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Multi‐Scale Applicability Analysis of Three Ecological Network Construction Methods in Resilience Assessment
Land Degradation & Development
Abstract
Anthropogenic interference causes ecological fragmentation and vulnerability, weakening urban ecosystems' adaptive capacity. The ecological network is based on the principles of landscape ecology, connecting resource patches through linear corridors to protect biodiversity and landscape integrity, enhance environmental carrying capacity, and improve ecosystem resilience. However, current research on ecological network resilience often relies on single methods and scales, overlooking the potential discrepancies between different approaches and scales. This study uses Zhejiang to construct ecological networks with structural, functional, and integrated approaches at provincial, urban agglomeration, and city levels. The performance of these methods in protecting structure, maintaining function, and ensuring overall resilience was compared, yielding the following results: First, the spatial output consistency of source areas across different scales for the three methods ranged from 50.48% to 97.81%. Second, the integrated approach was not optimal for all three resilience goals. The structure‐oriented method demonstrated cross‐scale applicability for the structural resilience goal, while the function‐oriented strategy performed well in maintaining functional and overall resilience. Third, the scale analysis showed consistency in results at the provincial and urban agglomeration levels when meeting the same objectives, but discrepancies at the city level. By expanding the methodologies and scale perspectives in the field of ecological network resilience, this study assesses the applicability of different scales and methods for ecological network resilience. It was found that integrated methods do not always effectively coordinate multiple protection objectives; thus, large‐scale strategies cannot be directly applied at smaller scales in practical applications. This study proposes and validates a multi‐scale, multi‐method framework for assessing the resilience of ecological networks. It reveals the potential differences between scales and methods, providing valuable theoretical insights and practical guidance for future research on ecological network resilience, particularly regarding the applicability of methods at different scales.
Ecological networks (ENs) are vital for maintaining regional ecological security and preserving biodiversity. While various methods exist for constructing ENs, their effectiveness across different spatial scales, particularly in urban agglomerations, has not been thoroughly investigated. This study focuses on the Yangtze River Delta urban agglomeration (YRDUA), constructing ENs at three scales: urban agglomeration, metropolitan area, and city. Two methods were employed at each step, and the outcomes were evaluated and ranked using specific indicators. The results indicate: (1) For ecological source identification, the spatial distribution of ecological sources identified by different methods is consistent at the same scale, with the number of ecological sources identified at the three scales being around 600, 140, and 160, respectively. (2) For resistance surface construction, although there are differences between the two methods, the final resistance value shows relatively small changes. (3) Regarding the number of corridors, the quantities of the three scales are around 1470, 380, and 410, respectively. For specific indicators, α values of the three scales are around 0.71, 0.85, and 0.81, respectively; β values are around 2.42, 2.68, and 2.61, respectively; γ values are around 0.81, 0.90, and 0.88, respectively; Cr values are around 0.88, 0.80, and 0.68, respectively. Comparing and ranking all indicators can yield: at the urban agglomeration scale, ecological sources identified by the MSPA method, resistance surfaces constructed by Spatial Principal Component Analysis (SPCA), and corridors extracted by Linkage Mapper yielded optimal results. At the metropolitan and city scales, ecological sources identified by the MSPA method, resistance surfaces constructed by the Analytical Hierarchy Process (AHP), and corridors extracted by Graphab yielded optimal results. These findings provide methodological guidance for constructing ENs across different scales and offer new insights for landscape planning at multiple levels.
Urbanization has facilitated economic development while simultaneously resulting in various ecological issues. Constructing a multi-scale nested and composite functional urban-rural ecological network is crucial for improving ecological security. This study utilizes Dali City as a case study and employs methods including MSPA, circuit theory, and landscape connectivity index to develop the urban-rural habitat network, water green network, and recreation network, focusing on the " red-green-blue " spatial framework. An analysis of the spatial characteristics of source areas, corridors, ecological strategic points, and other spatial elements is conducted to establish a multi-level, multi-objective, and multifunctional composite urban-rural ecological network. The results show that: (1) 13 ecological source areas were identified in both the municipal and main urban areas, along with 22 ecological corridors in the municipal and 20 main urban areas. The distribution of ecological corridors was uniform across the study area. (2) The optimal width for the municipal biological corridor is 150 m, the main urban area should have a width of 90 m. The optimal width for rainwater corridors in municipal and main urban areas is 60 m. (3) The multi-scale nested ecological network identified 4 common ecological sources, 11 ecological corridors, 3 rainwater corridors, 6 wetland nodes, and 7 amusement nodes. Overall, the number of ecological nodes is limited, indicating a need for enhanced node construction. The research findings offer insights for developing ecological networks that integrate urban and rural functions, serving as a reference for ecological protection and restoration in pertinent regions.
The aim of this paper is to evaluate the coupled coordination degree of climate, environmental, socio-economic, and ecosystem resilience in Zhejiang Province from 2010 to 2022 and to propose optimization strategies. With the increasing impact of global climate change, the need to explore the construction of resilient cities and sustainable development models has become increasingly pressing. Assessing the coupled coordination among climate, environment, socio-economic, and ecosystem resilience aids in suggesting more precise and effective social and ecological recovery strategies in the context of climate change. Zhejiang Province, serving as a model for China’s urbanization development, demonstrates a balance between the natural environment, economic growth, and social development but still suffers from ecological and environmental pollution problems. In this study, an evaluation system was constructed utilizing the entropy weight method (EWM), and the coupled coordination among climate, environmental, socio-economic, and ecosystem resilience in Zhejiang Province was empirically analyzed over the period from 2010 to 2022. The results show that (1) the climatic-environmental, socio-economic, and ecological subsystems of cities in Zhejiang Province generally show an upward trend, despite fluctuations over different periods. (2) The climatic-environmental-social-ecological system resilience of the cities in Zhejiang Province increased as a whole, and six cities (Hangzhou: 0.805, Quzhou: 0.811, Huzhou: 0.827, Taizhou: 0.829, Wenzhou: 0.856, and Jinhua: 0.857) reached the “well-coordinated” level by 2022; however, the coupling coordination of Jiaxing City and Lishui City decreased from good to intermediate coordination. (3) The coupled coordination degree of climatic-environmental-social-ecological system resilience generally stagnated in each city during 2020–2022. Thus, the climate change adaptation strategy proposed in this study aims to enhance urban adaptive capacity to climate change impacts by controlling pollutant emissions, restoring ecosystems, optimizing industrial structures, and designing urban green spaces.
China announced the development of its first 5 national parks in 2021, the primary objective of which is to conserve the natural state and integrity of natural ecosystems. As such, ecosystem services and biodiversity levels are crucial assessment factors for the parks. For Giant Panda National Park (GPNP), we evaluated ecological sensitivity based on water and soil erosion and rocky desertification; ecosystem services based on headwater conservation, soil and water conservation, and biodiversity conservation; and presence of giant panda ( Ailuropoda melanoleuca ) and sympatric species (e.g., takin [ Budorcas taxicolor ], Asiatic black bear [ Ursus thibetanus ]) habitat suitability derived from niche modeling to identify the ecosystem status and assess ecological problems within the park. From our results, we proposed ecologically critical areas to target to meet the park's goals. The suitable habitat for pandas and sympatric species encompassed 62.98% of the park and occurred mainly in the Minshan Mountains. One quarter of the total area (25.67%) contained areas important for ecosystem services. Ecologically sensitive and extremely sensitive areas covered 88.78% of the park and were distributed mainly in Qionglaishan and Minshan Mountains. This coverage indicated that there was much habitat for pandas and sympatric species but that the ecosystems in GPNP are vulnerable. Therefore, ecologically critical areas encompassed all suitable habitats for all the species examined and areas important and extremely important to ecosystem service provision,ecologically sensitive and extremely sensitive areas, encompassed 15.17% of panda habitat, accounted for 16.37% of the GPNP area, and were distributed mainly in the Minshan Mountains. Our results indicated where conservation efforts should be focused in the park and that by identifying ecologically critical areas managers can provide targeted protection for wildlife habitat and ecosystems and effectively and efficiently protect the composite ecosystem. Additionally, our methods can be used to inform development of new national parks.
Metropolitan regions usually encounter sustainability difficulties such as overexploitation of resources, severe land scarcity, and ecological degradation, resulting in the progressive collapse of ecological networks (ENs). It is therefore essential to strengthen the construction and protection of ENs by integrating various resources, improving the quality of the urban ecological environment and creating a favourable living environment. Using the Guangdong-Hong Kong-Macao Greater Bay Area as a case study, in this paper, the ecological resistance indicator system that balances natural condition and human disturbance is rebuilt. In doing so, a construction scheme (applicable to highly urbanised areas) is established to simulate ENs at a more precise scale. Moreover, a local evaluation model of ENs is proposed and the spatial patterns of multiple indicators are fully summarised. The findings show that the ENs of the Guangdong-Hong Kong-Macao Greater Bay Area exhibit apparent spatial disparity. Disturbance through human activities seriously affects the spatial pattern of ENs, leading to structural imbalance and quality impairment of ecological corridors. Based on our assessment, the construction of complementary ecological corridors in the "two green belts" planning of the Guangdong-Hong Kong-Macao Greater Bay Area will improve structural problems. The findings of this paper can provide a reference to the harmo-nisation of urban development and ecological protection, by guiding the scientific management of ecological spaces in highly urbanised regions.
Ecological network construction and optimization is an effective way to balance the contradiction between regional development and ecological protection in the process of urbanization. The urban–rural fringe is both a frontier zone in the direction of urban expansion and an important space for improving the urban ecological environment. However, there are few studies on how to construct and optimize the ecological networks in urban–rural fringe. In this paper, the morphological spatial pattern analysis (MSPA) and the minimum cumulative resistance model (MCR) were firstly employed to initially construct the ecological network and reveal the characteristics and problems of ecological security pattern in the study area. Then, a new ecological network optimization strategy with a multi-scenario coupling of urban–rural gradient spatial zoning was proposed to meet the maximization of integrated benefits of future urban development and ecological protection. The study results show that: (1) Urbanization caused a high fragmentation of ecological patches, and exerted a strong spatial hindrance to ecological processes. (2) The spatial distribution of the initially constructed ecological network was extremely uneven, and ecological communication in the north–south direction was severely difficult. The optimized ecological network was significantly improved in this respect, and the priority construction of important corridors will also help to strengthen ecological communication in the direction of urban–rural gradient. (3) The proposed optimization strategy improved the connectivity and accessibility of the ecological network in Licheng District, and enhanced its structure, which will promote the overall ecological process cycle and better balanced the urban development and ecological protection. (4) Policy makers should strengthen the construction and implementation of ecological green corridors and forest belts in urban–rural fringe to achieve a balance between urban development and ecological protection. This study can provide scientific references for biodiversity conservation, green infrastructure planning, and sustainable development in the process of urbanization.
Gephi is an open source software for graph and network analysis. It uses a 3D render engine to display large networks in real-time and to speed up the exploration. A flexible and multi-task architecture brings new possibilities to work with complex data sets and produce valuable visual results. We present several key features of Gephi in the context of interactive exploration and interpretation of networks. It provides easy and broad access to network data and allows for spatializing, filtering, navigating, manipulating and clustering. Finally, by presenting dynamic features of Gephi, we highlight key aspects of dynamic network visualization.
Habitat fragmentation, a contributor to biodiversity degradation in urbanized regions, will result from rapid urbanization. Due to the low quality of habitats and the complexity of land use in high-density cities, traditional ecological corridor development approaches may not be viable for urban contexts. Furthermore, unlike other ecological corridors, the width of urban ecological corridors is not fixed due to very constrained land use and a high density of structures in urbanized areas. However, we discovered few studies on how to build urban ecological corridors in densely populated areas. Aside from that, earlier studies primarily concentrated on identifying potential paths for ecological corridors, with the spatial range of ecological corridors typically being determined subjectively. The goal of this research was to develop an integrated approach for determining the suitable areas of ecological corridors in a rapidly urbanizing region. Firstly, key species for urban ecological corridors were identified and Morphological Spatial Pattern Analysis (MSPA) was applied to identify core areas and established corridors in the city, which was then integrated with NDVI and InVEST to construct resistance surfaces. Potential corridor paths were identified and graded for importance by Linkage Mapper. Finally, our research established a metric and indicators system, four indicators were set in this framework: the suitable width for animal migration, the maximum cost-weighted distances animals can migrate, areas with high mobility potential, and areas with greatest restoration opportunities. A total of 33 urban ecological sources and 63 ecological corridors were identified. The corridor is only 10 m wide at its narrowest point and 100 m at its widest point. Delimiting the appropriate areas of ecological corridors can provide spatial guidance for the implementation of corridors and ensuring ecological security in densely populated areas.
The ecological source area is the basis of regional ecological security, clearing the important performance of the ecological source area in the region to provide targeted measures for ecological construction. Taking the Changsha-Zhuzhou-Xiangtan ecological green core as an example, the ecological importance evaluation system was constructed from five aspects of spatial location, scale advantage, spatial layout, spatial connection, and ecological composition. For the spatial structure based on ecological networks, the ecological importance evaluation was carried out, and the ecological function was defined. It can provide a reference for the protection and construction of the Changsha-Zhuzhou-Xiangtan ecological green core. The results show the following: (1) The research method of inferring the ecological functions of ecological source sites based on the spatial characteristics of ecological networks and then completing the evaluation of ecological importance is feasible and effective, reflecting the macroecological functions played by ecological source sites in regional ecosystems and providing ideas for exploring the multiple ecological functions of ecological source sites from a combination of macro and micro perspectives. (2) The ecological importance of the Changzhutan Ecological Green Center is much higher than other ecological sources in Changzhutan Urban Cluster, and its main ecological function is the spatial structure strengthening function, followed by the spatial connection function, and the ecological service function is lower. The internal landscape pattern of interlocking arable land and woodland, with arable land blocking the ecological landscape, requires landscape pattern optimization. (3) The ecological green heart of Changzhutan is close to the regional mass center, and the ecological service area accounts for 14.57% of the area of Changzhutan urban agglomeration, which is connected to 55% of the ecological sources through ecological corridors, is the core hub connecting the north-south ecosystem of Changzhutan urban agglomeration, and is in a dominant position in the regional ecosystem. In the absence of the Changzhutan ecological green heart, the patch density, average proximity, cohesion, and aggregation all drop to the lowest, connectivity drops to the second lowest, and subdimensionality reaches the highest, highlighting the significance of the Changzhutan ecological green heart to maintain the ecological green volume of the Changzhutan urban cluster, enhance the overall ecosystem connectivity, and reduce landscape fragmentation. (4) There are five important ecological connection points between the Changzhutan Ecological Green Center and external ecosystem, which need to take different measures to strengthen ecological protection and construction.
Ecological protection and restoration is an important bridge to adjust the contradiction between ecological protection and economic development, and it is essential for ecological security and sustainable development. An integrated evaluation framework for multiscale ecological protection and restoration based on multi-scenario trade-offs of ecosystem services was proposed in this study, and the city of Nanjing was taken as an example to identify key areas and land strategies for ecological protection and restoration. In our framework, carbon storage, habitat quality, nitrogen retention, and water conservation services were quantified by InVEST model, and recreational service was quantified as the total areas of green spaces within ecological land accessibility. The ordered weighted averaging model was used to simulate the priority areas of ecological protection under 11 scenarios of trade-offs of ecosystem services, and ecological sources, ecological corridors, ecological pinch points and ecological barriers at the Nanjing city scale and the main urban scale were identified based on circuit theory. We also nested the ecological conservation and restoration patterns at two scales and analyzed the coincidence degree between two scales. Our results showed that the S7 scenario had the highest average conservation efficiency among the 11 scenarios. The priority areas for ecological protection in this scenario had an area of 1582 km² and are mainly distributed in the central and southern parts of Nanjing. In our study, 50 ecological sources (with an area of 1153.36 km²), 77 ecological corridors (with a length of 443.04 km), 25 key nodes for ecological protection and 31 key nodes for ecological restoration were identified in Nanjing. By nesting the ecological protection and restoration patterns of two scales, we found that the overlap of ecological sources and ecological pinch points at two scales is 100%, and the overlap of ecological corridors and ecological barriers is 45.28% and 57.14%, respectively, which means that the ecological protection and restoration patterns at the two scales in Nanjing were well connected, but the ecological network at the large scale cannot fully reflect the real ecological problems and needs at the small scale. We suggest regarding the ecological protection and restoration pattern at large scale as the basis and the pattern at small scale as the supplement. We also propose that priority should be given to the protection and restoration of key areas where the two scales overlap, and strictly control their land development to promote sustainable development. This framework and these strategies are applicable to other rapidly urbanizing regions of the world.
The ecological security pattern is an important way to coordinate the contradiction between regional economic development and ecological protection and is conducive to promoting regional sustainable development. This study examines Guangxi, a karst region in China. The ecosystem service function and ecological environment sensitivity were both selected to evaluate the ecological conservation importance, and based on the results of the ecological conservation importance evaluation, suitable patches were selected as ecological sources. Meanwhile, resistance factors were selected from both natural factors and human activities to construct a comprehensive resistance surface, circuit theory was used to identify ecological corridors, ecological pinch points, and ecological barrier points, and ecological protection suggestions were then proposed. The results show that there are 50 patches of ecological sources in Guangxi, with a total area of 60,556.99 km2; 115 ecological corridors, with the longest corridor reaching 194.97 km; 301 ecological pinch points, whose spatial distribution is fragmented; and 286 ecological barrier points, most of which are concentrated in the central part of Guangxi. The results of this study provide a reference for the construction of ecological security patterns and ecological conservation in developing countries and karst areas.
Ecological security patterns are employed to characterize the health and integrity of an ecosystem. It is essential to achieve sustainable and high-quality development of cities and urban agglomerations and to enhance human well-being. Considering the Guanzhong Plain urban agglomeration as an example, this paper proposes a technical framework for the delineation of ecological security patterns at the urban agglomeration scale with the objective of protecting and restoring mountains-rivers-forests-farmlands-lakes-grasslands. The ecological sources were indicated by the importance-sensitivity ecological assessment method. Ecological corridors were identified by a minimum resistance model, and the ecological security pattern was derived. Twenty-three important ecological source sites were identified within the urban agglomeration, mainly located in the southern part of the Guanzhong Plain urban agglomeration, with an area of 9122.36 km², accounting for 8.52% of the study area. The ecological sensitivity of the mountainous areas was relatively high, with ecological corridors showing a denser distribution in the south. The results of the study suggest that green infrastructure in the northern region should be strengthened, that the ecological functions of ecologically sensitive areas should be protected and enhanced, and that the connectivity of ecological corridors should be strengthened. The results provide guidance for the optimization of regional ecological security patterns for and the joint prevention and control of environmental pollution in the Guanzhong Plain.
Resilience as a concept is multi-faceted with complex dimensions. In a disaster context, there is lack of consistency in conceptualizing social resilience. This results in ambiguity of its definition, properties, and pathways for assessment. A number of key research gaps exist for critically reviewing social resilience conceptualization, projecting resilience properties in a disaster-development continuum, and delineating a resilience trajectory in a multiple disaster timeline. This review addressed these research gaps by critically reviewing social resilience definitions, properties, and pathways. The review found four variations in social resilience definitions, which recognize the importance of abilities of social systems and processes in disaster phases at different levels. A review of resilience properties and pathways in the disaster resilience literature suggested new resilience properties—“risk-sensitivity” and “regenerative” in the timeline of two consecutive disasters. This review highlights a causal pathway for social resilience to better understand the resilience status in a multi-shock scenario by depicting inherent and adaptive resilience for consecutive disaster scenarios and a historical case study for a resilience trajectory in a multiple disaster timeline. The review findings will assist disaster management policymakers and practitioners to formulate appropriate resilience enhancement strategies within a holistic framework in a multi-disaster timeline.
Context
A landscape is defined as a “system of ecosystems” and this is a model in which karst areas can easily be integrated. In karst areas, much of the connectivity between the units of the landscape is underground, with aquifers and caves forming a continuous layered tissue. However, underground environments are among the least studied landscapes on Earth because of limited accessibility and the difficulty of performing surveys.
Objectives
The aim of this paper is to provide a conceptual framework for applying principles of landscape ecology to research on karst environments.
Methods
By adapting the standard patch-corridor-matrix model to a 3d model, the main issues that need to be addressed were identified. These include identifying the main morphological (surface and underground) karst features; determining the landscape structure through its features, composition, and configuration; and developing adequate indices.
Results
The landscape spatial structure of different karst areas influences fundamental ecological functions and biodiversity patterns. Determining how structure, biodiversity, and functions relate reveals important insights into the functioning of karst systems. Emphasizing the provisioning of ecosystem services is essential in supporting the concept that karst regions are vital for human well-being because they host valuable resources and fundamental ecosystem processes. The paper discusses how this framework helps address anthropogenic impacts and conservation issues on karst.
Conclusions
The potential of applying a landscape approach to karst systems lies in developing models that provide ecological information relevant to understanding karst systems and understanding their implications for natural resources management.
Rapid urbanization has led to increasingly fragmented urban habitat patches, and the biodiversity within these patches and in their surrounding areas is severely threatened. This ecological problem is spreading from cities to counties dominated by villages and towns, and is especially prevalent in economically developed areas. Constructing a reasonable ecological network is an effective way to balance the contradiction between regional development and ecological protection. Taking Anji County of the Zhejiang Province, China as an example, this study first identified ecological sources based on morphological spatial pattern analysis (MSPA) and connectivity analysis, and then extracted and constructed ecological networks by using a minimum cumulative resistance (MCR) model and network analysis. Finally, the results were optimized by adding additional ecological sources and setting stepping stones. The priority of the corridor is determined by the gravity model, and the analysis of the ecological networks in this study drills down to the town scale. The results show that the initially constructed ecological network includes 10 ecological sources and 22 ecological corridors, of which six are important ecological corridors that need priority construction. However, the ecological networks were less distributed in the central and northern regions, so four supplementary ecological sources and two stepping stones were added to optimize the ecological network. The connectivity of the optimized ecological network improved, and the values of α (the closure), β (line-point rate) and γ (network connectivity) increased by 4.6%, 10.45% and 2.18%, respectively. In addition, there were obvious differences in the area and land use types of ecological networks among towns, so it is necessary to formulate targeted construction strategies. Through an in-depth analysis from county to town, this study makes the construction and management of ecological networks more operable for country administration, and provides reference for the balance of ecological protection and regional development at the county level.
Greenspace ecological networks (GENs) optimization is an effective way to prevent landscape fragmentation and promote ecological processes. Built land sprawl is an important factor affecting this optimization. However, few studies have specifically analyzed the encroachments caused by existing built land on GENs. Given the insights from China’s total built land control policy, this study proposed a new idea of linking GENs optimization into urban expansion planning through land transformation. This idea was implemented in the Su-Xi-Chang area and integrated a series of methods, emphasizing the importance of built land encroachments removal for restoring the connectivity and quality of GENs. We identified that the built land encroached on GENs. Furthermore, we proposed to transfer the scattered rural/industrial land, whose amount was set as the land quota for urban expansion planning. Four scenarios of urban expansion were simulated based on China’s land use policies/practices and assessed by landscape metrics. The land transformation happened between rural and urban land. The main findings indicated that more inclusive urban expansion planning with consideration of the GENs optimization can be obtained. This study has practical contributions regarding GENs optimization and urban expansion planning for policymakers and our ideas of land transformation provide a reference for similar studies.
ContextSpatial planning system needs the support of approaches toward achieving sustainability, with sustainable landscape pattern (SLP) for one potential spatial approach. However, the scientific definition of SLP has not been clarified in previous studies, and the support of SLP for spatial planning is also few summarized.Objectives
The scientific definition and conceptual connotation of SLP were proposed, and its application status and development directions of theory and practice in spatial planning were further summarized.Methods
We systematically reviewed the literature on landscape sustainability, urban growth boundary, ecological network, green infrastructure, ecological security pattern, ecological red line and others close to SLP, and qualitatively summarized the key theoretical and practical support of SLP for spatial planning.ResultsSLP is defined as a certain combination of composition and configuration of landscape elements that enables social-ecological processes to sustainably provide stable ecosystem services for promoting human well-being in a particular region. SLP effectively supports spatial planning to determine planning targets, analyze spatial patterns, and compare and select schemes by assessing target landscape elements, identifying key spatial areas, and simulating future development scenarios. It is proposed that frontier concepts (i.e. spatial resilience, metacoupling framework and landscape multifunctionality) provide new research perspectives for SLP, and that SLP can also be applied to ecological restoration, urban agglomeration coordinated development, and nature-based solution in the future.Conclusions
Clarifying the scientific connotation of SLP can provide theoretical and methodological support for spatial planning practice and also a spatial approach for sustainable development.
With rapid urbanization and frequent disasters, regional ecosystem resilience decreased continuously. Strengthening the resilience of the ecological network is conducive to improving the ecological benefits and the quality of ecological products. The research on the resilience of ecological networks is increasingly concerned, and it is necessary to construct a comprehensive research framework to evaluate the resilience of ecological networks. Taking Wuhan metropolitan area as a case, this research aimed to constructs an ecological network and evaluates network resilience from the perspective of complex networks. Firstly, we construct the evaluation Index of network resilience from the structure and function dimensions. Secondly, regions with high importance are selected as ecological sources according to the evaluation of landscape connectivity. Thirdly, the MCR model is used to establish the ecological network. Finally, we analyzed the resilience characteristics of the network under different node failure scenarios. The results show that: (1) Ecological nodes correspond to a wide variety of land types, including forest, water bodies, croplands, and urban and build-up; (2) The overall ecological connection of the ecological corridor is relatively high and the main components of the landscape are croplands, forest and water bodies; (3) The trend of structural and functional resilience does not always show convergence under different shock simulation which is related to the redundancy of networks. The research results will help to analyze the network and regional resilience and provide references for the optimization of ecological networks and the improvement of sustainable ecosystem management and restoration.
Ecological protection and the restoration of full-array ecosystems is an important part of ecological civilization construction, which is a powerful measure to implement the concept of green development and help bridge the gap between the respective inevitable requirements of the current ecological environment and economic development. To solve this problem, a multi-scale index system was constructed to identify ecological sources comprehensively. The minimum-cost path method, the circuit theory, and the cyclic window search method were adopted to quantitatively identify the important ecological sources and corridors in scale nesting and pinch points and barrier points that affect multi-level connectivity. Furthermore, the specific optimization layout strategy of the ecological network structure of the Hefei metropolitan area was proposed. According to the results, if ecological sources and corridors at two scales are overlaid, the coincident area of ecological sources at two scales is 1719.95 km². As important ecological sources, Chaohu Lake Basin, Niuwangzhai, and Wuding Mountain, which are important areas to maintain the ecological network, need to be protected. Ten overlapping ecological corridors, which are mainly distributed in Changfeng County, are easily damaged long term. As a result, ecological nodes should be set up as temporary habitats for species transfer. In addition, based on the circuit theory and the cyclic window search method, calculating areas of pinch points at two scales yields 1637.75 km² and 434.22 km², respectively, and for areas of barrier points yields 2182.75 km² and 126.97 km², respectively. The ecological pinch points at two overlapping scales among them are important areas for future protection. Due to the small and fragmented spatial distribution in the urban area, pinch points with an average size of 0.58 km² are easy to be restored and will greatly improve the connectivity of the ecological network after restoration. Furthermore, through the quantitative identification of ecological network elements of two scales, the paper puts forward an optimization strategy for an ecological network in the Hefei metropolitan area from three aspects of “point-line-polygon.” The research results can reference decision-making concerning the delineation of urban growth boundary, regional ecological security pattern, land space renovation, and ecosystem restoration.
Rapid urbanization has had a segmented effect on the ecological land and natural environment in cities. Constructing an ecological network is of vital importance to protect ecological resources and maintain regional ecological security. However, ecological spaces at different administrative scales have their own ecological functions and elemental characteristics. Therefore, we formed the ecological network sequence to present the integrative connection of multi-scale with municipal area (MA), main urban area (MUA) and central urban area (CUA) in Nanjing. Ecological sources were identified through “landscape—function—structure” framework, and ecosystem services value (ESV) was used as an auxiliary method to identify supplementary sources. Ecological corridors and some key points were identified through circuit theory. The results show that the area of ecological sources in MA, MUA and CUA was 427.3 km2, 62.5 km2 and 16.2 km2, respectively. By integrating sources of three scales, we got 14 sources (442.7 km2) in the first sequence and 10 sources (7.7 km2) in the second sequence. Apart from that, we also got 4 new supplementary sources with area of 13.5 km2. The length of ecological corridors in MA, MUA and CUA was 252.5 km, 263.9 km and 22.7 km, respectively. By integrating corridors of three scales, we found that the western corridors between the ecological sources had a higher gravitation. The ecological nodes are generally distributed in the landscape heterogeneity transition zone, ecological resource fringe zone and ecological spatial contiguous zone. The ecological pinch points are generally distributed along the water system. The ecological barrier points are generally distributed in the combination area among the urban block, village and road. In conclusion, this study made up for the research gap of finding the nesting and integration relationship among ecological networks at multi-scale.
Transportation resilience is a multifaceted construct, including technical, socioeconomic, and geospatial factors. Developing effective plans demands evaluation of all resilience aspects across two major resilience dimensions: robustness and rapidity. Quantitative evaluation and monitoring of resilience aspects provides a thorough understanding of changes in transportation resilience over time. This paper proposes a resilience index framework to quantitively measure the road transportation systems' resilience to wind and water-related hazards in coastal areas. The framework streamlines abundant information derived from various resilience factors in a hierarchical structure and allows transportation planners to analyze changes in system resilience and identify corresponding root causes. Case study results indicate that the framework can effectively capture and track progress/deterioration in various resilience aspects and enhance our understanding of multidimensional transportation resilience. Transportation planners can utilize the developed index to set resilience goals, monitor progress toward goals, and prioritize projects to address the root causes of resilience deficiency.
Ecosystem services (ESs) flow, the spatial transfer of ESs from supply to demand, is critical but remains underexplored. Traditional studies often quantify ESs flow by crudely overlaying supply-demand, which lacks authenticity. This work develops a simulative model based on the flow-medium-path agent to simulate and quantify ESs flow, and subsequently evaluate regional ESs budget by incorporating ESs flow, because ESs aren't static but could flow to remote area, thereby altering the supply-demand relationship. Three prominent ESs, crop production (CP), water yield (WY), and carbon sequestration (CS) in Hangzhou Bay area were selected as cases. The results show: (1) a noticeable mismatch between ESs supply and demand; (2) ESs flow appears diverse features, e.g., the WY flow is single-directional and can only deliver to the downstream, determined by the topography; (3) Traditional ESs budget reveals the number of towns as supply exceeding demand for CP, WY, and CS is 313, 411, and 171. Contrastively, regional final budget considering ESs flow suggests that is 202, 581, and 0 as supply-demand balanced, indicating the ecological state is altered by integrating ESs flow into ESs budget evaluation. This study contributes to the researches on ESs comprehensive evaluation, ESs flow quantification, and ecological strategies references.
China is making great efforts to build an ecological civilization. To reveal the effectiveness and spatial characteristics of the ecological civilization development in China, we constructed an Ecological Civilization Evaluation Index (ECI) based on the economic-social-natural complex system. We evaluated the development level of the ecological civilization in China from 2004 to 2020 and discussed the coupling and coordination relationship between subsystems. We found that the ecological civilization of China has achieved remarkable results. The relationship among the three subsystems has been improved to some extent, but the high-quality development of the economic system still requires effort. The development level of the ecological civilization in China presents spatial heterogeneity. From east to west, 30 provinces can be classified into four different types of development. On the whole, the development of China’s ecological civilization has provided experiences for the world.
Urban greenspace systems are key components of urban ecosystems. However, a quantitative index for the recovery ability of urban green space and a corresponding effective restoration model is lacking. We selected the key indicators that characterize the damage degree and recovery ability of green space ecosystems, constructed an evaluation index system of green space damage, and established a recovery capacity model using the attributes of self‐organization and resilience of green space ecosystems as core attributes. Using the ecosystem damage and recovery capacity indexes, a discrimination matrix of the ecological restoration model, with a total of 12 different scenarios, was constructed to provide a differentiated model of ecological restoration. The highly urbanized Shenzhen Metropolis was selected as the study area. Based on the results, most of the green space in Shenzhen had no damage, however, 13.70% of the space had moderate and severe damage. Most of Shenzhen's green space had a medium recovery capacity level; while 14.21% and 15.69% of the areas had high and low recovery capacities, respectively. We outlined the areas where ecological restoration modes such as nature conservation, auxiliary restoration, and ecological reconstruction need to be applied. Our findings can be used to evaluate the self‐restoration ability of ecological restoration sites and provide a conceptual basis and a case study reference for ecological restoration planning and management of urban green space.
The resilience of the urban ecological network is an indispensable aspect of reflecting the recovery capacity after the external risk shock. Improving the resilience of the ecological network is conducive to enhancing the ecological benefits. However, the current studies are lack of resilience evaluation from a comprehensive perspective. Thus, in this study, taking three typical urban agglomerations as cases, a comprehensive evaluation framework was proposed to assess ecological network resilience. First, we selected the comprehensive reserve as ecological sources and combined them with ecological corridors to construct the ecological network. Then we evaluated the resilience of ecological networks from the perspectives of robustness and redundancy. Finally, we analyzed the resilience of the network under different importance nodes failed. The results showed that (1) the average values of the comprehensive reserve value (CRV) in three urban agglomerations were over than 0.8. (2) the resilience of ecological networks in three urban agglomerations was blow the optimal value throughout during the period from 1985 to 2020. (3) the resilience change trends of multiple urban agglomerations were significant differences after removing certain important nodes, indicating the current ecological network is redundant. The research will help to improve the evaluation of urban ecological resilience and enhance the improvement of sustainable urban management and ecological restoration.
Landscape fragmentation due to urban sprawl and industrialization has caused habitat loss and threatened global biodiversity. However, the magnitude, spatial pattern, and mechanisms of how landscape fragmentation leads to habitat loss remain unclear. The Yellow River Basin (YRB) and the Yangtze River Economic Belt (YZREB) are important ecological security barriers that play a decisive role in landscape connectivity and biodiversity conservation in China. From a comparative perspective, this study analyzes the temporal-spatial changes of land cover in the YRB and the YZREB from 2005 to 2018 and simulates the land use pattern in 2031 using a patch-level simulation (PLUS) model. Then the degree and tendency of landscape fragmentation during 2005-2031 are measured based on the entire region and a 10 km grid, respectively. The habitat quality (HQ) is measured using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model. The temporal-spatial evolution characteristics of HQ are analyzed across multiple dimensions, including the entire region, urban agglomerations and watersheds (upstream, midstream, and downstream). Finally, spatial econometric models are applied to examine the spatial dependence of HQ and quantify the spatial impact of landscape fragmentation on HQ in the YRB and YZREB based on 10 km grids. Results show that: (1) there would be a significant trend of landscape fragmentation and habitat degradation in both the YRB and YZREB during 2005-2031. (2) HQ in the YRB and YZREB has the spatial distribution characteristics of being low in coastal areas and urban agglomerations but high in inland areas and mountainous forest areas. (3) The spatial distribution and spatial relationship of landscape fragmentation and HQ in YRB and YZREB differ significantly in multi-spatiotemporal dimensions. The findings could provide support for landscape planning and biodiversity conservation strategies in China and other developing countries.
A land use simulation model with coupling constraints of ecological security patterns (ESPs) and multiple scenarios (MSs) was developed using the PLUS model. The research scale was zoned with environmental functional regions, where land management policies were formulated. A case study in Anji County successfully demonstrated the application of the ESP-MS-PLUS model. First, we constructed three different levels of ESPs as ecological constraints by utilizing ecosystem services evaluation and circuit theory. Second, four scenarios of land use and land cover changes (LUCCs) in 2034 were assumed, namely business as usual (BAU), priority given to urban development (PUD), priority given to ecological protection (PEP), and balanced urban development and ecological protection (BUE). Then, the basic ecological constraints (ecological red line areas and waters) and three types of ESPs were coupled with the four scenarios. The results of the simulation and analysis of landscape metrics under each scenario showed that the PEP and BUE scenarios would effectively reduce the degree and speed of ecological destruction. In addition, there were three environmental functional areas that could be used as priority areas for urban construction to ensure economic development. This study provides a new mechanism for land use optimization in the context of ecological protection at scales conducive to practice.
Human disturbance of urban ecosystems is intensifying, as is ecological fragmentation. As such, effective connections between green spaces must be established and restored to form structurally resilient urban ecological networks. In this study, we focused on indicators of city-scale ecological network resilience. We constructed a network model, analyzed the disturbance simulation results, and identified key nodes. Shenzhen, a megacity in China was selected for empirical research. First, we used Floyd algorithm to extract least-cost paths and then generate the corridor network, constructing an ecological network model with 386 nodes and 4910 edges. Second, focusing on the nodes of the constructed ecological network, we adopted a selected attack strategy to conduct dynamic simulations, using two parameters, network efficiency and maximum connectivity, to evaluate the resilience of the ecological network to changes under various disturbance scenarios. The results showed that the ecological network structure in the study area was relatively stable, and the first 30 % of nodes substantially impacted network resilience. The outcomes reflect the state of urban ecosystems that have been disturbed by socio-economic systems and are practically important for formulating adaptive spatial planning and management policies.
Ecological networks (ENs) can bridge the paradox between conservation and development. Although many useful methods can be applied to establish ENs, their differences in spatial outputs and scale applicability need to be examined as landscape planners and policymakers start including implementation concerns. Dividing Jiangsu into three scales (i.e., provincial, city cluster, and city scale), we comparatively analyzed the spatial consistency of the structure-oriented, function-oriented and integration-oriented methods in establishing three types of ENs (i.e., SENs, FENs and IENs), and comprehensively assessed their scale applicability under specific goals in improving network connectivity, optimizing landscape pattern and maintaining ecosystem services value (ESV). Our results show that the consistency of the three methods in identifying spatially priorities of protection ranged from 81.03% to 93.70%. A structure-oriented method to establish SENs had applicability in improving network connectivity despite scale changes, while an integration-oriented method to establish IENs had the advantages of forming an ecological space with low fragmentation, high complexity and dominance, and maintaining the maximum ESV, relatively. We discussed the speciality of each method performed at each scale and suggested the possible trade-offs of decision-making in landscape planning which would be complicated during scale changes. Thus, although the applicable method could be selected under clear goals/orientations, its applicability would be limited to different contexts and observational scales. The seemingly inconsistent results could be used synergistically to promote ENs implementation across scales under inclusive decision-making. The developed multi-scale analysis framework and study results can provide new insights to incorporate ENs into landscape planning practice.
Measuring and evaluating network resilience has become an important aspect since the network is vulnerable to both uncertain disturbances and malicious attacks. Networked systems are often composed of many dynamic components and change over time, which makes it difficult for existing methods to access the changeable situation of network resilience. This paper establishes a novel quantitative framework for evaluating network’s multi-stage resilience using the Dynamic Bayesian Network. First, we define the dynamic capacities of network components and establish the network’s five core resilience capabilities to describe the resilient networking stages including preparation, resistance, adaptation, recovery, and evolution; the five core resilience capabilities consist of rapid response capability, sustained resistance capability, continuous running capability, rapid convergence capability, and dynamic evolution capability. Then, we employ a two-time slices approach based on the Dynamic Bayesian Network to quantify five crucial performances of network resilience based on proposed core capabilities. The proposed approach can ensure the time continuity of resilience evaluation in time-varying networks. Finally, our proposed evaluation framework is applied to different attack and recovery conditions in typical simulations and real-world network topology. Results and comparisons with existing studies indicate that the proposed method can achieve more accurate and comprehensive evaluation and can be applied to network scenarios under various intensities of attack and recovery.
Ecological security patterns (ESPs) have become an important spatial approach to alleviate the contradiction between ecological protection and economic development. The identification of ecological sources is the primary part of studying ESP, and methods based on ecosystem services (ESs) have been widely used. However, the current method of simply overlaying ESs for ecological source identification has difficulty supporting different regional decision‐making needs of the target. Taking the West Liaohe River Basin in China as an example, the study aims at four regional sustainable development goals (RSDGs) of carbon neutrality, water security, soil security, and biodiversity protection. Six ESs, including net primary production (NPP), water retention (WR), water purification (WP), soil conservation (SC), soil loss by wind (SL) and habitat quality (HQ), in the West Liaohe River Basin from 2010 to 2020 were evaluated. Based on the current mainstream research paradigm of "source identification‐resistance surface construction‐corridor extraction‐safety pattern identification", combined RSDGs and ESs, the minimum cumulative resistance (MCR) model was used to identify the West Liaohe River Basin facing different development goals. The pattern of ecological security was discussed, and the identification, optimization and construction plan of the regional comprehensive ESP were discussed in combination with the actual situation of the region. The study found that simply overlaying ESs to identify ecological sources leads to the neglect of some areas that provide key ESs, and it is difficult to directly support regional ecological protection decisions under different objectives, while a multiobjective‐oriented comprehensive ecological security pattern helps to promote ESs and their relationships. The research results will help to improve the understanding of the ESP and provide a basis for the ecological protection and restoration of the basin and the optimization of the spatial structure to promote the sustainable development of the "social‐economic‐ecological" complex system in the West Liaohe River Basin. This article is protected by copyright. All rights reserved.
Realistic problems typically have many conflicting objectives. Therefore, it is instinctive to look at the engineering problems as multi-objective optimization problems. This paper briefly explains the multi-objective optimization algorithms and their variants with pros and cons. Representative algorithms in each category are discussed in depth. Applications of various multi-objective algorithms in various fields of engineering are discussed. Open challenges and future directions for multi-objective algorithms are suggested. This study covers relevant aspects of multi-objective algorithms that which will help the new researchers to apply these algorithms in their research field.
Ecological network (EN) resilience is important for the integrity and connectivity of ecosystems. However, most of the current studies have conducted resilience assessment studies on abstract complex ENs composed of points and lines, ignoring the fact that ENs are landscape entities with considerable spatial range and landscape characteristics in ecosystems. In this study, taking the Shandong Peninsula urban agglomeration as an example, we assessed network resilience based on identifying the spatial range of ENs in 2000, 2010 and 2018. We constructed a new evaluation framework of EN resilience from overall structure, component quality and network function and analyzed the spatiotemporal changes in EN resilience. The results show that (1) from 2000-2018, the spatial range of the ENs shrunk 14.3%. (2) The overall structure of ENs was damaged, the component quality of ENs decreased, and the network function of ENs decreased, leading to a significant decrease of 16.8% in EN resilience. (3) The results of Spearman's correlation coefficient and cubic model show that the decline in network resilience has a good temporal correlation and spatial fitting degree with the changes in urbanization indicators. Based on the results, this study proposed improving EN resilience through measures such as network structure optimization, ecological protection and restoration for key areas. This study has improved the identification method of EN spatial ranges, adapted and updated the assessment method and framework of EN resilience, enriched the methods and theories of EN identification and assessment, and provided guidance for enhancing ecosystem functions and achieving sustainable management of urban agglomerations.
The construction of the urban ecological network has a comprehensive effect on urban aesthetics, society and economy, and provides the driving force for urban sustainable development. However, we found few studies on constructing and optimizing urban ecological networks in cities with the highest human density. In this paper, landscape pattern indexes were applied to analyze the landscape characteristics and morphological pattern analysis (MSPA) to identify the ecological source, the landscape connectivity and the region attributes revised the ecological resistance surface, and urban ecological network was constructed by MCR model. The results show that: (1) many ecological land types mainly distributed in the tributaries of the Yangtze River, while only forest land and water areas occupied in the northwest are. (2) Compared with 1995 and 2005, the number of ecological corridors in 2015 was decreasing. Although the ecological connectivity was improved, which of the Yangtze River was limited. (3) The coordinated development and the ecological protection ecological network optimization plan would promote the connectivity of the urban ecological functioning stability. This study provides recommendations for the optimization of the urban ecological network, which are of great significance for protecting biodiversity, improving ecosystem functions, and maintaining the regional ecological security pattern.
In this study, we measure the resilience of the road networks in two Mediterranean regions: Valencia (Spain) and Sardinia (Italy). We apply a framework that is able to monitor the deterioration in territorial accessibility of the two systems in response to the cumulative elimination of sections. Road sections are removed according to different elimination types: random order, deterministic order of criticality, and deterministic order in areas at high risk of flooding. The results show that the Sardinian network is more resilient than the Valencian network, despite its poorer quality. We demonstrate that the framework can integrate climate change considerations in the resilience assessment. As the framework identifies the most critical sections, the method can be adopted as a support system by transport planners and policy makers.
Rapid urbanization has led to landscape fragmentation, habitat loss, and the disruption of ecosystem functions. Ecological networks (ENs) are effective comprehensive spatial regulation schemes for mitigating the negative impacts of rapid urbanization on ecosystems. However, the methods of constructing ENs were not sufficiently developed for determining its spatial range and overlooked its internal defects and external threats which may affect its function and effectiveness. Taking the Shanghai metropolitan region as a case study area, this study developed an integrated approach to identify the spatial range, internal defects and external threats of ENs based on circuit theory and assessment of ecological degradation risk to identify the restored and conserved priority areas of ENs. The results show that the restored priority areas included the obstacles and ecological fracture points of ecological corridors in the terrestrial ecosystem (TEC), covering an area of 79.21 km², and the conserved priority areas were composed of 273.3 km² of areal ecological patches in the TEC, and 891.35 km of waterways of ecological corridors in the aquatic ecosystem (AEC). This approach attempts to provide a spatial reference for the identification and implementation of ENs in metropolitan regions by focusing on restored and conserved priority areas.
An efficient and safe transportation system is essential to communities during the long-term recovery period after earthquakes. A disrupted transportation network due to infrastructure damage or failure affects the functionality of the traffic system and poses increased traffic safety risks. A rational assessment of the traffic network performance in terms of both traffic efficiency and safety cannot only provide comprehensive quantification of system resilience, but also enable more risk-informed post-hazard recovery planning. A new methodology to assess the resilience performance of transportation networks during post-earthquake long-term recovery period is developed in this study with two main innovative contributions: (1) modeling the traffic performance of partially closed road segments in the network simulation and optimization, which offers useful tool to capture the time-progressive recovery process; and (2) integrating both traffic efficiency and safety into the resilience assessment and recovery prioritization. After a resilience indicator is introduced to characterize the overall traffic efficiency and safety of the transportation network using probabilistic sampling method, a new restoration priority measure is proposed to support post-earthquake restoration of damaged bridges. A demonstrative study is conducted on a hypothetical network system located in an earthquake-prone area.