Driving forces of ＂poplar expansion and cropland shrinkage＂ in the North China Plain：A case study of Wen＇an County,Hebei Province

以Landsat5TM遥感影像、农户调查数据和统计数据为基础数据,运用3S技术提取了案例区河北省文安县1995～2007年土地利用变化信息,分析了杨树扩张的时空格局;并从农户杨树种植决策行为视角,运用数理统计、投入产出法分析了杨树扩张占地的驱动因素。结论如下：（1）杨树林地扩张幅度大、速率快。（2）杨树扩张所用土地92.14%来源于耕地,＂杨上粮下＂现象突出。（3）杨树扩张速率的空间差异显著。杨树扩张受生产要素、土地产品市场及政策因素的综合驱动,其中劳动力因素和经济因素起主要作用。（4）非农从业人员比率和农民年人均收入越高,杨树扩张速度越快。在劳动力由富余转为相对稀缺的情况下,农户为提高经济收益,倾向选择耗工少,劳动生产率较大的杨树,是杨树扩张占地的根本原因。     

Spatiotemporal mismatch of land use functions and land use efficiencies and their influencing factors:A case study in the Middle Reaches of the Yangtze River,China

Identification of the spatial mismatch between land use functions(LUFs) and land use efficiencies(LUEs) is essential to regional land use policies. However, previous studies about LUF-LUE mismatch and its driving factors have been insufficient. In this study, we explored the spatiotemporal mismatch of LUFs and LUEs and their influencing factors from 2000 to 2018 in the Middle Reaches of the Yangtze River(MRYR). Specifically, we used Spearman correlation analysis to reveal the trade-off relations...     

Soil quality and sustainable land use in urban-rural marginal area: a case study of Kaifeng

Soil quality is closely related to the sustainability of environment and development[1], hence people have paid more and more attention to soil quality research in recent years, and have made a thorough inquiry of the definition of soil quality as well as the method and theory of its expression[2-4]. As a zone devoting to most intensive modern agricultural land use, urban-rural marginal area has become a region where intensity of soil quality change is most remarkable. Moreover, with the devel…     

Evaluation of suitability,adaptability, and reserve potential of construction land on the Qinghai-Tibet Plateau

Construction land is the leading carrier of human activities such as production and living. Evaluating the construction land suitability(CLS) on the Qinghai-Tibet Plateau(QTP) holds significant implications for harmonizing the relationship between ecological protection and human activity and promoting population and industry layout optimization. However, no relevant studies provide a complete CLS assessment of the QTP. In this study, we developed a model-based CLS evaluation framework coupling o...     

Forest Fire Alert System: a Geo Web GIS prioritization model considering land susceptibility and hotspots – a case study in the Carajás National Forest,Brazilian Amazon

To increase the monitoring potential of forest fires, an alert classification methodology using satellite-mapped hotspots has been established to help forest managers in the prioritization of which hotspot to be verified in the field, thus potentially improving the distribution of fire-fighting resources. A computer application was developed based on web-distributed geographical information technology whose main function is to interact automatically generated satellite hotspots and risk areas indicated in fire-susceptibility maps and classify them into five alert levels. The location of the hotspots is available continuously every 4 h, and a susceptibility map is produced daily through map algebra algorithm, which uses static (topography, vegetation and land use) and dynamic (weather) variables. Every process runs through automated geoprocessing routines. The methodology was tested during the dry period of 2007 in the Carajás National Forest, in the Brazilian Amazon, within an area of 400,000 ha. It is a critical area constantly threatened by fires caused by invasions and deforestation owing to intense agribusiness advances and mining activities in its surroundings. This situation results in observations of many hotspots inside the study area for the same day and almost the same time period, in places of extreme opposites, demanding complex rapid analysis and hindering the decision of the displacement of fire-fighting teams. Further, a major mining company operates within the National Forest area, maintaining actions of protection as part of its environmental mining license. Results are presented under three aspects: (i) the credibility of the daily susceptibility map (algorithm), which showed strong correlation between areas of greatest risks and the confirmed forest fires; (ii) the reliability of hotspots (alert levels), confirming 71% of fires; (iii) accuracy in the decision of which hotspot to be checked, which revealed the same number of verifications at different alert levels, 82% confirmed alert 5 hotspots (maximum) and only 50% from alert 1 (minimum), resulting in faster fire-fighting actions, minimizing burned areas and, in some cases, allowing fire control before its spreading. Therefore, the methodology demonstrated that GIS routines are able to determine the relationship between a reality-based, interpreted susceptibility map of the area and satellite-generated hotspots, highlighting the ones of highest hazard level through the alert classification, becoming an important tool to help decisions from the fire-control center, especially for high-risk regions. The methodology may be extrapolated to other forested areas.     

Driving factors and spatiotemporal effects of environmental stress in urban agglomeration: Evidence from the Beijing–Tianjin–Hebei region of China

Environmental stress is used as an indicator of the overall pressure on regional environmental systems caused by the output of various pollutants as a result of human activities. Based on the pollutant emissions and socioeconomic databases of the counties in Beijing–Tianjin–Hebei region, this paper comprehensively calculates the environmental stress index(ESI) for the urban agglomeration using the entropy weight method(EWM) at the county scale and analyzes the spatiotemporal patterns and the differences among the four types of major functional zones(MFZ) for the period 2012–2016. In addition, the socioeconomic driving forces of environmental stress are quantitatively estimated using the geographically weighted regression(GWR) method based on the STIRPAT model framework. The results show that:(1) The level of environmental stress in the Beijing–Tianjin–Hebei region was significantly alleviated during that time period, with a decrease in ESI of 54.68% by 2016. This decrease was most significant in Beijing, Tangshan, Tianjin, Shijiazhuang, and other central urban areas, as well as the Binhai New Area. The level of environmental stress in counties decreased gradually from the central urban areas to the suburban areas, and the high-level stress counties were eliminated by 2016.(2) The spatial spillover effect of environmental stress increased further at the county scale from 2012 to 2016, and spatial locking and path dependence emerged in the cities of Tangshan and Tianjin.(3) Urbanized zones(development-optimized and development-prioritized zones) were the major areas bearing environmental pollution in the Beijing–Tianjin–Hebei region in that time period. The ESI accounted for 65.98% of the whole region, where there was a need to focus on the prevention and control of environmental pollution.(4) The driving factors of environmental stress at the county scale included population size and the level of economic development. In addition, the technical capacity of environmental waste disposal, the intensity of agricultural production input, the intensity of territorial development, and the level of urbanization also had a certain degree of influence.(5) There was spatial heterogeneity in the effects of the various driving factors on the level of environmental stress. Thus, it was necessary to adopt differentiated environmental governance and reduction countermeasures in respect of emission sources, according to the intensity and spatiotemporal differences in the driving forces in order to improve the accuracy and adaptability of environmental collaborative control in the Beijing–Tianjin–Hebei region.     

A green space between life and death – a case study of activities in Gamlebyen Cemetery in Oslo,Norway

The amount of green space in urban areas is shrinking. Densification and the introduction of new user groups in most cities today is leading to more intensive use of public spaces and the need for more space. Urban cemeteries constitute a unique type of public space: while some may consider them primarily religious and contemplative spaces, others see them as primarily recreational or as heritage sites steeped in history. The authors examine the extent to which the pressure on cities’ open green areas combined with influences from intercultural encounters is mirrored in the use and character of cemeteries today – exemplified by Gamlebyen Cemetery (Gamlebyen Gravlund) in Oslo, Norway. They used observations in combination with short semi-structured interviews with those using the cemetery. The findings of pilot study conducted in 2013 suggest that religious aspects played a minor role and that the recreational aspects were more important to most of the interviewees. Many of them considered that the cemetery provided a pleasant green walkway on their way to work, busses or city services. The cemetery offered a combination of calmness, an aesthetically pleasant environment, and ‘cultivated nature’ in an urban context, and was thus an arena that invited respect and esteem.     

A study on the spatial flow intensity of overseas travelers in tourist hotspots of China──taking Beijing as an example

A series of spatial ~feding for traVeler's retUrn from the starting place of touriSt source conshtUtes thewhole process of tourist flow ti]. The tourist flow is the bilatelal directions of touristS in the whole processby going to tile tourist destinations from the place of tourist souxces and returning to that source. ThetouriSt flow is tile main and core body that has the decisive and restricted funchons for touriSt matter flowand energy flow [21. There are few researches on the fiXing amo…     

Urban expansion and intra-urban land evolution as well as their natural environmental constraints in arid/semiarid regions of China from 2000–2018

Rapid urbanization has occurred in arid/semiarid China, threatening the sustainability of fragile dryland ecosystems; however, our knowledge of natural environmental constraints on multiscale urban lands in this region is still lacking. To solve this issue, this study retrieved 15-m multiscale urban lands. Results indicated that urban area increased by 68%during 2000–2018, and one-third of the increase was contributed by only three large cities.The coverage of impervious surface area(ISA) and ve...     

Identification and analysis of root causes of desertification in semi-arid region of China──a case study from Ejin Horo Banner, Inner Mongolia

1 IntroductionDeseamcation. defined as land degradation in tri4 send-arid and dry SUb-htald areas reSulhng fromvarious factors, including cljjnatic variahons and human activihes, is a world-wide phenomenon whichcauses the end's ecosystems to deteriorate. Nowadays it edicts about tWo-thirds of the coUntries of theworld, and one-third of the earth's surface, on which one-ffe of the world population liVe.Desertilicahon is accompanied by a reduction in the natUI'al potenhal Of the land ecosyst…     

Impacts and effects of government regulation on farmers’ responses to drought: A case study of North China Plain

Frequent extreme weather events like drought, etc. in the context of climate change present huge challenges to agricultural production. To find out if farmers have taken measures against them and identify governments’ impact on their response measures are the foundation of and key to further improving relevant policies and farmers’ responsiveness. Taking the North China Plain as an example, the study analyzes farmers’ responses to frequent climate change-induced drought, and assesses the impacts of governments’ early-warning, policy support and other factors on farmers’ responses based on questionnaire survey data and an econometric approach. The results show that: (1) Farmers are responsive to drought, and they are more likely to take measures as the degree of drought deepening. (2) Governments’ regulation affects farmers’ responses, although only part of its regulation measures has remarkable effects. Governments’ early-warning messages can increase the possibility of farmers’ responding to drought, however, only when they get the early-warning in all the processes including before, during, and after disasters can the effects be significant. Currently, as the primary channel through which early-warning information is released, television cannot change farmers’ behaviors significantly. Early-warning is most effective when spread via two or more types of channels. In addition, governments’ (especially town and village level institutions’) policy support has certain impacts on farmers’ responses to drought, yet with less prominent effects in disaster years than in normal years; to provide subsidies, as a regulation measure, can encourage farmers’ initiative a lot in adopting response measures, but most of the farmers haven’t got support from any institutions. Both the structure and strength of government regulation need to be improved. (3) Farmers with different conditions respond differently. Farmer households in irrigation areas, those whose farmland is lower fragmented, and those with numerous agricultural family members tend to take response measures. The study can provide scientific reference to the making of relevant regulation policies under the background of acidifications.     

Urban investment and development corporations,new town development and China’s local state restructuring – the case of Songjiang new town,Shanghai

This article seeks to understand China’s new urban space production and associated state space rescaling through a microscopic investigation of urban investment and development corporations (UIDCs), based on a case study of Shanghai’s Songjiang New Town Development Corporation (SNTDC). It argues that the introduction of UIDCs as both developers and managers of designated urban regions is a creation of institutional reformation to accomplish customized place- and scale-specific spatial projects under the state strategy of new urban spatial development, playing an essential part in the rescaling of state space. UIDCs are economically independent of other social groups, politically bonded with the local government, and assume entrepreneurial and administrative functions within designated areas, acting as intermediary agents to enable local states greater capacity in governing new urban space production, engineering social change, and propelling economic development.     

The altitudinal climatic effect on the stable isotope compositions of Agave and Opuntia in arid environments – A case study at the Big Bend National Park,Texas, USA

Several environmental factors potentially influence the stable isotope compositions of plants, depending on species and local environment. Although several studies have discussed these aspects in C₃ and C₄ plants, only a few have attempted to identify the major drivers of δ¹³C, δ¹⁸O, and δ¹⁵N in CAM plants. In this study, stable isotopic ratios of CAM plants collected along an altitudinal transect in the Chisos Mountains/USA during two growth seasons, are used to understand major factors governing isotopic variability. A strong and significant relationship between δ¹³C and altitude, positive for agave at <1700 m and negative for both agave and cacti at >1500 m, suggests variable carbon isotope fractionation at different altitudes, which may be unique to CAM plants. Our data suggest that temperature primarily governs δ¹³C of the studied plants. The significant negative correlations observed between the δ¹⁸O of agaves and the recorded air temperature (0.59‰/°C) are similar to the δ¹⁸O of precipitation vs. temperature variability in global data. The δ¹⁵N variations suggest a similar N-source for both agaves and cacti, and reflect progressive changes in the dominant N-source across desert–grassland–woodland zones. We conclude that the stable carbon and oxygen isotope composition of agave reflects the climatic conditions along the elevation transect.     

Simulating,adjusting and testing regional sustainable development──a case study of Jiangxi Province

IntroductionRegional sustainable development refers to a Synthehc System of coordinated growth of populationsresources, economy and environmental protechon. The most Anpoltant thing in regional suStainabledeVelopment is to establish a SyStemic cycle between socio-economic activihes, resources, environmentand POpulation.Each region is an open and complex System[']. And every regional System has its own deVelopmentpattern However, it should be noted that there is one major difference in re…     

Spatial precipitation and evapotranspiration in the typical steppe of Inner Mongolia,China – A model based approach using MODIS data

We present a simple method to derive spatial precipitation (P) and evapotranspiration (ET) for the typical steppe of the Xilin river catchment at 1 km and 8-day resolution during the main vegetation period (23 April to 28 August) of 2006. The hydrological model BROOK90 was parameterised from eddy covariance measurements. The daily model input data, precipitation, minimum (Ta_min) and maximum air temperature (Ta_max), were derived by manipulating MODIS leaf area index (LAI) and surface temperature data. P was estimated based on a linear regression of P measured at several sites against the mean gain of the MODIS LAI of surrounding 3 × 3 pixels areas (R² = 0.76). Ta_min and Ta_max were derived using a relationship between measured Ta_min and Ta_max and MODIS surface temperatures (R² = 0.92 and R² = 0.88, respectively). The mean precipitation was 145 mm; it varied between 52 mm in the north-western region and 239 mm in the eastern region. In spring, the modelled ET was low (<0.8 mm d⁻¹); evaporation dominated over transpiration and spatial differences were small. At the end of June, the mean ET reached its maximum (2 mm d⁻¹) and spatial differences were pronounced. From July on, transpiration dominated over declining evaporation, and spatial differences decreased in August.     

The impact of cropland conversion on environmental effect in the Loess Plateau：a pilot study based on the national experimental bases

1 Introduction The soilerosion in Loess Plateau is mostserious on the globe mainly due to the destroying of naturalvegetation and cultivation on slope land overextensive areas(Yang and Yu,1992;Jiang, 1997).To convertsloping cropland (cropped land on slope…     

Evaluation of the SNOWPACK model’s metamorphism and microstructure in Canada: a case study

The snow thermodynamic multi-layer model SNOWPACK was developed to address the risk of avalanches by simulating the vertical properties of snow. Risk and stability assessments are based on the simulation of the vertical variability of snow microstructure, as well as on snow cohesion parameters. Previous research has shown systematic error in grain size simulations (equivalent optical grain size) over several areas in northern Canada. To quantify the simulated errors in snow grain size and uncertainties in stability, the snow specific surface area (SSA) was measured with a laser-based instrument. Optical grain size was retrieved to validate the optical equivalent grain radius from SNOWPACK. The two study plots are located in Glacier National Park, BC, and Jasper National Park, AB, Canada. Profiles for density and stratigraphic analysis were obtained as well as grain size profiles, combined with snow micropenetrometer (SMP) measurements. Density analysis showed good agreement with the simulated values (R² = 0.76). Optical grain size analysis showed systematic overestimation of the modeled values, in agreement with the current literature. The error in SSA evolution for a rounding environment was mostly constant, whereas error for conditions driven by a temperature gradient was linked to the size of the facetted grains.     

Plant life in the Umm as Samim,Oman – A case study in a major inland sabkha

The Umm as Samim is a vast salt flat of central Oman, in which many wadis which flow south-westwards from the central sector of the northern mountains converge. Most of the area is devoid of vegetation due to extraordinary salinity (sabkha). Significant plant growth is possible chiefly on miniature dunes, called nabkhas, which enable the plants to prosper in an otherwise harsh environment.The site conditions are depicted by mapping of miniature dunes and vegetation, accompanied by an account of morphometric parameters, i.e. height of nabkha, height of plant growth, and status of plant life. Within the chosen sample plot, 12.3% of the sabkha is covered by nabkhas. The total plant cover amounts to 5.0%, but only 3.1% of it is alive, while 2.0% is dead or lifeless.Two nabkhas were longitudinally excavated to examine the salinity of soil samples in relation to dune structure and root and shoot system position. The salinity analysis was done via electrical conductivity (EC_{1:5 extract}). Extremely high EC values were found on current or former sabkha surfaces and on the periphery of nabkhas, whereas central nabkha parts and bottom soil offer more favourable salinity values for plant and root growth.     

Farmers' decision making on land use—the importance of soil conditions in the case of Río Cabuyal watershed,Colombia

Biophysical conditions and in particular soil conditions are generally seen as important determinants of land use and receive much emphasis both in land use planning and in attempts to understand actual land use patterns. This paper explores the justification for this emphasis. Based on a study of farmers' decisions regarding land use type (forest, pasture, fallow or crop) and crop choice in the Colombian Andes, the paper shows that despite farmers' detailed knowledge of the diverse soil conditions in the area, other factors, such as total farm size and market and input-related concerns, are more important for farmers' actual choice of land use type and crop.     

An active crawler for discovering geospatial Web services and their distribution pattern – A case study of OGC Web Map Service

The increased popularity of standards for geospatial interoperability has led to an increasing number of geospatial Web services (GWSs), such as Web Map Services (WMSs), becoming publicly available on the Internet. However, finding the services in a quick and precise fashion is still a challenge. Traditional methods collect the services through centralized registries, where services can be manually registered. But the metadata of the registered services cannot be updated timely. This paper addresses the above challenges by developing an effective crawler to discover and update the services in (1) proposing an accumulated term frequency (ATF)–based conditional probability model for prioritized crawling, (2) utilizing concurrent multi-threading technique, and (3) adopting an automatic mechanism to update the metadata of identified services. Experiments show that the proposed crawler achieves good performance in both crawling efficiency and results' coverage/liveliness. In addition, an interesting finding regarding the distribution pattern of WMSs is discussed. We expect this research to contribute to automatic GWS discovery over the large-scale and dynamic World Wide Web and the promotion of operational interoperable distributed geospatial services.