2015 Vol. 25, No. 4

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Spatial Differences of Coastal Urban Expansion in China from 1970s to 2013
SHI Lifeng, LIU Fang, ZHANG Zengxiang, ZHAO Xiaoli, LIU Bin, XU Jinyong, WEN Qingke, YI Ling, HU Shunguang
2015, 25(4): 389-403. doi: 10.1007/s11769-015-0765-y
As the 'economic engines' of China, coastal cities have developed and expanded considerably since the 1970s. In this study, information on the urban expansion process of Chinese coastal cities from the 1970s to 2013 was retrieved. Through the analysis of stage characteristics, spatial expansion modes, influences on land use, centroid shifts, and spatial morphological evolutions, the spatial differences of coastal urban expansion were revealed. Results indicate that 1) the expansion stages of southern coastal cities are more complex than those of northern coastal cities, and the expansion ranges and speeds of the former are far higher than those of the latter; 2) the spatial expansion of southern coastal cities mostly adopt a single mode, whereas northern coastal cities mostly adopt a mixed mode; 3) significant spatial differences in the occupations of different land sources exist between the south and the north along the coastline; 4) the centroid of coastal cities tends to migrate toward the coastline, and the centroid shift distances of southern coastal cities are clearly higher than those of northern coastal cities; and 5) the spatial morphology of southern coastal cities tends to be compact, whereas that of northern coastal cities tends to be loose. Policies have a powerful significance in terms of guiding urban expansion and its spatial differences in coastal cities. Urban expansion in coastal cities will encounter new opportunities and challenges under the guidance of new types of urbanization strategies.
Responses of Phytolith in Guinea Grass (Leymus chinensis) Leaves to Simulated Warming, Nitrogen Deposition and Elevated CO2 Concentration in Songnen Grassland, Northeast China
LI Bo, FENG Yingying, GUO Jixun, JIE Dongmei, SHI Lianxuan
2015, 25(4): 404-413. doi: 10.1007/s11769-015-0766-x
Deposited in plant cells and their intercellular space, phytoliths, a special form of silica, could be used to determine information on plant structure and physiology especially their size and content. With the hypothesis that phytolith in plant would change under variable climate and environment, the dominant plant species in Songnen grassland, guinea grass (Leymus chinensis), was treated by an open-top chamber (OTC) to elevate CO2 concentration, infrared heaters, and artificial nitrogen (N) addition for three years from 2006-2008. Phytoliths were extracted by wet-ashing method and analyzed by variance analysis and so on. We found that the responses to elevated CO2 are complicated, and warming is positive while N addition is negative to the deposition of phytoliths in L. chinensis leaves. Especially, warming could reduce the negative impact of N addition on phytolith in L. chinensis. The short cell's taxonomic in graminea is significant because of no disappearance with simulated environmental changes. The phytolith originated in the long cell and plant intercellular space are more sensitive to elevated CO2 concentration, warming, and N addition, and could become some new indicators for environmental changes. In conclusion, different phytolith types have various responses to simulated warming, N addition and elevated CO2 concentration.
Building African Ecosystem Research Network for Sustaining Local Ecosystem Goods and Services
Armand Sedami Igor YEVIDE, WU Bingfang, YU Xiubo, LI Xiaosong, LIU Yu, LIU Jian
2015, 25(4): 414-425. doi: 10.1007/s11769-015-0767-9
A new form of producing and sharing knowledge has emerged as an international (United States of America, Asia, and Europe) research collaboration, known as the Long-Term Ecological Research (LTER) Network. Although Africa boasts rich biodiversity, including endemic species, it lacks the long-term initiatives to underpin sustainable biodiversity managements. At present, climate change may exacerbate hunger and poverty concerns in addition to resulting in ecosystem degradation, land use change, and other threats in Africa. Therefore, ecosystem monitoring was suggested to understanding the effects of climate change and setting strategies to mitigate these changes. This paper aimed to investigate ecosystem monitoring ground sites and address their coverage gaps in Africa to provide a foundation for optimizing the African Ecosystem Research Network (AERN) ground sites. The geographic coordinates and characteristics of ground sites-based ecosystem monitoring were collected from various networks aligned with the LTER implementation in Africa. Additionally, climatic data and biodiversity distribution maps were retrieved from various sources. These data were used to assess the size of existing ground sites and the gaps in description, ecosystems and biomes. The results reveal that there were 1089 sites established by various networks. Among these sites, 30.5%, 27.5%, and 28.8% had no information of area, year of establishment, current status, respectively. However, 68.0% of them had an area equal to or greater than 1 km2. Sites were created progressively over the course of the years, with 68.9% being created from 2000 to 2005. To date, only 41.5% of the sites were operational. The sites were scattered across Africa, but they were concentrated in Eastern and Southern Africa. The unbalanced distribution pattern of the sites left Central and Northern Africa hardly covered, and many unique ecosystems in Central Africa were not included. To sustain these sites, the AERN should be based on operational sites, seeking secure funding by establishing multiple partnerships.
Soil Moisture Response to Rainfall in Forestland and Vegetable Plot in Taihu Lake Basin, China
LI Qian, ZHU Qing, ZHENG Jinsen, LIAO Kaihua, YANG Guishan
2015, 25(4): 426-437. doi: 10.1007/s11769-014-0715-0
Soil moisture and its spatial pattern are important for understanding various hydrological, pedological, ecological and agricultural processes. In this study, data of rainfall and soil moisture contents at different depths (10 cm, 20 cm, 40 cm and 60 cm) in forestland and vegetable plot in the Taihu Lake Basin, China were monitored and analyzed for characteristics of soil moisture variation and its response to several typical rainfall events. The following results were observed. First, great temporal variation of soil moisture was observed in the surface layer than in deeper layer in vegetable plot. In contrast, in forestland, soil moisture had similar variation pattern at different depths. Second, initial soil moisture was an important factor influencing the vertical movement of soil water during rainfall events. In vegetable plot, simultaneous response of soil moisture to rainfall was observed at 10-and 20-cm depths due to fast infiltration when initial soil was relatively dry. However, traditional downward response order occurred when initial soil was relatively wet. Third, critical soil horizon interface was an active zone of soil water accumulation and lateral movement. A less permeable W-B soil horizon interface (40-cm depth) in vegetable plot can create perched water table above it and elevate the soil water content at the corresponding depth. Fourth, the land cover was an effective control factor of soil moisture during small and moderate rainfall events. In the forestland, moderate and small rainfall events had tiny influences on soil moisture due to canopy and surface O horizon interception. Fifth, preferential flow and lateral subsurface interflow were important paths of soil water movement. During large and long duration rainfall events, lateral subsurface flow and preferential flow through surface crack or soil pipe occurred, which recharged the deep soil. However, in more concentrated large storm, surface crack or soil pipe connected by soil macropores was the main contributor to the occurrence of preferential flow. Findings of this study provide a theoretical foundation for sustainable water and fertilizer management and land use planning in the Taihu Lake Basin.
Vegetation Development and Water Level Changes in Shenjiadian Peatland in Sanjiang Plain, Northeast China
WANG Chunling, ZHAO Hongyan, WANG Guoping
2015, 25(4): 451-461. doi: 10.1007/s11769-015-0768-8
This paper documents a 7800-year proxy record from the Shenjiadian peatland on the Sanjiang Plain in Northeast China. High-resolution plant macrofossil and colorimetric humification methods were used to reconstruct the vegetation and hydrologic history from a 193 cm-long sedimentary profile. Detrended correspondence analysis (DCA) was applied to transform the raw plant macrofossil data into latent indices of peatland water level. The vegetation community transited from an Equisetum fluviatile community to a Carex lasiocarpa community at approximately 3800 cal yr BP and was followed by a Carex-shrub community at approximately 480 cal yr BP. Based on the plant macrofossil DCA axis 1 scores and humification values, we distinguished four hydrologic periods: a wet period from 7800 cal yr BP to 4500 cal yr BP, dry periods up to 1600 cal yr BP, drier periods until 300 cal yr BP, and the driest period from 300 cal yr BP until the present. Through a comparison with other climate records, we suggest that the East Asian summer monsoon (EAM) was the main driving force for vegetation and water level changes to the Shenjiadian peatland through its impacts on precipitation.
Change in Urban Wetlands and Their Cold Island Effects in Response to Rapid Urbanization
ZHANG Wei, JIANG Jingang, ZHU Yubi
2015, 25(4): 462-471. doi: 10.1007/s11769-015-0764-z
The cold-island effect of urban wetlands has received increasing attention in recent years due to its important role in the alleviation of urban heat islands. Hangzhou, a representative rapidly urbanizing city with rich wetlands in China, was selected as a case study for researching the changes that the urban wetlands have undergone and their impact on the urban thermal environment. Land surface temperature (LST) was acquired from the thermal infrared data of Landsat 5 Thematic Mapper (TM) images in 1990, 1995, 2000, 2006, and 2010, using the single-channel method. The results are as follows: 1) considering the changes in land use, the urban wetlands located to the west of Hangzhou have decreased significantly during 1990­-2010 because of rapid urbanization. In the Xixi Wetland, the change in land use was relatively small and most of the water body and vegetation were preserved. However, to the east of the Xixi Wetland, large areas of water body and vegetation have been replaced by built-up land as a result of the urbanization process; 2) considering the change in LST, it was found from land surface temperature retrieval that the changing spatial pattern of the thermal field was highly correlated with land use changes. Low temperature regions of the eastern Xixi Wetland were gradually eroded by high temperature regions, and the centroid of the heat island in East Xixi was found to be constantly shifting westward. In addition, the difference in LST between the Xixi Wetland and East Xixi has increased; 3) considering the impact factors for this area, land use structure and patch shape were found to have a significant impact on LST, shown by the results of multiple linear stepwise regressions. Increasing the size of the wetlands in urban planning is considered to be the most effective measure in alleviating the urban heat island effect. Moreover, reducing the spatial complexity of landscape patches also contributes to the alleviation of the urban heat island effect.
Measuring Social Vulnerability to Natural Hazards in Beijing-Tianjin-Hebei Region, China
HUANG Jianyi, SU Fei, ZHANG Pingyu
2015, 25(4): 472-485. doi: 10.1007/s11769-015-0769-7
Social vulnerability in this study represents the differences between the capacity to cope with natural hazards and disaster losses suffered within and between places. The assessment of social vulnerability has been recognized as a critical step in understanding natural hazard risks and enhancing effective response capabilities. This article presents an initial study of the social vulnerability of the Beijing-Tianjin-Hebei (B-T-H) Region in China. The goal is to replicate and test the applicability of the United States Social Vulnerability Index (SoVI) method in a Chinese cultural context. Thirty-nine variables adapted from the SoVI were collected in relation to two aspects: socioeconomic vulnerability and built environment vulnerability. Using factor analysis, seven factors were extracted from the variable set: the structure of social development, the level of economic and government financial strength, social justice and poverty, family structure, the intensity of space development, the status of residential housing and transportation, and building structure. Factor scores were summed to get the final SoVI scores and the most and least vulnerable units were identified and mapped. The highest social vulnerability is concentrated in the northwest of the study area. The least socially vulnerable areas are mainly distributed in the Beijing, Tianjin and Shijiazhuang core urban peripheral and central city areas of the prefecture-level cities. The results show that this method is a useful tool for revealing places that have a high level of vulnerability, in other words, areas which are more likely to face significant challenges in coping with a large-scale event. These findings could provide a scientific basis for policy making and the implementation of disaster prevention and mitigation in China.
Spatial-temporal Pattern Evolution of Manufacturing Geographical Agglomeration and Influencing Factors of Old Industrial Base: A Case of Jilin Province, China
LI Linshan, MA Yanji
2015, 25(4): 486-497. doi: 10.1007/s11769-014-0730-1
The primary object of this paper is to examine the spatial-temporal pattern evolution of manufacturing geographical agglomeration of the old industrial base. Industrial spatial agglomeration index and concentration ratio are used in this paper. Multiple linear regression models are also applied to try to explore the internal driving mechanisms on manufacturing geographical agglomeration. The results show that: 1) the manufacturing agglomeration degree of Jilin Province is increasing gradually. The spatial polarization structure is visible; and the central region is the agglomeration area, in addition, the manufacturing industries of Changchun Proper present a trend of dispersion; 2) the structure of manufacturing industries has changed, and the concentration ratio of labor-intensive manufacturing industry is declining, while the proportions of technology-intensive and capital-intensive manufacturing industry are relatively rising; 3) marketing level, location accessibility, labor resources, capital, science and technology innovation capability, scale economy and the level of globalization affect manufacturing agglomeration with different degree. There are significant differences of the effects about employment, technology, the quality of residents and the export-oriented market on the industrial concentration ratio; 4) in the future, the impact of policy and institution, export-oriented market and quality of resident on manufacturing geographical agglomeration pattern will be more profound.
Road Centrality and Landscape Spatial Patterns in Wuhan Metropolitan Area, China
LIU Yaolin, WANG Huimin, JIAO Limin, LIU Yanfang, HE Jianhua, AI Tinghua
2015, 25(4): 511-522. doi: 10.1007/s11769-015-0749-y
Road network is a corridor system that interacts with surrounding landscapes, and understanding their interaction helps to develop an optimal plan for sustainable transportation and land use. This study investigates the relationships between road centrality and landscape patterns in the Wuhan Metropolitan Area, China. The densities of centrality measures, including closeness, betweenness, and straightness, are calculated by kernel density estimation (KDE). The landscape patterns are characterized by four landscape metrics, including percentage of landscape (PLAND), Shannon's diversity index (SHDI), mean patch size (MPS), and mean shape index (MSI). Spearman rank correlation analysis is then used to quantify their relationships at both landscape and class levels. The results show that the centrality measures can reflect the hierarchy of road network as they associate with road grade. Further analysis exhibit that as centrality densities increase, the whole landscape becomes more fragmented and regular. At the class level, the forest gradually decreases and becomes fragmented, while the construction land increases and turns to more compact. Therefore, these findings indicate that the ability and potential applications of centrality densities estimated by KDE in quantifying the relationships between roads and landscapes, can provide detailed information and valuable guidance for transportation and land-use planning as well as a new insight into ecological effects of roads.
Spatial Distribution and Environmental Determinants of Denitrification Enzyme Activity in Reed-Dominated Raised Fields
LAN Yan, CUI Baoshan, HAN Zhen, LI Xia, LI Fengju, ZHANG Yongtao
2015, 25(4): 438-450. doi: 10.1007/s11769-014-0721-2
Denitrification is an important process of nitrogen removal in lake ecosystems. However, the importance of denitrification across the entire soil-depth gradients including subsurface layers remains poorly understood. This study aims to determine the spatial pattern of soil denitrification enzyme activity (DEA) and its environmental determinants across the entire soil depth gradients in the raised fields in Baiyang Lake, North China. In two different zones of the raised fields (i.e., water boundary vs. main body of the raised fields), the soil samples from -1.0 m to 1.1 m depth were collected, and the DEA and following environmental determinants were quantified: soil moisture, pH, total nitrogen (TN), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3--N), total organic carbon (TOC), and rhizome biomass of Phragmites australis. The results showed that the soil DEA and environmental factors had a striking zonal distribution across the entire soil depth gradients. The soil DEA reached two peak values in the upper and middle soil layers, indicating that denitrification are important in both topsoil and subsurface of the raised fields. The correlation analysis showed that the DEA is negatively correlated with the soil depth (p < 0.05). However, this phenomenon did not occur in the distance to the water edge, except in the upper layers (from 0.2 m to 0.7 m) of the boundary zone of the raised fields. In the main body of the raised fields, the DEA level remained high; however, it showed no significant relationship with the distance to the water edge. The linear regression analysis showed significant positive correlation of the DEA with the soil TN, NO3--N, NH4+-N, and TOC; whereas it showed negative correlation with soil pH. No significant correlations with soil moisture and temperature were observed. A positive correlation was also found between the DEA and rhizome biomass of P. australis.
Structure of Chinese City Network as Driven by Technological Knowledge Flows
MA Haitao, FANG Chuanglin, PANG Bo, WANG Shaojian
2015, 25(4): 498-510. doi: 10.1007/s11769-014-0731-0
Based on patent cooperation data, this study used a range of city network analysis approaches in order to explore the structure of the Chinese city network which is driven by technological knowledge flows. The results revealed the spatial structure, composition structure, hierarchical structure, group structure, and control structure of Chinese city network, as well as its dynamic factors. The major findings are: 1) the spatial pattern presents a diamond structure, in which Wuhan is the central city; 2) although the invention patent knowledge network is the main part of the broader inter-city innovative cooperation network, it is weaker than the utility model patent; 3) as the senior level cities, Beijing, Shanghai and the cities in the Zhujiang (Pearl) River Delta Region show a strong capability of both spreading and controlling technological knowledge; 4) whilst a national technology alliance has preliminarily formed, regional alliances have not been adequately established; 5) even though the cooperation level amongst weak connection cities is not high, such cities still play an important role in the network as a result of their location within 'structural holes' in the network; and 6) the major driving forces facilitating inter-city technological cooperation are geographical proximity, hierarchical proximity and technological proximity.