Relocating built-up land for biodiversity conservation in an uncertain future.

Land use changes associated with habitat loss, fragmentation, and degradation exert profoundly detrimental impacts on biodiversity conservation. Urban development is one of the prevailing anthropogenic disturbances to wildlife habitat, because these developments are often considered permanent and irreversible. As a result, the potential benefits of built-up land relocation for biodiversity conservation have remained largely unexplored in environmental management practices. Here, we analyze recent built-up land relocation in Shanghai and explore how such restoration programs can affect future land change trajectories with regards to biodiversity conservation. Results show that 187.78 km2 built-up land in Shanghai was restored to natural habitat between 2017 and 2020. Further simulation analysis highlights that relocating built-up land can substantially promote conserve biodiversity. In particular, there would be less habitat loss, better natural habitat quality and more species habitat-suitable range under the scenarios with built-up land relocation. Species extinction assessment suggest that amphibians, mammals, and reptiles will all have an increasingly high extinction risk without built-up land relocation. However, there will even be a marginal decrease in extinction risk over time for mammals and reptiles if the relocation of built-up land is permitted, but still a moderate increase in extinction risk for amphibians. This study highlights the importance of incorporating rigorous conservation planning prior to development activities, thereby underpinning a sustainable approach to environmental management.

Effects of endogenous factors on regional land-use carbon emissions based on the Grossman decomposition model: a case study of Zhejiang Province, China.

The impact of land-use change on greenhouse gas emissions has become a core issue in current studies on global change and carbon cycle. However, a comprehensive evaluation of the effects of land-use changes on carbon emissions is very necessary. This paper attempted to apply the Grossman decomposition model to estimate the scale, structural, and management effects of land-use carbon emissions based on final energy consumption by establishing the relationship between the types of land use and carbon emissions in energy consumption. It was shown that land-use carbon emissions increase from 169.5624 million tons in 2000 to 637.0984 million tons in 2010, with an annual average growth rate of 14.15%. Meanwhile, land-use carbon intensity increased from 17.59 t/ha in 2000 to 64.42 t/ha in 2010, with an average annual growth rate of 13.86%. The results indicated that rapid industrialization and urbanization in Zhejiang Province promptly increased urban land and industrial land, which consequently affected land-use extensive emissions. The structural and management effects did not mitigate land-use carbon emissions. By contrast, both factors evidently affected the growth of carbon emissions because of the rigid demands of energy-intensive land-use types and the absence of land management. Results called for the policy implications of optimizing land-use structures and strengthening land-use management.

Global 30 meters spatiotemporal 3D urban expansion dataset from 1990 to 2010.

Understanding the spatiotemporal dynamics of global 3D urban expansion over time is becoming increasingly crucial for achieving long-term development goals. In this study, we generated a global dataset of annual urban 3D expansion (1990-2010) using World Settlement Footprint 2015 data, GAIA data, and ALOS AW3D30 data with a three-step technical framework: (1) extracting the global constructed land to generate the research area, (2) neighborhood analysis to calculate the original normalized DSM and slope height of each pixel in the study area, and (3) slope correction for areas with a slope greater than 10° to improve the accuracy of estimated building heights. The cross-validation results indicate that our dataset is reliable in the United States(R2 = 0.821), Europe(R2 = 0.863), China(R2 = 0.796), and across the world(R2 = 0.811). As we know, this is the first 30-meter 3D urban expansion dataset across the globe, which can give unique information to understand and address the implications of urbanization on food security, biodiversity, climate change, and public well-being and health.

Construction of a multi-scale effectiveness evaluation system for ecological restoration and protection of territorial space.

The ecological restoration and protection of territorial space is a systematic project for the protection and restoration of ecosystems damaged or degraded by human disturbance. Effectiveness evaluation is of great significance to the optimization, adjustment, and sustainability of ecological restoration and protection. Current research and practices tend to focus on a single element and the site scale. Based on the study on the connotation of ecological restoration and protection of territorial space and the multi-scale characteristics of ecosystems, we constructed a multi-scale effectiveness evaluation system for ecological restoration and protection of territorial space and a full-cycle monitoring system for effectiveness evaluation. The multi-scale effectiveness evaluation system consisted of the regional/watershed scale, the protection and restoration unit scale, and the sub-project scale. The full-cycle monitoring system contained the basic information investigation system before construction, the construction monitoring system during construction, and the multi-scale effectiveness evaluation system after construction. At the regional/watershed scale, structure, quality, and services of ecosystem were concerned and remote sensing was used as the main method to capture data. At the protection and restoration unit scale, ecological stress factors, ecosystem quality and services were concerned, and the main methods were remote sensing combined with field survey. At the sub-project scale, engineering technology measures were concerned and the field survey was used as the main method. In the implementation of the multi-scale effectiveness evaluation, it would be necessary to focus on and solve the key issues including the spillover effect, transmission mechanism, and potential impact of ecological restoration.

Water footprint of nations amplified by scarcity in the Belt and Road Initiative.

The growing water scarcity due to international trade poses a serious threat to global sustainability. Given the intensified international trade throughout the Belt and Road Initiative (BRI), this paper tracks the virtual water trade and water footprint of BRI countries in 2005-2015. By conducting a multi-model assessment, we observe a substantial increase in BRI's water footprint after taking water scarcity into account. Globally the BRI acts as a net exporter of virtual water, while the export volume experiences a decreasing trend. Noticeable transitions in nations' role (net exporters vs. net importers) are found between the BRI and global scales, but also between with and without considering water scarcity. Overall economic and population growth is major drivers of scarcity-weighted water footprint for BRI nations, as opposed to the promotion of water-use efficiency and production structure that can reduce water scarcity. Improving international trade and strengthening cooperation on water resources management deserve priority in alleviating the water scarcity of BRI.

[Evaluation of ecological conservation red line from the perspective of ecological security pattern: Taking Zhejiang Province, China as an example]. / ç”Ÿæ€å®‰å ¨æ ¼å±€è§†è§’ä¸‹çš„ç”Ÿæ€ä¿æŠ¤çº¢çº¿è¯„ä¼°­­ä»¥æµ™æ±Ÿçœä¸ºä¾‹.

To investigate the scientificity of the ecological conservation red line in Zhejiang Province, we evaluated the ecological effect based on the concept of ecosystem processes from the perspective of ecological security pattern. On the basis of clarifying the triple connotation of the ecological conservation red line, we constructed an evaluation index system to identify ecological sources and evaluate the importance of red line patches with InVEST model and net primary productivity quantitative analysis. Minimum resistance model and gravity model were used to construct the ecological corridors and evaluate the connectivity of red line. Moreover, landscape pattern index and overlay analysis were applied to evaluate the fragmentation and coordination of red line. The results showed that, from the perspective of ecological importance, the protection scale in Zhejiang Province was relatively large, but 13.5% of the red line areas were not of high importance. About 40% of the provincial ecological sources were not included in the ecological conservation red line. From the perspective of spatial structure, the connectivity of the ecological conservation red line was insufficient. The protection rate of the first-level ecological corridor was less than 15%. The red line patches in some counties and cities were relatively broken. From the perspective of natural-social system coordination, cross-administrative red line areas were well connected. However, it was still necessary to pay attention to the fact that the conflict between supply and demand in the plain area had led to spatial mismatch and fragmentation of red line. Using the ecological security pattern for reference, we put forward the relevant strategies of red line optimization and adjustment, which could provide scientific reference for ecological space management.

Waterbody loss due to urban expansion of large Chinese cities in last three decades.

Urban waterbodies are one of the most pertinent issues involved in multiple aspects of Sustainable Development Goals (SDGs). However, waterbodies in large Chinese cities are highly vulnerable to urban-land expansion, which is mostly due to economic development, population growth, and rural-urban migration. In this work, we selected 159 Chinese cities of over one million in population to investigate the encroachment on waterbodies due to rapid urbanization from 1990 to 2018. Overall, 20.6% of natural waterbody area was lost during this period to urban expansion, and this fraction varied from city to city which was related to waterbody abundance. With the acceleration of urbanization, waterbody occupation is becoming more serious (P < 0.01). However, in all cities, this encroachment has eased since 2010, which justifies the effective implementation of national-scale policies to conserve urban waterbodies. Meanwhile, gains have occurred during urbanization, in addition to the loss of waterbodies. Especially, cities lacking waterbody placed a greater emphasis on ecological factors, whose urban waterbody areas showed an increasing trend. In the future, ecological resources, including waterbody, should be considered in urban planning to provide reasonable protection to waterbodies in the quest for urban sustainability.

Influences of landform and urban form factors on urban heat island: Comparative case study between Chengdu and Chongqing.

Although the degraded urban thermal environment has been widely concerned, whether monocentric or polycentric urban development can alleviate urban heat island (UHI) is still debatable, particularly considering different types of cities in plain and mountainous settings. To fill the gap, this study chose the cases of Chengdu on alluvial flatlands and Chongqing on mountainous landforms in China for comparison. Adapting to natural landforms, Chengdu has a dominated monocentric urban form, whereas Chongqing has a naturally polycentric urban form. This study found that areas with high UHI intensity were located in the urban center and peripheral suburbs in Chengdu, while those were located in the peripheral industrial zones in Chongqing. The spatial error model and random forest regression results showed that natural elements such as vegetation and water had similar influences and contributions to UHI. However, distinct landforms and urban forms played critical roles in UHI differences among the two cities. Impervious surface and building density were the dominant variables to UHI of Chengdu, while sky view factor and industrial zones were the main contributors to UHI of Chongqing. The findings called for corresponding policy strategies to optimize urban form and improve the urban thermal environment.

[Territorially ecological restoration zoning and optimization strategy in Guyuan City of Ningxia, China: Based on the balance of ecosystem service supply and demand]. / 基于生态系统服务供需平衡的宁夏固原生态修复分区与优化策略.

Scientifically identifying the territorially ecological restoration zoning is a vital prerequisite for implementing ecological restoration projects and enhancing environmental quality. Based on remote sensing data, we syste-matically assessed supply and demand for ecosystem service and their relationship in Guyuan City, China by using the InVEST model, coordination degree model, and spatial autocorrelation analysis. We carried out territorially ecological restoration zoning by coupling the ecosystem service supply and demand. Furthermore, the corresponding optimization strategies were put forward according to the regional characteristics of natural resources and socio-economic development. The results showed that the areas with high water yield, carbon storage, soil conservation and habitat quality were mainly located in the southern part of Guyuan City. The areas with high population density, economic development level and high ecological demand were mainly located in the central urban area and the location towns of the county government. The spatial mismatch of supply and demand for ecosystem services in Guyuan City was dominant, as indicated by the fact that the areas with high ecological supply having low ecological demand and low ecological supply having high ecological demand. The average coordination index was 0.5, indicating that the relationship between ecological supply and ecological demand was basically coordinated. Based on the diffe-rences between supply and demand of ecosystem services and regional natural geographical pattern, the administrative township units in Guyuan could be classified into six ecological restoration zonings: key ecological restoration area, potential ecological restoration area, ecological economic reconstruction area, characteristic agricultural development area, ecological core protection area, and ecological industry construction area. Different management strategies were proposed to provide scientific support for ecological restoration.

Inequality of public facilities between urban and rural areas and its driving factors in ten cities of China.

Urban development continues to face the dilemma of spatial inequality of public facilities, particularly educational and medical facilities. Identifying inequalities in various types of public facilities and their driving mechanisms is crucial in reducing social inequality. However, information on this topic is limited. This study took 10 typical cities in China as cases. We used the methods of the Gini coefficient and hedonic price model as bases in evaluating the equality of nine types of education and medical facilities, focusing on the differences between urban and rural areas. Moreover, we further analyzed the driving factors of facility equality. Results showed that equality of public facilities in urban areas was significantly higher than that in rural areas. Primary schools, middle schools, and health service centers were relatively equal, and kindergartens and pharmacies were unequal only in rural areas. However, the equality of facilities with large-size or commercial attributes was not optimistic. Furthermore, there remained a significant gap among counties (or districts), which was mainly driven by population, economy, and building density in the form of logarithm and logarithmic linear models. Our research contributes to an in-depth understanding of the inequality of public facilities and further supports decision-making to improve social equality.

Effects of Land Use on Land Surface Temperature: A Case Study of Wuhan, China.

In this study, we aim to understand the impact of land use on the urban heat island (UHI) effect across an urban area. Considering the case study of Wuhan, China, land use factors and land surface temperatures (LSTs) of 589 planning management units were quantified in order to identify the spatial autocorrelation of LST, which indicated that a traditional regression would be invalid. By investigating the relationships between land use factors and the LST in summer, based on spatial regression models including the spatial lag model and the spatial error model, four conclusions were derived. First, the spatial error model effectively explains the relationships between LST and land use factors. Second, the impact on LST of the percentage of industrial areas is significant even though the impacts of land cover and building-group morphology indicators are combined, indicating that anthropogenic heat emission of industrial production contributes to high LSTs. Third, the relationship between the percentage of commercial area and LST is significant in the Pearson correlation analysis and traditional regression models, while not significant in spatial error model, suggesting that the urban heat environment of a commercial area is determined by the land use factors of the surrounding area. Fourth, the UHI effect in industrial and commercial areas could be precisely mitigated by not locating industrial areas beside residential areas, and setting up buffer zones between commercial areas and surrounding traditional residential areas. Overall, the results of this study innovatively deepen the understanding of the impact of the percentage of different urban land use types on the urban heat environment at the scale of planning management units, which is conducive to formulating precise regulation measures for mitigating UHI effects and improving public health.

Estimation of anthropogenic heat emissions in China using Cubist with points-of-interest and multisource remote sensing data.

Rapid urbanization and industrialization in China stimulated the great increase of energy consumption, which leads to drastic rise in the emission of anthropogenic waste heat. Anthropogenic heat emission (AHE) is a crucial component of urban energy budget and has direct implications for investigating urban climate and environment. However, reliable and accurate representation of AHE across China is still lacking. This study presented a new machine learning-based top-down approach to generate a gridded anthropogenic heat flux (AHF) benchmark dataset at 1 km spatial resolution for China in 2010. Cubist models were constructed by fusing points-of-interest (POI) data of varying categories and multisource remote sensing data to explore the nonlinear relationships between various geographic predictors and AHE from different heat sources. The strategy of developing specific models for different components and exploiting the complementary features of POIs and remote sensing data generated a more reasonable distribution of AHF. Results showed that the AHF values in urban centers of metropolises over China range from 60 to 190 W m-2. The highest AHF values were observed in some heavy industrial zones with value up to 415 W m-2. Compared with previous studies, the spatial distribution of AHF from different heating components was effectively distinguished, which highlights the potential of POI data in improving the precision of AHF mapping. The gridded AHF dataset can serve as input of urban numerical models and can help decision makers in targeting extreme heat sources and polluters in cities and making differentiated and tailored strategies for emission mitigation.

Improved population mapping for China using remotely sensed and points-of-interest data within a random forests model.

Remote sensing image products (e.g. brightness of nighttime lights and land cover/land use types) have been widely used to disaggregate census data to produce gridded population maps for large geographic areas. The advent of the geospatial big data revolution has created additional opportunities to map population distributions at fine resolutions with high accuracy. A considerable proportion of the geospatial data contains semantic information that indicates different categories of human activities occurring at exact geographic locations. Such information is often lacking in remote sensing data. In addition, the remarkable progress in machine learning provides toolkits for demographers to model complex nonlinear correlations between population and heterogeneous geographic covariates. In this study, a typical type of geospatial big data, points-of-interest (POIs), was combined with multi-source remote sensing data in a random forests model to disaggregate the 2010 county-level census population data to 100 × 100 m grids. Compared with the WorldPop population dataset, our population map showed higher accuracy. The root mean square error for population estimates in Beijing, Shanghai, Guangzhou, and Chongqing for this method and WorldPop were 27,829 and 34,193, respectively. The large under-allocation of the population in urban areas and over-allocation in rural areas in the WorldPop dataset was greatly reduced in this new population map. Apart from revealing the effectiveness of POIs in improving population mapping, this study promises the potential of geospatial big data for mapping other socioeconomic parameters in the future.

Environmental consequences of rapid urbanization in zhejiang province, East china.

Since reforms carried out in the late 1970s, China has experienced unprecedented rates of urban growth. Remote sensing data and surface observational data are used to investigate the urbanization process and related environmental consequences, focusing on extreme heat events and air pollution, in Zhejiang Province (ZJP, East China). Examination of satellite-measured nighttime light data indicates rapid urbanization in ZJP during the past decade, initially forming three urban clusters. With rapid urban sprawl, a significant Urban Heat Island (UHI) effect has emerged. During extreme heat events in summer, the UHI effect significantly exacerbates nocturnal heat stress in highly urbanized areas. Taking a long-term view, urbanization also causes additional hot days and hot degree days in urban areas. Urbanization also imposes a heavy burden on local and regional air quality in ZJP. Degraded visibility and an increase in haze days are observed at most meteorological stations, especially in the three urban clusters. The results show that urbanization has led to serious environmental problems in ZJP, not only on the city scale, but also on the regional scale. Maintaining a balance between the continuing process of urbanization and environmental sustainability is a major issue facing the local government.

[Remote sensing estimation of urban forest carbon stocks based on QuickBird images].

Urban forest is one of the positive factors that increase urban carbon sequestration, which makes great contribution to the global carbon cycle. Based on the high spatial resolution imagery of QuickBird in the study area within the ring road in Yiwu, Zhejiang, the forests in the area were divided into four types, i. e., park-forest, shelter-forest, company-forest and others. With the carbon stock from sample plot as dependent variable, at the significance level of 0.01, the stepwise linear regression method was used to select independent variables from 50 factors such as band grayscale values, vegetation index, texture information and so on. Finally, the remote sensing based forest carbon stock estimation models for the four types of forest were established. The estimation accuracies for all the models were around 70%, with the total carbon reserve of each forest type in the area being estimated as 3623. 80, 5245.78, 5284.84, 5343.65 t, respectively. From the carbon density map, it was found that the carbon reserves were mainly in the range of 25-35 t · hm(-2). In the future, urban forest planners could further improve the ability of forest carbon sequestration through afforestation and interplanting of trees and low shrubs.

[Spatiotemporal changes of wetlands in Hangzhou Bay Industrial Belt].

By using RS and GIS techniques, the spatiotemporal changes of wetlands in Hangzhou Bay Industrial Belt, one of the most developed zones in Zhejiang Province, from 1990 to 2005 were studied. There was a frequent conversion between the wetlands and other land use types and between the wetlands themselves, mainly manifested in the conversion between wetland and farmland, and from wetland to construction land and from tidal flat to aquiculture area. The comparative advantage of other land use types and the policy of cultivated land's requisition-compensation balance decided the inherent mechanisms of these spatiotemporal changes. Driven by the aquaculture's comparative advantage to traditional agriculture, large areas of inland farmland and of the tidal flat along the coast of Hangzhou Bay were reclaimed into aquiculture area, and the rapid expansion of construction land, limited land resources, and the implement of cultivated land's requisition-compensation balance policy induced the wetlands being occupied.

[Spatial variance characters of urban synthesis pattern indices at different scales].

Scale holds the key to understand pattern-process interactions, and indeed, becomes one of the corner-stone concepts in landscape ecology. Geographic Information System and remote sensing techniques provide an effective tool to characterize the spatial pattern and spatial heterogeneity at different scales. As an example, these techniques are applied to analyze the urban landscape diversity index, contagion index and fractal dimension on the SPOT remote sensing images at four scales. This paper modeled the semivariogram of these three landscape indices at different scales, and the results indicated that the spatial variance characters of diversity index, contagion index and fractal dimension were similar at different scales, which was spatial dependence. The spatial dependence was showed at each scale, the smaller the scale, the stronger the spatial dependence. With the scale reduced, more details of spatial variance were discovered. The contribution of spatial autocorrelation of these three indices to total spatial variance increased gradually, but when the scale was quite small, spatial variance analysis would destroy the interior structure of landscape system. The semivariogram models of different landscape indices were very different at the same scale, illuminating that these models were incomparable at different scales. According to above analyses and based on the study of urban land use structure, 1 km extent was the more perfect scale for studying the spatial variance of urban landscape pattern in Shanghai. The spatial variance of landscape indices had the character of scale-dependence, and was a function of scale. The results differed at different scales we chose, and thus, the influence of scales on pattern could not be neglected in the research of landscape ecology. The changes of these three landscape indices displayed the regularity of urban spatial structure at different scales, i. e., they were complicated and no regularity at small scale, polycentric at moderate scale, and circle-zoning at big scale.