Ecological land rent is the excess profit produced by resource scarcity, and is also an important indicator for measuring the social and economic effects of resource scarcity. This paper, by calculating the respective ecological land rents of all the provinces in China for the years 2002 and 2007, and with the assistance of the software programs ArcGIS and GeoDA, analyzes the spatial differentiation characteristics of ecological land rent; then, the influencing factors of ecological land rent differentiation among the provinces are examined using the methods of traditional regression and spatial correlation analysis. The following results were obtained: First, ecological land rent per unit of output in China shows stable distribution characteristics of being low in the southwestern and northeastern provinces, and high in Hebei and Henan provinces. There is also an increasing tendency in the central and western provinces, and a decreasing one in the eastern provinces. In general, the spatial distribution of ecological land rent per unit of output in China is quite scattered. Second, the total ecological land rent shows significant spatial aggregation characteristics, in particular the provinces in China possessing high total amounts of ecological land rent tend to be adjacent to one another, as do those with low total amounts, and the spatial difference characteristics of the eastern, central and western provinces are distinguished. The Bohai Rim, Yangtze River Delta and Pearl River Delta are shown to be highly clustering regions of total ecological land rent, while the western provinces have very low ecological land rent in terms of total amount. Third, population distribution, economic level and industrial structure were all important influencing factors influencing ecological land rent differentiation among provinces in China. Furthermore, population density, urbanization level, economic density, per capita consumption level and GDP per capita were all shown to be positively related to total ecological land rent, which indicates that spatial clustering exists between ecological land rent and these factors. However, there was also a negative correlation between ecological land rent and agricultural output percentage, indicating that spatial scattering exists between ecological land rent and agricultural output percentage.
The changes in cropland quantity and quality due to land use are critical concerns to national food security, particularly for China. Despite the significant ecological effects, the ecological restoration program (ERP), started from 1999, has evidently altered the spatial patterns of China’s cropland and agricultural productivity. Based on cropland dynamic data from 2000 to 2008 primarily derived from satellite images with a 30-m resolution and satellite-based net primary productivity models, we identified the impacts on agricultural productivity caused by ERP, including “Grain for Green” Program (GFGP) and “Reclaimed Cropland to Lake” (RCTL) Program. Our results indicated that the agricultural productivity lost with a rate of 132.67×104 t/a due to ERP, which accounted for 44.01% of the total loss rate caused by land use changes during 2000-2005. During 2005-2008, the loss rate due to ERP decreased to 77.18×104 t/a, which was equivalent to 58.17% of that in the first five years and 30.22% of the total loss rate caused by land use changes. The agricultural productivity loss from 2000-2008 caused by ERP was more attributed to GFGP (about 70%) than RCTL. Although ERP had a certain influence on cropland productivity during 2000-2008, its effect was still much less than that of urbanization; moreover, ERP was already converted from the project implementation phase to the consolidation phase.
The urban ecosystem possesses dissipating structures that can absorb substances and energy from the external environment and export products and wastes to maintain order within the system. Given these circumstances, this paper analyzed the ability of the urban ecosystem in Guangzhou City to sustain development from the perspective of entropy. The research was carried out in three steps. First, an evaluation index system that considers the ability of the urban ecosystem for sustainable development was formed based on the structures and functions of the urban ecosystem and the change in the entropy of the urban socioeconomic ecosystem. Second, the sustainable development ability assessment model for the urban ecosystem was built using information entropy. Last, by combining the time series variation of the evaluation indicators with the entropy weights, this paper analyzed the influence of the combined factors on the sustainable development ability of the urban ecosystem in Guangzhou and suggested some measures to promote the sustainable development of the urban ecosystem in Guangzhou. The conclusions of this study can be summarized as follows: (1) The urban ecosystem has developed in an orderly and healthy direction, with effective control over the urban environmental pollution problems in Guangzhou between 2004 and 2010. (2) The sustainable development ability of the urban ecosystem had been on an upward trend in Guangzhou during the study period. The ability of the natural urban ecosystem to support the urban socioeconomic ecosystem increased continuously, and the improved ecoenvironment enhanced the harmony and vitality of the urban ecosystem in Guangzhou.
China is physically and socio-economically susceptible to global warming-derived high temperature extremes because of its vast area and high urban population density. This article presents a scenario-based analysis method for high temperature extremes aimed at illustrating the latter’s hazardous potential and exposure across China. Based on probability analysis, high temperature extreme scenarios with return periods of 5, 10, 20, and 50 years were designed, with a high temperature hazard index calculated by integrating two differentially-weighted extreme temperature indices (maximum temperature and high temperature days). To perform the exposure analysis, a land use map was employed to determine the spatial distribution of susceptible human activities under the different scenarios. The results indicate that there are two heat-prone regions and a sub-hotspot occupying a relatively small land area. However, the societal and economic consequences of such an environmental impact upon the North China Plain and middle/lower Yangtze River Basin would be substantial due to the concentration of human activities in these areas.
Based on a monthly dataset of precipitation time series (1961-2010) from 12 meteorological stations across the Three-River Headwater Region (THRHR) of Qinghai Province, China, the spatio-temporal variation and abrupt change analysis of precipitation were examined by using moving average, linear regression, spline interpolation, the Mann-Kendall test and so on. Major conclusions were as follows. (1) The long-term annual and seasonal precipitation in the study area indicated an increasing trend with some oscillations during 1961-2010; however, the summer precipitation in the Lantsang (Lancang) River Headwater Region (LARHR), and the autumn precipitation in the Yangtze River Headwater Region (YERHR) of the THRHR decreased in the same period. (2) The amount of annual precipitation in the THRHR and its three sub-headwater regions was greater in the 1980s and 2000s. The springs were fairly wet after the 1970s, while the summers were relatively wet in the 1960s, 1980s and 2000s. In addition, the amount of precipitation in the autumn was greater in the 1970s and 1980s, but it was relatively less for the winter precipitation, except in the 1990s. (3) The normal values of spring, summer, winter and annual precipitation in the THRHR and its three sub-headwater regions all increased, but the normal value of summer precipitation in the LARHR had a negative trend and the normal value of winter precipitation declined in general. (4) The spring and winter precipitation increased in most of the THRHR. The summer, autumn and annual precipitation increased mainly in the marginal area of the west and north and decreased in the regions of Yushu, Zaduo, Jiuzhi and Banma. (5) The spring and winter precipitation in the THRHR and its three sub-headwater regions showed an abrupt change, except for the spring precipitation in the YARHR. The abrupt changes of spring precipitation were mainly in the late 1980s and early 1990s, while the abrupt changes of winter precipitation were primary in the mid- to late 1970s. This research would be helpful for further understanding the trends and periodicity of precipitation and for watershed-based water resource management in the THRHR.
The paper presents results of a study on the sediment supply and movement of highly turbid sediment plume within Malindi Bay in the Northern region of the Kenya coast. The current velocities, tidal elevation, salinity and suspended sediment concentrations (TSSC) were measured in stations located within the bay using Aanderaa Recording Current Meter (RCM-9), Turbidity Sensor mounted on RCM-9, Divers Gauges and Aanderaa Temperature-Salinity Meter. The study established that Malindi Bay receives a high terrigenous sediment load amounting to 5.7×106 ton·yr-1. The river freshwater supply into the bay is highly variable ranging from 7 to 680 m3·s-1. The high flows that are > 150 m3·s-1 occurred in May during the South East Monsoon (SEM). Relatively low peak flows occurred in November during the North East Monsoon (NEM) but these were usually <70 m3·s-1. The discharge of highly turbidity river water into the bay in April and May occurs in a period of high intensity SEM winds that generate strong north flowing current that transports the river sediment plume northward. However, during the NEM, the river supply of turbid water is relatively low occurring in a period of relatively low intensity NEM winds that result in relatively weaker south flowing current that transports the sediment plume southward. The mechanism of advection of the sediment plume north or south of the estuary is mainly thought to be due to the Ekman transport generated by the onshore monsoon winds. Limited movement of the river sediment plume southward towards Ras Vasco Da Gama during NEM has ensured that the coral reef ecosystem in the northern parts of Malindi Marine National Park has not been completely destroyed by the influx of terrigenous sediments. However, to the north there is no coral reef ecosystem. The high sediment discharge into Malindi Bay can be attributed to land use change in the Athi-Sabaki River Basin in addition to rapid population increase which has led to clearance of forests to open land for agriculture, livestock grazing and settlement. The problems of heavy siltation in the bay can be addressed by implementing effective soil conservation programmes in the Athi-Sabaki Basin. However, the soil conservation programmes in the basin are yet to succeed due to widespread poverty among the inhabitants and the complications brought about by climate change.
Based on measured data of coastline and bathometry, processed by softwares of Surfer and Mapinfo, and combined with sediment loads in different phases at Lijin gauging station, temporal and spatial evolution of coastline and subaqueous geomorphology in muddy coast of the Yellow River Delta is analyzed. The results show that ~68% of sediments were delivered by the Yellow River deposited around the river mouth and in the littoral area from 1953 to 2000. Coastline in different coasts had distinctive changes in response to shifts of river course. Coastline was stable in the west of the Diaokou river mouth. Coastline from the east of the Diaokou river mouth to the north of the Gudong oilfield had experienced siltation, then serious erosion, and finally kept stable with sea walls conservation. Generally, coastline of the survived river mouth of the Qingshuigou river course stretched seaward, whereas the south side of sand spit at the Qingshuigou old river mouth was eroded after the Yellow River inpouring near the position at the Qing 8. The subaqueous geomorphology off the survived river mouth exhibited siltation from 1976 to 1996, with flat topset beds and steeper foreset beds. From 1996 to 2005, the subaqueous geomorphology off the Qingshuigou old river mouth was eroded in the topset and foreset beds, but silted in the bottomset beds. The subaqueous geomorphology off the new river mouth sequentially performed siltation with small degree compared to that of 1976-1996.
There exists great potential of rural land consolidation in China due to the aggravated hollowed villages against the background of rapid rural-urban transformation. The paper aims to investigate the potential of rural land consolidation within four urbanization scenarios: Complete urbanization, Semi-urbanization, Urbanization in batches and prospective urbanization in 2020. Research findings show that, (1) the potentials of rural land consolidation in complete and semi-urbanization are 809.89×104 hm2 and 699.19×104 hm2 respectively while rural consolidation rates are 50.70% and 43.77%. As for the urbanization in batches and urbanization in 2020, the potentials are 757.89×104 hm2 and 992.16×104 hm2. (2) Beside Tibet and Ningxia, rural consolidation rates in most provinces are between 40% and 60%, and the land increase rates are between 3% and 12%. Significant correlation between potential of rural land consolidation and the degree of hollowed villages is also found. (3) Evident differences of potential of rural land consolidation exist across provinces. Rural consolidation rates in the East and Central provinces are higher than that in the West provinces. Villages in the developed areas have higher consolidation rates than those in the less developed areas, and villages in the plain areas tend to have higher consolidation rates than those in the mountainous areas.
This paper provides a detailed analysis of the factors influencing the evolution of rural settlements, including natural environmental constraints, infrastructure, regional cultural inheritance and integration, urbanization and rural industrial transformation, land use reformation and innovation, rural household behavior conversion, macro-control policy factors, and so on. Based on differences between the ways and degree of effect on rural settlement evolution, these factors are classified into basic factors, new-type factors and mutation factors. The drive of basic factors mainly focuses on the traditional inheritance of rural settlements, the new-type factors mainly affect rural settlement transition, and the mutation factors may bring about sudden changes. All these factors constitute a “three-wheel” driving mechanism for the evolution of rural settlements, and shape three typical driver paths: slow smooth path under the basic factors, new path to rapid development under the new-type factors, and the sudden change path under the mutation factors. The paper also investigates the overall situation of rural settlement evolution in the aspects of settlement system, settlement scale, settlement morphology, settlement function, settlement culture, settlement environment, etc. The general process of rural settlement evolution is divided into four stages: initial, transitional, developmental, and mature stages.
Given the great number of studies focusing on the temporal interaction between economic and environmental subsystems, it is useful to perform a quantitative spatial assessment of these subsystems. In this paper, comprehensive assessment indicators for regional economic development and environmental pollution subsystems are constructed. Then, the degree of coupling and coordination of the regional economy-environment system is calculated for 350 prefectural units in China. It is found that the economic development and environmental pollution in most prefectural units is still at a low level of coupling and coordination. According to the coupling and coordination values, the Chinese territory can be divided into four types of area: economy-environment harmonious area, economy-environment gearing area, economy-environment rivaling area and low coupling degree of economy-environment area. Based on a structural analysis of the industrial sector in the four types of areas, there is a spatial relationship between the regional industrial sector structure and the coupling-coordination level. In the economy-environment harmonious area, the sectors of manufacturing of high-technology and high value-added products, such as communications, computer and electronic equipment, transport equipment and electrical machinery, account for a large proportion of the value of local industrial output. The industrial value of the economy-environment gearing area is concentrated on the manufacturing of machinery and equipment, and contains a few polluting sectors such as ferrous and non-ferrous metallurgy, chemical manufacturing and electricity generation. The economy-environment rivaling area is the type of area where polluting sectors concentrate, such as iron and steel, petrifaction, coal mining, building materials and electricity generation. In the low coupling degree of economy-environment area, its industry is concentrated on the production and processing of primary products.
Choosing site area, cultural layer thickness, significant relics and significant remains as the variables, we applied cluster analysis to the ancient settlements of four cultural periods, respectively, which were Peiligang, Yangshao, Longshan and Xiashang, in 9000-3000 a BP, around Songshan Mountain. Through application of the SOFM (self-organizing feature map) networks, every type of ancient settlements was classified into different size-grades. By this means, the Peiligang settlements were divided into two grades, Yangshao and Longshan settlements were divided into three grades, respectively, and Xiashang settlements were divided into four grades. The results suggested that the size-grade diversity of ancient settlements was not significant during the Peiligang period in this area. Around the middle-late Yangshao period (5000 a BP), the size-grade diversity of ancient settlements began to appear, a process that continued during the Longshan period and finally matured in the Xiashang period. Moreover, the results reflected the regional differences in cultural characteristics in a particular period, which were mainly represented in that there were three Peiligang cultural systems distributed in different areas. Such differences also existed in the spatial distributive characteristics between the Xia and Shang cultures. Based on the size-grade study of ancient settlements in the Circum-Songshan area, it was found that the SOFM networks method was very suitable for size-grade classification of ancient settlements, since, using this method, adjacent cells would compete and learn from each other, a benefit that reduced the effect on classification by the inaccuracy of site acreages.
Regional development differentiation is a complicated spatial and temporal dynamic process. Recent developments in spatial statistics and Geographic Information Systems (GIS) have led to an increasing interest in quantitative analysis and visualization of the process. However, so far, few direct connections have been made between the newly developed methods and classic spatial development theories, which would be very helpful for the interpretation and understanding of regional spatiotemporal differentiation. Using basic concepts and academic principles of polarized growth theory and gradient transfer theory, this paper quantifies the concept of regional development space. It then proposes a method based on GIS to visually simulate and analyze regional development spatiotemporal differentiation through a case study of the Beijing-Tianjin-Hebei Metropolitan Region (BTHMR), China. The main research results are as follows. 1) The proposed method, built on classic theories and well-developed GIS technology, presents a good picture of regional development spatiotemporal differentiation. 2) The levels of regional development, in terms of per capita GDP across BTHMR, diminished significantly with increased distances away from city propers (which can be seen as the regional growth poles), leading to the appearance of development valley zones between different cities. The development valley zones between each city coincided with their boundary areas, which indicates that administrative boundaries have some impact on regional development, if the regional division is based on administrative boundaries. 3) From 1993 to 2007, the development level in the whole BTHMR improved significantly, of which polarized growth was dominant, especially for Beijing and Tianjin. However, as the two economic development engines in BTHMR, the pull effects of both Beijing and Tianjin on their peripheral areas were comparatively weak, except for those on Tangshan. 4) The structure and pattern of gradient transfer and balanced development in the BTHMR had not been completely developed yet, and the sustained polarized development of the regional economy in BTHMR was still going to be the main trend in the next 5-10 years.
Statistical models using historical data on crop yields and weather to calibrate relatively simple regression equations have been widely and extensively applied in previous studies, and have provided a common alternative to process-based models, which require extensive input data on cultivar, management, and soil conditions. However, very few studies had been conducted to review systematically the previous statistical models for indentifying climate contributions to crop yields. This paper introduces three main statistical methods, i.e., time-series model, cross-section model and panel model, which have been used to identify such issues in the field of agrometeorology. Generally, research spatial scale could be categorized into two types using statistical models, including site scale and regional scale (e.g. global scale, national scale, provincial scale and county scale). Four issues exist in identifying response sensitivity of crop yields to climate change by statistical models. The issues include the extent of spatial and temporal scale, non-climatic trend removal, colinearity existing in climate variables and non-consideration of adaptations. Respective resolutions for the above four issues have been put forward in the section of perspective on the future of statistical models finally.