Ecological Security Research Articles

Kinetic features and mechanism of scorodite formation via multivalent iron source from arsenic-bearing solution

Arsenic-bearing wastes from non-ferrous metallurgy exhibit poor stability during long-term storage, and are transferred as pollutants to the atmosphere and groundwater, thereby, threatening human health and ecological security. Immobilising arsenic as scorodite crystals via a multivalent iron source (Fe(OH)3-FeSO4·7 H2O) is one effective approach for controlling arsenic pollution. However, the kinetic features and mechanisms of this method have not yet been revealed, thereby, necessitating further research. Herein, the kinetics of scorodite generation influenced by the initial pH, Fe/As ratio, Fe(III)/Fe(II) ratio, and reaction temperature were investigated. Prominent features included variations in the minimum pH, oxidation–reduction potential (ORP) platform, Fe/As ratio (1.0), and the delay or advance of scorodite generation. The complicated mechanism of scorodite formation can be divided into coordinated polymerisation, acidic Fe(OH)3 dissolution, polymer oxidation, Fe(II) oxidation, and scorodite crystallisation. The fast coordinated polymerisation of precursors ([Fe(H2O)4(H2AsO4)]nn+) in stage I resulted in a decrease in pH; Fe(OH)3@scorodite and Fe(H2O)2AsO4 basic units were formed via the oxidation of ionic Fe(III) in stage II. Furthermore, regular octahedral scorodite was generated from two sources: the crystallisation of Fe(H2O)2AsO4 basic units and Ostwald ripening of flaky scorodite from Fe(III)–As(V) precipitates at stage III. The Fe(II) in the polymers was mainly oxidised by ferric ions generated from the oxidation of ferrous ions via dissolved O2 from the oxygen gas. Fe(II) ions as carriers for transferring electrons from O2 to polymers. Scorodite formation was controlled by the oxidation of Fe(II) by oxygen gas. Overall, this study provides guidance for the effective immobilisation of arsenic wastes into scorodite via multivalent iron sources to eliminate arsenic pollution.

Understanding of Plant Salt Tolerance Mechanisms and Application to Molecular Breeding.

Soil salinization is a widespread hindrance that endangers agricultural production and ecological security. High salt concentrations in saline soils are primarily caused by osmotic stress, ionic toxicity and oxidative stress, which have a negative impact on plant growth and development. In order to withstand salt stress, plants have developed a series of complicated physiological and molecular mechanisms, encompassing adaptive changes in the structure and function of various plant organs, as well as the intricate signal transduction networks enabling plants to survive in high-salinity environments. This review summarizes the recent advances in salt perception under different tissues, physiological responses and signaling regulations of plant tolerance to salt stress. We also examine the current knowledge of strategies for breeding salt-tolerant plants, including the applications of omics technologies and transgenic approaches, aiming to provide the basis for the cultivation of salt-tolerant crops through molecular breeding. Finally, future research on the application of wild germplasm resources and muti-omics technologies to discover new tolerant genes as well as investigation of crosstalk among plant hormone signaling pathways to uncover plant salt tolerance mechanisms are also discussed in this review.

Evaluation of the Ecosystem Services Value of Agricultural Industrial Parks under the Background of Tianfu Granary Construction - A Case Study of the Daoming and Longxing Districts in Chongzhou City

In the new era, China faces two major challenges of food security and ecological protection. The agricultural industrial parks constructed in the process of developing the Tianfu Granary play a significant role in China's food supply and ecological security as a special type of farmland ecosystem. Accurately calculating the value of ecosystem services in agricultural industrial parks is of great importance for achieving sustainable agricultural development and comprehensively realizing rural revitalization. This paper takes the Daoming and Longxing Agricultural Industrial Parks in Chongzhou City as the research subjects, constructs an evaluation index system for ecosystem service value, and assesses and calculates the supply, support, regulation, and cultural services of the agricultural industrial parks. The research findings show that the total value of ecosystem services reaches 260.64 million yuan, which is 4.65 times the value of the agricultural products supplied, and its significant ecosystem service value cannot be ignored. Among the ecosystem service values of the park, the cultural service value is the highest, followed by the social security service value. Based on the above conclusions, this paper discusses how to achieve high-standard construction of agricultural industrial parks, providing a scientific basis for the government and policymakers to make correct decisions in the rational use of resources, reduce and avoid short-term economic behaviors that damage ecosystem service functions, and promote sustainable agricultural development.

Gridded Grazing Intensity Based on Geographically Weighted Random Forest and Its Drivers: A Case Study of Western Qinghai–Tibetan Plateau

ABSTRACTOvergrazing affects the grass‐livestock balance and endangers grassland ecological security. Despite extensive studies conducted on identifying and quantifying grazing intensity, there is still room for improvement in the research on gridding grazing intensity, particularly in areas with limited data on the Qinghai–Tibet Plateau. Therefore, we proposed a grazing intensity spatialization method using geographically weighted random forest (GWRF) to gain further insights into the spatial heterogeneity of alpine grassland grazing intensity. This method incorporates multiple remote sensing data related to human activities and natural factors, as well as annual livestock statistics at the township level over several years, while adequately considering the spatial autocorrelation of grazing intensity. Additionally, we employed Lindeman Merenda Gold (LMG), the geographical detector model, and the structural equation model (SEM) to assess the contribution and influence path of driving factors to grazing intensity. We also utilize partial correlation analysis and dual‐phase mapping to examine the impact of natural and human activities on the spatial distribution of grazing intensity. The results demonstrate that the GWRF‐based grazing intensity spatial model accurately predicts grazing intensity by demonstrating its consistency with township‐scale livestock data (R 2 = 0.92 (p < 0.01), RMSE = 1.07). This provides valuable technical support for quantifying grazing intensity in alpine pastoral areas with limited data availability. We evaluate trends in grazing intensity and observe an increase in Gar and Purang counties. Furthermore, population density, normalized difference vegetation index (NDVI), and temperature are identified as three influential factors affecting grazing intensity in alpine pastoral areas. Additionally, other factors indirectly impact grazing intensity by influencing population density and NDVI levels, while their interactions amplify their overall influence. The dual‐phase mapping technique has demonstrated a significant impact of population density on 45.92% (p < 0.01) of the study area, emphasizing the substantial influence of human activities on grazing intensity. Our study provides a novel framework for spatially analyzing grazing intensity and unraveling the intricated driving mechanisms behind spatiotemporal changes, particularly in areas with limited data availability.

Assessment and forecasting of water ecological security and obstacle factor diagnosis in the Hexi Corridor of Northwest China

The water ecological security pattern is a core factor. A scientific, accurate, and practical evaluation of water ecological security provides a theoretical basis for regional water ecological management. Using water resource data from five cities in the Hexi Corridor of Gansu Province (Jiuquan (JQ), Jiayuguan (JYG), Zhangye (ZY), Jinchang (JC), and Wuwei (WW)) from 2006 to 2021, a water ecological security evaluation index system based on the PSR (pressure-state-response) framework was constructed, covering 27 factors related to water resources, socio-economics, and the ecological environment. The main obstacle factors of water ecological security were identified using the obstacle degree model, and the grey GM(1,1) model was employed to predict water ecological security. Results indicated that the comprehensive assessment index of water ecology in the Hexi Corridor increased from 2006 to 2021, showing a transition from relatively unsafe (0.319) to basic safety and then to relatively safe (0.672). The pressure and response systems were the main limiting factors affecting water ecological security in the Hexi Corridor. After a slight decline in 2008, the overall spatial distribution continued to rise, with WW City and ZY City leading since 2016. ZY had a higher safety grade proportion (25%) compared to other areas in the Hexi region. The pressure system was the most significant obstacle to water ecological security after 2006. Prediction results indicated that the comprehensive evaluation index of water ecological security would continue to rise annually from 2022 to 2031, reaching a very safe level by 2025. The evaluation results provide a scientific basis for ecological security and risk decision-making in the study area.

Construction of Cross-basin Ecological Security Patterns Based on Carbon Sinks and Landscape Connectivity

Artificial water system creation and land use changes have great effects on ecosystems. The construction of cross-basin ecological security patterns based on carbon sinks and landscape connectivity plays a key role in regional ecological environment protection. The linkage area between the Xiang River and the Li River was selected as the research object. Based on the land use data from 2000 to 2020, this study examined the ecological security network of the Xiang-Li connected region using the InVEST model combined with morphological spatial pattern analysis （MSPA） and evaluated the temporal and spatial evolution of carbon storage and ecological security patterns. The results showed that： ① From 2000 to 2020, the land cover types of the Xiang-Li linkage area were mainly forest land and arable land. The changes of land use types were characterized by decreases in arable land, forest land, and grassland and by increases in watersheds and construction land. ② The carbon storage in the Xiang-Li linkage area was characterized by a blocky distribution, and the high and medium areas were dominant. The carbon stock increased slowly from 2000 to 2010 and decreased dramatically from 2010 to 2020, with a cumulative decrease of 18.32×103 t due to the influence of land use changes. ③ The area of ecological sources （five in total） decreased firstly and then increased, whereas the length of ecological corridors （ten in total） increased firstly and then decreased in the Xiang-Li linkage area. Overall, in the process of urbanization, the distribution of the high ecological resistance value in the Xiang-Li linkage area gradually shifted to the northeast with an expansion, whereas the barycenter of the ecological safety pattern shifted to the southwest. Determining the dynamic distribution and stability of ecological sources by coupling carbon storage patches and landscape patterns can provide a new way to construct ecological security patterns in cross-basin ecosystems.

Spatio-temporal Situation, Regional Differences, and Dynamic Evolution of the Distribution of Ecological Compensation in the Yellow River Basin

In the context of regional coordinated development and modernization of ecological and environmental governance capacity, the spatial collaborative governance of transboundary river basins has received extensive attention, but the ecological compensation of river basins is faced with the intertwined relationship of rights and responsibilities, and the horizontal ecological compensation mechanism has not yet been perfected. Based on the emergy ecological footprint model, the ecological compensation amount of 90 cities in the Yellow River Basin in 2007-2021 was measured, and the spatiotemporal pattern, regional differences, and dynamic evolution characteristics of distribution were explored by combining exploratory spatial data analysis, Dagum Gini coefficient, kernel density estimation, and spatial Markov chain analysis. The results showed that： ① The spatiotemporal pattern of ecological compensation in the Yellow River Basin was different, the ecological compensation amount decreased slightly in the fluctuation and increased from the northwest to southeast gradient in general, and the high-value areas were concentrated in the areas with a superior ecological background or developed economy, and some upstream cities had given up many development opportunities to maintain the ecological security of the Yellow River Basin, however, failed to obtain reasonable ecological compensation. ② A significant positive spatial agglomeration phenomenon was observed in ecological compensation and the overall spatial distribution trend was "cold in the north and hot in the south." The number of low-payment areas and low-compensation areas gradually decreased, showing a gradually shrinking agglomeration layout from the periphery to the center, whereas the number of high-payment areas and high-compensation areas continued to increase and formed a spatial evolution characteristic of the coexistence of scattered distribution and group distribution. ③ The overall regional differences in ecological compensation expanded. The over-variation density was the main source of the overall differences, and the focus on alleviating the intra-regional and inter-regional differences was located in the downstream areas. ④ A slight multi-level differentiation phenomenon was present in ecological compensation. The influence of different neighbors on the horizontal transfer of ecological compensation was quite different. This spatial spillover effect easily formed a "space club convergence" phenomenon within a certain geographical spatial range, but with the expansion of time, the probability of maintaining the original level of ecological compensation in each city decreased, and mobility gradually increased. Therefore, increasing the investment in ecological compensation in different fields, strengthening the coordinated development between regions, and giving full play to the spatial spillover effect are important ways to solve the current spatial imbalance of ecological compensation in the Yellow River Basin.

Spatiotemporal Eolution and Prediction of Ecosystem Service Value in Taihang Mountains Based on MCCA Land Use Scenario Simulation

Ecosystem service value （ESV） is an important indicator related to regional ecological well-being, and understanding its evolution can provide references for regional ecological civilization construction and sustainable development. The Taihang Mountains, an important ecological security barrier in North China, were taken as an example. Based on land use data from 2000 to 2020, this study revealed the changes in land use and ecosystem service value in the Taihang Mountains and conducted multi-scenario simulations of ESV in 2035. Additionally, the land use transfer matrix, improved equivalent factor method, and mixed-cell cellular automata model were used. The results showed that： ① From 2000 to 2020, the main land use types in the Taihang Mountains were cropland, forest land, and grassland. The area of cropland and grassland significantly decreased, whereas the area of forest land and construction land remained stable. The scale of land use transfer was 2.06×104 km2, with a high intensity of transfer from cropland and grassland to other areas, mainly guided by ecological construction. ② The ecosystem service functions in the Taihang Mountains were mainly dominated by regulation services, and the overall ESV showed a stable upward trend, increasing by 1.51×1010 RMB from 2000 to 2020. The spatial distribution of ESV was uneven, and the polarization phenomenon was evident, with high-value areas concentrated in the high-altitude areas in the northern and central-southern parts and low-value areas mostly located in the flat foothills and central plateaus on both sides. They were greatly influenced by human activities. ③ By 2035, compared with that in 2020, the ESV in the Taihang Mountains was projected to increase by 5.37 billion RMB in the natural growth scenario, 4.34 billion RMB in the urban development scenario, and 7.64 billion RMB in the ecological tourism scenario, mainly due to the conversion from cropland and grassland to forest land. The natural growth scenario showed a high intensity of spatial transformation of ESV, the urban development scenario experienced severe ESV loss in cropland, and the ecological tourism scenario showed a significant increase in ESV, which was an effective path for promoting green development in the Taihang Mountains. The research results can provide scientific references for the healthy management and sustainable development of the ecosystem in the Taihang Mountains.

Spatiotemporal evolution and driving factors of ecosystem service value in the Upper Minjiang River of China.

The stability of ecosystems in high mountain canyon areas is poor, and the interaction between humans and the land is complex, making these ecosystems more vulnerable to destruction. Quantitatively assessing the ecosystem service value (ESV) in high mountain canyon areas and revealing its spatiotemporal evolution patterns and driving factors play a crucial role in the construction of regional ecological barriers and the assurance of ecological security. This study focuses on the Upper Minjiang River as the research area, using the InVEST model and the Equivalent Factor Method to estimate ESV. This combination aims to address the inadequacy of the Equivalent Factor Method in reflecting the variability of ESV across different regions, and the sensitivity of the InVEST model to data changes that results in insufficient accuracy of ESV assessments. By harnessing spatial au-tocorrelation and the geodetector method, we unravel the spatiotemporal evolution characteristics and driving factors of ESV. The results show that: (1) From 2000 to 2020, the ESVs estimated by the two estimations increased by 31.28% and 22.47%, respectively, both indicating that the eco-environment quality of the upper Minjiang River has been continuously improved. (2) When Moran's I was greater than 0.5 (p < 0.05), the spatial clustering of "High-High" and "Low-Low" ESV was obvious. It is clear that the ESV varies geographically. High values are primarily found in the study area's center and southern regions, as well as on both banks of the Minjiang River, whereas low values are more common in the region's northern region. (3) Slope and human activity intensity (HAI) are the principal contributors to the spatial differentiation of the ESV, more than 60% of the interaction types between the two factors were classified as dual-factor enhancement. The synergistic reinforcing effects of HAI, slope, elevation, and temperature collectively shape the shifts in ESV spatial distribution. This study offers a novel evaluative lens on the ESV of the Upper Minjiang River area, supplying a sturdy data support for crafting specific ecological preservation and rejuvenation strategies in the coming years.

Mapping Ecological Security Patterns Based on Ecosystem Service Valuation in the Qinling-Daba Mountain Area, China: A Multi-Scenario Study for Development and Conservation Tradeoffs

When focusing on biodiversity maintenance, ecological security pattern (ESP) planning gradually becomes a multi-objective planning strategy for sustainable development; wildlife conservation and ecosystem health maintenance should be balanced with local economic development and people’s livelihood enhancement goals. This study focuses on ESP mapping in the Qinling-Daba Mountain area, which is an ecologically significant and socioeconomically underdeveloped area. The tradeoff between conservation and development is made by varying the area of ecological sources and incorporating ecosystem service tradeoffs into ecological source identification through multi-scenario designation. ESPs under six scenarios were generated based on the minimum resistance model, and the important ecological corridors and strategic points in each scenario were identified and compared. The results show the following: (1) The scenario that sets around 30 percent of the study area as ecological sources maintains the integrity of natural ecosystems and leaves space for food and material supply to residents. (2) In this scenario, the ecological sources are connected by 60 corridors that cross 137 townships with high population densities (&gt;100 people/km2) and intersect with major traffic lines at 71 points. Engineering, management, or education strategies must be taken in these townships or intersections to avoid human–wildlife conflicts. (3) The study area needs to construct both short (north–south) corridors linking proximate ecological sources for species’ daily movement and long (west–east) corridors connecting large and distant sources for species’ seasonal migration and gene flow. (4) The multi-scenario approach turns out to be an effective strategy for ESP planning with considerations for development–conservation tradeoffs.

Assessment of the Spatiotemporal Dynamics of Suitable Habitats for Typical Halophytic Vegetation in China Based on Maxent Model and Landscape Ecology Theory

The widespread and complex formation of saline soils in China significantly affects the sustainable development of regional ecosystems. Intense climate changes and regional land use further exacerbate the uncertainties faced by ecosystems in saline areas. Therefore, studying the distribution characteristics of typical halophytic vegetation under the influence of climate change and human activities, and exploring their potential distribution areas, is crucial for maintaining ecological security in saline regions. This study focuses on Tamarix chinensis, Tamarix austromongolica, and Tamarix leptostachya, integrating geographic information systems, remote sensing, species distribution models, and landscape ecological risk (LER) theories and technologies. An optimized MaxEnt model was established using the ENMeval package, incorporating 143, 173, and 213 distribution records and 13 selected environmental variables to simulate the potential suitable habitats of these three Tamarix species. A quantitative assessment of the spatial characteristics and the area of their potential geographical distribution was conducted. Additionally, a landscape ecological risk assessment (LERA) of the highly suitable habitats of these three Tamarix species was performed using land use data from 1980 to 2020, and the results of the LERA were quantified using the Landscape Risk Index (LERI). The results showed that the suitable areas of Tamarix chinensis, Tamarix austromongolica, and Tamarix leptostachya were 9.09 × 105 km2, 6.03 × 105 km2, and 5.20 × 105 km2, respectively, and that the highly suitable habitats for the three species were concentrated in flat areas such as plains and basins. Tamarix austromongolica faced increasing ecological risk in 27.22% of its highly suitable habitat, concentrated in the northern region, followed by Tamarix chinensis in 16.70% of its area with increasing ecological risk, concentrated in the western and northern highly suitable habitats; Tamarix chinensis was the least affected, with an increase in ecological risk in only 1.38% of its area. This study provides valuable insights for the protection of halophytic vegetation, represented by Tamarix, in the context of China’s national land development.

Construction of an Ecological Security Pattern for the National Park of Hainan Tropical Rainforest on the Basis of the Importance of the Function and Sensitivity of Its Ecosystem Services

The National Park of Hainan Tropical Rainforest (NPHTR) plays the crucial role of an ecological barrier for Hainan Island. It also serves as a valuable repository of tropical biological heritage for the world. The scientific establishment of an ecological security pattern (ESP) for the NPHTR is therefore essential for ensuring the robustness and stability of this regional ecosystem, safeguarding tropical biodiversity, and promoting sustainable development. This study integrates ecosystem service functions (ESFs) and ecological sensitivity to identify ecological sources (ESs) so that regional integrity is promoted and ecological security is ensured. Ecological corridors (ECs) are established on the basis of a minimum cumulative resistance (MCR) model and circuit theory. We integrate ESs, nodes, and corridors to construct the ESP of the NPHTR. The areas of extreme importance and sensitivity in the NPHTR account for 25.17% and 25.47% of its overall area, respectively, and are predominantly situated in the higher elevations of its eastern and central regions. Further, the ESs are mainly distributed in its western region, specifically Ba Wangling (BWL), Jian Fengling (JFL), and Ying Geling (YGL), covering an area of 1624.67 km2 (38.06% of the total area) of the NPHTR. After correction, 47 ECs with a distance of 870.9 km have been established, with BWL and YGL serving as the core areas. The ecological pinch- and barrier points in the NPHTR cover areas of 11.49 km2 and 16.35 km2, respectively, primarily consisting of man-made landscapes such as farmlands and buildings. These areas are significantly disturbed by human activities. The NPHTR has an ESP of “one screen, one district, three belts, multiple points, and multiple corridors”. BWL and YGL, which contain numerous sources and corridors, are crucial ecological functional zones. To ensure the horizontal connectivity of rare wildlife, such as of Nomascus hainanus and Cervus eldii hainanus, the NPHTR should establish buffer or development zones. These findings offer valuable insights for the development and planning of ecological civilization on Hainan Island, as well as for the establishment and management of the ESP of other national parks and nature reserves.

Combination of the degrading bacterium Bacillus cereus MZ-1 and corn straw biochar enhanced the removal of imazethapyr from water solutions

Long residual herbicide imazethapyr has caused a serious threat to subsequent sensitive crop plants and ecological security. Efficient immobilized microorganism technology offers a sustainable solution for remediating pesticides contamination. In this study, three corn straw biochars produced at 300℃, 500℃, and 700℃ were used as carriers to immobilize the imazethapyr degrading strain Bacillus cereus MZ-1, aiming to efficiently remove imazethapyr from the water environment. Response surface methodology was employed to optimize the best immobilization conditions based on the efficiency of imazethapyr removal. The results indicate that the biochar produced at 500 ℃ was the most effective carrier for immobilization, despite having a lower imazethapyr removal capacity compared to the biochar produced at 700 ℃. Additionally, the optimal strain addition amount was a suspension of strain MZ-1 (OD600=1) in a 3.5-fold biochar solution, and the best immobilized time was 18 h. The prepared immobilized MZ-1 achieved a maximum imazethapyr removal efficiency of 79.85 %. Moreover, the immobilized MZ-1 demonstrated enhanced detoxification efficacy against imazethapyr-induced harm in sensitive oilseed rape crops, surpassing the effects of using MZ-1 or biochar alone. Results of this work suggests biochar immobilized degradation strain MZ-1 is a highly effective in-situ remediation strategy for bioremediation of imazethapyr contamination.

Coupling coordination analysis and spatiotemporal heterogeneity between urban land green use efficiency and ecosystem services in Yangtze River Economic Belt, China

Rapid urbanization has resulted in the conversion of different land types, leading to a serious disruption of the balance of ecosystems, and the contradiction between land use and ecological security becomes increasingly severe. As a key factor affecting ecosystem services (ESs), improving the urban land green use efficiency (ULGUE) can effectively mitigate the decline in the ecosystem services function. This study tried to verify the profound impact of land use on ESs by measuring the coupling coordination degree (CCD) between ULGUE and ESs from the perspective of coupling coordination. However, the traditional CCD model suffers from volatility and non-comparable confidence levels in results. For this background, this study adopted the improved CCD model to measure the association between ULGUE and ESs in the Yangtze River Economic Belt (YREB). Also, a comprehensive spatial evolution of the CCD was further explored. The main conclusions are as follows: (a) The overall level of ULGUE in YREB showed an increasing trend with the distribution of ULGUE in most cities ranging from 0.71 to 1.00, showing a higher level overall and the spatial distribution character of “small aggregation, large distribution”; (b) The ESs of YREB from 2005 to 2020 demonstrated a decreasing trend and majority of cities’ current ecological protection efforts are lagging behind the extent of ecosystem damage caused by human activities; (c) The overall average CCD of YREB was largely at basically balanced level and the average CCD change ranges from 0.38 to 0.45 between 2005 and 2020, but the overall CCD had a strong spatial correlation strength. (4) To some extent, the improved CCD model solved the problems of volatility and credibility based on the traditional CCD results, which have strong rationality and scientific validity. Identifying the coupling and coordination characteristics and mechanisms can effectively provide theoretical support for the sustainable development of watersheds.

Do China's ecological civilization advance demonstration zones inhibit fisheries' carbon emission intensity? A quasi-natural experiment using double machine learning and spatial difference-in-differences

China's National Ecological Civilization Demonstration Zone (NECDZ) policy has a significant role in ensuring national ecological security, and it is essential to investigate how the NECDZ policy affects the carbon emissions intensity of fisheries (CEIF) to advance China's commitment to reducing carbon emissions. This study evaluates the CEIF in 30 Chinese provinces from 2007 to 2021 using ecological civilization demonstration areas as a quasi-natural experiment and double machine learning (DML)to examine the impact and internal mechanisms of NECDZ implementation on the CEIF. We also explore spatial spillover effects using a spatial difference-in-differences approach. The results reveal that NECDZ implementation has a significantly negative impact on the CEIF and this effect continues over time. NECDZ policy potentially affects the CEIF through technology development, industrial structure improvement, and reduced energy consumption. Further investigation reveals that NECDZ implementation has spillover effects and inhibits the CEIF in surrounding regions. Therefore, it is essential to focus on developing the NECDZ policy to enhance fisheries' industrial structure, encourage low-carbon innovation in fishery technologies, and increase energy consumption efficiency. This could be supported by facilitating exchanges and cooperation with other areas, considering regional disparities, and assigning common but distinct responsibility for reducing the CEIF.

Quantification of uncertainty in short-term tropospheric column density risks for a wide range of carbon monoxide

The short-term risks associated with atmospheric trace gases, particularly carbon monoxide (CO), are critical for ecological security and human health. Traditional statistical methods, which still dominate the assessment of these risks, limit the potential for enhanced accuracy and reliability. This study evaluates the performance of traditional models (ARIMA), machine learning models (LightGBM, ConvLSTM2D), and optimized machine learning solutions (Bayes residual optimization ConvLSTM2D LightGBM, Bayes_CL) in predicting Sentinel 5P columnar CO levels. This study findings demonstrate that machine learning models and their optimized versions significantly outperform traditional ARIMA models in cross-validation (CV), visualization, and overall prediction performance. Notably, machine learning model based on Bayes and residual optimization (Bayes_CL) achieved the highest CV score (Bayes_CL R2 = 0.8, LightGBM R2 = 0.79, ConvLSTM2D R2 = 0.75, ARIMA R2 = 0.61), along with superior visualization and other metrics. Using Bayes_CL, we effectively quantified a 2.4% increase in columnar CO levels in mainland China in the second half of 2023, following the complete lifting of COVID-19 lockdowns. This study confirms that machine learning models can effectively replace traditional methods for short-term risk assessment of Sentinel 5P columnar CO. This transition holds significant implications for policy formulation, greenhouse effect assessment, and population health risk evaluation, especially in uncertain situations where human activities are severely disrupted, thereby affecting environmental safety.

A Gaussian interval type-2 fuzzy characterization method based on heterogeneous big data and its application in forest ecological assessment

The under-forest economy is a new agricultural and forestry production mode. It can improve the utilization efficiency of forest land and make full use of forest resources, forest space, and forest ecological environment through different forms of industries such as understory planting and breeding. The under-forest economy has important ecological and economic benefits, significant to rural revitalization and industrial structure adjustment. It has been widely discussed by people in recent years. The forest ecological security level is a core factor to be considered in selecting sites for the under-forest economy. In practice, some forest ecological security evaluation indexes usually show heterogeneous forms. To comprehensively evaluate the level of forest ecological security, this study constructs a new multi-indicator fuzzy evaluation method based on heterogeneous big data. Firstly, a new linguistic scale function is defined to realize the consistent conversion of multi-granularity linguistic information. A Gaussian interval type-2 fuzzy aggregation formula for heterogeneous large-scale data is proposed. This formula is used to describe the differences in evaluation information between individuals caused by different knowledge backgrounds of evaluators. Then, the Gaussian interval type-2 fuzzy cross-entropy is defined, and it is verified to satisfy the excellent properties. This cross-entropy is applied to determine the objective weights of evaluation indexes. Considering the risk-averse psychology of experts and combining the prospect theory, the MULTIMOORA method in the Gaussian interval type-2 fuzzy environment is proposed. Finally, the applicability of the constructed Gaussian interval type-2 fuzzy comprehensive evaluation method (GIT2FCE) is verified through a case study conducted on the site selection of the under-forest economic industry.

Diagnosis of ecological security and the spatial heterogeneity of its driving factors in the mining-impacted watershed, based on ecosystem health-risk-services framework

A comprehensive diagnosis of ecological security (ES) and its driving mechanisms in the watershed under mining influence is essential for the conservation and restoration of watershed ecosystems. Few studies have comprehensively evaluated ES by considering the condition of the ecosystem itself, the ecological function it provides, and the risk it faces. Therefore, by innovatively synthesizing ecosystem health (EH), ecological risk (ER), and ecosystem services (ESs), an ES evaluation framework based on EH-ER-ESs was constructed. Based on quantifying the ES of a typical watershed with mines clustered in China’s Northern Sand Prevention Belt, a spatial correlation analysis was used to elucidate the spatial differentiation characteristic of ES and verify the necessity of the evaluation framework. The driving mechanism of ES and the spatial heterogeneity of its key driving factors were explored using the Geodetector model and the geographically-weighted regression model. The results show that (1) ES was generally medium-security, and very low-security areas (8.16%) were mainly concentrated in the eastern mining aggregation areas. (2) ES showed high-high and low-low spatial clusters. Overall, ES was positively correlated with EH and ESs, while negatively correlated with ER, but there were individual cases of “high health-low security” and “high services-low security”, and combining EH, ER, and ESs to diagnose ES comprehensively was necessary. (3) Drought index, vegetation cover, distance from mining land, population density, and CONTAG were the key driving factors of ES. The explanatory power of factor interactions was higher than that of single factors. The impact of driving factors showed significant spatial heterogeneity, with the effects of mine agglomeration on ES primarily concentrated in the east. The EH-ER-ESs framework can be used for ES evaluation in other ecosystems, and the findings provide important guidance for conducting integrated watershed management.

Unraveling the synergistic interplay of sulfur and wheat straw in heterotrophic-autotrophic denitrification for sustainable groundwater nitrate remediation

Nitrate pollution in groundwater is a global environmental issue that poses significant threats to human health and ecological security. This study focuses on elucidating the mechanisms of heterotrophic-autotrophic cooperative denitrification (HAD) by employing wheat straw and elemental sulfur as electron donors in varying proportions. The research initially underscores that heterotrophic denitrification (HD) accelerates the denitrification process due to its high-energy metabolism. However, as readily degradable organic matter diminished, reliance on more complex substrates such as lignocellulose posed a challenge to HD. This marks a pivotal transition towards autotrophic denitrification (AD), which, despite a slower initial rate, exhibits a more sustained denitrification performance. A low proportion of heterotrophic denitrification layer (e.g., 3:1) at the bottom facilitating efficient and sustainable denitrification. HD is capable of simultaneous removal of nitrates and nitrites, whereas AD demonstrates a higher affinity for nitrates, with nitrite accumulation reaching 100% at high influent nitrate concentrations (100 mg/L). HD not only provides the necessary alkaline environment for AD but also reduces sulfate production, whereas AD utilizes the residual organic carbon and ammonia produced by HD. The heterotrophic layer is characterized by a diverse community, whereas the autotrophic layer is predominantly composed of Thiobacillus. By delineating the interactive mechanisms and characteristics of HAD, this study highlights the importance of balancing heterotrophic and autotrophic activities for the effective remediation of groundwater nitrates.

Exploring urban and agricultural land use planning

Socio-economic development has accelerated urban expansion, leading to the encroachment of urban space into agricultural space land and seriously undermining the stability of ecosystems. Scientifically optimizing the layout of urban-agricultural space can guarantee China's food security, promote urban development and maintain ecological stability. In this study, we focused on the rapidly growing city of Nankang. We used land, ecological and geographic location data to calculate land suitability, predicted future urban space through the GeoSOS-FLUS model, and finally optimized the agricultural-urban space conflict. The results show that: the areas of farmland with quality evaluation results for grades 1-4 were 7783.13 hm2, 9411.01 hm2, 8738.99 hm2 and 3032.73 hm2, and the areas suitable for construction, more suitable for construction, unsuitable for construction and prohibited from construction accounted for 12.19%, 16.23%, 41.34% and 30.24%, respectively. Combining the FLUS model with the land suitability evaluation results, we found that there is a conflict area of 1841.96 hm2 in the delineation scheme. Adjusting their layout according to the principle of conflict coordination, the optimized area of agricultural-urban space is 28429.34 hm2 and 8968.23 hm2 respectively, accounting for 16.32% and 5.15% of the study area. The result of spatial contradiction optimization satisfies the balance between production and residential space, promotes urban development, protects ecological security, and can provide scientific reference for regional urban ecological environment construction.