2020 Vol. 30, No. 3

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Balancing Carbon Emission Reductions and Social Economic Development for Sustainable Development: Experience from 24 Countries
KANG Meimei, ZHAO Wenwu, JIA Lizhi, LIU Yanxu
2020, 30(3): 379-396. doi: 10.1007/s11769-020-1117-0
The impact of human carbon emissions on climate has generated widespread global concern. We selected 24 countries as research objects and analysed the changes in carbon emissions in different countries between the establishment of emission reduction actions in 1990 and 2014. Then, we selected 19 factors representing four categories (economy, population, technology and energy) to explore the key factors that led to changes in carbon dioxide (CO2) emissions in different countries. Emission reduction actions since 1990 did not lead to marked improvements, and only five countries (Russia, Germany, the United Kingdom, Italy and France) achieved reductions in carbon emissions. The factors that influenced CO2 emissions varied among countries. In most developing countries, reductions in CO2 emissions were caused by reductions in poverty and inherent natural conditions. Moreover, the extent of influence of a given factor on CO2 emissions differed among countries. The global economic crisis may cause similar fluctuations in CO2 emissions in many countries. Adjustments to energy and industrial structures are the main reason for the reduction in carbon emissions, whereas economic growth and urbanization are the two major contributors to the growth of carbon emissions. According to historical carbon emissions data, a green energy revolution must be implemented to address global climate change and ensure the sustainable development of human societies.
A Synthesizing Land-cover Classification Method Based on Google Earth Engine: A Case Study in Nzhelele and Levhuvu Catchments, South Africa
ZENG Hongwei, WU Bingfang, WANG Shuai, MUSAKWA Walter, TIAN Fuyou, MASHIMBYE Zama Eric, POONA Nitesh, SYNDEY Mavengahama
2020, 30(3): 397-409. doi: 10.1007/s11769-020-1119-y
This study designed an approach to derive land-cover in the South Africa with insufficient ground samples, and made a case demonstration in Nzhelele and Levhuvu catchments, South Africa. The method was developed based on an integration of Landsat 8, Sentinel-1, and Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM), and the Google Earth Engine (GEE) platform. Random forest classifier with 300 trees is employed as land-cover classification model. In order to overcome the defect of insufficient ground data, the stratified sampling method was used to generate the training and validation samples from the existing land-cover product. Likewise, in order to recognize different land-cover categories, the percentile and monthly median composites were employed to expand input metrics of random forest classifier. Results showed that the overall accuracy of the land-cover of Nzhelele and Levhuvu catchments, South Africa in 2017-2018 reached to 76.43%. Three important results can be drawn from our research. 1) The participation of Sentinel-1 data can slightly improve overall accuracy of land-cover while its contribution on land-cover classification varied with land types. 2) Under-fitting problem was observed in the training of non-dominant land-cover categories using the random sampling, the stratified sampling method is recommended to make sure the classification accuracy of non-dominant classes. 3) When related reflectance bands participated in the training process, individual Normalized Difference Vegetation index (NDVI), Enhanced Vegetation Index (EVI), Soil Adjusted Vegetation Index (SAVI), Normalized Difference Built-up Index (NDBI) have little effect on final land-cover classification result.
Vegetation Mapping for Regional Ecological Research and Management: A Case of the Loess Plateau in China
LIU Yuanxin, LYU Yihe, BAI Yingfei, ZHANG Buyun, TONG Xiaolin
2020, 30(3): 410-426. doi: 10.1007/s11769-020-1120-5
Vegetation maps are fundamental for regional-scale ecological research. However, information is often not sufficiently up to date for such research. The Loess Plateau is a key area for vegetation restoration projects and a suitable area for regional ecological research. To carry out regional vegetation mapping based on the principles of hierarchical classification, object-oriented methods, visual interpretation, and accuracy assessment, this study integrated land cover, high-resolution remote sensing images, background environmental data, bioclimate zoning data, and field survey data from the Loess Plateau. To further clarify the implications of vegetation mapping, we compared the deviation of the 2015 vegetation map of the Loess Plateau (VMLP) and the widely used vegetation map of China (VMC) (1:1 000 000) for the expressed vegetation information and the evaluation of ecosystem services. The results indicated that 1) the vegetation of the Loess Plateau could be divided into 9 vegetation type groups and 18 vegetation types with classification accuracies of 87.76% and 83.97%, respectively; 2) the distribution of vegetation had obvious zonal regularity; 3) a deviation of 29.56×104km2 occurred when the vegetation coverage area was quantified with the VMC; 4) the vegetation classification accuracy affected the ecosystem service assessment, the total water yield of the Loess Plateau calculated by the VMC and other required parameters was overestimated by 2.2×106 mm in 2015. Because vegetation mapping is a basic and important activity, that requires greater attention, this study provides supporting data for subsequent multivariate vegetation mapping and vegetation management for conservation and restoration.
Response of Soil Moisture to Rainfall Event in Black Locust Plantations at Different Stages of Restoration in Hilly-gully Area of the Loess Plateau, China
CHEN Weiliang, LI Zongshan, JIAO Lei, WANG Cong, GAO Guangyao, FU Bojie
2020, 30(3): 427-445. doi: 10.1007/s11769-020-1121-4
Precipitation plays an important role in the water supplies that support ecological restoration by sustaining large-scale artificial plantations in arid and semiarid regions, especially black locust (Robinia pseudoacacia) plantations (RP plantations), which are widely planted due to R. pseudoacacia being an excellent pioneer species. Characterizing the response of soil moisture to rainfall events at different stages of restoration is important for assessing the sustainability of restoration in RP plantations. In this study, we quantified the response of soil moisture to rainfall events at different years of restoration (15, 20 and 30 yr) representing different restoration stages in RP plantations in a typical hilly-gully area, i.e., the Yangjuangou Catchment, of the Loess Plateau, China. Over the growing season (June to September) of 2017, smart probes were placed at nine depths (10, 20, 40, 60, 80, 100, 120, 150, and 180 cm below the soil surface) to obtain volumetric soil water information at 30-min intervals in the three RP plantations. The advance of the wetting front was depicted, and the total cumulative water infiltration was measured. Soil moisture was mainly replenished by eight heavy rainfall events (mean rainfall amount=46.3 mm), accounting for 88.7% of the rainfall during the growing season. The mean soil moisture content profiles of RP plantations at the three restoration stages were ordered as 30-yr (14.07%) > 20-yr (10.12%) > 15-yr (8.03%), and this relationship displayed temporal stability. Soil moisture was primarily replenished by rainfall at the 0-60 cm soil depth, and soil moisture remained stable below the 100-cm soil depth. The rainfall regime influenced the advancement of the wetting front. Here, a single rainfall event of 30 mm was the rainfall threshold for infiltration into the 60-cm soil layer. The total infiltration time ranged from 310.5-322.0 h, but no significant differences were found among RP plantations at different restoration stages. Young and old RP plantations had more total infiltration (more than 228.2 mm) and deeper infiltration depths (80-100 cm) than middle-aged plantations. The RP plantation at the intermediate restoration stage exhibited minimal total infiltration (174.2 mm) and a shallow infiltration depth (60 cm) due to the soil physical structure of the plot, which may have limited rain infiltration. More stand conditions that may affect infiltration should be considered for priority afforestation areas.
The Response of Vegetation Biomass to Soil Properties along Degradation Gradients of Alpine Meadow at Zoige Plateau
LIU Miao, ZHANG Zhenchao, SUN Jian, XU Ming, MA Baibing, TIJJANI Sadiy Baba, CHEN Youjun, ZHOU Qingping
2020, 30(3): 446-455. doi: 10.1007/s11769-020-1116-1
Alpine grassland of the Tibetan Plateau has undergone severe degradation, even desertification. However, several questions remain to be answered, especially the response mechanisms of vegetation biomass to soil properties. In this study, an experiment on degradation gradients was conducted in an alpine meadow at the Zoige Plateau in 2017. Both vegetation characteristics and soil properties were observed during the peak season of plant growth. The classification and regression tree model (CART) and structural equation modelling (SEM) were applied to screen the main factors that govern the vegetation dynamics and explore the interaction of these screened factors. Both aboveground biomass (AGB) and belowground biomass (BGB) experienced a remarkable decrease along the degradation gradients. All soil properties experienced significant variations along the degradation gradients at the 0.05 significance level. Soil physical and chemical properties explained 54.78% of the variation in vegetation biomass along the degradation gradients. AGB was mainly influenced by soil water content (SWC), soil bulk density (SBD), soil organic carbon (SOC), soil total nitrogen (STN), and pH. Soil available nitrogen (SAN), SOC and pH, had significant influence on BGB. Most soil properties had positive effects on AGB and BGB, while SBD and pH had a slightly negative effect on AGB and BGB. The correlations of SWC with AGB and BGB were relatively less significant than those of other soil properties. Our results highlighted that the soil properties played important roles in regulating vegetation dynamics along the degradation gradients and that SWC is not the main factor limiting plant growth in the humid Zoige region. Our results can provide guidance for the restoration and improvement of degraded alpine grasslands on the Tibetan Plateau.
Investigating the Effects of Greenhouse Vegetable Cultivation on Soil Fertility in Lhasa, Tibetan Plateau
WANG Zhaofeng, GONG Dianqing, ZHANG Yili
2020, 30(3): 456-465. doi: 10.1007/s11769-020-1118-z
The area of land utilized for growing vegetables in greenhouses has expanded rapidly on the Tibetan Plateau over recent decades. However, the effects of greenhouses on soil fertility as well as variations in these effects between the plateau and plain remain unclear on the Tibetan Plateau. This study assessed the effects of vegetable greenhouses in the vicinity of Lhasa, using open field soil as a control. A total of 92 plough layer (0-20 cm depth) soil samples including 54 from greenhouses and 38 from open fields were taken, and soil pH, electrical conductivity (EC), total soluble salt (TS), soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP), and available potassium (AK) were measured. The results reveal that, soil pH was lower 1.0 units in greenhouses than that in open field. TS was higher 82% and AP was higher 160% overall. Similarly, SOM and TN were higher 32% and 46%, respectively, while AK changed slightly at a higher 1% rate. Results also show that soil properties varied depending on cultivation time and vegetable types. Overall, pH continuously decreased with cultivation time while other soil fertility indicators reached a maximum value after nine years of cultivation before starting to decrease. The effect of leafy vegetable planting on soil was slight overall, while the impact of fruits on soil was more serious. Compared with changes in plain greenhouse soil fertility measured across the eastern China, the effects of greenhouses on soil in Lhasa remain relatively limited; and the change in the degree of soil fertility was lower and the extreme values of soil fertility occurred later in Lhasa.
Potential Effects of Episodic Deposition on Nutrients and Heavy Metals in Decomposing Litters of Suaeda glauca in Salt Marsh of the Yellow River Estuary, China
CHEN Bingbing, SUN Zhigao
2020, 30(3): 466-482. doi: 10.1007/s11769-019-1088-1
Episodic deposition has been recognized as a major factor affecting the decomposition rate of detrital material in salt marshes. In this paper, three one-off burial treatments, no burial treatment (0 cm, NBT), current burial treatment (10 cm, CBT) and strong burial treatment (20 cm, SBT), were designed in intertidal zone of the Yellow River Estuary to determine the potential influences of episodic deposition on nutrient (C, N) and heavy metal (Pb, Cr, Cu, Zn, Ni, Mn, Cd, V and Co) variations in decomposing litters of Suaeda glauca. Results showed that although various burial treatments showed no statistical difference in decomposition rate of S. glauca, the values generally followed the sequence of CBT (0.002 403/d) > SBT (0.002 195/d) > NBT (0.002 060/d). The nutrients and heavy metals in decomposing litters of the three burial treatments exhibited different variations except for N, Cu, Cr, Ni and Co. Except for Mn, no significant differences in C, N, Pb, Cr, Cu, Zn, Ni, V and Co concentrations occurred among the three treatments (P>0.05). With increasing burial depth, Cr and Cd levels generally increased while Cu, Ni and Mn concentrations decreased. Although episodic deposition was generally favorable for C and N release from S. glauca, its influence on release was insignificant. In the three burial treatments, Pb, Cr, Zn, Ni, Mn, V and Co stocks in S. glauca generally evidenced the export of metals from litter to environment, and, with increasing burial depth, the export amounts increased greatly. The S. glauca were particular efficient in binding Cd and releasing Pb, Cr, Zn, Ni, Mn, V and Co, and, with increasing burial depth, stocks of Cu in decomposing litters generally shifted from release to accumulation. The experiment indicated that the potential eco-toxic risk of Pb, Cr, Zn, Ni, Mn, V and Co exposure would be serious as the strong burial episodes occurred in S. glauca marsh.
Impacts of Climate and Nutrients on Carbon Sequestration Rate by Wetlands: A Meta-analysis
CHENG Caifeng, LI Min, XUE Zhenshan, ZHANG Zongsheng, LYU Xianguo, JIANG Ming, ZHANG Hongri
2020, 30(3): 483-492. doi: 10.1007/s11769-020-1122-3
Global numerous wetlands are the most productive ecosystem and have high carbon sequestration potential to mitigate increasing CO2 in the atmosphere. However, few are available on estimating average carbon sequestration rates by global wetlands (Carbonsq) at century timescale. In this article, Carbonsq data of 473 wetland soil/sediment cores from the literatures were collected in detail by the meta-analysis method. These cores were no more than 300 years old and spanned a latitudinal range from 33.6° S to 69.7° N. Globally, the average Carbonsq was 185.2 g/(m2·yr) regardless of wetland types. Carbonsq varied remarkably between wetland types and ranked as an order of salt marsh (247.7 g/(m2·yr)) > mangrove (229.8 g/(m2·yr)) > freshwater marsh (196.7 g/(m2·yr)) > peatland (76.9 g/(m2·yr)). Carbonsq was positively related to mean annual temperature (AMT) and annual precipitation (Pre). Nitrogen was the most common and primary factor controlling Carbonsq regardless of wetland types.
Spatio-temporal Pattern and Driving Forces of Comprehensive Agricultural Productivity in Jilin Province, China
LIU Yunda, TONG Lianjun
2020, 30(3): 493-504. doi: 10.1007/s11769-020-1123-2
Improving comprehensive agricultural productivity is an important measure to realize agricultural modernization. Based on the data from Jilin Statistical Yearbook, this study analyzed the spatial and temporal characteristics of comprehensive agricultural productivity discrepancy in the main agricultural production areas of Jilin Province, China. The comprehensive agricultural productivity of 25 county-level administrative units were evaluated by a comprehensive index system based on five aspects which included 20 indicators from 2004 to 2017. The pattern of the discrepancy was analyzed by the spatial differentiation indices and spatial convergence theory. The results were as follows:1) the overall comprehensive agricultural productivity was in a ‘W-type’ rising trend; 2) the discrepancy was in ‘inverted W-type’ trend; 3) the spatial distribution characteristics were mainly discrete plaque and ‘inverted V-type’; 4) the formation of differences was forced by a combination of internal and external driving forces. Our study demonstrates the effectiveness of rising agricultural productivity and the level of economic and social developments in different counties in Jilin Province.
Spatial Pattern Evolution and Influencing Factors of Cold Storage in China
LI Jinfeng, XU Haicheng, LIU Wanwan, WANG Dongfang, ZHOU Shuang
2020, 30(3): 505-515. doi: 10.1007/s11769-020-1124-1
Cold storage is the vital infrastructure of cold chain logistics. In this study, we analyzed the spatial pattern evolution characteristics, spatial autocorrelation and influencing factors of cold storage in China by using kernel density estimation (KDE), spatial autocorrelation analysis (SAA), and spatial error model (SEM). Results showed that:1) the spatial distribution of cold storage in China is unbalanced, and has evolved from ‘one core’ to ‘one core and many spots’, that is, ‘one core’ refers to the Bohai Rim region mainly including Beijing, Tianjin, Hebei, Shandong and Liaoning regions, and ‘many spots’ mainly include the high-density areas such as Shanghai, Fuzhou, Guangzhou, Zhengzhou, Hefei, Wuhan, Ürümqi. 2) The distribution of cold storage has significant global spatial autocorrelation and local spatial autocorrelation, and the ‘High-High’ cluster area is the most stable, mainly concentrated in the Bohai Rim; the ‘Low-Low’ cluster area is grouped in the southern China. 3) Economic development level, population density, traffic accessibility, temperature and land price, all affect the location choice of cold storage in varying degrees, while the impact of market demand on it is not explicit.
Post-industrial Economic Restructuring and Wage Inequality in Urban China, 2003-2015: A Sectoral Perspective
YANG Fiona Fan, HU Fox Zhiyong, WANG Yuhua
2020, 30(3): 516-531. doi: 10.1007/s11769-020-1125-0
Income inequality in urban China has attracted growing attention from China's urban researchers and policy makers. Whereas many studies have interrogated the pattern and process of the income gap in Chinese cities undergoing the institutional transformation from plan to market, relatively little is known about how such unequal distribution of income is related to China's ongoing structural transformation toward a post-industrial economy. Drawing on a decomposition methodology based on the Theil index, this study aimed to address this lacuna through an empirical investigation of China's urban wage inequality from a sectoral perspective. Our empirical study identified the low-wage manufacturing sector and the high-wage producer services sector as the two biggest contributors to urban wage inequality in China. Urban wage inequality within the producer services was found to be caused by the spatial concentration of a disproportionate number of high-paying jobs in a few developed, high-tier city-regions on the eastern coast. Our empirical findings have important implications for the formulation of policies to address the income inequality that plagues China's continuing urbanization.
Urban Agglomeration Formation and Its Spatiotemporal Expansion Process in China: From the Perspective of Industrial Evolution
NIU Fangqu, YANG Xinyu, WANG Fang
2020, 30(3): 532-543. doi: 10.1007/s11769-020-1094-3
Urban agglomeration research has received increasing attention in China's national development strategies, and has become a hot topic in academic research. This study develops a theoretical framework that explores the formation mechanism and expansion process of urban agglomerations from the perspective of industrial evolution, and identifies the development issues and their causes by taking Yangtze Delta and Beijing-Tianjin-Hebei urban agglomerations as case studies. In the process of urban agglomeration formation within a free market, as has happened in Yangtze Delta region, the central city develops first, its secondary industry is then transferred to its neighboring cities, and the work division and cooperation with the neighboring cities is gradually established. However, in the 1990s, aiming to become an international metropolis, Beijing implemented a series of administrative policies to encourage the reduction of the secondary industry and the development of the tertiary industry, before its secondary industry were fully developed and transferred to its neighboring cities. This delayed the integration process and the development of the Beijing-Tianjin-Hebei urban agglomeration. This study builds a good foundation for the construction of the theoretical system's urban agglomeration study, and provides references for decision making in an urban agglomeration development.
Influences of Different Transport Routes and Road Nodes on Industrial Land Conversion: A Case Study of Changchun City of Jilin Province, China
ZHANG Suwen, LI Chenggu, MA Zuopeng, LI Xin
2020, 30(3): 544-556. doi: 10.1007/s11769-020-1126-z
Nowadays, urban transit system has become one of the major forces underlying urban pace transformation via changing accessibility of related land parcels, which leads to the changes of land value and land use structure. This paper studied the interaction between land use changes and related transport routes, particular about how different transport routes and road nodes influence the conversion of industrial lands to residential and commercial uses respectively. Taking Changchun, an old industrial city in the rust belt of China as a case of study, we explored and compared the influences of different transport routes and road nodes on industrial land conversion. We found that surrounding the studied transport routes, more industrial lands were replaced by residential lands than by commercial lands. Also, apparent differences exist in the corridor effects of different transport routes (i.e., light rail, expressway and trunk road) and road nodes (i.e., expressway nodes and trunk road nodes) while the industrial lands convert to residential and commercial uses. Our research findings help us to illuminate the interactive relationships between transportation and industrial land conversion in old industrial cities which are undergoing social, economic and the related urban transition in Northeast China.