2021 Vol. 31, No. 2

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panjinghu Contents
2021, 31(2): 1-17.
Effect of Hydrological Connectivity on Soil Carbon Storage in the Yellow River Delta Wetlands of China
Jiuge FENG, Jinfeng LIANG, Qianwei LI, Xiaoya ZHANG, Yi YUE, Junqin GAO
2021, 31(2): 197-208. doi: 10.1007/s11769-021-1185-9
Hydrological connectivity has significant effects on the functions of estuarine wetland ecosystem. This study aimed to examine the dynamics of hydrological connectivity and its impact on soil carbon pool in the Yellow River Delta, China. We calculated the hydrological connectivity based on the hydraulic resistance and graph theory, and measured soil total carbon and organic carbon under four different hydrological connectivity gradients (Ⅰ 0‒0.03, Ⅱ 0.03‒0.06, Ⅲ 0.06‒0.12, Ⅳ 0.12‒0.39). The results showed that hydrological connectivity increased in the north shore of the Yellow River and the south tidal flat from 2007 to 2018, which concentrated in the mainstream of the Yellow River and the tidal creek. High hydrological connectivity was maintained in the wetland restoration area. The soil total carbon storage and organic carbon storage significantly increased with increasing hydrological connectivity from Ⅰ to Ⅲ gradient and decreased in Ⅳ gradient. The highest soil total carbon storage of 0‒30 cm depth was 5172.34 g/m2, and organic carbon storage 2764.31 g/m2 in Ⅲ gradient. The hydrological connectivity changed with temporal and spatial change during 2007‒2018 and had a noticeable impact on soil carbon storage in the Yellow River Delta. The results indicated that appropriate hydrological connectivity, i.e. 0.08, could effectively promote soil carbon storage.
Impact of Land Use Change on Vegetation Carbon Storage During Rapid Urbanization: A Case Study of Hangzhou, China
Zhi WANG, Lihua XU, Yijun SHI, Qiwei MA, Yaqi WU, Zhangwei LU, Liwei MAO, Enqi PANG, Qi ZHANG
2021, 31(2): 209-222. doi: 10.1007/s11769-021-1183-y
Land use changes have significant impacts on the carbon balance in an urban ecosystem. When there is rapid development in urbanizing regions, land use changes have a dramatic effect on vegetation carbon storage (VCS). This study investigates the impact of land use change on VCS in a period of rapid urbanization in Hangzhou, China. The results show that: 1) from 2000 to 2015, land use in Hangzhou underwent huge changes, mainly reflected in decrease in cropland and wetland and the increased settlement. More than 34.58% of the land was transformed, and the land use changes are primarily characterized by a significant decrease in cropland due to the occupation by settlement. 2) over the 15 years, changes in land use led to a decrease of 3.93 × 105 t of VCS in the urban ecosystem. The large-scale transformation of cropland and wetland, which have a comparatively high carbon density, into land for settlement exerted a negative impact on VCS. 3) The central city, which with the Circle-E/I/O mode, had the lowest comprehensive land use dynamic degree, leading to moderate land use change and an increase in VCS; Yuhang and Xiaoshan, which with Multicore-E/O/I mode and Fan-E/O/I modes, had a higher comprehensive land use dynamic degree, drastic changes in land use, and a decrease in VCS. This study proposes a reliable method of estimating changes in VCS, clarifies the relationship between land use change and VCS during rapid urbanization, and provides recommendations for sustainable urban development.
Spatial Distribution and Ecological Risk Assessment of Heavy Metals in Surface Sediment of Songhua River, Northeast China
Baolin LIU, Deming DONG, Xiuyi HUA, Weihua DONG, Ming LI
2021, 31(2): 223-233. doi: 10.1007/s11769-021-1186-8
The Songhua River, one of the seven major rivers in China, locates in Northeast China with 1897 km long. This study aims to investigate the concentrations, distribution, source apportionment and ecological risk assessment of heavy metals including copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), nickel (Ni) and chromium (Cr) in main stream and tributaries of the Songhua River in Jilin Province, Northeast China. Surface sediment samples (0–15 cm) were collected from 39 sampling sites in the Songhua River in July 2012. Concentrations of Cu, Zn, Cd, Pb, Ni and Cr were analyzed. The mean concentrations of heavy metals were (24.0 ± 9.2) mg/kg, (59.3 ± 18.0) mg/kg, (4.0 ± 2.1) mg/kg, (39.0 ± 27.9) mg/kg, (18.5 ± 8.6) mg/kg and (56.1 ± 17.6) mg/kg for Cu, Zn, Cd, Pb, Cr and Ni, respectively. The average contents of Cu, Cd, Pb, Cr and Ni were higher than their background values. Higher concentrations of heavy metals were found in the lower reaches with industrial enterprises and cities along the Songhua River. Zn, Pb and Ni might come from industrial sewage and mineral processing, while Cu and Cd were derived from electroplating wastewater and agricultural non-point source sewage. Cr originated from lithogenic sources. The concentrations of Cu, Zn and Cr were below the effect range low (ERL) at all sites, while Cd, Pb and Ni concentrations were detected ranging from ERL to the effect range median (ERM) at more than 15% of samples. Concentrations of Ni exceeded ERM in more than 50% of samples. The mean toxic units of heavy metals in the Songhua River decreased following the order: Cd (6.7) > Pb (2.2) > Ni (1.6) > Cu (0.7) > Cr (0.5) = Zn (0.5). Potential ecological risk index was found to be higher in middle and lower reaches of the Songhua River, where Cd could impose an extremely high ecological risk.
Influences of Seasonal Freezing and Thawing on Soil Water-stable Aggregates in Orchard in High Cold Region, Northeast China
Yunjiang LIANG, Xu DENG, Tao SONG, Guoshuang CHEN, Yuemei WANG, Qing ZHANG, Xinrui LU
2021, 31(2): 234-247. doi: 10.1007/s11769-021-1187-7
Soil aggregate stability, as an important indicator of soil functions, may be affected by seasonal freezing and thawing (SFT) and land use in high cold and wet regions. Therefore, comprehensive understanding the effects of SFT on aggregate stability in orchards during winter and spring is crucial to develop appropriate management strategies that can effectively alleviate the degradation of soil quality to ensure sustainable development of orchard ecosystems. To determine the mechanism of degradation in orchard soil quality, the effects of SFT on the stability of water-stable aggregates were examined in apple-pear orchards (Pyrus ussuriensis var. ovoidea) of four different ages (11, 25, 40, and 63 yr) on 0 to 5% slopes before freezing and after thawing from October 2015 to June 2016 in Longjing City, Yanbian Prefecture, Northeast China, involving a comparison of planted versus adjacent uncultivated lands (control). Soil samples were collected to investigate water-stable aggregate stability in three incremental soil layers (0–20, 20–40 and 40–60 cm). In the same samples, iron oxide, organic matter, and clay contents of the soil were also determined. Results showed that the destructive influences of SFT on water-stable aggregates were more pronounced with the increased orchards ages, and SFT exerted severe effects on water-stable aggregates of older orchards (40 and 63 yr) than juvenile orchards. Undergoing SFT, the soil instability index and the percentage of aggregate destruction increased by mean 0.15 mm and 1.86%, the degree of aggregation decreased by mean 1.32%, and the erosion resistance weakened, which consequently led to aggregate stability decreased. In addition, soil free, amorphous, and crystalline iron oxide as well as soil organic matter and clay contents are all important factors affecting the stability of water-stable aggregates, and their changes in their contents were consistent with those in the stability of water-stable aggregates. The results of this study suggest that long-term planting fruit trees can exacerbate the damaging effects of SFT on aggregate stability and further soil erosion increases and nutrient losses in an orchard, which hider sustainable use of soil and the productivity orchards.
Spatiotemporal Trends and Ecological Determinants in Population by Elevation in China Since 1990
Chaoqun MA, Yanfen HE
2021, 31(2): 248-260. doi: 10.1007/s11769-021-1188-6
It is very important to understand the ecological and socio-economic factors in population distribution and their changes over time for the compilation of regional development planning and the guidance of rational population flow. Using surface-based population data for China from 1990 to 2015, the national distribution and dynamics of the human population by elevation are quantified based on 1-km cell-size gridded distribution datasets and 1-km cell-size DEM (digital elevation model). A geographical detector model is used to quantitatively analyze the dominant role of natural geographical factors, such as topography and climate, on the spatial distribution of population. Results show that: 1) the population size and density decrease rapidly with elevation below 1000 m above the sea level, and the gap in population density between low-altitude areas and high-altitude areas increases with time because of the continuous growth of population density in low-altitude areas; 2) the distribution of the population can be divided into five steps according to integrated population density (IPD), in proportions of 43∶35∶21∶1∶0, and that these proportions have remained stable over the last 25 yr; 3) the basic pattern of population spatial distribution is determined by natural geographical environment factors, such as topography, climate, geomorphology, and their interactions; and 4) the development of society and the economy are the driving forces for the dynamic change in the population distribution during the study period, with the distribution pattern and dynamics of population by altitude in China providing a comprehensive reflection of various geographical elements on different spatial scales.
Land Use/Cover Change and Its Policy Implications in Typical Agriculture-forest Ecotone of Central Jilin Province, China
Yulin DONG, Zhibin REN, Yao FU, Ran YANG, Hongchao SUN, Xingyuan HE
2021, 31(2): 261-275. doi: 10.1007/s11769-021-1189-5
During the 21st century, policies toward agriculture, forestry, and urbanization have emerged to ensure food security, ecological restoration, and human well-being by managing land in Northeast China. However, the integrated effects and relationships of various policies are still not well understood. This study observed the land use land cover changes in Central Jilin from 2000 to 2019 and, by considering policy involvement, aimed to understand the effects and trade-offs of policies. Results showed that the cropland, including dryland and rice paddy, and the forest, including coniferous forest and deciduous forest, are dominant land types in Central Jilin. During 2000–2019, the land changed diversely, of which the main changes were the expanded dryland (+0.43 million ha), the increased deciduous forest (+22 million ha), the decreased coniferous forest (–0.08 million ha), and the expanded urban settlement (+0.04 million ha). With these changes, despite the unit grain yield showing a rising trend, the yield contribution of Central Jilin to the national total decreased. The poor cultivating structure made for the cropland expansion and reduced the implementation space of environmental restoration projects such as the Grain to Green. Thus, in Central Jilin that transits from the agri-food production zone to the eco-regulation zone, environmental projects coexisted in a trade-off manner with agricultural policies that aim to liberate agricultural productivity. In the key urban agglomerations of Central Jilin, the increase in the proportion of green space improved the thermal environment and carbon balance. The gross domestic product of the large city and its local proportion also rose. These improvements benefited from the promotion of development policies and urbanization policies at key time points. In the future, it is necessary to coordinate agricultural policies and environmental projects and promote the progress of small- and medium-sized cities to ensure the equality of regional development. This study has implications for making decisions to revitalize Northeast China and researchers who inform decisions.
Dynamic Analysis of Supply and Demand Coupling of Ecosystem Services in Loess Hilly Region: A Case Study of Lanzhou, China
Pengjie LI, Chunfang LIU, Licheng LIU, Weiting WANG
2021, 31(2): 276-296. doi: 10.1007/s11769-021-1190-z
The relationship between the supply and demand for ecosystem services (ESs) is a key issue for the rational allocation of natural resources and optimisation of sustainable development capacity. This paper investigateed the dynamic evolution features of supply and demand of four ESs in Lanzhou of China, namely, water supply, food supply, carbon fixation and soil retention services. The cross-sectional data of 2005 and 2017 were used for calculating ESs value and its supply and demand through ArcGIS software, InVEST model, elastic coefficient model and coupling coordination model. Results showed that: 1) from 2005 to 2017, the supply of water supply services increased, the demand of soil retention services decreased, and the supply and demand of food supply and carbon fixation services increased. The high-value areas of service supply were mainly distributed in the rocky mountain areas in the southeast and northwest with high vegetation coverage, while the high-value areas of demand were mainly distributed in the urban areas and surrounding areas with high population density. 2) There were five different types of coupling relations. Water supply service was dominated by a negative coupling type D, which means that the decrease in demand for ESs has had a positive response on the supply of ESs. Negative coupling type C was the main type of food supply and carbon fixation services, which means that the increase in demand for ESs has had a negative response on the supply of ESs. All three services were supplemented by a positive coupling type A, which means that the increase in demand for ESs has had a positive response on the supply of ESs. Soil retention service generally exhibits a positive coupling type B, which means that the decrease in demand for ESs has had a negative response on the supply of ESs. 3) Over the past 12 yr, the coordination degree of supply and demand of water supply, food supply and soil retention services decreased, and the coordination degree of carbon fixation service increased. Various types of ES had a low degree of coupling and coordination, showing different characteristics of temporal and spatial evolution. The areas with imbalanced ESs supply and demand were mainly distributed in urban areas dominated by construction land. The research results are valuable to the optimisation of urban and rural ecological environments and the sustainable development of territory space under the framework of ecological civilisation, including similar ecologically vulnerable areas in other developing countries.
Geography of Talent in China During 2000–2015: An Eigenvector Spatial Filtering Negative Binomial Approach
Hengyu GU, ROWE Francisco, Ye LIU, Tiyan SHEN
2021, 31(2): 297-312. doi: 10.1007/s11769-021-1191-y
The increase in China’s skilled labor force has drawn much attention from policymakers, national and international firms and media. Understanding how educated talent locates and re-locates across the country can guide future policy discussions of equality, firm localization and service allocation. Prior studies have tended to adopt a static cross-national approach providing valuable insights into the relative importance of economic and amenity differentials driving the distribution of talent in China. Yet, few adopt longitudinal analysis to examine the temporal dynamics in the stregnth of existing associations. Recently released official statistical data now enables space-time analysis of the geographic distribution of talent and its determinants in China. Using four-year city-level data from national population censuses and 1% population sample surveys conducted every five years between 2000 and 2015, we examine the spatial patterns of talent across Chinese cities and their underpinning drivers evolve over time. Results reveal that the spatial distribution of talent in China is persistently unequal and spatially concentrated between 2000 and 2015. It also shows gradually strengthened and significantly positive spatial autocorrelation in the distribution of talent. An eigenvector spatial filtering negative binomial panel is employed to model the spatial determinants of talent distribution. Results indicate the influences of both economic opportunities and urban amenities, particularly urban public services and greening rate, on the distribution of talent. These results highlight that urban economic- and amenity-related factors have simultaneously driven China’s talent’s settlement patterns over the first fifteen years of the 21st century.
Evaluation and Influence Factor of Green Efficiency of China’s Agricultural Innovation from the Perspective of Technical Transformation
Weichun HE, Erling LI, Zhizhen CUI
2021, 31(2): 313-328. doi: 10.1007/s11769-021-1192-x
Agricultural innovation is important for the green transformation of agriculture. Based on the perspective of technology transformation, this paper builds a theoretical analysis framework and evaluation index system for green efficiency of agricultural innovation, and discusses the evolution laws and influencing factors of the green efficiency of China’s agricultural innovation from 2005 to 2017 utilizing the DEA model, Malmquist index, and Tobit regression analysis. The results show that: 1) The overall green efficiency of China’s agricultural innovation is not high, the green efficiency of agricultural innovation in eastern China is mainly driven by pure technical efficiency, while that in central and western China is mainly driven by the scale efficiency. The green efficiency of agricultural innovation shows significant spatial differences, and the low efficiency and relatively low-efficiency regions moved to central and southeastern China. 2) Technical progress is the main force affecting the change of green total factor productivity of China’s agricultural innovation, seeing a trend of decrease followed by an increase. Pure technical efficiency and scale efficiency exhibit an increasing-decreasing trend, and gradually transform into key factors that restrict the improvement of the green total factor productivity of agricultural innovation. 3) Agricultural technologies’ diffusion, absorption, and implementation are three influencing factors of the green efficiency of agricultural innovation. The local level of informatization, the number of agricultural technicians in enterprises and institutions, average education level of residents, and the level of agricultural mechanization have positive impacts on the promotion of the green efficiency of agricultural innovation, promoting the diffusion, absorption and implementation of agricultural innovation technology can significantly improve the green efficiency of agricultural innovation.
Spatio-temporal Differentiation and Driving Factors of Industrial Ecology of Restricted Development Zone from Adaptive Perspective: A Case Study of Shandong, China
Fuyou GUO, Siqi GAO, Lianjun TONG, Fangdao QIU, Hengzhou YAN
2021, 31(2): 329-341. doi: 10.1007/s11769-021-1184-x
Based on the adaptive analysis paradigm, this paper constructs an evaluation index system and an evaluation model of the level of industrial ecology of a restricted development zone from the perspective of the industrial system and of the environmental system, and studies the spatial-temporal differentiation characteristics and the driving factors of the level of industrial ecology of the restricted development zone of the Shandong Province, China, by using a variety of measurement methods. The results show that: 1) In the temporal dimension, the level of industrial ecology of the research area increased from 2005 to 2017, while in the regional dimension, it was higher in the eastern coastal areas, followed by the northwestern area and the southwestern area; 2) In the spatial dimension, from 2005 to 2017 the level of industrial ecology of the research area had a clear spatial dependence, and the regional spatial agglomeration of the restricted development zones with similar industrial ecology levels become increasingly evident; 3) On the whole, the industrial ecology level in the study area had a clear spatial differentiation pattern, as it was higher in the north and in the east and lower in the south and in the west. Moreover, its evolution model changed from a ‘three-core driven model’ to a ‘spatial scattered mosaic distribution model’, and then to a ‘single-core driven model’; 4) Industrial ecology was positively correlated with economic development, foreign investment, science and technology, and negatively correlated with the government role, while industrial structure and environmental regulation failed to pass the statistical significance test.
Spatial Pattern of Long-term Residence in the Urban Floating Population of China and its Influencing Factors
Le CHEN, Meijun XI, Wanfu JIN, Ya HU
2021, 31(2): 342-358. doi: 10.1007/s11769-021-1193-9
Exploring long-term residence among the urban floating population is crucial to understanding urban growth in China, particularly since the 2008 financial crisis. By using China Migrants Dynamic Survey data for 2012–2014, China Labor-force Dynamics Survey data for 2014–2016, and macroscale urban matched data, we analyzed the spatial pattern of long-term residential behavior in China’s urban floating population in 2012–2016 and developed an urban spatial utility equilibrium model containing ‘macro’ urban factors and ‘micro’ individual and household factors to explain the pattern. The results first revealed that long-term residence is defined as ≥ 6 yr for the urban floating population in China. Second, members of this population are more likely to be long-term residents of the megacities in the three urban agglomerations in eastern China as well as of small and medium-sized cities in western and northeastern China, whereas short-term residence is more likely in cities in central China and near the three urban agglomerations. Third, urban population density and housing prices, both have a significant U-shaped effect, are main factors affecting the spatial pattern of long-term residence.
Spatial Mismatch or Not? Evidence from Public Janitors in Xi ’an, China
Chen CHEN, Lin CHENG, Chunliang XIU, Jiuquan LI
2021, 31(2): 376-386. doi: 10.1007/s11769-021-1194-8
Research on the spatial mismatch experienced by low-income minority residents is US-centric. However, spatial mismatch is not necessarily an appropriate term when considering the situation of low-wage workers in cities of northwestern China where there is higher proximity between jobs and housing and lower levels of residential segregation. This paper empirically examines the jobs-housing spatial relationship for one of the most typical low-wage groups, namely, public janitors, in Xi’an, China. Also, the causes of the jobs-housing spatial relationship are discussed in detail. Individual-level data based on in-depth interviews and questionnaires, as well as the GIS network analysis method, are used to provide baseline analyses of the jobs-housing spatial relationship. Results indicate that there is no jobs-housing spatial mismatch for public janitors in Xi’an. This can be implied from the short commuting distance and time. A basic cause is that most public janitors rent low-cost accommodation in villages-in-the-city, and in old residential quarters, near to their places of work. Other causes lie in off-peak commuting and high sensitivity to commuting distance due to the greater extent of non-motorized commuting modes. The conclusions, based on a large number of social surveys, are an illuminating analysis of the spatial mismatch issue among low-wage workers in Chinese cities.