWT and NPPA in BIM demonstrated a notable decreasing trend during the same period,underscoring the positive impact of human activities on NPP.Inferences drawn from our findings suggest that with the implementation of rational and efficient crop management practices,there is a 36.80% potential improvement in NPPA compared to NPPWT in the BIM region,with India and Myanmar showing potential increases of 39.20% and 38.29%,respectively.These insights provide guidance for practical measures aimed at water resource management to enhance cropland productivity in the BIM,and they present a methodology for quantifying the effects of climatic changes and human activities at a regional scale.

Spatial Differences in the Response of Runoff to Climate and Land Use Changes in the Yiluo River Basin

Accurately identifying the spatial differences in the response of regional runoff to climate and land use changes can clarify the mechanism of regional runoff changes and provide a scientific basis for adopting the appropriate water resource protection policies.In this study,based on the Budyko theory,we quantitatively evaluated the spatial differences in the response of runoff to climate and land use changes in the Yiluo River Basin after 2000;calculated the sensitivity of runoff changes to precipitation(P),potential evapotranspiration(E_(0))and land use changes;and quantified the contributions of those three factors to runoff changes.The findings revealed that with decreasing elevation,precipitation gradually decreases,potential evapotranspiration gradually increases,and runoff gradually decreases in the Yiluo River basin.Influenced by the population density,both cultivated land and construction land are widely distributed with the middle and lower reaches of the basin,while the upper reaches are dominated by forest land.Compared with the base period(1985-1989),precipitation and potential evapotranspiration in the watershed during the change period(2000-2017)basically showed decreasing and increasing trends,respectively,with obvious spatial differentiation.P increased significantly in the upper reaches of the Yi River,with an average of 35.2 mm(-83.8-84.7 mm),while P increased and decreased in the other five subbasins,but the decreasing trend was more prominent.Among the subbasins,the upper and middle reaches of the Luo River showed the largest reductions in P,with an average of-34.2 mm(-145.9-20.6 mm),whereas the middle reaches of the Yi River showed the smallest reduction in P,with an average of-10.9 mm(-84.2-59.5 mm).The E_(0)in the different regions during the change period showed an increasing trend,and the increase in E_(0)gradually decreased from the upper reaches to the lower reaches.The E_(0)in the upper reaches of the Luo River showed the largest change,with an average of 45.3 mm(38.2-48.3 mm),while the lower reaches of the Yiluo River showed the smallest change,with an average of 7.3 mm(-3.2-17.1 mm).Land use changes were primarily from cultivated to construction land in the middle and lower reaches.Runoff changes were positively correlated with precipitation changes and negatively correlated with potential evapotranspiration and land use changes.The absolute values of the sensitivity coefficients of runoff to these environmental factors decreased with lower altitude,indicating a reduced responsiveness of the basin runoff under a warming and drying climate trend.Reductions in precipitation and changes in potential evapotranspiration have led to reductions in runoff ranging from 4.7 to 17.4 mm and from 0.7 to 9.1 mm,respectively,while land use changes led to corresponding runoff reductions of 23.0 to 46.5 mm,suggesting that land use changes are more likely to trigger runoff changes in the basin than climatic fluctuations.Given the dominance of cultivated land,especially in the middle and lower reaches,and the region’s high susceptibility to human activities,there has been a significant reduction in runoff in recent years.The contribution of land use change to the runoff reduction in the Yiluo River Basin was greater at lower elevations,up to 86.1%,while climatic effects were more significant at higher elevations,up to 27.8%.Therefore,promoting the implementation of projects such as water ecological restoration and returning farmland to forests are of great significance to curb the over-exploitation of groundwater,to formulate scientific management and scheduling policies in order to realize the transformation of the water balance in the river basin from a non-steady state to a steady state,and to promote the integrity of the ecosystem of the lower reaches of the Yellow River and ensure its sustainable development.

Comparative Analysis of the Spatial-temporal Distribution and Influencing Factors of the Tourism Industry in Three Cities along Beijing-Hangzhou Grand Canal in China

The temporal-spatial pattern of linear cultural heritage in the context of the tourism industry is closely linked to heritage management.Using the 1800 km long Beijing-Hangzhou Grand Canal as an example,this study compared the dynamic evolution of tourism businesses in Beijing,Liaocheng,and Yangzhou at three time points(2010,2015,and 2019)via nearest neighbor analysis,kernel density estimation,and the standard deviational ellipse.Next,a Geo-detector was used to examine the influencing factors.The results reveal significant growth regardless of the quantity or agglomeration degree from 2010 to 2019,and the direction of industrial expansion is consistent with the flow direction of the canal.Moreover,the explanatory powers of factors related to socioeconomic development and canal resources are obviously stronger than those of the natural environment.The findings of this study offer theoretical constructs and policy recommendations for the sustainable development of the Beijing-Hangzhou Grand Canal and other linear cultural heritage sites.

Driving Factors of Coordinated Development in Chinese Border Cities:A Case Study of Lincang City in Southwest China

In the context of the“Belt and Road Initiative”,the sustainable development of border cities is paramount for facilitating intergovernmental exchanges.Using the system dynamics approach,we integrated border policy factors to create the Border City Coordinated Development(BCCD-SD)model,encompassing three dimensions:Economic,Social,and Resource-Environment.Furthermore,a comprehensive evaluation indicator,the City Coordinated Development Index(CCDI),was devised.Using Lincang City in Southwest China as a case study,this article examines the trends in city development under three scenarios:Inertial Development,Rapid Development,and Green Development.The research findings demonstrate that the model adeptly captures trends in the city coordinated development indicators.Among the three scenarios,the rapid development scenario stands out,yielding the most favorable economic indicators,superior public infrastructure,and the highest employed population.However,the rapid development path,which is heavily focused on economic growth,intensifies resource and environmental pressures,giving rise to sustainability challenges.In contrast,although the green development scenario trails slightly in economic performance compared to rapid development,it fosters a larger urban population and transition of the employed population into citizens while excelling in resource and environmental aspects.Overall,the CCDI attains its highest score under the green development scenario,surpassing those of rapid and inertia development,signifying superior city development coordination along the green path.This scenario effectively combines economic growth,social progress,and resource-environment protection.This study also emphasizes the pivotal role of ports in the coordinated development of border cities and underscores the necessity of expediting the transition from a“gateway”economy to a“port+”economy.One objective of this article is to encourage border cities to serve as more effective windows to the outside world,promote regional coordination,and achieve high-quality development.

Cultivated Grassland Development on the Tibetan Plateau:Current Status,Challenges,Suggestions

The Tibetan Plateau is vital for animal husbandry in China,and relies heavily on its natural grasslands.However,grassland degradation,increasing livestock numbers,and uneven grazing practices are exacerbating the grass-livestock imbalance.Cultivated grasslands are a key strategy to address this issue.In this review,we evaluate the current status,challenges,and suggestions for developing and managing Tibetan Plateau cultivated grasslands.While discernible advancements have been made in the cultivated grasslands in this region,persistent challenges exist.These challenges stem from issues like low awareness and enthusiasm among farmers and herders,uneven cultivated grassland distribution,and limited scientific and technological contributions.Based on these challenges,we propose strengthening the promotion of artificial forage,implementing a rationalized grassland layout,and improving the scientific and technological contributions to forage species selection,sowing,management,and storage.In summary,cultivated grasslands in the Tibetan Plateau offer promising prospects but still face significant challenges.Overcoming these obstacles will require innovative approaches to unlock the full potential of cultivated grasslands in this unique ecological niche.

Contributions of Social-ecological Drivers to Land Use Transitions in Protected Areas on the Tibetan Plateau:Shifting from Strong Intervention to a New Balance

The establishment and management of protected areas(PAs)often involve modifying traditional land use rights and changing the production and living activities of locals,which can lead to changes in the factors that drive land use transitions.Our understanding of the spatiotemporal patterns of land use transition and the contributions of social-ecological drivers remains incomplete.In this study,we focused on the Yarlung Zangbu Grand Canyon National Park and examined how social-ecological factors influence land use transitions by developing a theoretical model of land use transitions within PAs.Our findings revealed that cropland,shrubland,grassland,and wetland experienced net losses in area,while forestland,water,ice/snow,barren land,and impervious land exhibited fluctuating growth patterns from 1985 to 2020.The net decrease in grassland was 157425.60 ha,while the net increase in forest was 140709.20 ha.The quality of land habitat increased from 0.5158 to 0.6656.Land use dominant and recessive transitions displayed varying spatial characteristics and scales across different time periods.In particular,the degree of influence of policy factors on land use dominant transition declined from 0.0800 in 1985-1990 to -0.0432 in 2010-2020,while its influence on land use recessive transition declined from 0.00058 in 1985-1990 to 0 in 2010-2020.The results show that social-ecological factors intricately influenced different types of land use transitions,leading to a shift from a balanced state to a new equilibrium.These results enhance our understanding of the spatiotemporal patterns and complex dynamics of land use transitions within PAs,providing insights and practical implications for effective land management in PAs by considering the land-human relationships.

The Natural Environment Suitability and the Suitability Degree of Human Settlements in Mid-southern Liaoning Urban Agglomerations,China,in Relation to the Population Distribution

Human settlement is a necessary factor for human survival and development.The scientific assessments of the natural suitability and appropriateness of human settlements contribute to addressing the discord between ecological environments and economic development and fostering sustainable development in the relationship between humans and nature.Building upon established methods for assessing human settlement suitability,this study investigated the natural suitability of the living environment in the urban agglomeration of mid-southern Liaoning.Based on this exploration,the suitability of the degree of human settlements for the population distribution in the study area from 2000 to 2020 was calculated.The results revealed three important points.(1)Nearly one-fifth of the study area,the area around the offshoot of Changbai Mountain,is a critically suitable area.More than half of this area,generally the buffer zone connecting the Liaohe Plain and the offshoot of Changbai Mountain,is generally suitable for human settlements.The proportion of suitable areas is only 25.53%,mostly on the Liaohe Plain along the Liaodong Peninsula by the Yellow Sea.(2)The overall spatial distribution of human settlement exhibits a pattern that is moderate-low in the middle and high on both sides;and higher in the southern part and lower in the northern part.(3)The human settlement suitability degree is higher in the western regions and lower in the eastern regions,with Shenyang and Panjin in the west having the highest suitability,while Benxi in the east exhibits the lowest habitat suitability.From 2000 to 2020,except for Shenyang and Panjin where suitability remained constant,the suitability degree of other cities has improved.Among them,Dandong experienced the most significant increase in suitability.

Impact of Human Activities and Climate Change on Grassland Productivity in Xilingol League

Natural grasslands are increasingly subjected to the dual stresses of grazing pressures and climate change.However,the contribution of human activities,especially grassland ecology conservation projects,to grassland improvement remains ambiguous.Utilizing MODIS satellite data in conjunction with the VPM model,the gross primary productivity(GPP)changes in the Xilingol grassland from 2000 to 2020 were assessed.Based on GPP data derived from remote sensing,this study quantitatively assessed the spatiotemporal dynamics of the impacts of climate change and human activities on the productivity of grassland in the Xilingol League.From 2000 to 2020,the grasslands exhibited a greening trend characterized by a significant annual GPP increment of 2.66 gC m^(-2) yr^(-1)(P<0.05).Climate change and human activities jointly contributed to this greening trend,with relative contribution rates of 55%and 45%,respectively.However,the relative contributions of climate change and human activities to the trend of GPP varied greatly in different regions.Climate change emerged as the principal driver in the central and eastern regions of Xilingol League with robust grass growth,accounting for more than 65%of the GPP enhancement.Conversely,human activities were the dominant factors in less verdant western regions and the agro-pastoral ecotone,representing more than 60%of the GPP change.Grassland productivity was sensitive to grassland ecological restoration measures,with significant changes in the trends of grassland productivity attributed to human activities in pivotal policy implementation years such as 2005 and 2011.Specifically,measures such as the control of wind/sand sources and returning grazing land to grassland from 2000 to 2005 gradually alleviated the pressure of human activities on grassland productivity,as they significantly improved vegetation growth in high-quality grasslands.Under the forage-livestock balance policy from 2005 to 2011,inadequate compensation for grassland ecological protection led to a significant reduction in GPP,as some herders increased their livestock holdings despite grazing restrictions,and this particularly affected the high-quality grasslands.The implementation of the Grassland Ecological Protection Subsidy and Reward Program from 2011 to 2020 generally promoted the recovery of productivity in eastern and western Xilingol League grasslands,but significant ecological pressure persisted.This study provides theoretical support for optimizing grassland ecosystem management and forming a virtuous cycle of grassland conservation in pastoral areas.

Characteristics of Spatial and Temporal Vegetation Index Variability and Its Responses to Temperature and Precipitation in Mongolia

The Mongolian Plateau,a vital ecological barrier in northern China,is of great importance for studying vegetation dynamics in Mongolia against the background of climate warming.Such studies can enhance our understanding of regional vegetation responses to global warming and contribute to the establishment of a stronger ecological barrier in northern China.Here,we analyzed the spatial and temporal characteristics of the NDVI(normalized difference vegetation index)in Mongolia using 8 km resolution GIMMS NDVI3g data from 1990 to 2022,along with temperature,precipitation,and elevation data.Trend analysis and correlation methods were used to examine the relationships between the NDVI and temperature,as well as precipitation.The results showed four important aspects of these relationships.(1)The NDVI in Mongolia increased significantly from 1990 to 2022 at a rate of 0.0015 yr^(-1)(P<0.05).(2)Mongolia’s NDVI increased from 1990 to 2022 in 60.73%of the country.Of this total,the area with a significant increase accounted for 31.67%and was concentrated on the eastern and western edges.The area experiencing a significant decrease accounted for 15.67%and was mainly located on the southwestern edges.(3)The NDVI analysis revealed significant increasing trends in all regions except for those at elevations of 1500-2000 m.The greatest rate of increase was observed between 500 and 1000 m,and the increasing trend weakened as elevation continued to increase before gradually becoming significant again.Additionally,the NDVI increased significantly across different slopes,and the rate of increase decreased as the slope increased.(4)From 1990 to 2022,Mongolia’s NDVI was mostly negatively correlated with temperature.This occurred over 66.75%of the total land area,with 17.21%of the region exhibiting a significant negative correlation,mainly in the southwest.Conversely,the NDVI demonstrated a positive correlation with precipitation,encompassing 86.71%of the total land area.Approximately 40.44%of the region had a significant positive correlation,primarily in the southwest.In conclusion,throughout the experimental period,the vegetation state in Mongolia improved.However,due to the warming and drying climate,more attention should be paid to vegetation degradation in the south-central region.

Issues,Progress,and Recommendations in the Construction of Ecological Barrier on the Mongolian Plateau from the Perspective of Big Data

The Mongolian Plateau(MP),situated in the transitional zone between the Siberian taiga and the arid grasslands of Central Asia,plays a significant role as an Ecological Barrier(EB)with crucial implications for ecological and resource security in Northeast Asia.EB is a vast concept and a complex issue related to many aspects such as water,land,air,vegetation,animals,and people,et al.It is very difficult to understand the whole of EB without a comprehensive perspective,that traditional diverse studies cannot cover.Big data and artificial intelligence(AI)have enabled a shift in the research paradigm.Faced with these requirements,this study identified issues in the construction of EB on MP from a big data perspective.This includes the issues,progress,and future recommendations for EB construction-related studies using big data and AI.Current issues cover the status of theoretical studies,technical bottlenecks,and insufficient synergistic analyses related to EB construction.Research progress introduces advances in scientific research driven by big data in three key areas of MP:natural resources,the ecological environment,and sustainable development.For the future development of EB construction on MP,it is recommended to utilize big data and intelligent computing technologies,integrate extensive regional data resources,develop precise algorithms and automated tools,and construct a big data collaborative innovation platform.This study aims to call for more attention to big data and AI applications in EB studies,thereby supporting the achievement of sustainable development goals in the MP and enhancing the research paradigm transforming in the fields of resources and the environment.

Assessing and Comparing Smallholders’Vulnerability to Climate Change among Countries in the Pan-Third Pole Region

A comprehensive assessment of climate change vulnerability is imperative for formulating effective adaptation strategies and advancing sustainable development goals.As one of the most climate-vulnerable regions globally,the Pan-Third Pole area lacks transnational vulnerability assessments,which poses a significant obstacle to efficient climate adaptation.This study conducted transnational comparisons based on primary micro-survey data collected uniformly across Nepal,Cambodia,Thailand,and Myanmar,which are all located in the Pan-Third Pole region.Evaluating and comparing the vulnerabilities employed an extended framework of climate change indicators.The findings reveal substantial variations in vulnerability among the countries,with Cambodia exhibiting the highest vulnerability,followed by Thailand,Myanmar,and Nepal in descending order,primarily due to differences in exposure.Household exposure to climate change also varied significantly.Sensitivity scores decreased in the order of Nepal>Cambodia>Thailand>Myanmar,with demographic factors,tap water accessibility,and land being the major contributors and sources of differentiation among the countries.Regarding adaptability,Thailand demonstrated the highest adaptability,with human and financial capital as the key differentiators.The outcomes underscore the need for tailored policy measures addressing the diverse vulnerabilities,including enhancing household disaster prevention and capital protection.Furthermore,targeted international investments are crucial for improving adaptability among smallholders in this unique region.

The Progress of Resources and Environment Carrying Capacity: from Single-factor Carrying Capacity Research to Comprehensive Research

As a concept to describe development restrictions,resources and environment carrying capacity（RECC）research has developed over more than 100 years since it was first proposed at the beginning of the 20th century.It is now regarded as a significant factor in evaluating the level of cooperation between regional population,resources,and environment;and it is currently used as an effective and operational tool to guide regional sustainable development.This article first reviews the origin of RECC and its early headway.It then reviews the historical development of RECC from single factors,such as land resources carrying capacity,water resources carrying capacity and environmental carrying capacity（environmental capacity）,to more comprehensive research,such as comprehensive evaluation,emergy analysis,and ecological footprint analysis.In general,it appears that comprehensive research will become increasingly important in RECC research.However,there are several deficiencies in the current state of comprehensive research.Firstly,comprehensive RECC research lacks a common measurement standard,though some scholars have attempted to create one.Secondly,the RECC evaluation of open systems and dynamic studies should be strengthened.Thirdly,more attention should be paid to standardization,digitalization,and systematization to promote the applicability of RECC research to national practical demands.

Spatial Differentiation of Rural Touristization and Its Determinants in China: A Geo-detector-based Case Study of Yesanpo Scenic Area

Tourism has emerged as a major driving force in the growth and expansion of rural settlements. After several studies revealed spatial differentiation of touristization among rural settlements, studies were conducted to explain this phenomenon. However, most of these studies explained spatial differentiation of rural touristization in a qualitative way. More robust and detailed quantitative results are needed to evaluate the relative roles of different factors. In this study, which takes Yesanpo tourism as a case study, the Geo-detector method was introduced to evaluate determining factors of rural touristization. Results show that ＂distance to core entry＂, ＂tourist number and sojourn time＂, and ＂distance to the nearest scenic area＂ have had a strong effect on the rural touristization in Ye- sanpo, whereas ＂distance to river＂, ＂elevation＂, ＂distance to main road＂, and ＂slope＂ have had a weak influence. The latter did, however, contribute a lot to touristization when interacting with ＂distance to core entry＂, ＂tourist number and sojourn time＂, and ＂distance to the nearest scenic＂, indicating the importance of these four factors. Higher rural touristization occurred in the zone near the core entry, with many tourists, long sojourn times, and proximity to the scenic area.

Evaluation Methods and Research Trends for Ecological Carrying Capacity

With the intensive research into global coupling relationships,ecological carrying capacity（ECC）,seen as the crucial link between natural ecosystems and human systems,has gradually become an important tool for interdisciplinary research in ecology,resources science and environmental science,as well as for research on regional sustainable development.However,ECC research remains immature and lacks a complete theoretical system,as a result of many limiting factors and different space-time conditions.At present,Chinese and foreign studies focus on methods to evaluate ECC while neglecting to identify the internal driving mechanisms of ECC.In this article,based on the development and conceptualization of ECC,we introduce three evaluation methods for ECC：ecological footprint（EF）,human appropriation of net primary production（HANPP）and ecosystem services consumption（ESC）.Furthermore,we illuminate research focuses and developmental directions for ECC with respect to driving mechanisms,threshold,comprehensive evaluation systems and coupling dynamic model of multi ecological factors,in order to provide a reference for future ECC research.

Changes in China’s Grain Production Pattern and the Effects of Urbanization and Dietary Structure

Grain production patterns are the basis of a nation’s food security.Since China’s reform and opening-up began in 1978,China’s urbanization process,driven by rapid social and economic development,has accelerated steadily.During this time,the dietary structure of urban and rural Chinese has also changed significantly.Accordingly,grain production patterns have undergone major changes.First,traditional grain production patterns in the north and the south have changed,and the food production center has shifted toward the north.In 1980,the grain yield of southern provinces accounted for 60%of China’s total,while that of northern provinces accounted for 40%.In 2015,the grain yield of southern provinces accounted for 56%of the total,while that of northern provinces accounted for 44%.Second,grain production by regions of the country is“shrinking in the east but expanding in the central regions,”meaning that grain production in eastern coastal provinces has decreased significantly,while that in the central region has expanded.The proportions of the nation’s total grain production from the eastern,central and western regions were 38%,36%and 26%,respectively,in 1980.These had changed to 27%,46%,and 27%,respectively,in 2015.Third,the spatial centralization of grain production has increased.The total grain yield of 13 major grain-producing provinces and regions in the country accounted for 69.27%of nation’s total in 1980,and it had reached 76.18%in 2015,showing that the impact of major grain-producing areas on national food security has increased.The influence of rapid urbanization on grain production areas shows remarkable regional differences.As the level of urbanization has increased,build-up land occupies a large number of high-quality farmland,especially in east coastal provinces and thus the grain planting area decreased obviously.The effect of dietary structure changes on grain production patterns was evident in two ways.On the one hand,as dietary diversity has increased,total grain consumption has decreased.The reduction in the proportion of planting area for grain crops to total crop planting area dropped from 82%in 1980 to 68%in 2015,making this change in total grain consumption evident.On the other hand,the ratio of grain for human consumption declined as the ratio of grain consumed by animals increased.The reduction in the proportion of rice and wheat grown and an increase in the proportion of feed grain production(mostly maize)from 20%in the 1980s to 36%in 2015 makes this change in grain production and consumption evident.In the future,with the establishment of national functional areas for grain production,the spatial pattern of grain production will return,while the demand for feed grains will continue to increase but with the space for expansion limited.

An Overview of Ecological Research Conducted on the Qinghai-Tibetan Plateau

The Qinghai-Tibetan Plateau is the highest biogeographic unit on earth and widely regarded as its ‘third pole＇.The high-altitude,frigid and arid alpine ecosystems that form the Plateau are extremely sensitive to climate change and human disturbance.Unsurprisingly,the Plateau is therefore a global epicenter of ecological and global change research and provides the ideal conditions and context to study the impacts of global change.Ecological research conducted on the Plateau can be partitioned into four developmental and chronological phases,beginning with the gathering of primitive knowledge and progressing towards a description of mechanistic processes.Throughout the course of Plateau research paradigm shifts from standalone surveys of biogeographic patterns to fixed monitoring and mechanism research;from isolated population,community and ecosystem approaches to more integrated,multidisciplinary research;and from pure theoretical research to an emphasis on effective resource utilization and sustainable development.Future ecological research will likely pay increasing attention to quantifying the impacts of climate warming and human activity on ecosystem change,and climate and ecosystem feedback processes.Multidisciplinary and comprehensive research should be strengthened amongst fields such as ecosystem ecology,physical geography,environmental science and remote sensing in order to support climate change adaptation and sustainable development in this fragile and unique region.