Linking ecosystem services and circuit theory to identify ecological security patterns

Measuring the resilience of mountain city ecological network: a methodological framework integrating real disaster shocks and simulated disturbance scenarios

A structurally resilient ecological network (EN) is crucial for enabling mountain city ecosystems to cope with shocks from natural and social events and maintaining system connectivity and integrity. In this study, we focus on EN resilience indicators during the impact of natural disasters. Taking mountain fires in the Chongqing metropolitan area in the summer of 2022 as the entry point, the spatial evolution of the EN during the acute shock of mountain fires was reconstructed. Then, the EN was abstracted as a complex network, and the global efficiency, network connectivity, and diversity were employed evaluate the recovery ability of the network after the loss of nodes or connections in real disasters shock processes and simulated disturbance scenarios. The results indicated that 143 mountain fires over 14 days caused the loss of 52 ecological corridors, with a cumulative reduction of 24.1 %. The network structure evolved from a fishing-net-like structure to a branching structure relying on a few corridors connected in series. The three resilience indicators decreased by 16.1 %, 21.9 %, and 25.2 %, respectively. Compared with the loss of connections in real situations, the decline in the network resilience level in the simulated disturbance scenarios was more rapid. This study proposes a research perspective that combines the reproduction of real shock processes and the simulation of disturbance scenarios, thereby providing a new framework for EN resilience study.

Integrating mining district data into ecological security pattern identification: a case study of Chenzhou

Resource-intensive cities face significant ecological challenges due to mining activities, which degrade landscapes, pollute ecosystems, and disrupt ecological security patterns. This study proposes a process for identifying ecological security patterns (ESP) in mining cities, integrating landscape risk assessment, remote sensing ecological quality evaluation, and mining district spatial data. We introduce the ecological source index (ECSI) to identify ecological sources in Chenzhou and construct an ecological resistance surface (ERS) by incorporating mining district locations. Using circuit theory, we map key ecological corridors and nodes, establishing the ecological security framework for Chenzhou. Our findings show 2,903 km² of primary ecological sources, 1,735 km² of secondary ES, and 2,124 km² of tertiary ES, along with 90 ecological corridors (1,183.66 km), 22 inactive corridors (983.37 km), 3 major river corridors, 68 pinch points, and 80 barriers. The ecological sources are organized in a "dominant source with multiple subsidiary cores" structure, connected by a "three horizontal and four vertical" corridor network. Ecological sources are primarily located in the east, while corridors, pinch points, and barriers are concentrated in the west. Barriers are mainly urban areas, mining zones, and farmland, while pinch points occur in narrow corridor sections, especially near towns and mining areas. Mining activities cause localized shifts and fragmentation of ecological corridors. We propose recommendations for mining management, such as implementing strict mining approval processes, constructing artificial ecological corridors, and expanding ecological channel boundaries in pinch point clusters. These findings provide essential guidance for ecological restoration and sustainable development in resource-dependent cities.

Identifying priority areas for conservation based on the evaluation of ecological network resilience in the Hyrcanian Forest ecosystem

Habitat loss and fragmentation in forest ecosystems are serious threats that lead to reduced resilience. The integrity and stability of the ecosystem are fostered by recognizing and protecting areas that are essential to maintaining the resilience of the ecological network. Research in the field of ecological network resilience has garnered attention in recent years, although the necessity of developing various assessment methods for network resilience is evident. Taking the Hyrcanian Forest ecosystem as a case study, this research aimed to identify the most important areas of the ecological network in maintaining and enhancing the resilience. To achieve this goal, first, a combination of the morphological spatial pattern analysis method and the assessment of the significance of ecosystem services was used to extract ecological source areas. Next, utilizing circuit theory and the least-cost path method, a network connecting sources was constructed, and pinch points were identified. After that, high-risk areas in ecological sources were found using the habitat risk assessment method. Using this integrated approach leads to the identification of valuable areas that are vulnerable to human threats and disturbances. Finally, the node removal method coupled with the calculation of network resilience indices, connectivity, and efficiency was employed to prioritize conservation areas. The results of the study indicated that the most important nodes were located in the northern edges of the forest, which have been under threat in recent years. Additionally, the region ranked moderately in terms of connectivity, indicating the importance of focusing on the conservation of forest patches before the complete fragmentation of the area. Furthermore, our findings underscore the importance of considering landscape connectivity and ecological network resilience in conservation planning for policymakers and managers aiming to protect biodiversity in the Hyrcanian Forest ecosystem.

Evaluation of Ecosystem Service Capacity Using the Integrated Ecosystem Services Index at Optimal Scale in Central Yunnan, China

Understanding and quantifying the dynamic features of local ecosystem services (ESs) and integrating diverse ecosystem assessment results form crucial foundations for regional ES management. However, existing methods for integrating and objectively evaluating multiple ESs remain limited. Consequently, this research evaluates four key services based on the InVEST and RUSLE models in the Central Yunnan Province (CYP)-from 2000 to 2020: water yield (WY), carbon storage (CS), habitat quality (HQ), and soil conservation (SC). It then constructs an Integrated Ecosystem Service Index (IESI) using principal component analysis (PCA). Additionally, this study explores the factors driving the spatial divergence of ESs by employing the optimal parameter-based geographical detector model (OPGD) at the optimal spatial scale. The results indicated that (1) the IESI was effectively applied in the CYP and could quantitatively and comprehensively integrate the assessment results of the four key ESs. (2) During the study period, the ESs in the CYP showed increasing trends for WY, HQ, and SC, while CS showed a decreasing trend. (3) The IESI during the study period exhibited a trend of initially decreasing and then increasing. The average IESI values for CYP were 0.7338 in 2000, 0.6981 in 2005, 0.6947 in 2010, 0.6650 in 2015, and 0.6992 in 2020. (4) A 4500 m × 4500 m grid was identified as the optimal spatial scale for detecting the spatial divergence of comprehensive ecosystem service (CES) in CYP, and relief degree of land surface (RDLS), slope, and the NDVI were the top three drivers based on q-values. This study offers a more scientific and effective method for evaluating regional CES. It also provides a comprehensive analytical tool for balancing land use competition and assessing the effectiveness of policy implementation.

Using natural vegetation succession to evaluate how natural restoration proceeds under different climate in Yunnan, Southwest China

Currently, natural restoration has been widely proposed as the primary method of ecological restoration and has been studied for a long time. However, research on how to quantify the progress of natural restoration in different climate conditions, especially using long-term succession monitoring data combined with habitat quality data across various succession stages, has been scarce. Our study aims to address this issue in Yunnan, southwest China. To quantify the progress of natural restoration under different climates in Yunnan, we introduced an index, the Natural Succession Index. Utilizing topography and meteorological data, we divided the study area into different climate sub-areas using the Two-stage clustering algorithm. We then combined 1703 sets of 30-year succession monitoring data, each with six observations taken at five-year intervals from 1987 to 2017, with habitat quality data from different succession stages (grassland, shrub, and forest) to quantify the Natural Succession Index. Yunnan province was divided into 14 sub-areas, namely C(I to II), M(I to III), W(I to IV), and H(I to IV), each possessing a unique environment. The indices in each sub-area were calculated, with the results showing a specific order: H-I (0.7812) >  H-IV (0.7739) >  W-I (0.6498) >  M-III (0.6356) >  H-III (0.6316) >  M-II (0.5735) >  W-III (0.5644) >  W-IV (0.5571) >  C-II (0.4778) >  W-II (0.3980) >  M-I (0.3624) >  H-II (0.3375) >  C-I (0.2943). The times for natural succession to reach the forest stage vary from 5 to 19 years, which aligns with the order of indices. The stand volumes of vegetation in the forest stage range from 5 m³ to 110 m³, with a higher Natural Succession Index value corresponding to a higher stand volume of vegetation. In the future, the index could be utilized to reallocate investments in natural restoration projects for better returns. Constant vigilance is required in the first five years following the implementation of restoration actions to avoid failure due to calculation errors.

Conservation methods for Trollius mountain flowers in Xinjiang, China under climate change: Habitat networks construction based on habitat suitability and protected areas optimization response

Mountain flower species tend to be more climate-sensitive. Trollius is a mountain flower species of ecological and cultural significance in Xinjiang, China, but climate change has caused habitat fragmentation, which is the dominant threat to their survival. However, the precise mechanism of how climate change affects their distribution and the extent of habitat fragmentation remains unclear. Accordingly, Modeling was employed to obtain Trollius's habitat changes and fragmentation indices under different periods and climate scenarios. Based on this, the study identified potential corridors, evaluated habitat network patterns, and performed spatial optimization. The results demonstrated that Trollius species don't have the same climate adaptation ability. T. asiaticus exhibits exceptional climate adaptation with habitat expansion and minimal fragmentation, but the other species' habitat area and connectivity index dropped markedly. The Tien Shan and Altay Mountains represent the primary habitat sources of Trollius, while the Western Junggar Mountains serve as a crucial stepping stone. Habitat clusters are predominantly connected by short but efficient primary corridors, which showed stability when facing climatic fluctuation. Highly centralized "source-corridor" systems require enhanced identifying of pinch points and removing barrier points to ensure high connectivity. Furthermore, the protected areas system is inadequate in its protective function, with less than 7% of habitat areas covered by nature reserves and less than 15% covered by nature parks. The findings can provide scientific basis and methodological support for regional climate strategy making on biodiversity conservation and the optimization of protected areas.

Integrating ecological and recreational functions to optimize ecological security pattern in Fuzhou City

The scientific establishment of the Ecological Security Pattern (ESP) is crucial for fostering the synergistic development of ecological and recreational functions, thereby enhancing urban ecological protection, recreational development, and sustainable growth. This study aimed to propose a novel method of constructing ESP considering both ecological and recreational functions, and to reconstruct ESP by weighing the relationship between ecological protection and recreational development. Utilizing Fuzhou City as a case study, a comprehensive application of methodologies including Morphological Spatial Pattern Analysis (MSPA), landscape connectivity analysis, ArcGIS spatial analysis, social network analysis (SNA), and circuit theory is employed to develop both the ESP and the Recreational Spatial Pattern (RSP). A trade-off matrix is created to facilitate the reconstruction of the ESP, delineate functional zones, and identify strategic points, followed by a thorough optimization and development strategy. The analysis revealed 36 ecological source areas (ESAs) within Fuzhou City, encompassing a total area of 5807.90 km², predominantly situated in the western and northern regions. Additionally, 98 ecological corridors (ECs) were identified, extending over 2500.55 km, alongside 100 ecological pinch points (EPPs) and 146 ecological barrier points (EBPs). The city also contains 57 recreational nodes (RNs),, which display a spatial distribution characterized by a "dense in the east, sparse in the west" pattern. Furthermore, 165 recreational corridors (RCs) were extracted, covering a distance of 3795.21 km. Based on the trade-off matrix, Fuzhou City was categorized into eight functional zones: ecological core zone, ecological important zone, eco-recreation key trade-off zone, eco-recreation secondary trade-off zone, recreational core zone, recreational important zone, recreational development zone, and elastic development zone.The study identified 95 key strategic points and 475 sub-strategic. A multifunctional and complex ESP was constructed, characterized by "one core, five districts, six corridors, and seven wedges", and a tailored ecological and recreational planning and development strategy for Fuzhou City was proposed. This research contributes a theoretical framework for the construction and optimization of a multifunctional ESP and supports the coordinated high-quality development of ecological protection and recreational activities in urban environments.

Urban ecosystem services, ecological security patterns and ecological resilience in coastal cities: The impact of land reclamation in Macao SAR

Land reclamation from the sea is a common practice to create territorial space and accommodate urbanisation in coastal cities. However, previous studies did not adequately examine the changes in ecosystem service values, the spatial transformation of the ecological network and the ecological resilience at an urban scale in the context of land reclamation. This study uses Macao SAR, a fully urbanised city with two-thirds of its land reclaimed from the sea, as a case study. We quantify urban ecosystem services (UES) values and model the spatial transformation of the ecological security patterns (ESPs) throughout the city's land reclamation history from 2000 to 2020. Subsequently, we evaluate the resilience of the ESPs' components and their relationships with urbanisation by using spatial element elasticity indices and regression analysis. Results show that urban land expanded by 27% through land reclamation, increasing the value of UES by 13%. The growth rates of different categories of UES vary significantly. ESPs extended over the newly reclaimed and urbanised lands, but the resilience levels of ecological sources, corridors and nodes decreased. There is a strong positive correlation between UES values and urbanisation, and a strong negative correlation between ecological resilience and urbanisation. This study recommends five specific environmental spatial planning and management strategies to address the expansion and integration of ESPs, aiming not only to provide ecological services but also to enhance ecological resilience in coastal cities.

Constructing ecological security patterns using remote sensing ecological index and circuit theory: A case study of the Changchun-Jilin-Tumen region

Rapid urbanization and the implementation of ecological civilization initiatives are increasingly influencing regional ecosystems, necessitating a balance between urban development and ecological conservation for sustainable progress. The Changchun-Jilin-Tumen (CJT) region, a critical grain production base and ecological security barrier in China, faces the challenge of managing urban growth, food security, and ecological stability. This study proposes an integrated approach combining the Remote Sensing Ecological Index (RSEI) and circuit theory to develop an Ecological Security Pattern (ESP) for the region. Habitat quality is assessed using RSEI, while Morphological Spatial Pattern Analysis (MSPA) identifies ecological sources. Circuit theory is then employed to map ecological corridors, pinch points, and barriers. The results indicate that ecological sources cover 2985.33 km2 (4.15% of the study area), and ecological corridors extend across 22,433.89 km2 (31.21% of the area), with 150 optimal corridors totaling 3675.23 km in length. Based on these findings, the study proposes a comprehensive ESP structure consisting of "three zones, one barrier, and one belt," along with targeted restoration optimization measures. The integration of RSEI and circuit theory offers a novel methodology for identifying priority areas for ecological restoration and provides essential guidance for land spatial planning and sustainable regional development.

Did green infrastructure improve water purification ecosystem services in Shandong Peninsula urban agglomeration? Evidence from total phosphorus

Non-point source pollution significantly impacts the sustainable development of river ecosystems. Water purification ecosystem services (WPES) play a crucial role in mitigating non-point source pollution. Green infrastructure (GI) maintains ecosystem services; however, how GI affects WPES remains poorly explored. Using total phosphorus (TP), we investigated the mechanisms by which GI and its structure and functions influence WPES in the Shandong Peninsula urban agglomeration. Results show that GI significantly improved WPES, with the lower TP loads (49-fold) and TP export capacity (3-fold) in GI areas compared to non-GI areas. These effects are associated with specific GI attributes, including structural connectivity, vegetation coverage, and soil conservation capability, which exhibit cascading effects (|r| > 0.8). Optimizing GI structural connectivity can indirectly regulate WPES by enhancing GI ecological functions (vegetation coverage and soil conservation), making it a crucial land management strategy. Specifically, the enhancement of vegetation coverage, which is critical for improving WPES (|r| > 0.6), should focus on both the 'scale' and 'health' of the vegetation. Cultivating GI (|r| > 0.6) offers greater benefits for WPES than forests and grasslands alone (|r| < 0.6). Effectively leveraging the relationships between GI attributes and WPES can significantly reduce TP risks.

Modeling airflow dynamics and their effects on PM2.5 concentrations in urban ventilation corridors of Hangzhou

Urban Ventilation Corridors (UVCs) have been shown to effectively mitigate the urban heat island effect and enhance air quality. However, the simulation of large-scale UVCs airflow and its impact on fine particulate matter (PM2.5) remains insufficiently explored without resorting to complex aerodynamic calculations. This study introduces a novel circuit-theoretic approach that integrates the Ventilation Potential Coefficient (VPC) and the Ventilation Resistance Coefficient (VRC). This method is combined with Local Climate Zone (LCZ) maps to analyze the internal attributes of UVCs and their relationship with PM2.5 concentrations both within UVCs and in non-UVCs areas. The results show that: (1) UVCs are more effective at reducing PM2.5 concentrations compared to non-UVC areas, with an average reduction of 25.2 % more than in non-UVC areas. The airflow simulation value for UVCs exhibits a nonlinear relationship with PM2.5 concentration, showing an increase in PM2.5 below 0.4 and a significant decrease above 0.6. (2) UVCs are predominantly composed of natural LCZs, which make up 71 % of the total area. Among these, LCZ 1, LCZ 10, and LCZ E show the highest PM2.5 concentrations. Natural LCZs generally have lower average PM2.5 levels compared to LCZs of built-up areas, with LCZ A demonstrating the lowest PM2.5 concentration, showing a notable difference of 5.38 μg/m3. (3) Within UVCs, natural LCZs provide the most substantial PM2.5 reduction, with LCZ E reducing PM2.5 concentrations by up to 2.78 μg/m3 compared to non-UVCs areas. These findings offer a scientific foundation for the systematic planning and pollutant control of UVCs.

Integrating revised DPSIR and ecological security patterns to assess the health of alpine grassland ecosystems on the Qinghai-Tibet Plateau

Alpine grassland ecosystems on the Qinghai-Tibet Plateau (QTP) provide critical services but face threats from human activity and climate change. Ensuring ecosystem health is vital for sustainability and preserving ecosystem services and processes, especially in delicate ecosystems such as the Gannan alpine grasslands. However, there is currently a lack of a comprehensive model that integrates ecosystem structure, function, processes, and socioeconomic factors. This study proposes a comprehensive ecosystem health assessment approach that combines the revised driver-pressure-state-impact-response (DPSIR) framework with ecological security patterns (ESPs), overcoming the limitations of previous models that focused primarily on ecosystem structure without sufficiently addressing dynamic ecosystem processes. This method aims to diagnose the health of the Gannan alpine grasslands on the QTP from 2000 to 2020. We found that in the context of global climate change, the ecological health was maintained at a relatively high level (covering 75.41 % of the area) in most areas of Gannan, whereas lower levels (12.09 %), were found in the northern areas of Gannan and southwestern areas of Maqu likely resulting from higher livestock density, increased population density, and weaker landscape connectivity. The results of the driver analysis showed that livestock inventory (with an influence Q-value of 0.70) significantly affected the health of the Gannan alpine grassland ecosystem, suggesting that sustainable livestock management is essential for maintaining ecological corridor connectivity, protecting core zones and promoting regional sustainability.

Unveiling the lifeblood of cities: Identifying urban ecological networks from the perspective of biodiversity conservation

Urban biodiversity faces threats from habitat loss, landscape fragmentation, and human disturbances. Ecological networks (ENs) can enhance habitat connectivity and bolster population resilience to disruptions. To safeguard the biodiversity of Nanjing's urban area, this study selected understory insectivorous birds as indicator species for biodiversity, employing a comprehensive approach integrating the maximum entropy (MaxEnt) model and the area threshold method to delineate ecological source areas. Key indicators directly linked to the species distribution were extracted based on the habitat suitability assessment results, and an ecological resistance surface was crafted using spatial principal component analysis. Subsequently, the circuit theory model was applied to pinpoint ecological corridors, pinch points, and barrier points. The findings unveiled the following: (1) The normalized difference vegetation index (NDVI), human activities (HA), and canopy height (CH) were critical indicators influencing biodiversity. The response curves of the NDVI and CH were positively correlated with the probability distribution of indicator species, while the response curve of the HA showed an overall negative correlation with the same distribution. (2) The spatial distribution characteristics of the ecological network revealed a 'one axis, two cores, intersecting' pattern. Ecological sources were supported by mountainous forests and riverside green spaces, symmetrically distributed on both sides of the Yangtze River. Ecological corridors were forming continuous tree belts along highways and riverways, predominantly concentrated on the eastern side of the Yangtze River. Ecological pinch points and barriers were primarily located at the intersections of fragmented green spaces and developed areas in the northeastern and southeastern regions of the study area. (3) This study finally identified 30 ecological source areas, 65 ecological corridors, 8 pinch points, and 8 barrier points. This study presents a construction paradigm for urban ENs from the vantage point of biodiversity conservation, including both regional specificity and universal applicability, providing vital theoretical underpinnings and pragmatic insights for urban sustainability.

Assessing spatio-temporal heterogeneity and drivers of ecosystem services to support zonal management in mountainous cities

With complex topography and geomorphology, mountainous cities possess abundant natural resources. They are constrained by ecological environment and topographic conditions, leading to a prominent contradiction between urbanization development and ecological protection. As a result, ecosystem services (ESs) are under greater regulatory pressure. The identification of ecosystem services bundles (ESBs) can be the foundation for developing zonal ecological protection planning policies. We took Chongqing as a case study, investigated the impact mechanisms of socio-ecological factors on the level of ES supply in each ESB. The findings reveal that: (1) The quantitative assessment of ESs for 2000, 2010, and 2020 showed that ESs were temporally stable and spatially heterogeneous. Areas with high supplies of food production (FP) and water yield (WY) were predominantly found in the northwestern cropland and urban built-up regions, whereas high supply areas for the other four ESs were primarily located in the northeastern Dabashan Mountains and the southern Wuling Mountains. (2) The quantification of trade-offs and synergies between ESs showed that FP had a trade-off effect with all five other ESs, while most other ES pairs exhibited synergistic effects. It was found that the interrelationships produced changes over time. (3) Then, three types of ESBs were identified. After examining the influence mechanisms of socio-ecological factors across the three ESBs, individual ESs were found to have essentially the same types of main impact factors in three ESBs, but varies in impact. (4) Finally, with reference to changes in ES levels and interrelationships and the driving mechanisms of socio-ecological factors in each zone, this study proposed zonal strategies for managing ecosystem services and optimizing territorial space based on the geographic characteristics and socio-economic development in different ESBs, with the goal of attaining sustainable urban development and improving human welfare.

Enhancing bird habitat networks in metropolitan areas: Resilience assessment and improvement strategies - A case study from Shanghai

Constructing bird habitat networks (BHNs) is crucial for maintaining the health and service equilibrium of urban ecosystems, especially in large metropolitan areas where the pressure of urbanization is intense. However, most existing BHNs fail to account for the dynamic changes and unique requirements of local species, leading to homogenized construction outcomes and ecological corridor objectives. This study employs a comprehensive approach to identify bird habitat patches using multiple high-quality sources, then utilize circuit theory and complex network theory to construct and assess the resilience of BHN. Our key findings showed: (1)93 bird habitat sources were identified, predominantly situated in the continuous green spaces of southern and southeastern Shanghai, whereas habitat sources in the city center and other densely built-up areas are more dispersed, highlighting them as prime targets for future ecological restoration efforts. (2) The distribution of bird habitat corridors exhibits significant spatial heterogeneity, with primary corridors predominantly spanning the southwestern and eastern parts of the study area, while secondary corridors are more abundant in the western and northern parts, forming a denser network, whereas the central area shows fewer and more isolated corridors. (3) The decline in structural and functional resilience was notably more rapid under targeted attacks than under random attacks, underscoring the need to prioritize crucial bird habitat sources on the city's periphery, especially near highly urbanized areas, in urban planning and biodiversity conservation efforts to sustain ecological balance and biodiversity. These insights provide a crucial scientific basis for urban planners, emphasizing the integration of biodiversity conservation into urban development strategies by optimizing ecological sources and corridors to balance development with ecological preservation.

Construction and optimization of ecological corridors in coastal cities based on the perspective of "structure-function"

The contradiction between the demand of urban economic development and ecological environmental protection is becoming more and more prominent, and the reasonable construction of ecological corridors is of great significance for the protection of urban ecosystems. Taking Changle District of Fuzhou coastal city as an example, this study proposes an ecological source identification method from the perspective of "structure-function" by combining Morphological Spatial Pattern Analysis (MSPA) and Remote Sensing Ecological Index (RSEI) methods, and constructs and optimizes ecological corridors by means of the model of Minimum Cumulative Resistance (MCR) and Circuit Theory. The results show that: (1) a total of 20 ecological sources were extracted based on MSPA-RSEI; (2) a total of 31 ecological corridors were extracted based on Linkage Mapper, including 8 Level 1 corridors, 13 Level 2 corridors, and 10 Level 3 corridors; (3) the Pinch Point and Barrier Mapper software was utilized to identify 6.01 km2 and 2.59 km2, respectively, as Level 1 "pinch points" and barrier points within the study area. The land use types of these areas were as follows: The majority of "pinch points" were forested (60.72%), while the majority of barrier points were composed of construction land (55.27%), bare land (17.27%), and cultivated land (13.90%). (4) the optimal width of the corridor was determined by using the buffer zone method and gradient analysis: 30 m for the Level 1 corridor, 60 m for the Level 2 and Level 3 corridors, and the average current density before and after the construction of the eco-corridor was increased from 0.1881 to 0.4992. The results of the study can provide a reference for the decision-making of the ecological construction of the Changle District and the coastal urban areas of eastern China.

Optimization of multiple ecological infrastructures across the land-sea interface for coordination management: A case study around Laizhou Bay in China

Ecological infrastructure (EI), providing ecosystem services across the land-sea interface, has been proposed as a key element in sustainable terrestrial-marine ecosystem coordinated governance. Terrestrial and marine ecosystems should be regarded as an integrated unit for guaranteeing coastal ecological security. However, the existing EI construction framework focused on terrestrial ecosystems, and few studies consider the composite characteristics of the terrestrial-marine ecosystem in coastal areas. In the case study of Laizhou Bay, China, this study proposes an optimization method for multiple ecological infrastructures (MEIs) across the land-sea interface. The method is oriented towards achieving trans-regional scale cohesion, enhancing terrestrial-riverine-marine linkages, providing adequate pathways for marine ecological protection, and promoting coordinated conservation of terrestrial and marine ecosystems. The results showed that: (1) The new optimization framework synthetically considering the terrestrial multi-scale EI networks cohesion, hydrological corridors, and marine conservation network is available. (2) The preliminary ecological sources (PESs) are mainly distributed in the eastern mountainous areas, the estuary of the Yellow River, and six marine protected areas. The spatial imbalance of EI resulted in four marine protected areas in the southwest of the Bohai Sea insufficiently connected between sea-to-sea ecological sources. (3) The integrated MEIs includes four newly added ecological sources (two each for land and sea), eight trans-regional ecological corridors, 17 hydrological corridors, and 11 marine ecological corridors. Through optimization, the MEIs avoid fragmentation across multi-scale terrestrial regions, promote river-based connectivity between land and sea, and increase pathways for marine ecological protection, thereby ensuring effective circulation of regional ecological materials. (4) MEIs-conserved priority areas include 12.4 km2 ecological pinch points and 6.39 km2 marine biological protective points. Focusing on these conserved priority areas provides spatial references for the implementation planning of MEIs. Compared with traditional respective ecosystem networks, the MEIs across land-sea interface optimization approach is feasible for terrestrial-marine ecosystem coordinated management.

Construction of urban-rural ecological networks with multi-scale nesting and composite functions based on the "red-green-blue" spatial perspective: A case study of Dali City, China

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.

Multi-scenario analysis and optimization strategy of ecological security pattern in the Weihe river basin

For many years, the Weihe River Basin (WRB) has struggled to achieve a balance between ecological protection and economic growth. Constructing an Ecological Security Pattern (ESP) is extremely important for ensuring ecological security (ES). This study employed a coupling of multi-objective programming (MOP) and the patch-generating land use simulation (PLUS) model to project land use change (LUCC) in 2040 across three scenarios. Leveraging circuit theory, we generated ecological corridors and identified key ecological nodes, enabling a comparative analysis of ESPs within the WRB. The main results showed that: (1) The Ecological Protection (EP) scenario showed the highest proportions of forestland, grassland, and water, indicating an optimal ecological environment. Conversely, the Economic Development (ED) scenario features the greatest proportion of construction land, particularly evident in the rapid urban expansion. The Natural Development (ND) scenario exhibits a more balanced change, aligning closely with historical trends. (2) The ecological source areas in the EP scenario is 13,856.70 km2, with the largest and most intact patch area. The ecological source patches that have been identified in the ED scenario exhibit fragmentation and dispersion, encompassing a total area of 8018.82 km2. The ecological source areas in the ND scenario is most similar to the actual situation in 2020, encompassing 8474.99 km2. (3) The EP scenario demonstrates minimal landscape fragmentation. The ED scenario presents a more intricate corridor pattern, hindering species and energy flow efficiency. The ND scenario is more similar to the actual distribution in 2020. Protecting and restoring key ecological nodes, and ensuring the integrity and connectivity of ecological sources are crucial for ESP optimization in various scenarios. Combining all results, we categorize the WRB's spatial pattern into "three zones, three belts, and one center" and offer strategic suggestions for ecological preservation, promoting sustainable local ecological and socioeconomic development.

Construction of ecological security pattern in combination with landslide sensitivity: A case study of Yan'an City, China

The ecological security pattern can harmonize the relationship between natural environmental protection and socio-economic development. This study proposes a regional ecological security pattern optimization framework by integrating theory and practice with landslide sensitivity and landscape structure. Using Yan'an City as an example, this study optimizes the landscape layout of preliminary ecological sources. The landslide sensitivity index is generated using the information value model and then used to adjust the ecological resistance surface. The Minimum Cumulative Resistance (MCR) approach is used to extract ecological corridors, locate ecological nodes utilizing circuit theory, and outline crucial ecological control areas. The results demonstrate: (1) the ecological sources are primarily composed of forestlands, with a total area of 2,352.2400 km2, concentrated in the southwest, central, and southeast regions. The optimal landscape granularity for the source patches is 600 m. (2) Yan'an is divided into four landslide sensitivity level zones: extremely high, high, medium, and low, with the overall landslide sensitivity of the region being high. (3) The highest ecological resistance is observed in built-up land and the lowest in forestland. The total number of ecological corridors is 26, avoiding most of the highly sensitive areas of landslides. (4) The number of ecological pinch points is 61, while the ecological barrier points amounted to 54. The critical ecological control areas consist mainly of cropland, forestland, and grassland, and differentiated restoration strategies are proposed to address their unique characteristics. The findings of the research can offer scientific guidance for the practice of ecological security protection in geohazard-prone areas.

Urban biodiversity conservation: A framework for ecological network construction and priority areas identification considering habit differences within species

The construction of ecological networks within the context of urbanization is an effective approach to cope with the challenges of urban biodiversity decline, representing a crucial goal in urban planning and development. However, existing studies often overlook the richness and uniqueness within species communities by homogenizing traits of species in the same class. This study proposes a framework for constructing and optimizing ecological networks focused on differential conservation within the same class. By classifying birds into three groups (specialists of water, forest or urban areas) based on their ecological requirements and urbanization tolerance, we constructed an ecological network tailored to their distinct migratory dispersal patterns. We then identified strategic areas including pinch points, barriers, and breakpoints specific to each bird group. Our findings reveal notable variations in suitable habitat distribution among different bird groups in urban environments. Corridor layouts varied according to habitat preferences and migratory dispersal patterns. Despite these differences, urban built-up areas persist as central hubs for the distribution of suitable habitats for 75% of bird species, with peripheral mountain-plain transition areas constituting 63% of crucial dispersal corridors. This emphasizes the critical role of urban built-up areas in maintaining biodiversity and ecological connectivity. Prioritizing connectivity between central urban areas and distant natural spaces is imperative. Our approach innovatively classifies and constructs networks to identify strategic areas with diverse species-specific attributes, providing valuable spatial information for land planning and guiding solutions to enhance target species. While the primary focus is on bird conservation in Beijing, our framework is broadly applicable to global biodiversity management and green planning under urbanization challenges. Overall, this study offers innovative insights for urban planning development and serves as decision support for prioritizing urban actions.

To explore the effectiveness of various ecological security pattern construction methods in many growth situations in the future: A case study of the West Liaohe River Basin in Inner Mongolia

The Ecological Security Pattern (ESP) has emerged as a prominent area of focus in global ecosystem research, offering valuable scientific insights for reconciling ecological preservation with economic progress. Understanding the differences among different approaches to constructing ESP serves as a fundamental step in ensuring its efficacy. However, there has been a scarcity of studies that quantitatively assess the disparities in the effectiveness of various ESP construction methods. This study focuses on the West Liaohe River Basin as its research subject. Leveraging remote sensing data alongside county-level statistical information, the study employs three distinct ecological source identification methodologies to establish ESP frameworks. Subsequently, it analyzes the discrepancies in ecological protection outcomes across different ESP construction methods under varying future development scenarios. The findings reveal that the ESP centered around ecosystem services emerges as particularly suited for diverse development scenarios, consistently yielding optimal ecological protection outcomes. Our research not only furnishes a theoretical foundation and practical guidance for ESP development in the West Liaohe River Basin but also offers methodological insights transferrable to other regions.

A comprehensive analysis to optimizing national-scale protected area systems under climate change

With the intensification of climate change, incorporating climate information into protected areas planning has become crucial in reducing biodiversity loss. However, the current natural reserve system in China does not take climate information into account. Therefore, we assessed the effectiveness of existing protected areas through climate refuge and connectivity rankings, and Zonation software was used to identify the ecological priority zone in China by combining climate indicators and human footprint. The results show that the current natural protected areas in China have certain limitations in dealing with climate change, and some protected areas may struggle to maintain their value in biodiversity conservation under climate change. Moreover, China still has lots of important areas that can maintain biodiversity under climate change, but most of them are not covered by protected areas. The results provide support for the planning of China's nature protected area system in response to climate change.

Study on trade-offs and synergies of rural ecosystem services in the Tacheng-Emin Basin, Xinjiang, China: Implications for zoning management of rural ecological functions

Rural areas are the main source of ecosystem services in arid and semi-arid areas, and ecosystem services are the background conditions for rural revitalization. In this study, the spatial pattern of key ecosystem services in the countryside was assessed, and the trade-offs and synergistic relationships among ecosystem services were investigated, using the Tacheng-Emin Basin in China as the study area. Finally, the types of ecological function zoning and development strategies for the countryside are proposed. The results showed that: (1) the area of ecological land was large, and the average land use intensity was 2.48, which belonged to the medium intensity. (2) The mean values of the six ecosystem services are all in the middle and lower classes, and the spatial distribution of the five ecosystem services is similar, except for food production. (3) Except for grain production, the other five ecosystem services showed positive feedback to elevation. The other five ecosystem services are synergistic, and there are trade-offs between grain production and other ecosystem services. In the nonlinear interaction mechanism of ecosystem services, the fluctuation constraint occupies the largest proportion. (4) At smaller spatial scales, there are more types of ecosystem service clusters. Combining the results of the study, the villages in the study area can be categorized into five types. This study formulates five priority levels of rural ecological revitalization and proposes different development recommendations for the sustainable development of each type of village. This study is helpful for the fine management of land resources and the revitalization of rural ecology and provides a reference for the sustainable development of ecosystem services in arid and semi-arid areas.

Simulation of the nutritional requirements and energy balance of adult cows in a northern temperate grassland

The forage-livestock balance is an important component of natural grassland management, and realizing a balance between the nutrient energy demand of domestic animals and the energy supply of grasslands is the core challenge in forage-livestock management. This study was performed at the Xieertala Ranch in Hulunbuir City, Inner Mongolia. Using the GRAZPLAN and GrazFeed models, we examined the forage-livestock energy balance during different grazing periods and physiological stages of livestock growth under natural grazing conditions. Data on pasture conditions, climatic factors, supplemental feeding, and livestock characteristics, were used to analyze the metabolizable energy (ME), metabolizable energy for maintenance (MEm), and total metabolizable energy intake (MEItotal) of grazing livestock. The results showed that the energy balance between forage and animals differed for adult cows at different physiological stages. In the early lactation period, although the MEItotal was greater than MEm, it did not meet the requirement for ME. MEItotal was greater than ME during mid-lactation, but there was still an energy imbalance in the early and late lactation periods. In the late lactation period, MEItotal could meet ME requirements from April-September. Adult gestational lactating cows with or without calves were unable to meet their ME requirement, especially in the dry period, even though MEItotal was greater than MEm. Adult cows at different physiological stages exhibited differences in daily forage intake and rumen microbial crude protein (MCP) metabolism, and the forage intake by nonpregnant cows decreased as follows: early lactation > mid-lactation > late lactation, pregnant cows' lactation > dry period. For the degradation, digestion and synthesis of rumen MCP, early-lactation cows were similar to those in the mid-lactation group, but both were higher than those in the late-lactation group, while pregnant cows had greater degradation, digestion, and synthesis of MCP in the lactation period relative to the dry period. For lactating cows, especially those with calves, grazing energy requirements, methane emission metabolism and heat production were highest in August, with increased energy expenditure in winter. Overall, grazing energy, methane emissions and heat production by dry cows were low. In the context of global climate change and grassland degradation, managers must adopt different strategies according to the physiological stages of livestock to ensure a forage-livestock balance and the sustainable utilization and development of grasslands.

Identification of ecological security patterns of alpine wetland grasslands based on landscape ecological risks: A study in Zoigê County

Climate change and human activities have increased ecological risks and degraded ecosystem functions in alpine wetland grassland regions, where ecological security remains largely unexplored. The construction of ecological security patterns (ESP) can help to synchronize regional ecological security and sustainable development and provide ideas to address these challenges. This article determines the current ESP of Zoigê County, China, by analyzing the spatial and temporal characteristics of landscape ecological risk (LER) and generating an ecological network by combining the InVEST model, the landscape connectivity index, and the circuit theory model. Management zoning and targeted conservation recommendations are proposed. The results indicate that the region has significant spatial heterogeneity in IER. Ecological risk exposure is increasing, with high values mainly concentrated in the central part of the region. Meanwhile, ecological protection areas were identified, which included 2578.44 km2 of ecological sources, 71 key ecological corridors, 25 potential ecological corridors, 4 river ecological corridors, 66 pinch points, and 58 barriers. This study provides a valuable reference for the ecological development of Zoigê County, as well as insights into the formation of ESP in other alpine wetland grassland regions.

Stability in change: building a stable ecological security pattern in Northeast China under climate and land use changes

Climate change and land use change caused by human activities have a profound impact on ecological security. Simulating the spatio-temporal changes in ecosystem service value and ecological security patterns under different carbon emission scenarios in the future is of great significance for formulating sustainable development policies. This study quantified the four major ecosystem services (habitat quality, water retention, soil erosion, and carbon storage) in Northeast China (NC), identified ecological source areas, and constructed a stable ecological security pattern. The results show that the spatial patterns of soil erosion, carbon storage, water retention, and habitat quality, the four major ecosystem services in NC, are relatively stable in the next 30 years, and there is no significant difference from the current spatial pattern distribution. The SSP1-2.6 carbon emission scenario is a priority model for the development of NC in the next 30 years. In this carbon emission scenario, the NC has the largest ecological resources (191,177 km2) and the least comprehensive resistance value (850.006 × 10-4). At the same time, the relative resistance of the corridor in this scenario is the smallest, and the area of the mandatory reserve pinch points is the least. The ecological corridors in the SSP1-2.6 scenario form a network distribution among the ecological sources, connecting several large ecological sources as a whole. This study fills the knowledge gap in building a stable ecological security pattern in NC under the background of global change, and provides a scientific basis for the decision-making of regional ecological security and land resource management.

Changes in the land-use landscape pattern and ecological network of Xuzhou planning area

Ongoing rapid urbanization has triggered significant changes in land use, rendering landscape patterns adversely impacted and certain habitat patches degraded. Ecological networks have consequently contracted overall. As such, an investigation into how land-use landscape patterns and ecological networks change over time and space is of major significance for ecological restoration and regional sustainability. Taking Xuzhou Planning Area as a case study, we examined spatiotemporal changes and features of the landscape pattern by employing the land-use change degree, the land-use transition matrix, and quantified landscape pattern indices. An ecological network analysis, which studies the changes in network connectivity and robustness, as well as their causes and contributors, was undertaken to probe into the features and trends of spatiotemporal changes in the land-use landscape pattern and ecological network amid expeditious urbanization. Analysis results unveiled the following: (1) From 1985 to 2020, there was a decline in the area of farmland, forest, and grassland, accompanied by an increase in land for construction, water bodies, and unused land. The southwestern research area witnessed farmland substantially give way to land for construction for this period, and the most dramatic change in land use occurred between 2000 and 2010. (2) The area of dominant patches in the research area shrank, along with more fragmented, complex landscapes. The land for construction was emerging as the dominant landscape by area, whereas patches of farmland, forest, grassland, and water bodies became less connected. (3) The ecological network was densely linked in the northeast, with sparser connections in the southwest. Spatial shrinkage was observed in the research area's southwestern and central ecological corridors. Overall, the number of ecological sources and corridors rose and subsequently dropped before a rebound. (4) The ecological network grew more connected and robust from 1985 through 1990, as portions of farmland were converted into water bodies, which led to an increase in ecological sources. Given a reduction in ecological sources and corridors in the southwestern and central regions between 1990 and 2010, network connectivity and robustness declined, which was reversed from 2010 onward with the addition of two ecological sources-Pan'an Lake and Dugong Lake. With an optimal ecological network in 1990, however, it deteriorated significantly by 2010. The research area saw the minimum value of its network connectivity indices of network stability index (α), evenness index (β), and connectivity index (γ), in 2010, when its ecological network was highly fragmented and vulnerable, attributing to a strong contrast between the maximal connected subgraph's relative size and connectivity robustness. The research findings can lay scientific groundwork for addressing ecological issues, restoring landscape patterns, and developing ecological networks amid urbanization.

Construction of a cold island network for the urban heat island effect mitigation

The urban heat island (UHI) effect seriously challenges sustainable urban development strategies and livability. Numerous studies have explored the UHI problem from the perspective of isolated blue and green patches, ignoring the overall function of cold island networks. This study aims to explore the construction method of cold island network by integrating scattered cold island resources, rationally guiding urban planning and construction, and providing effective ideas and methods for improving the urban thermal environment. Taking the central city of Fuzhou as an example, the identification of the cold island core source (CICS) was optimized by applying relative land surface temperature (LST), morphological spatial pattern analysis, and landscape connectivity analysis. The combined resistance surface was constructed based on a spatial principal component analysis. Subsequently, the cold island network was constructed by applying circuit theory and identifying the key nodes. The results showed that the central and eastern parts of the study area experienced the most significant UHI effects and there was a tendency for them to cluster. Overall, 48 core sources, 104 corridors, 89 cooling nodes, and 34 heating nodes were identified. The average LST of the CICSs was 28.43 °C, significantly lower than the average LST of the entire study area (31.50 °C), and the 104 cold corridors were classified into three categories according to their importance. Different targeting measures should be adopted for the cooling and heating nodes to maintain the stability of the cold island network and prevent the formation of a heat network. Finally, we suggest a model for urban cold island network construction and explore methods for mitigating issues with UHI to achieve proactive and organized adaptation and mitigation of thermal environmental risks in urban areas, as well as to encourage sustainable urban development.

Ecosystem service valuation and multi-scenario simulation in the Ebinur Lake Basin using a coupled GMOP-PLUS model

The Ebinur Lake Basin is an ecologically sensitive area in an arid region. Investigating its land use and land cover (LULC) change and assessing and predicting its ecosystem service value (ESV) are of great importance for the stability of the basin's socioeconomic development and sustainable development of its ecological environment. Based on LULC data from 1990, 2000, 2010, and 2020, we assessed the ESV of the Ebinur Lake Basin and coupled the grey multi-objective optimization model with the patch generation land use simulation model to predict ESV changes in 2035 under four scenarios: business-as-usual (BAU) development, rapid economic development (RED), ecological protection (ELP), and ecological-economic balance (EEB). The results show that from 1990 to 2020, the basin was dominated by grassland (51.23%) and unused land (27.6%), with a continuous decrease in unused land and an increase in cultivated land. In thirty years, the total ESV of the study area increased from 18.62 billion to 67.28 billion yuan, with regulation and support services being the dominant functions. By 2035, cultivated land increased while unused land decreased in all four scenarios compared with that in 2020. The total ESV in 2035 under the BAU, RED, ELP, and EEB scenarios was 68.83 billion, 64.47 billion, 67.99 billion, and 66.79 billion yuan, respectively. In the RED and EEB scenarios, ESV decreased by 2.81 billion and 0.49 billion yuan, respectively. In the BAU scenario, provisioning and regulation services increased by 6.05% and 2.93%, respectively. The ELP scenario, focusing on ecological and environmental protection, saw an increase in ESV for all services. This paper can assist policymakers in optimizing land use allocation and provide scientific support for the formulation of land use strategies and sustainable ecological and environmental development in the inland river basins of arid regions.

Ecological security warning in Central Asia: Integrating ecosystem services protection under SSPs-RCPs scenarios

Ecological security patterns (ESPs) are designed to enhance ecosystem structure and functionality while preserving vital ecosystem services (ESs). This study not only integrated the ES trade-offs related to ecological security warning, but also considered the effects of future climate changes and human activities on ESPs. By combining the revised universal soil loss equation (RUSLE), the revised wind erosion equation (RWEQ), the dry sedimentation (DS) model, the recreation opportunity map (ROM) and the integrated valuation of ESs and trade-offs (InVEST) model, this study projected provisioning services, regulation services and cultural services in Central Asia (CA) for historical periods (1995-2014) and future scenarios (2021-2099). An ecological security early-warning (source - corridor - barriers) framework was constructed based on the protection of ESs under the SSP126, SSP245 and SSP585 scenarios. The ordered weighted averaging method (OWA) was applied to this framework to identify ecological sources. The Minimum cumulative resistance model (MCR) and circuit theory were used to construct ecological corridors and barriers. Our results revealed that ES hotspot areas will decrease by 11.75 % to 16.42 % in CA under the SSP126, SSP245, and SSP585 scenarios. Under the ecological warning framework, the ecological source warning area will reach 792 km2-1942 km2 and 6591 km2-17,465 km2 under the SSP126 and SSP585 scenarios, respectively. In particular, in the 2050s under the SSP245 scenario, the number of key ecological corridor warnings will exceed 50 % of the total number of corridors. We found that ecological barrier warnings will mainly be distributed in desert areas with low vegetation coverage in southwestern CA. Building upon the reorganization of ESs within the ESP framework, we propose an ecological early warning strategy referred to as "one axis, two belts, two cores, and three zones". This novel approach aims to enhance our ability to predict and respond to ecological threats and challenges.

Integrated assessment and prediction of ecological security in typical ecologically fragile areas

In order to safeguard and restore ecological security in ecologically fragile regions, a regionally appropriate land use structure and ecological security pattern should be constructed. Previous ecological security research models for ecologically fragile areas are relatively homogenous, and it is necessary to establish a multi-modeling framework to consider integrated ecological issues. This study proposes a coupled "PLUS-ESI-Circuit Theory" framework for multi-scenario ecological security assessment of the Ningxia Hui Autonomous Region (NHAR). Firstly, the PLUS model was used to complete the simulation of four future development scenarios. Secondly, a new ecological security index (ESI) is constructed by synthesizing ecological service function, ecological health, and ecological risk. Finally, the Circuit Theory is applied to construct the ecological security pattern under multiple scenarios, and the optimization strategy of ecological security zoning is proposed. The results show that (1) from 2000 to 2030, the NHAR has about 80% of grassland and farmland. The built-up area is consistently growing. (2) Between 2000 and 2030, high ecological security areas are primarily located in Helan Mountain, Liupan Mountain, and the central part of NHAR, while the low ecological security areas are dominated by Shapotou District and Yinchuan City. (3) After 2010, the aggregation of high-security areas decreases, and the fragmentation of patches is obvious. Landscape fragmentation would increase under the economic development (ED) scenario and would be somewhat ameliorated by the ecological protection (EP) and balanced development (BD) scenarios. (4) The number of sources increases but the area decreases from 2000 to 2020. The quantity of ecological elements is on the rise. Ecological restoration and protection of this part of the country will improve its ecological security.

Carbon nanowall-based gas sensors for carbon dioxide gas detection

Carbon nanowalls (CNWs) have attracted significant attention for gas sensing applications due to their exceptional material properties such as large specific surface area, electric conductivity, nano- and/or micro-porous structure, and high charge carrier mobility. In this work, CNW films were synthesized and used to fabricate gas sensors for carbon dioxide (CO2) gas sensing. The CNW films were synthesized using an inductively-coupled plasma (ICP) plasma-enhanced chemical vapor deposition (PECVD) method and their structural and morphological properties were characterized using Raman spectroscopy and electron microscopy. The obtained CNW films were used to fabricate gas sensors employing interdigitated gold (Au) microelectrodes. The gas sensors were fabricated using both direct synthesis of CNW films on interdigitated Au microelectrodes on quartz and also transferring presynthesized CNW films onto interdigitated Au microelectrodes on glass. The CO2gas-sensing properties of fabricated devices were investigated for different concentrations of CO2gas and temperature-ranges. The sensitivities of fabricated devices were found to have a linear dependence on the concentration of CO2gas and increase with temperature. It was revealed that devices, in which CNW films have a maze-like structure, perform better compared to the ones that have a petal-like structure. A sensitivity value of 1.18% was obtained at 500 ppm CO2concentration and 100 °C device temperature. The CNW-based gas sensors have the potential for the development of easy-to-manufacture and efficient gas sensors for toxic gas monitoring.

Integrating land-sea coordination into construction of an ecological security pattern for urban agglomeration: a case study in the Guangdong-Hong Kong-Macao Greater Bay Area

The construction of ecological security pattern (ESP) is of great scientific significance for solving the problem of habitat fragmentation in urban environment. However, previous studies mainly focused on the ESP in land area, leaving the sea area to be ignored. This study took the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) and its offshore area as an example and integrated the land-sea coordination into the construction of ESP based on the minimum resistance model, gravity model, and graph theory centrality. The results showed that there are 171 and 56 ecological sources for land area and offshore area, accounting for 31.46% and 21.51% of total area, respectively. Twenty-four important ecological corridors with a total length of 2738.05 km were identified in GBA, and the width is proposed to be less than 100 m. Moreover, the α, β, and γ index of the ecological network in the study area is 0.19, 1.33, and 0.5, respectively, indicating that the ecological network structure is complex and the connectivity between ecological nodes is good. The ecological restoration area includes 286.6 km2 of ecological pinch points and 140.44 km2 of ecological barrier. The overall ESP of the study area is "one ring, two belts, and four zones." The main body of the area with a superior ecological environment is distributed in a ring-like pattern near the outer edge of the study area, and two belts (important ecological corridor and ecological corridor) are distributed in a network. According to the ecological characteristics, the study area was divided into four zones: ecological preservation areas, ecological restoration areas, limited construction areas, and optimized construction areas. The ESP established herein institute provides a reference for the revision of ecological space control and optimization measures in the GBA. It also provides effective and systematic means to solve ecological problems in the current territorial spatial planning and territorial ecological restoration of coastal urban agglomeration.

Regarding reference state to identify priority areas for ecological restoration in a karst region

Widespread degradation of natural ecosystems around the globe has resulted in several ecological problems. Ecological restoration is considered a global priority as an important means of mitigating ecosystem degradation and enhancing ecosystem services provision. Regarding ecosystem reference state is a prerequisite for ecological restoration. However, there were few studies focusing on how to regard reference state for ecological restoration, especially under a changing climate. Taking Guizhou Province, a typical karst region in China, as a case study area, in this study we firstly assessed ecosystem services under homogeneous climate conditions. Secondly, we defined the optimal ecosystem services as ecosystem reference state, and then evaluated restoration suitability under a comprehensive framework. Finally, ecological restoration priority areas (EPRAs), which included ecological reconstruction areas, assisted regeneration areas and conservation priority areas needing restoration, were identified by integrating restoration suitability and conservation priority areas. The results showed that the services of water conservation and habitat maintenance only increased less than 10% from 2001 to 2018. Identified ecological reconstruction areas and assisted regeneration areas covered 1078 km2 and 1159 km2 respectively. Additionally, 15 conservation priority areas with the total area of 18,507 km2 were identified as conservation priority areas needing restoration. Accounting for 11.78% of the total area, ERPAs were mostly located in the eastern part of Guizhou, including Qiandongnan, Tongren, and Zunyi. The approach proposed here for regarding ecosystem reference state after controlling climate variables and the framework for identifying ERPAs can provide a scientific reference for large-scale ecological restoration planning.

Regional proximity effects of landscape pattern evolution: Evidence from 325 county-level areas in the middle reaches of the Yangtze River, China

Unravelling the evolution of landscape patterns is essential to understand regional socio-ecological processes and to solve conflicts between environment protection and human development. However, the role of landscape transition in regional landscape pattern evolution remains unclear. Taking 325 county-level areas in the middle reaches of the Yangtze River (MRYR) as an example, this study explored the spatiotemporal associations between landscape quantity and pattern from the 1970s to 2020. Employing the methods of landscape metrics and trend and correlation analysis, associations between landscape transition and landscape pattern were found. The main results were as follows: (1) From the 1970s to 2020, urban land nearly doubled from 0.93 to 1.89 million km2. Arable land and forest showed the largest quantity reductions of 0.88 million km2 and 0.28 million km2, respectively. Other landscapes showed both decreasing and increasing trends with a spatial overlap among counties. (2) Transition in landscape quantity drives the change in landscape patches, thus affecting the landscape pattern in counties. The percentage of landscape area at the class level (CPLAND) showed relative changes in the quantities of landscape categories in each observation year, but their extreme outliers presented larger changes. (3) Diverse correlation coefficients in terms of magnitude and direction suggested that the transition from natural landscape to human-influenced landscape and the reverse processes occurred. Aggregation and diversity metrics showed spatial interaction with similar distances and the perimeter-area fractal dimension (PAFRAC) showed spatial autocorrelation at local scale. Optimal bandwidths among arable land, forest, and urban land (129.2 km) revealed direct spatial interactions and causal relationships, as did waters and unused land (66.7 km). The findings explained the evolution of landscape patterns and highlighted key areas where various landscape changes occurred, and can provide scientific support for policy-making in regional landscape transition governance.

Linking ecosystem service flow to water-related ecological security pattern: A methodological approach applied to a coastal province of China

Water security is a critical concern due to intensifying anthropogenic activities and climate change. Delineating a water-related ecological security pattern can help to optimize spatial configuration, which in turn can inform sustainable water management. However, the methodology remains unclear. In this study, we developed a framework linking ecosystem service flow to water-related ecological security pattern; hence, we identified the sources, sinks, key corridors, and vulnerable nodes in Fujian Province, China. Our results revealed that the sources were located inland at high altitudes with a decreasing area trend in the south and an increasing area trend in the north, whereas the sinks were spread in coastal areas and exhibited a decreasing trend with relatively stable spatial distribution. The water-related ecological security has degraded as represented by a decreasing ecological supply-demand ratio over the last 30 years. Key corridors were identified in 17.12% of the rivers, and 22.5% of the vulnerable nodes were recognized as early warning nodes. Climate variability affected source distribution, while anthropogenic activities drove sink dynamics. These findings have important implications including landscape pattern planning and sustainable water management in the context of accelerated land use/cover and climate changes.

Spatial analysis enables priority selection in conservation practices for landscapes that need ecological security

Global urbanization has not only promoted social and economic development, but also contributed to seriously ecological challenges. As a type of sustainable landscape patterns, ecological security pattern is considered as an effective spatial pathway to simultaneously conserve ecological security and maintain social-economic development. However, the fragmentation issue of ecological sources of ecological security pattern has not been effectively addressed, although many case studies have been conducted to identify ecological security pattern. In this study, we used spatial conservation prioritization to identify the ecological security pattern of the city belt along the Yellow River in Ningxia, China. Ecological sources were selected using Zonation model while ecological corridors and key ecological nodes were identified with circuit model. The results showed that the ecological security pattern was composed of 97 ecological sources, 226 ecological corridors, 267 pinch points and 22 barriers, covering a total area of 7713.1 km2 and accounting for 34% of the study area. Ecological sources were concentrated in the Helan Mountain, Xiang Mountain and along the Yellow River. Besides, ecological corridors were dense in the southern and eastern part of the study area. Both indicated that the Yellow River and Helan Mountain were the conservation hotspots. Landscape connectivity of ecological sources identified through Zonation-based spatial conservation prioritization was better than that with the scoring approach based on ecosystem service importance. Particularly, in the Zonation approach the landscape connectivity increased with 44% while the average patch area increased with 28% when comparing with the scoring approach. The spatial conservation prioritization approach proposed in this study provides a new effective tool to construct ecological security pattern, which is conducive to the synergic enhancement of landscape connectivity and ecosystem services conservation.

Identifying Migration Routes of Wild Asian Elephants in China Based on Ecological Networks Constructed by Circuit Theory Model

Humans overlap with Asian elephants, resulting in frequent costly human-elephant conflicts, which disturb and even threaten local residents. In this study, we treat provincial and national nature reserves where Asian elephants still exist and other alternative habitats suitable for Asian elephants in southern Yunnan, China, as ecological patches. By using this approach, we can treat the terrain and surface state factors that hinder the migration of Asian elephants as a form of ecological resistance surface. We can then use a circuit theory model and remote sensing data to construct an ecological network, which allows us to identify ecological corridors and ecological pinch points. Herein, the possible migration routes of wild Asian elephants were identified. The main results are as follows: (1) In the study area, dense forests with steep slopes and high altitudes, cultivated land, and building land have greater migration resistance, while the gently undulating shrubs, bamboo forests, and grasslands far away from the city have less migration resistance. (2) There are three ecological corridor groups in the study area, mainly composed of shrub and grassland. The ecological corridors identified in this paper are the most likely migration routes of wild Asian elephants in China, and areas with higher simulated current densities reflect a higher probability of Asian elephants passing through. (3) According to the analysis, the ecological pinch points in the study area are 602 km2 in total, and woodland and grassland account for 89.2% of the total ecological pinch area. The areas where the pinch points are located have a high probability of Asian elephants passing through and a narrow space. Our findings can provide suggestions and solutions for the current conservation of wild Asian elephant species, alleviate human-elephant conflicts, promote the harmonious coexistence between humans and nature, and provide reference for biological protection and biological reserve planning.

Construction and optimization of ecological security pattern based on the circuit theory: a case study of Hohhot City

The construction of ecological security pattern aims to determine the bottom line of ecological land supply and effective spatial distribution and provides a scientific basis for ensuring regional ecological security. The basic paradigm of "source recognition-resistance surface creation-corridor identification-key areas determination" was used to construct the ecological security pattern of Hohhot City in 2009 and 2019. The circuit theory was employed to determine the demand for protection and restoration of crucial ecological area and to divide the core ecological protection and restoration area, the core restoration area, the core protection area, and the general ecological protection area; then, the optimization of Hohhot's ecological security pattern could be proposed. The results show that there was no interconnected and closed ecological network in 2009 and 2019 in the study area, and the area of significant ecological elements were decreasing: ecological source areas decreased from 266.97 to 261.21 km2, the number of ecological corridors decreased from 10 to 6, and the total area of ecological protection and restoration areas decreased from 342.15 to 199.91 km2. The results show that in the past 10 years, the ecological space in Hohhot had problems such as quality degradation, fragmentation intensifying, and effective landscape connectivity declining. It is urgent to optimize the ecological sources layout, strengthen the restoration of barrier areas and the protection of pinch point areas, and improve habitat connectivity to ensure the improved regional ecological security. Our results can provide a scientific reference for coordinating ecological protection and economic development, as well as the policy formulation and implementation of relevant departments.

Integrating ecosystem services and complex network theory to construct and optimize ecological security patterns: a case study of Guangdong-Hong Kong-Macao Greater Bay Area, China

The urban agglomerations' rapid expansion and population growth have led to the fragmentation of landscape patterns and the degradation of ecosystems, seriously threatening regional ecological security. Ecological security pattern (ESP) is a spatial planning approach to effectively balance the development of urbanization and ecological protection. However, previous studies have ignored the difference in the importance of ecosystem services and the spatial compactness of ecological sources. The quantitative management objectives for maintaining the resilience of ESP are also rarely discussed. In this study, taking the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as an example, ecological sources were identified by simulating multiple ES weight assignment scenarios through GeoSOS area optimization. Ecological corridors and strategic points were extracted by Linkage Mapper. The robustness analysis based on complex network theory was performed to quantify the management objectives of ESPs. The results showed that ESPs include 26,130.61 km² ecological sources (accounting for 46.6% of the area of GBA), 557 ecological corridors, and 112 ecological strategic points. In more detail, ecological sources are mainly distributed in the western and eastern mountainous areas, and ecological corridors primarily link peripheral edge areas of GBA in a circular radial shape. Compared with the current nature reserves, the identified ecological sources are more compact in landscape pattern. According to the robustness analysis, at least 23% of the important ecological sources should be strictly restricted from development activities to maintain the ESP's ability to resist ecological risks. This study also proposed corresponding differentiated ESPs management strategies. By optimizing the existing ESPs construction method and clarifying the ESPs management strategies, this study provides a completely scientific framework for the construction and management of ESPs in urban agglomerations.

Supporting the planning of urban blue-green infrastructure for biodiversity: A multi-scale prioritisation framework

Primary considerations for urban blue-green infrastructure (BGI) encompass sustainable stormwater/urban heat management while biodiversity conservation is often considered an inherent benefit rather than a core planning requirement. However, ecological function of BGI as 'stepping stones' or linear corridors for otherwise fragmented habitats is undisputed. While quantitative approaches for modelling ecological connectivity in conservation planning are well established, mismatches in scope and scale with models that support the planning of BGI makes their adoption and integration difficult across disciplines. Technical complexities have led to ambiguity around circuit and network-based approaches, focal node placement, spatial extents, and resolution. Furthermore, these approaches are often computationally intensive, and considerable gaps remain in their use for identifying local-scale critical "pinch-points" that urban planners may respond to with the integration of BGI interventions that address biodiversity enhancement among other ecosystem services. Here, we present a framework that simplifies and integrates the merits of regional connectivity assessments with a focus on urban areas to prioritise BGI planning interventions while reducing computational demands. Our framework facilitates: (1) modelling potential ecological corridors at a coarse regional scale, (2) prioritising local-scale BGI interventions based on the relative contribution of individual nodes in this regional network, and (3) inferring connectivity hot- and cold-spots for local-scale BGI interventions. We illustrate this in the Swiss lowlands, demonstrating how, compared to previous work, we are able to identify and rank different priority locations across the region for BGI interventions in support of biodiversity enhancement and how their local-scale functional design may be benefited by addressing specific environmental variables.

Linking ecosystem services and circuit theory to identify priority conservation and restoration areas from an ecological network perspective

The Yellow River basin has been experiencing ecosystem fragmentation, conversion, and degradation. The ecological security pattern (ESP) can provide a systematic and holistic perspective for specific action planning to maintain ecosystem structural, functional stability, and its connectivity. Thus, this study focused on Sanmenxia, one of the most representative cities of the Yellow River basin, to construct an integrated ESP to provide evidence-based support for ecological conservation and restoration. We adopted four main steps, including measuring the importance of multiple ecosystem services, identifying ecological sources, constructing the ecological resistance surface, and linking the MCR model and circuit theory to identify the optimal path, optimal width, and key nodes of ecological corridors. Overall, we identified various ecological conservation and restoration priority areas in Sanmenxia, including 3593.08 km² of ecosystem service hotspots, 28 corridors, 105 pinch points, and 73 barriers, and we highlighted multiple priority actions. This study provides an effective starting point for the future identification of ecological priorities at the regional or river basin scale.

Optimization of landscape pattern in the main river basin of Liao River in China based on ecological network

As a main stream method of landscape pattern optimization, the ecological network plays an important role in maintaining ecosystem stability, improving landscape connectivity, and promoting landscape sustainable development. Based on landscape connectivity index and morphological spatial pattern analysis (MSPA), a comprehensive evaluation system of ecological patches was constructed in the main river basin of Liao River, and ecological sources were extracted. According to the habitat characteristics of the study area, the ecological cumulative resistance surface was constructed, and the ecological corridors and nodes were extracted by the minimum cumulative resistance (MCR) model. The ecological network of the study area was comprehensively evaluated by using the network analysis method, and the importance level of the ecological corridor was divided by the gravity model, so as to put forward the optimization suggestions of the landscape pattern based on the ecological network. The results showed that the ecological network in the main river basin of Liao River is composed of 20 ecological sources, 108 ecological corridors, and 72 ecological nodes, with the distribution characteristics of dense east and sparse west. The main landscape components are cropland and woodland. The closure degree, line point rate, and connectivity index of the ecological network are 0.27, 1.50, and 0.51, respectively, and the cost ratio is 0.23. In the optimization of landscape pattern, priority should be given to the restoration of primary ecological sources and ecological corridors, followed by the ecological construction of secondary and tertiary ecological sources and ecological corridors, the rational use of engineering technology for habitat remodeling, and the adoption of the "patch-corridor-substrate" model to improve the stability and landscape connectivity of the regional ecosystem. The construction of ecological network in the main river basin of Liao River is of great significance to regional ecological security and biodiversity conservation, and provides data support for optimizing the landscape pattern of the basin and promoting regional sustainable development.

Interpreting regional ecological security from perspective of ecological networks: a case study in Ningxia Hui Autonomous Region, China

The rapid economic development and intense human activities have seriously restricted the sustainable development of ecology and the maintenance of ecosystem services. Ecological network can effectively connect fragmented habitats and is an important way to couple landscape structure, ecological process, and function. This study proposes a multimodel coupling framework to explore the ecological security status of Ningxia Hui Autonomous Region (NHAR) under different development scenarios from the perspective of ecological networks. The conclusions are as follows: (1) From 2000 to 2030, grassland and arable land were the main land types of NHAR. Grassland is the main expansion land type under the ecological land protection (ELP) scenario, while construction land is the main expansion land type in two other scenarios. (2) The main gather and change of the ecological sources occurred in the central region, and the ecological expansion should develop from the middle to the south. (3) The average area of ecological sources under BAU and RED scenarios is smaller than that under ELP scenario, and more ecological corridors are needed to connect. (4) The centrality of the ecological sources under the BAU scenario is generally high, but the ecological sources under ELP and RED scenarios have undergone spatial migration. In addition, the urbanization trend of NHAR is different under different scenarios, and more attention should be paid to the maintenance and protection of ecological networks in typical areas. This study can provide important reference for NHAR's ecological space planning and ecological protection policy formulation.

Improving the ecological network optimization with landscape connectivity: a case study of Neijiang City, Sichuan Province

Rapid urbanization intensifies the fragmentation of landscape patches and affects the stability of ecosystems. The construction of an ecological network can effectively promote the connection of important ecological spaces and improve the landscape integrity. However, the landscape connectivity, directly affecting the stability of ecological network, was less considered in the ecological network construction of recent researches, which easily caused the instability of constructed ecological network. Therefore, this study introduced landscape connectivity index to establish a modified ecological network optimization method based on the minimum cumulative resistance (MCR) model. The results showed that, compared with the traditional model, the modified model focused on the spatially detailed measurement of regional connectivity, and emphasized the impact of human disturbance on ecosystem stability at the landscape scale. The constructed corridors in the optimized ecological network of the modified model not only effectively improved the connection degree between important ecological sources but also avoided the areas with low landscape connectivity and high obstacles to ecological flow, especially in the counties of Zizhong, Dongxing, and Longchang within the focal study area. The ecological network established by the traditional model and modified model generated 19 and 20 ecological corridors with lengths of 334.49 km and 364.35 km, respectively, and the number of ecological nodes was 18 and 22. Evaluated by the Gravity method, the modified model identified the important ecological corridors in the ecological network, and the energy transfer efficiency of the network was improved. This study provided an effective way to improve the structural stability of ecological network construction and can provide scientific support for regional landscape pattern optimization and ecological security construction.

Constructing the Landscape Ecological Security Pattern in the Dawen River Basin in China: A Framework Based on the Circuit Principle

With the rapid development of urbanization, land cover, and land use patterns have greatly changed in China, which has damaged the landscape structure, affected the energy balance and material flow within the system, and reduced the value of ecosystem services. The construction of landscape ecological security patterns could promote species exchange between biological groups and increase material and energy exchange between landscape elements. Few studies have focused on the randomness of species to migration path, thus failing to objectively reflect the process of species migration and diffusion. Therefore, circuit theory was used in this study to better match the random selection of migration paths by species. In this paper, 14 typical mammal species from the Dawen River basin of the lower Yellow River in China were selected as examples, and the conclusions were as follows: (1) The ecological sources of the Dawen River basin were 49, with forest land and lakes as the main sources, and they were crucial to the stability of the regional ecological security pattern. A total of 128 ecological corridors were identified, among which 83 were key corridors and the rest were potential corridors. The key corridors throughout the whole region need priority protection and can be used as a core area for the observation and monitoring of natural resources. (2) Based on the circuit principle, 32 pinch points and 21 barrier points were identified, indicating that regional habitat connectivity must be further improved. (3) Four types of zones were determined, and optimization measures were proposed. (4) On the basis of conceptual protection, the ecological protection network of the Dawen River basin was built to enhance ecological resilience. The landscape ecological security pattern of the Dawen River basin was constructed from the three levels of points, corridors, and areas. Based on the concept of regional ecological security, a resource optimization strategy for ecological security patterns was proposed, which is significant for maintaining the integrity of watershed ecosystems.

Construction and optimization strategy of ecological security pattern based on ecosystem services and landscape connectivity: a case study of Guizhou Province, China

Rapid urbanization and irrational human activities have induced in numerous environmental problems, seriously threatening regional ecological security. The establishment and optimization of ecological security patterns (ESPs) were considered as a nature-based solution and an effective way for sustainable development. In this study, the Guizhou Province, a representative karst mountainous region in the southwest of China, was used as the study region. The ecological sources were identified and optimized through integrating ecosystem services and landscape connectivity, and the ecological resistance surface was corrected by representative features of karst areas. The circuit theory was adopted to extract the ecological corridors and barriers. We found that the three ecosystem services (i.e., water conservation, biodiversity maintenance, and soil conservation) had remarkable spatial heterogeneity. The area of optimized ecological sources was enlarged 4752.14 km². The number of corridors was reduced from 73 to 47 after optimization, with a total length decreased by 1251.97 km. The optimized ecological network structure considerably enhanced ecological connectivity, among the γ index increased by 0.0014, the β index reduced by 0.0833, while the α index did not change significantly. We concluded that quantitatively exploring the impacts of ecological source optimization are significant for enhancing ecological connectivity. The approach of our study proposes a novel idea into the ESP construction that can provide a meaningful reference for ecological protection and restoration.

Identification of priority areas for ecological restoration based on ecological security and landscape elements

Accurate identification of priority areas for ecological restoration is an important prerequisite for ecological protection and restoration, but it is a current challenge in landscape planning. Northern Shaanxi, which is located in the middle of the Loess Plateau in China, was selected as a study area in this paper. A three-dimensional framework including natural potential, human disturbance, and landscape pattern factors was used to construct an ecological security evaluation index system, and spatial principal component analysis (SPCA) was used to quantitatively evaluate the ecological security levels of the study area. The ecological security assessment result was used as a resistance surface, and landscape elements were identified by morphological spatial pattern analysis (MSPA), minimum cumulative resistance (MCR) model and the gravity model. On this basis, priority areas for ecological restoration were identified by considering ecosystem security and the matching degree of landscape elements. The resulting area with low and moderately low security levels was 27,574.87 km² in size, accounting for 34.48% of the total study area, and the ecological security situation was not ideal. We identified seventeen ecological sources with an area of 5789.36 km², and the important ecological sources were mainly distributed in the south of the study area. We identified one hundred and thirty-six potential ecological corridors with a total length of 7431.12 km, including 16 important ecological corridors with a length of 1279.43 km. We also identified 83 ecological nodes, including 17 important ecological nodes. We found that the high matching degree of landscape elements included four watersheds with an area of 7571.17 km², mainly distributed in the southern part of the study area. Fifty-one basins with a low matching degree of landscape elements were identified, covering an area of 50,399.44 km² and mainly distributed in the west and north of the study area. We identified three levels of areas to be restored, of which the level I ecological restoration priority area was the smallest, at 7047.61 km². The areas of the level II ecological restoration priority area and the level III ecological restoration priority area were 20,379.35 km² and 27,866.35 km², respectively. The two areas were large and mainly distributed in the west and north of the study area. We discussed ecological restoration strategies for different levels of ecological restoration priority areas and provided new methods for identifying priority ecological restoration areas in the future.

Constructing a resilient ecological network by considering source stability in the largest Chinese urban agglomeration

The dynamics of ecological sources and their impact on the resilience of ecological networks (ENs) have attracted increasing attention from both researchers and managers. Although a couple of studies have recognized the source-loss effects on network resilience, there is a knowledge gap in integrating spatiotemporal changes of the sources while constructing resilient ENs. Here, we propose the concept of dynamic stability (DS) to explore the sources' changes over a certain period and improve source identification by grading the DS in the largest urban agglomeration located in the middle reaches of the Yangtze River in China. An investigation of the five selected ecosystem service (ES) indicators in 2000, 2010, and 2018 identified 49, 54, and 68 preliminary sources, respectively, from which 11, 14, and three sources were extracted, respectively, with high, moderate, and low levels of DS, respectively. A three-tier EN was constructed by considering both the ESs and DSs of the extracted sources. The constructed network was scale-free and featured in small world in topology analysis. Moreover, a carefully designed attack test found that this EN was of good resilience as the three critical nodes that might cause a marked decay of resilience were in high or moderate DSs and were preferentially protected by the Ecological Conservation Red Line policy in China. In conclusion, the improved approach of considering the DSs of sources may help to precisely identify and protect the critical nodes threatening network resilience, which is highly desired in constructing ENs facing various rapid changes, especially in large-scale urbanized areas.