China’s different spatial patterns of population growth based on the “Hu Line”

The “Hu Line” has been regarded as one of the greatest geographical discoveries in China because it reveals the significant spatial relationship between human activity and natural environment. The spatial evolution of population on both sides of the “Hu Line” has had important implications for both urbanization and regional development and has attracted widespread attention during the dramatic economic and social changes since the implementation of reform and opening-up policy in China in 1978. Using Geographical Information System (GIS) techniques, this paper studied the stability of the “Hu Line” and the spatial patterns of population growth on each side by constructing a spatial database of China’s census data from 1982 to 2010. The findings are as follows: (1) In the last 30 years, the “Hu Line” has remained relatively stable, but a new tendency of population change has begun to emerge. The population ratio either side, namely, the southeast half (SEH) and the northwest half (NWH), of the “Hu Line” remains at roughly 94:6 (SHE: NWH). Noteworthy, the proportion of population in the SEH of the “Hu Line” has been decreasing slightly, while that in the NWH has been increasing slightly, as the latter has benefited from its higher rate of natural population growth. (2) The spatial patterns of population growth on both sides of the “Hu Line” were quite different. The degree of population concentration in the SEH increased faster than the NWH. Regions with a negative population growth rate have rapidly expanded; these were mainly located in the south of the “Qinling Mountains-Huaihe River belt” and northeastern China. Meanwhile, regions with a fast population growth rate were mainly concentrated in the Yangtze River Delta, the Pearl River Delta, and the Beijing-Tianjin metropolitan area. Thus, the spatial pattern of population growth in the SEH presented a concentration pattern that could be called “Matthew effect pattern”. (3) The spatial pattern of population growth in the NWH could be regarded as the “Relative Balance pattern.” In the NWH, the population growth rate was positive and the degree of population concentration was very low. There were many minority populations located in the NWH that usually lived in a dispersed pattern but had a higher rate of natural population growth due to the preferential population policy. There were also some regions with a negative rate of population growth in the NWH, which were mainly located close to the “Hu Line” and the Ancient Silk Road. (4) In the future, the spatial patterns of population growth on both sides of the “Hu Line” may continue to evolve. For the SEH, the capacity to attract more people to small and medium-sized cities and towns should be enhanced. For the NWH, the emphasis should be placed on promoting urbanization and enhancing population agglomeration in its major cities.     

中国城市空间网络分析——基于电子信息企业生产网络视角

通过分析国内外城市网络研究的理论与方法,基于电子信息企业生产网络视角,对中国城市网络的空间特征进行了探索。研究发现:在中国制造业企业500强和世界500强中,电子信息企业总部集中于以北京、上海和深圳为核心的三大沿海都市圈,以及中西部地区的特大城市和省会城市,其研发机构与总部区位特征具有一定相似性,生产基地分布相对分散。由中国企业和跨国公司所主导的中国城市网络,可划分为地方化和全球化两种类型,均以东部及中西部特大城市为网络核心节点。地方化型城市网络的企业总部节点城市较为分散,网络密度和连接度较小;全球化型城市网络则以北京和上海为核心节点,对外联系程度相对较高。与传统城市等级体系相比,城市网络体系具有更强的包容性,从中可以发现崛起中的专业化城市。     

Impacts of El Nino-Southern Oscillation events on China＇s rice production

This paper aims to demonstrate the relationships between ENSO and rice production of Jiangxi province in order to identify the reason that ENSO might have little effect on Chinese rice production. Using a data set with measures of Jiangxi’s climate and rice production, we find the reason that during 1985 and 2004 ENSO’s well correlated with rainfall did not promote Chinese rice production. First, the largest effects of ENSO mostly occur in the months when there is no rice in the field. Second, there is almost no temperature effect. Finally, the monthly distribution of rainfall is almost the same in ENSO and neutral years because the largest effects are during months when there is the least rain. In addition, due to the high irrigation share and reliable and effective irrigation facilities of cultivated land, China’s rice production is less climate-sensitive.     

The effect of environmental factors on spatial variability in land use change in the high-sediment region of China’s Loess Plateau

In areas with topographic heterogeneity, land use change is spatially variable and influenced by climate, soil properties, and topography. To better understand this variability in the high-sediment region of the Loess Plateau in which soil loss is most severe and sediment diameter is larger than in other regions of the plateau, this study builds some indicators to identify the characteristics of land use change and then analyze the spatial variability as it is affected by climate, soil property, and topography. We build two indicators, a land use change intensity index and a vegetation change index, to characterize the intensity of land use change, and the degree of vegetation restoration, respectively. Based on a subsection mean method, the two indicators are then used to assess the spatial variability of land use change affected by climatic, edaphic, and topographic elements. The results indicate that： 1） Land use changed significantly in the period 1998-2010. The total area experiencing land use change was 42,302 km2, accounting for 22.57%of the study area. High-coverage grassland, other woodland, and forest increased significantly, while low-coverage grassland and farmland decreased in 2010 compared with 1998.2） Land use change occurred primarily west of the Yellow River, between 35 and 38 degrees north latitude. The four transformation types, including （a） low-coverage grassland to medium-coverage grassland, （b） medium-coverage grassland to high-coverage grassland, （c） farmland to other woodland, and （d） farmland to medium-coverage grassland, were the primary types of land use change, together constituting 60% of the area experiencing land use change. 3） The spatial variability of land use change was significantly affected by properties of dryness/wetness, soil conditions and slope gradient. In general, land use changed dramatically in semi-arid regions, remained relatively stable in arid regions, changed significantly in clay-rich soil, remained relatively stable in clay-poor soil, changed dramatically in steeper slopes, and remained relatively stable in tablelands and low-lying regions. The increase in vegetation coincided with increasing changes in land use for each physical element. These findings allow for an evaluation of the effect of the Grain to Green Program, and are applicable to the design of soil and water conservation projects on the Loess Plateau of China.     

The comprehensive evaluation of China＇s urbanization and effects on resources and environment

This paper constructs a comprehensive evaluation index system for the urbanization level in China in terms of four aspects of urbanization connotation: population, economy, society, and land. A comprehensive measurement is carried out for the Chinese urbanization between 1981 and 2006 based on the Entropy method. The results show that the comprehensive level of urbanization in China has a continuous increase with the major features of economic growth and a rapid evolution of the geographical landscape, followed by population urbanization and then social urbanization of health care standard; the distinguished evolutional characteristics can also be found in each of the subsystems. The integrated evolution of urbanization has a profound effect on the resources, energy and the environment, making the land resources and energy security situation under severe pressure. The environment pressure is also increased further.     

Vulnerability of natural ecosystem in China under regional climate scenarios:An analysis based on eco-geographical regions简

Assessment of vulnerability for natural ecosystem to climate change is a hot topic in climate change and ecology, and will support adapting and mitigating climate change. In this study, LPJ model modified according to features of China＇s natural ecosystems was em- ployed to simulate ecosystem dynamics under A2, B2 and A1B scenarios. Vulnerability of natural ecosystem to climate change was assessed according to the vulnerability assessment model. Based on eco-geographical regions, vulnerability of natural ecosystem to climate change was analyzed. Results suggest that vulnerability for China＇s natural ecosystems would strengthen in the east and weaken in the west, but the pattern of ecosystem vulner- ability would not be altered by climate change, which rises from southeast to northeast gradually. Increase in ecosystem vulnerable degree would mainly concentrate in temperate humid/sub-humid region and warm temperate humid/sub-humid region. Decrease in eco- system vulnerable degree may emerge in northwestern arid region and Qinghai-Tibet Plateau region. In the near-term scale, natural ecosystem in China would be slightly affected by cli- mate change. However, in mid-term and long-term scales, there would be severely adverse effect, particularly in the east with better water and thermal condition.