2020 Vol. 30, No. 1
Display Method:
2020, 30(1): 1-15.
doi: 10.1007/s11769-019-1077-4
Abstract:
Resource-dependent cities (RCs) are a vulnerable group of urban settlements that often face population shrinkage; however, population changes in RCs in China are not well understood. This study offers new insight into this matter through a robust analysis that features a longer time scale, a larger sample of RCs, and a finer unit of analysis. It finds new evidence that problems of population shrinkage in RCs are more serious than previous literature has suggested. Approximately 30% of the studied units have experienced either long-term or short-term population shrinkage, and many more are experiencing a slowing down of population growth. Problems are especially common among three types of RCs:the resource-depleted RCs, the forestry-based RCs, and RCs in Northeast China. These results underscore transition policy inadequacies in addressing population loss, and call for a more comprehensive and diversified population policy that tackles the multifaceted factors that contribute to population shrinkage, including lack of industrial support, maladjustment to market oriented reformation, poor urban environment and natural population decline.
Resource-dependent cities (RCs) are a vulnerable group of urban settlements that often face population shrinkage; however, population changes in RCs in China are not well understood. This study offers new insight into this matter through a robust analysis that features a longer time scale, a larger sample of RCs, and a finer unit of analysis. It finds new evidence that problems of population shrinkage in RCs are more serious than previous literature has suggested. Approximately 30% of the studied units have experienced either long-term or short-term population shrinkage, and many more are experiencing a slowing down of population growth. Problems are especially common among three types of RCs:the resource-depleted RCs, the forestry-based RCs, and RCs in Northeast China. These results underscore transition policy inadequacies in addressing population loss, and call for a more comprehensive and diversified population policy that tackles the multifaceted factors that contribute to population shrinkage, including lack of industrial support, maladjustment to market oriented reformation, poor urban environment and natural population decline.
2020, 30(1): 16-29.
doi: 10.1007/s11769-020-1095-2
Abstract:
The change in land development intensity is an important perspective to reflect the variation in regional social and economic development and spatial differentiation. In this paper, spatial statistical analysis, Ordinary Least Squares (OLS), and Geographically weighted regression (GWR) methods are used to systematically analyse the spatial-temporal characteristics and driving forces of land development intensity for 131 spatial units in the western China from 2000 to 2015. The findings of the study are as follows:1) The land development intensity in the western China has been increasing rapidly. From 2000 to 2015, land development intensity increased by 3.4 times on average. 2) The hotspot areas have shifted from central Inner Mongolia, northern Shaanxi and the Beibu Gulf of Guangxi to the Guanzhong Plain and the Chengdu-Chongqing urban agglomeration. The areas of cold spots were mainly concentrated in the Qinghai-Tibet Plateau, Yunnan, and Xinjiang. 3) Investment intensity and the natural environment have always been the main drivers of land development intensity in the western China. Investment played a powerful role in promoting land development intensity, while the natural and ecological environment distinctly constrained such development. The effect of the economic factors on land development intensity in the western China has changed, which is reflected in the driving factor of construction land development shifting from economic growth in 2000 to economic structure, especially industrial structure, in 2015.
The change in land development intensity is an important perspective to reflect the variation in regional social and economic development and spatial differentiation. In this paper, spatial statistical analysis, Ordinary Least Squares (OLS), and Geographically weighted regression (GWR) methods are used to systematically analyse the spatial-temporal characteristics and driving forces of land development intensity for 131 spatial units in the western China from 2000 to 2015. The findings of the study are as follows:1) The land development intensity in the western China has been increasing rapidly. From 2000 to 2015, land development intensity increased by 3.4 times on average. 2) The hotspot areas have shifted from central Inner Mongolia, northern Shaanxi and the Beibu Gulf of Guangxi to the Guanzhong Plain and the Chengdu-Chongqing urban agglomeration. The areas of cold spots were mainly concentrated in the Qinghai-Tibet Plateau, Yunnan, and Xinjiang. 3) Investment intensity and the natural environment have always been the main drivers of land development intensity in the western China. Investment played a powerful role in promoting land development intensity, while the natural and ecological environment distinctly constrained such development. The effect of the economic factors on land development intensity in the western China has changed, which is reflected in the driving factor of construction land development shifting from economic growth in 2000 to economic structure, especially industrial structure, in 2015.
2020, 30(1): 30-44.
doi: 10.1007/s11769-019-1089-0
Abstract:
Using a heterogeneity stochastic frontier model (HSFM), we empirically investigated the economic efficiency of Beijing-Tianjin-Hebei from 2003 to 2016 and its influencing factors. The key findings of the paper lie in:1) in Beijing-Tianjin-Hebei, the overall economic and technological efficiency tended to increase in a wavelike manner, economic growth slowed down, and there was an obvious imbalance in economic efficiency between the different districts, counties and cities; 2) the heterogeneity stochastic frontier production functions (SFPFs) of Beijing, Tianjin and Hebei were different from each other, and investment was still an important impetus of economic growth in Beijing-Tianjin-Hebei; 3) economic efficiency was positively correlated with economic agglomeration, human capital, industrial structure, infrastructure, the informatization level, and institutional factors, but negatively correlated with the government role and economic opening. The following policy suggestions are offered:1) to improve regional economic efficiency and reduce the economic gap in Beijing-Tianjin-Hebei, governments must reduce their intervention in economic activities, stimulate the potentials of labor and capital, optimize the structure of human resources, and foster new demographic incentives; 2) governments must guide economic factors that are reasonable throughout Beijing-Tianjin-Hebei and strengthen infrastructure construction in underdeveloped regions, thus attaining sustainable economic development; 3) governments must plan overall economic growth factors of Beijing-Tianjin-Hebei and promote reasonable economic factors (e.g., labor, resources, and innovations) across different regions, thus attaining complementary advantages between Beijing, Tianjin, and Hebei.
Using a heterogeneity stochastic frontier model (HSFM), we empirically investigated the economic efficiency of Beijing-Tianjin-Hebei from 2003 to 2016 and its influencing factors. The key findings of the paper lie in:1) in Beijing-Tianjin-Hebei, the overall economic and technological efficiency tended to increase in a wavelike manner, economic growth slowed down, and there was an obvious imbalance in economic efficiency between the different districts, counties and cities; 2) the heterogeneity stochastic frontier production functions (SFPFs) of Beijing, Tianjin and Hebei were different from each other, and investment was still an important impetus of economic growth in Beijing-Tianjin-Hebei; 3) economic efficiency was positively correlated with economic agglomeration, human capital, industrial structure, infrastructure, the informatization level, and institutional factors, but negatively correlated with the government role and economic opening. The following policy suggestions are offered:1) to improve regional economic efficiency and reduce the economic gap in Beijing-Tianjin-Hebei, governments must reduce their intervention in economic activities, stimulate the potentials of labor and capital, optimize the structure of human resources, and foster new demographic incentives; 2) governments must guide economic factors that are reasonable throughout Beijing-Tianjin-Hebei and strengthen infrastructure construction in underdeveloped regions, thus attaining sustainable economic development; 3) governments must plan overall economic growth factors of Beijing-Tianjin-Hebei and promote reasonable economic factors (e.g., labor, resources, and innovations) across different regions, thus attaining complementary advantages between Beijing, Tianjin, and Hebei.
2020, 30(1): 45-58.
doi: 10.1007/s11769-020-1096-1
Abstract:
In recent years, researchers have devoted considerable attention to identifying the causes of urban environmental pollution. To determine whether migrant populations significantly affect urban environments, we examined the relationship between urban environmental pollutant emissions and migrant populations at the prefectural level using data obtained for 90 Chinese cities evidencing net in-migration. By dividing the permanent populations of these cities into natives and migrants in relation to the population structure, we constructed an improved Stochastic Impacts by Regression on Population, Affluence and Technology model (STIRPAT) that included not only environmental pollutant emission variables but also variables on the cities' attributes. We subsequently conducted detailed analyses of the results of the models to assess the impacts of natives and migrants on environmental pollutant emissions. The main findings of our study were as follows:1) Migrant populations have significant impacts on environmental emissions both in terms of their size and concentration. Specifically, migrant populations have negative impacts on Air Quality Index (AQI) as well as PM2.5 emissions and positive impacts on emissions of NO2 and CO2. 2) The impacts of migrant populations on urban environmental pollutant emissions were 8 to 30 times weaker than that of local populations. 3) Urban environmental pollutant emissions in different cities differ significantly according to variations in the industrial structures, public transportation facilities, and population densities.
In recent years, researchers have devoted considerable attention to identifying the causes of urban environmental pollution. To determine whether migrant populations significantly affect urban environments, we examined the relationship between urban environmental pollutant emissions and migrant populations at the prefectural level using data obtained for 90 Chinese cities evidencing net in-migration. By dividing the permanent populations of these cities into natives and migrants in relation to the population structure, we constructed an improved Stochastic Impacts by Regression on Population, Affluence and Technology model (STIRPAT) that included not only environmental pollutant emission variables but also variables on the cities' attributes. We subsequently conducted detailed analyses of the results of the models to assess the impacts of natives and migrants on environmental pollutant emissions. The main findings of our study were as follows:1) Migrant populations have significant impacts on environmental emissions both in terms of their size and concentration. Specifically, migrant populations have negative impacts on Air Quality Index (AQI) as well as PM2.5 emissions and positive impacts on emissions of NO2 and CO2. 2) The impacts of migrant populations on urban environmental pollutant emissions were 8 to 30 times weaker than that of local populations. 3) Urban environmental pollutant emissions in different cities differ significantly according to variations in the industrial structures, public transportation facilities, and population densities.
2020, 30(1): 59-74.
doi: 10.1007/s11769-019-1090-7
Abstract:
In this paper, we use factor analysis to evaluate the urban comprehensive quality of each city in the Lanzhou-Xining (Lan-Xi) urban agglomeration. The time distance was obtained by using GIS spatial analysis, and the structure and pattern of the spatial network were analyzed by using the gravity model and social network analysis method. The results show that:1) The scale effect of the Lan-Xi urban agglomeration is gradually emerging, and it is gradually forming the urban agglomeration with Lanzhou and Xining as the core, the Lan-Xi high-speed railway as the axis, and a high-dense connection. 2) Lanzhou and Xining are at the core of the Lan-Xi urban agglomeration, which has a strong attraction and spreads to neighboring cities. 3) In the network structure of the Lan-Xi urban agglomeration, Lanzhou, Baiyin, Gaolan, Yuzhong, Yongdeng, Dingxi, Lintao, Xining, Ledu, Huangzhong, Ping'an, Minhe and Datong are located in the network core position, which have the superiority position and lead to the entire regional communication enhancement and the regional integration development. 4) This urban agglomeration has significant subgroups, eight tertiary subgroups and four secondary subgroup; the tertiary subgroups which compose secondary subgroup have a close connection and mutually influence each other. 5) The Lanzhou Metropolitan Area and the Xining Metropolitan Area have an important impact on the surrounding cities, and the peripheral cities are basically controlled by the central city. The Dingxi subgroup, Lintao-Linxia subgroup, Gonghe subgroup have more structural holes than the subgroups within the Lanzhou Metropolitan Area and the Xining Metropolitan Area, so the peripheral cities of these subgroups have relatively less connection with surrounding cities.
In this paper, we use factor analysis to evaluate the urban comprehensive quality of each city in the Lanzhou-Xining (Lan-Xi) urban agglomeration. The time distance was obtained by using GIS spatial analysis, and the structure and pattern of the spatial network were analyzed by using the gravity model and social network analysis method. The results show that:1) The scale effect of the Lan-Xi urban agglomeration is gradually emerging, and it is gradually forming the urban agglomeration with Lanzhou and Xining as the core, the Lan-Xi high-speed railway as the axis, and a high-dense connection. 2) Lanzhou and Xining are at the core of the Lan-Xi urban agglomeration, which has a strong attraction and spreads to neighboring cities. 3) In the network structure of the Lan-Xi urban agglomeration, Lanzhou, Baiyin, Gaolan, Yuzhong, Yongdeng, Dingxi, Lintao, Xining, Ledu, Huangzhong, Ping'an, Minhe and Datong are located in the network core position, which have the superiority position and lead to the entire regional communication enhancement and the regional integration development. 4) This urban agglomeration has significant subgroups, eight tertiary subgroups and four secondary subgroup; the tertiary subgroups which compose secondary subgroup have a close connection and mutually influence each other. 5) The Lanzhou Metropolitan Area and the Xining Metropolitan Area have an important impact on the surrounding cities, and the peripheral cities are basically controlled by the central city. The Dingxi subgroup, Lintao-Linxia subgroup, Gonghe subgroup have more structural holes than the subgroups within the Lanzhou Metropolitan Area and the Xining Metropolitan Area, so the peripheral cities of these subgroups have relatively less connection with surrounding cities.
2020, 30(1): 75-88.
doi: 10.1007/s11769-020-1097-0
Abstract:
The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands (UHIs). Air temperature and relative humidity are two main factors of thermal environmental comfort and have a critical impact on the urban environmental quality of human settlements. We measured the 2-m height air temperature and relative humidity at the Beijing Olympic Park and a nearby building roof for more than 1 year to elucidate seasonal variations in air temperature and relative humidity, as well as to investigate the outdoor thermal comfort. The results showed that the lawn of the park could, on average, reduce the air temperature by (0.80±0.19)℃, and increase the relative humidity by (5.24±2.91)% relative to the values measured at the building roof during daytime. During the nighttime, the lawn of the park reduced the air temperature by (2.64±0.64)℃ and increased the relative humidity by (10.77±5.20)%. The park was cooler and more humid than surrounding building area, especially in night period (more pronounced cooling with 1.84℃). Additionally, the lawn of the park could improve outdoor thermal comfort through its cooling and humidifying effects. The level of thermal comfort in the park was higher than that around the building roof for a total of 11 days annually in which it was above one or more thermal comfort levels (average reduced human comfort index of 0.92) except during the winter.
The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands (UHIs). Air temperature and relative humidity are two main factors of thermal environmental comfort and have a critical impact on the urban environmental quality of human settlements. We measured the 2-m height air temperature and relative humidity at the Beijing Olympic Park and a nearby building roof for more than 1 year to elucidate seasonal variations in air temperature and relative humidity, as well as to investigate the outdoor thermal comfort. The results showed that the lawn of the park could, on average, reduce the air temperature by (0.80±0.19)℃, and increase the relative humidity by (5.24±2.91)% relative to the values measured at the building roof during daytime. During the nighttime, the lawn of the park reduced the air temperature by (2.64±0.64)℃ and increased the relative humidity by (10.77±5.20)%. The park was cooler and more humid than surrounding building area, especially in night period (more pronounced cooling with 1.84℃). Additionally, the lawn of the park could improve outdoor thermal comfort through its cooling and humidifying effects. The level of thermal comfort in the park was higher than that around the building roof for a total of 11 days annually in which it was above one or more thermal comfort levels (average reduced human comfort index of 0.92) except during the winter.
Vegetation Restoration in Response to Climatic and Anthropogenic Changes in the Loess Plateau, China
2020, 30(1): 89-100.
doi: 10.1007/s11769-020-1093-4
Abstract:
A thorough understanding of the vegetation succession in relation to both climatic changes and anthropogenic activities is vital for the formulation of adaptation strategies that address potential ecosystem challenges. Various climatic factors such as temperature, precipitation, and solar radiation, as well as anthropogenic factors such as ecological engineering and population migration, will affect the conditions for vegetation. However, the relationships among various factors remain unclear and the response of vegetation to climate change and anthropogenic activities in the Loess Plateau of China has not been well established. This study investigated the spatio-temporal characteristics and relationships between vegetation coverage and climatic factors in the Loess Plateau for the period of 1985-2015. Further analysis separated the anthropogenic and climatic factors on vegetation succession based on residual analysis. The results showed that the normalized difference vegetation index (NDVI) followed a significant upward trend with annual change rates of 0.15% during 1985-2015. The trend of human-induced NDVI increase was consistent with the spatial distribution of increasing forest areas in the eastern part of the Loess Plateau. Eco-restoration projects were the main driving factors that promoted vegetation coverage on the Loess Plateau. Furthermore, these results demonstrated that migrants to cities in the Loess Plateau could relieve ecological pressures and promote vegetation restoration. Therefore, the government should strive to increase population mobility and restore vegetation to sustain this particularly fragile ecological environment.
A thorough understanding of the vegetation succession in relation to both climatic changes and anthropogenic activities is vital for the formulation of adaptation strategies that address potential ecosystem challenges. Various climatic factors such as temperature, precipitation, and solar radiation, as well as anthropogenic factors such as ecological engineering and population migration, will affect the conditions for vegetation. However, the relationships among various factors remain unclear and the response of vegetation to climate change and anthropogenic activities in the Loess Plateau of China has not been well established. This study investigated the spatio-temporal characteristics and relationships between vegetation coverage and climatic factors in the Loess Plateau for the period of 1985-2015. Further analysis separated the anthropogenic and climatic factors on vegetation succession based on residual analysis. The results showed that the normalized difference vegetation index (NDVI) followed a significant upward trend with annual change rates of 0.15% during 1985-2015. The trend of human-induced NDVI increase was consistent with the spatial distribution of increasing forest areas in the eastern part of the Loess Plateau. Eco-restoration projects were the main driving factors that promoted vegetation coverage on the Loess Plateau. Furthermore, these results demonstrated that migrants to cities in the Loess Plateau could relieve ecological pressures and promote vegetation restoration. Therefore, the government should strive to increase population mobility and restore vegetation to sustain this particularly fragile ecological environment.
2020, 30(1): 101-114.
doi: 10.1007/s11769-020-1098-z
Abstract:
As an important means regulating the relationship between human and natural ecosystem, ecological restoration program plays a key role in restoring ecosystem functions. The Grain-for-Green Program (GFGP, One of the world's most ambitious ecosystem conservation set-aside programs aims to transfer farmland on steep slopes to forestland or grassland to increase vegetation coverage) has been widely implemented from 1999 to 2015 and exerted significant influence on land use and ecosystem services (ESs). In this study, three ecological models (InVEST, RUSLE, and CASA) were used to accurately calculate the three key types of ESs, water yield (WY), soil conservation (SC), and net primary production (NPP) in Karst area of southwestern China from 1982 to 2015. The impact of GFGP on ESs and trade-offs was analyzed. It provides practical guidance in carrying out ecological regulation in Karst area of China under global climate change. Results showed that ESs and trade-offs had changed dramatically driven by GFGP. In detail, temporally, SC and NPP exhibited an increasing trend, while WY exhibited a decreasing trend. Spatially, SC basically decreased from west to east; NPP basically increased from north to south; WY basically increased from west to east; NPP and SC, SC and WY developed in the direction of trade-offs driven by the GFGP, while NPP and WY developed in the direction of synergy. Therefore, future ecosystem management and restoration poli-cy-making should consider trade-offs of ESs so as to achieve sustainable provision of ESs.
As an important means regulating the relationship between human and natural ecosystem, ecological restoration program plays a key role in restoring ecosystem functions. The Grain-for-Green Program (GFGP, One of the world's most ambitious ecosystem conservation set-aside programs aims to transfer farmland on steep slopes to forestland or grassland to increase vegetation coverage) has been widely implemented from 1999 to 2015 and exerted significant influence on land use and ecosystem services (ESs). In this study, three ecological models (InVEST, RUSLE, and CASA) were used to accurately calculate the three key types of ESs, water yield (WY), soil conservation (SC), and net primary production (NPP) in Karst area of southwestern China from 1982 to 2015. The impact of GFGP on ESs and trade-offs was analyzed. It provides practical guidance in carrying out ecological regulation in Karst area of China under global climate change. Results showed that ESs and trade-offs had changed dramatically driven by GFGP. In detail, temporally, SC and NPP exhibited an increasing trend, while WY exhibited a decreasing trend. Spatially, SC basically decreased from west to east; NPP basically increased from north to south; WY basically increased from west to east; NPP and SC, SC and WY developed in the direction of trade-offs driven by the GFGP, while NPP and WY developed in the direction of synergy. Therefore, future ecosystem management and restoration poli-cy-making should consider trade-offs of ESs so as to achieve sustainable provision of ESs.
2020, 30(1): 115-126.
doi: 10.1007/s11769-020-1099-y
Abstract:
The Middle Route of the South-to-North Water Diversion Project (MR-SNWDP) in China, with construction beginning in 2003, diverts water from Danjiangkou Reservoir to North China for residential, agriculture and industrial use. The water source area of the MR-SNWDP is the region that is most sensitive to and most affected by the construction of this water diversion project. In this study, we used Landsat Thematic Mapper (TM) and HJ-1A/B images from 2000 to 2015 by an object-based approach with a hierarchical classification method for mapping land cover in the water source area. The changes in land cover were illuminated by transfer matrixes, single dynamic degree, slope zones and fractional vegetation cover (FVC). The results indicated that the area of cropland decreased by 31% and was replaced mainly by shrub over the past 15 years, whereas forest and settlements showed continuous increases of 29.2% and 77.7%, respectively. The changes in cropland were obvious in all slope zones and decreased most remarkably (-43.8%) in the slope zone above 25°. Compared to the FVC of forest and shrub, significant improvement was exhibited in the FVC of grassland, with a growth rate of 16.6%. We concluded that local policies, including economic development, water conservation and immigration resulting from the construction of the MR-SNWDP, were the main drivers of land cover changes; notably, they stimulated the substantial and rapid expansion of settlements, doubled the wetlands and drove the transformation from cropland to settlements in immigration areas.
The Middle Route of the South-to-North Water Diversion Project (MR-SNWDP) in China, with construction beginning in 2003, diverts water from Danjiangkou Reservoir to North China for residential, agriculture and industrial use. The water source area of the MR-SNWDP is the region that is most sensitive to and most affected by the construction of this water diversion project. In this study, we used Landsat Thematic Mapper (TM) and HJ-1A/B images from 2000 to 2015 by an object-based approach with a hierarchical classification method for mapping land cover in the water source area. The changes in land cover were illuminated by transfer matrixes, single dynamic degree, slope zones and fractional vegetation cover (FVC). The results indicated that the area of cropland decreased by 31% and was replaced mainly by shrub over the past 15 years, whereas forest and settlements showed continuous increases of 29.2% and 77.7%, respectively. The changes in cropland were obvious in all slope zones and decreased most remarkably (-43.8%) in the slope zone above 25°. Compared to the FVC of forest and shrub, significant improvement was exhibited in the FVC of grassland, with a growth rate of 16.6%. We concluded that local policies, including economic development, water conservation and immigration resulting from the construction of the MR-SNWDP, were the main drivers of land cover changes; notably, they stimulated the substantial and rapid expansion of settlements, doubled the wetlands and drove the transformation from cropland to settlements in immigration areas.
2020, 30(1): 127-141.
doi: 10.1007/s11769-020-1100-9
Abstract:
Biological invasion poses a huge threat to ecological security. Spartina alterniflora was introduced into China in 1979, and its arrival corresponded with negative effects on native ecosystems. To explore geographical variation of its expansion rate in coastal China, we selected 43 S. alterniflora sites from Tianjin Coastal New Area to Beihai. The area expansion rate, expansion rate paralleling and vertical to the shoreline were analysed based on Landsat images and field survey in 2015. Simple Ocean Data Assimilation (SODA) and climate data were collected to statistically analyse the influential factors of expansion rate. Results showed that significant difference of S. alterniflora area expansion rate among different latitude zones (P<0.01), increasing from 6.08% at southern (21°N-23°N) to 19.87% in Bohai Bay (37°N-39°N) along latitude gradient. There was a significant difference in expansion rate vertical to shoreline in different latitude zones (P<0.01) with the largest occurring in Bohai Bay (256 m/yr, 37°N-39°N), and showed an decreasing tendency gradually from north to south. No significant difference and latitudinal clines in expansion rate paralleling to shoreline were observed. Expansion rate had significant negative correlation with mean seawater temperature, the lowest seawater temperature, current zonal velocity and meridional velocity and presented a reducing trend as these biotic factors increased; however, they were not significantly correlated with the highest seawater temperature and mean seawater salinity. We identified significant correlations between expansion rate and annual mean temperature, the lowest temperature in January and annual precipitation, but there was little correlation with annual diurnal difference in temperature and the highest temperature in July. The rapid expansion rate in high-latitude China demonstrated a higher risk of potential invasion in the north; dynamic monitoring and control management should be established as soon as possible.
Biological invasion poses a huge threat to ecological security. Spartina alterniflora was introduced into China in 1979, and its arrival corresponded with negative effects on native ecosystems. To explore geographical variation of its expansion rate in coastal China, we selected 43 S. alterniflora sites from Tianjin Coastal New Area to Beihai. The area expansion rate, expansion rate paralleling and vertical to the shoreline were analysed based on Landsat images and field survey in 2015. Simple Ocean Data Assimilation (SODA) and climate data were collected to statistically analyse the influential factors of expansion rate. Results showed that significant difference of S. alterniflora area expansion rate among different latitude zones (P<0.01), increasing from 6.08% at southern (21°N-23°N) to 19.87% in Bohai Bay (37°N-39°N) along latitude gradient. There was a significant difference in expansion rate vertical to shoreline in different latitude zones (P<0.01) with the largest occurring in Bohai Bay (256 m/yr, 37°N-39°N), and showed an decreasing tendency gradually from north to south. No significant difference and latitudinal clines in expansion rate paralleling to shoreline were observed. Expansion rate had significant negative correlation with mean seawater temperature, the lowest seawater temperature, current zonal velocity and meridional velocity and presented a reducing trend as these biotic factors increased; however, they were not significantly correlated with the highest seawater temperature and mean seawater salinity. We identified significant correlations between expansion rate and annual mean temperature, the lowest temperature in January and annual precipitation, but there was little correlation with annual diurnal difference in temperature and the highest temperature in July. The rapid expansion rate in high-latitude China demonstrated a higher risk of potential invasion in the north; dynamic monitoring and control management should be established as soon as possible.
2020, 30(1): 142-156.
doi: 10.1007/s11769-020-1101-8
Abstract:
Regional ecological health, the core of comprehensive ecosystem assessments, is an important foundation for regional exploration, environmental conservation, and sustainable development. The mountainous areas in southwest China are backward in economy, but industrialization and urbanization have been rapid in recent years. This study assessed the ecosystem health of the Sichuan and Yunnan provinces in China using a pressure-state-response (PSR) model. Spatiotemporal patterns of regional ecosystem health were analyzed from 2000 to 2016, including overall characteristics as well as local characteristics. Ecosystem health in most regions was improved over time (Y=0.0058X-11.0132, R2=0.95, P<0.001), and areas with poorer ecosystem health decreased from half to one-third of the total area. Analysis of the primacy ratio and the variation coefficient confirmed that the gap in health scores between regions has gradually expanded since 2007, but there are more high quality regions overall (Z of Moran's index <1.96, P>0.05). Overall, the regional ecosystems to the east of the Hu line-an imaginary line dividing east and west China into roughly equivalent parts-were healthier than those to the west. The pressure and state scores of ecosystems were determined by physiographic condition, and the response scores by government policies and social concern. The spatiotemporal patterns of ecosystem health were dominated to a greater extent by natural than anthropogenic factors, which explains why the shift in the patterns aligned with the direction of the Hu line. Dividing regions into key management areas based on natural geographical conditions and socioeconomic development could contribute to the formulation of a reasonable ecological and environmental protection policy, guaranteeing ecosystem services in the long run.
Regional ecological health, the core of comprehensive ecosystem assessments, is an important foundation for regional exploration, environmental conservation, and sustainable development. The mountainous areas in southwest China are backward in economy, but industrialization and urbanization have been rapid in recent years. This study assessed the ecosystem health of the Sichuan and Yunnan provinces in China using a pressure-state-response (PSR) model. Spatiotemporal patterns of regional ecosystem health were analyzed from 2000 to 2016, including overall characteristics as well as local characteristics. Ecosystem health in most regions was improved over time (Y=0.0058X-11.0132, R2=0.95, P<0.001), and areas with poorer ecosystem health decreased from half to one-third of the total area. Analysis of the primacy ratio and the variation coefficient confirmed that the gap in health scores between regions has gradually expanded since 2007, but there are more high quality regions overall (Z of Moran's index <1.96, P>0.05). Overall, the regional ecosystems to the east of the Hu line-an imaginary line dividing east and west China into roughly equivalent parts-were healthier than those to the west. The pressure and state scores of ecosystems were determined by physiographic condition, and the response scores by government policies and social concern. The spatiotemporal patterns of ecosystem health were dominated to a greater extent by natural than anthropogenic factors, which explains why the shift in the patterns aligned with the direction of the Hu line. Dividing regions into key management areas based on natural geographical conditions and socioeconomic development could contribute to the formulation of a reasonable ecological and environmental protection policy, guaranteeing ecosystem services in the long run.
2020, 30(1): 157-169.
doi: 10.1007/s11769-020-1102-7
Abstract:
Reference values of erythrocyte sedimentation rate (ESR) are the key to interpret ESR blood test in clinic. The common local reference ESR values are more accuracy in blood test that are established with natural geographical factors by using the multiple linear regression (MLR) model and the artificial neural network (ANN). These knowledge-based methods have limitations since the knowledge domains of ESR and natural geographical factors are limited. This paper presents a new cases-depended model to establish reference ESR values with natural geographical factors and location using case-based reasoning (CBR) since knowledge domain of ESR and geographical factors is weak. Overall 224 local normal ESR values of China that calculated from 13 623 samples were obtained, and the corresponding natural geographical factors and location that include altitude, sunshine hours, relative humidity, temperature, precipitation, annual temperature range and annual average wind speed were obtained from the National Geomatics Center of China. CBR was used to predict the unseen local reference ESR values with cases. The average absolute deviation (AAD), mean square error (MSE), prediction accuracy (PA), and Pearson correlation coefficient (r) between the observed and estimated data of proposed model is 33.07%, 9.02, 66.93% and 0.78, which are better than those of ANN and MLR model. The results show that the proposed model provides higher prediction accuracy than those of the artificial neural network and multiple linear regression models. The predicted values are very close to the observed values. Model results show significant agreement of cases data. Consequently, the model is used to predict the unseen local reference ESR with natural geographical factors and location. In spatial, the highest ESR reference areas are distributed in the southern-western district of China that includes Sichuan, Chongqing, Guangxi and Guizhou provinces, and the reference ESR values are greater than 23 mm/60 min. The higher ESR reference values are distributed in the middle part and northern-eastern of China which include Hubei, Henan, Shaanxi, Shanxi, Jilin and Heilongjiang provinces, and the reference ESR values are greater than 18 mm/60 min. The lowest ESR reference values are distributed in the northern-western of China that includes Tibet and Xinjiang, and the reference ESR values are lower than 5 mm/60 min.
Reference values of erythrocyte sedimentation rate (ESR) are the key to interpret ESR blood test in clinic. The common local reference ESR values are more accuracy in blood test that are established with natural geographical factors by using the multiple linear regression (MLR) model and the artificial neural network (ANN). These knowledge-based methods have limitations since the knowledge domains of ESR and natural geographical factors are limited. This paper presents a new cases-depended model to establish reference ESR values with natural geographical factors and location using case-based reasoning (CBR) since knowledge domain of ESR and geographical factors is weak. Overall 224 local normal ESR values of China that calculated from 13 623 samples were obtained, and the corresponding natural geographical factors and location that include altitude, sunshine hours, relative humidity, temperature, precipitation, annual temperature range and annual average wind speed were obtained from the National Geomatics Center of China. CBR was used to predict the unseen local reference ESR values with cases. The average absolute deviation (AAD), mean square error (MSE), prediction accuracy (PA), and Pearson correlation coefficient (r) between the observed and estimated data of proposed model is 33.07%, 9.02, 66.93% and 0.78, which are better than those of ANN and MLR model. The results show that the proposed model provides higher prediction accuracy than those of the artificial neural network and multiple linear regression models. The predicted values are very close to the observed values. Model results show significant agreement of cases data. Consequently, the model is used to predict the unseen local reference ESR with natural geographical factors and location. In spatial, the highest ESR reference areas are distributed in the southern-western district of China that includes Sichuan, Chongqing, Guangxi and Guizhou provinces, and the reference ESR values are greater than 23 mm/60 min. The higher ESR reference values are distributed in the middle part and northern-eastern of China which include Hubei, Henan, Shaanxi, Shanxi, Jilin and Heilongjiang provinces, and the reference ESR values are greater than 18 mm/60 min. The lowest ESR reference values are distributed in the northern-western of China that includes Tibet and Xinjiang, and the reference ESR values are lower than 5 mm/60 min.
2020, 30(1): 170-179.
doi: 10.1007/s11769-020-1103-6
Abstract:
Landscape characters in estuarine regions generally controlled by tidal regimes and human activities like road construction. In this work, tidal channels and road construction in the Yellow River Delta (YRD) were extracted by visual interpretation methods so as to decipher impacts of tidal channel development and road construction on landscape patch change during 1989-2016. Spatial distribution history of three wetlands, which covered by Phragmites australis (freshwater marsh, FM), Suaeda salsa (salt marsh, SM), and mudflats (MD) were also established. Results indicated that tidal channel, number, frequency, and fractal dimension were all the maximum in 2003, and the minimum in 1998, respectively. Road length, number, and density showed increasing trend during 1989-2016. MD were the predominant landscape type, followed by FM and SM during 1989-2016. Principal component analysis implied two extracted factors, F1 and F2, which could represent 91.93% of the total variations. F1 mainly proxied tidal channel development, while F2 represented road construction. A multiple linear regression analysis showed positive effects of both F1 and F2 on FM patch numbers and negative impacts on SM patch areaes with R2 values of 0.416 and 0.599, respectively. Tidal channels were negatively related to MD patch numbers, while roads were positively related to that. In any case, road construction showed larger impacts on landscape type shifting than that of tidal channel development in the YRD.
Landscape characters in estuarine regions generally controlled by tidal regimes and human activities like road construction. In this work, tidal channels and road construction in the Yellow River Delta (YRD) were extracted by visual interpretation methods so as to decipher impacts of tidal channel development and road construction on landscape patch change during 1989-2016. Spatial distribution history of three wetlands, which covered by Phragmites australis (freshwater marsh, FM), Suaeda salsa (salt marsh, SM), and mudflats (MD) were also established. Results indicated that tidal channel, number, frequency, and fractal dimension were all the maximum in 2003, and the minimum in 1998, respectively. Road length, number, and density showed increasing trend during 1989-2016. MD were the predominant landscape type, followed by FM and SM during 1989-2016. Principal component analysis implied two extracted factors, F1 and F2, which could represent 91.93% of the total variations. F1 mainly proxied tidal channel development, while F2 represented road construction. A multiple linear regression analysis showed positive effects of both F1 and F2 on FM patch numbers and negative impacts on SM patch areaes with R2 values of 0.416 and 0.599, respectively. Tidal channels were negatively related to MD patch numbers, while roads were positively related to that. In any case, road construction showed larger impacts on landscape type shifting than that of tidal channel development in the YRD.
2020, 30(1): 180-188.
doi: 10.1007/s11769-019-1091-6
Abstract:
Stable oxygen isotopes in precipitation contain meaningful environmental information on a synoptic scale and can be applied to diagnose hydrometeorological processes. A series of rainstorms occurred at the southern Tianshan Mountains during the period from May to June 2013, and the event-based precipitation was sampled along the mountain range from west to east. Based on δ18O values in precipitation samples as well as the corresponding meteorological parameters, the moisture transport paths during the sampling period were identified. In late-May (stage 1), isotopes in precipitation collected generally showed a depleting trend. In mid-June (stage 2), there was no coherent trend of isotopes in precipitation for these stations, and only isotope values in Aksu showed a continually depleting trend. Checking other meteorological proxies during the sampling period, the event-based precipitation isotopes sensitively reflected the moisture process. In central Asia, both the westerly and monsoon moisture can be delivered to cause extreme precipitation events, and the isotopic information provides an alternative tool to investigate the atmospheric processes.
Stable oxygen isotopes in precipitation contain meaningful environmental information on a synoptic scale and can be applied to diagnose hydrometeorological processes. A series of rainstorms occurred at the southern Tianshan Mountains during the period from May to June 2013, and the event-based precipitation was sampled along the mountain range from west to east. Based on δ18O values in precipitation samples as well as the corresponding meteorological parameters, the moisture transport paths during the sampling period were identified. In late-May (stage 1), isotopes in precipitation collected generally showed a depleting trend. In mid-June (stage 2), there was no coherent trend of isotopes in precipitation for these stations, and only isotope values in Aksu showed a continually depleting trend. Checking other meteorological proxies during the sampling period, the event-based precipitation isotopes sensitively reflected the moisture process. In central Asia, both the westerly and monsoon moisture can be delivered to cause extreme precipitation events, and the isotopic information provides an alternative tool to investigate the atmospheric processes.
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