At present, the contradiction of unbalanced and inadequate development between urban and rural areas in China has become prominent. It is of great significance to accurately judge and understand the characteristics and changes of this contradiction for coordinating urban-rural integrated development and promoting the land use equity between urban and rural areas. Based on the perspective of urban and rural comparison, this paper established the theoretical analysis framework of land use relative equity, explored the temporal and spatial characteristics, obstacle factors and optimization paths of land use equity between urban and rural areas by using data from 291 municipal units in China from 2004 to 2021. The results showed that: (1) From 2004 to 2021, the comprehensive index of land use equity between urban and rural areas in China showed a trend of "first decreasing and then increasing", with spatial characteristics of "global dispersion and local agglomeration" and gradually showing a trend of "economic dependence". (2) The length of LISA time path from 2004 to 2021 showed that the spatial structure of land use equity between urban and rural areas fluctuated greatly in some regions, the curvature indicated that land use equity between urban and rural areas had strong temporal and spatial dependence and regional differences, and the moving direction revealed that the change of land use equity between urban and rural areas showed strong spatial integration. The temporal and spatial transition of LISA reflected that the land use equity between urban and rural areas was both inert and active. (3) From 2004 to 2021, due to the rapid urbanization and industrialization, the widening income gap between urban and rural residents, the unbalanced supply of public services, and the expansion of urban areas and the decline of rural areas in industrial restructuring are the key factors leading to the land use inequity between urban and rural areas. (4) The optimization of land use equity between urban and rural areas should take the balanced flow of resources and elements and the complementarity of structural and functional advantages as the key breakthrough points, adopt the path of "establishing a sound system and optimizing the mechanisms, filling in the gaps and strengthening the weaknesses", and promote the free flow and equal exchange of resources and elements in the multi-decision-making process, multi-stakeholder and multi-scale space.
Driven by the frontier of human-land system coupling science and the imperative for cultivated land protection and efficient use, it is critical to explore the dynamics and response mechanisms of cultivated land-use resilience in the context of China's rapid socioeconomic transition, based on the fundamental attribute of multifunctionality. Following the logical thread of environmental disturbance-agricultural production mode transition-change in cultivated land-use multifunction-response of cultivated land-use resilience, this study presents a research framework, curves, and a quantitative model of cultivated land-use resilience. Then, the changes and their response mechanisms of cultivated land-use resilience have been measured at the provincial level between 1988 and 2017. Results show that cultivated land-use multifunction exhibited a change pattern characterized as "two large segments nested within four small segments" between 1988 and 2017. From 1988-2003 to 2003-2017, the value of cultivated land-use resilience increased by 18.52% at the national level, while the value of the resilience rose from a range of 0.54-0.87 to 0.56-0.96 at the provincial level. Regions with high resilience value shifted from the southwest and northwest to the central and eastern China, forming a concentrated high-value area in the Huang-Huai-Hai region (excluding Beijing and Tianjin) and adjacent central provinces. The response mechanism of cultivated land-use resilience behaves as cascading effects of interactions among socioeconomic and public policy factors, which influence the resilience following the logical thread of "increasing population density, economic development, and implementation of cultivated land protection policies-adjustment of cultivated land-use objectives-market-induced substitution of agricultural production-transition from specialized to integrated production in agriculture-coordinated development of cultivated land-use functions-enhancement of cultivated land-use resilience". The resilience change of cultivated land utilization systems is primarily driven by two key mechanisms: (1) the market-induced substitution mechanism of agricultural production driven by population pressure, and (2) the transition mechanism of agricultural production patterns under economic-policy synergistic environments. Furthermore, this study explores policy implications, theoretical frameworks, and methodological approaches for enhancing the resilience of cultivated land utilization systems.
Urban-rural integration is a key path to implement the new-type urbanization and rural revitalization strategy, and the cultivated land transfer market can promote the flow and integration of factors such as land and labor between urban and rural areas, which is of great significance to enhance urban-rural production efficiency and promote high-quality development. This study focuses on the cultivated land transfer market at the county scale in China from 2009 to 2022, analyzes the spatial distribution pattern and clustering characteristics of the cultivated land transfer marketization and the cultivated land transfer rate in different regions, and explores the factors affecting the marketization and the transfer rate from the perspective of urban-rural integration by using the Logit and the Tobit models. The results show that: (1) the markets of the cultivated land transfer are more concentrated in the eastern and central regions of China, and gradually spreads from north to south, forming several market-oriented clustering areas. (2) The urban-rural integration promotes the marketization of cultivated land transfer and the enhancement of the transfer rate. The cultivated land transfer market has more development potential in areas with a higher proportion of added value of non-agricultural industries and a smaller urban-rural income gap. Terrain, population and cultivated land resource endowment affect the development of the cultivated land transfer market, especially in plain areas. (3) There are differences in the influencing factors of different geographic regions. Urban-rural integration promotes both transfer marketization and enhancement of the transfer rate in the eastern and western regions, and in the northeastern region it mainly enhances the transfer rate, and the impact on the central region is not obvious. In conclusion, the development of cultivated land transfer market is conducive to optimizing the allocation of cultivated land resources and improving the efficiency of agricultural production, so the governments at all levels should strengthen the institutional and financial support of cultivated land transfer to stimulate the market vitality, promoting agricultural modernization and urban-rural integration.
The construction of cropland photovoltaic plants (CPVP) and the evaluation of their integrated effects represent a critical scientific issue at the intersection of energy transition, food security, and rural economic development. By integrating remote sensing data with field surveys, we systematically analyze the spatio-temporal evolution of CPVP in China from 2010 to 2020. By comparing these facilities with conventional cropland both spatially, alongside similar areas, and temporally, before installation, we assess the impact of CPVP on cropland productivity. Results indicate that: (1) The total construction area of CPVP surged from 0.6 km² in 2010 to 735.3 km² in 2020, marking an approximately 1200-fold increase over the decade. Spatially, these installations are predominantly concentrated in the northeastern part of eastern China, delineated by the Hu Line. (2) CPVP installation has led to an average productivity decrease of 47 gC m-2 a-1, down 3.7%. Longitudinal data show that comparison of time scales, the cropland productivity can recover or even exceed the pre-construction levels after the installation of photovoltaic facilities. (3) The negative impact is more pronounced on high-productivity cropland, while dryland and cropland devoted to maize and wheat are less affected. (4) Optimal facility size, density, and regular shape can mitigate the negative impacts on cropland productivity. These findings alleviate concerns about the adverse effects of CPVP on food security, suggesting that such effects are minimal and manageable. The findings provide academic support for the spatial planning of photovoltaic infrastructure and offer the integrated advancement for energy transition, food security, and rural revitalization.
Optimizing crop selection and spatial configuration of cultivated land in southern China's arid zones is essential for efficient soil-water resource allocation and food security. This paper take the Hengyang-Shaoyang Arid Corridor as a case study, adhering to the "water-determined land" principle. Through analysis of data from meteorological stations, land-use data, and socioeconomic data, we quantify water supply-demand relationships across planting scenarios. This study integrates economic/ecological/water-saving benefits with food-security policies, addressing spatial objectives including irrigation requirements and land compactness for optimal agricultural water management. The results show that: (1) Spatiotemporal variations in water supply-demand create significant crop-specific water condition disparities. Double/single-season rice show acute supply-demand conflicts, whereas drought-resistant crops exhibit milder challenges. (2) Balancing water-saving development scenarios with "water-soil-grain" constraints is critical for implementing water-determined land use and advancing green agricultural transitions. Optimization trends indicate reducing single-season rice acreage and drought-crop proportions. With set water-saving goals and optimized control, cultivated land production benefits can be significantly enhanced, with economic scenarios showing a 6.83% increase in crop economic benefits and improvements in food security, total crop yield, and economic benefits. (3) Exploring cultivated land optimization from the perspective of crop cultivation supports crop rotation, fallow periods, and rational resource allocation. Optimized planting areas correspond to high-water-suitability zones with compact field configurations, enabling identification of optimal cultivation patterns. Different development scenarios classify local planting patterns into stable production zones, rotation zones, advantage production zones, and adaptive production zones, offering a path for optimizing both quantity structure and spatial layout. This research establishes a foundation for promoting "three-in-one" protection systems and agricultural transformation of cultivated land in Hunan province.
The specialty planting industry plays a key role in rural revitalization. It is highly significant to explore how this industry promotes rural revitalization. Such exploration can drive rural development, boost farmers' incomes, achieve rural prosperity, and narrow the urban-rural gap. Using Fengjie county's navel orange industry and its 11 typical townships in the Three Gorges Reservoir Area as a case study, we applied three methods: landscape pattern index analysis, moving-window analysis, and coupling coordination degree calculation. We reveal how specialty planting industry drives land use evolution and rural revitalization. The results show that: (1) Fengjie's specialty plantations concentrate at 200-600 m elevations and 20°-30° slopes, expanding from river valleys to lower altitudes, forming valley-slope dominant landscapes. (2) Navel orange orchards, forest land, and abandoned land increased while croplands and grasslands decreased. Study area shifted from cultivation to orchard-based land use, in 2000-2020. (3) The coupling coordination degree between specialty planting, landscape transformation, and rural revitalization improved from basic to moderate coordination, with dysfunctional townships decreasing. (4) The natural conditions, socioeconomic factors, and policies drove this development, with government and farmer demands being fundamental drivers, in 2000-2020. The research framework and its results offer methodological references for similar regions.
Although there are many lakeside cities in China, the localized research on Sustainable Development Goals (SDGs) for these cities has not been carried out systematically. Based on the development characteristics of lakeside cities and the new development philosophy of innovation, coordination, greenness, openness, and sharing, this paper analyzes the SDGs in a systematic way and constructs an evaluation system with 15 SDGs and 75 specific indicators in combination with the China National Program for the Implementation of the 2030 Agenda for Sustainable Development. The system focuses on the core ecological indicators of lakes, such as lake water transparency and watershed water conservation, as well as the key parameters of human-lake interactions, such as industrial economy, industrial ecology, and land use patterns, to quantify the core functions of lakes in climate regulation, economic support, and ecological balance. The study adopts game theory fused with subjective and objective empowerment methods to construct a sustainable development evaluation model and conducts empirical analysis using Kunming city, Yuxi city and Dali prefecture in Yunnan province as case studies. The results show that when the number of single-dimension indicators of the evaluation model is about 5, the stability of the model no longer increases significantly with further increase in indicators, and the optimal balance between the number of indicators and model stability can be achieved with reliable evaluation effectiveness; indicators with fixed values have a significant impact on the model's evaluation results and require focused calibration. From 2008 to 2021, the overall sustainable development level of the three case regions showed an upward trend, with synergistic effects among indicators outweighing trade-off effects; however, spatial heterogeneity was significant, which reflected the influence of differences in resource endowment, development foundation, and policy implementation on sustainable development paths. This paper provides a theoretical framework and methodological support for the sustainable development of lakeside cities, as well as a scientific path for quantitatively assessing the effectiveness of the practice of the new development philosophy, which has an important reference value for the localization of SDGs in lakeside areas around the world.
The oceans are strategically important for high-quality development. This study aimed to empirically analyze the driving degree of each factor type of the three main marine economic circles on the marine economic growth using the extended Cobb-Douglas production function, which contains elements, structures, institutions, and other factors. A spatial panel data model was used to test the working method of spatial convergence. The results show that (1) the factors influencing marine economic growth are ordered by their driving degree as follows: marine economic capital stock > sea-related human capital > marine technology capital > marine industrial structure > marine innovation and research capital, whereas institutional change has a negative effect. Among these, marine economic capital stock has the most significant driving effect, contributing approximately 4.29%, 4.35%, and 4.59% of the growth of marine economies in the northern, eastern, and southern marine economic circles, respectively. Currently, China's marine economy relies on capital for growth. There is substantial spatial dependence on marine economic growth in coastal areas. (2) The factors affecting the gap in regional marine economic growth include marine economic capital stock, marine innovation and research capital, marine technology capital, institutional change, and marine industry structure. Among these, marine economic capital stock is the most prominent, contributing 33.47%, 31.41%, and 30.92% to the gaps between the northern and eastern, northern, and southern, and eastern and southern marine economic circles, respectively. Furthermore, sea-related human capital can moderate the growth gap in the marine economy. (3) Convergence analysis shows that σ-convergence is more significant in the eastern marine economic circle, whereas the northern and southern marine economic circles are not obvious. In terms of β-convergence, the three major marine economic circles have significant absolute β and conditional β-convergence characteristics. The order of convergence speed is "eastern > southern > northern" and the conditional β-convergence speed is higher than that of the absolute β-convergence. Although the spatial gap narrows gradually, it cannot be eliminated in the short term.
Gridded meteorological data obtained by spatial interpolation play a crucial role in ecological, hydrological, and land surface process models. The key challenge in current spatial interpolation is to effectively match the physical behavior of meteorological variables with the mechanistic properties of interpolation methods to maximize accuracy. This study constructed 12 interpolation models using thin plate spline (TPS) and random forest (RF) with six combinations of covariates including elevation, slope, aspect, and reanalysis data. These models were applied to daily interpolation and comparative analysis of eight meteorological variables (maximum temperature, minimum temperature, precipitation, skin temperature, wind speed, relative humidity, surface pressure, and sunshine duration) across China from 2000 to 2020. The results indicated that: (1) TPS with elevation as a covariate was optimal for maximum temperature, minimum temperature, skin temperature, relative humidity, and sunshine duration; RF with elevation as a covariate performed best for precipitation and wind speed; RF with elevation, slope, and aspect as covariates was the best for surface pressure. (2) Minimum temperature and skin temperature were better interpolated using TPS with elevation, slope, and aspect in winter, while surface pressure was better interpolated using TPS with elevation in spring. The optimal interpolation methods for the other variables remained consistent across seasons. (3) The interpolation accuracy of maximum temperature showed an interval-dependent preference, with RF performing better for daily maximum temperature below 15 °C, whereas TPS was more accurate above this threshold.
Understanding the spatiotemporal dynamics and climatic consequences of long-term urbanization in arid and semi-arid regions is essential for sustainable development and improving human living environments. This study integrates historical documents and satellite imagery to reconstruct the urban expansion of the Hohhot-Baotou-Ordos (HBO) region from the 1900s to 2024. It also quantitatively evaluates the relative contribution of urbanization to regional warming since 1951, using meteorological observations and reanalysis data. Results show that the urban area in the HBO region expanded by approximately 93.73 times from the 1900s to 2024, with accelerated growth and prominent expansion in Hohhot. Concurrently, urban morphology showed reduced compactness and increased fractal dimension, indicating more complex urban boundaries alongside substantial regional socioeconomic growth. Between 1951 and 2023, urbanization predominantly influenced the regional climate by increasing minimum temperatures (urbanization-induced trend [OMR]: +0.44 ℃/decade; contribution rate: 63.17%) and narrowing the diurnal temperature range (observed trend: -0.36 ℃/decade; OMR: -0.41 ℃/decade). In contrast, the impact on maximum temperatures was minimal (OMR: +0.03 ℃/decade), with urban maximum temperatures consistently lower than those in adjacent suburban areas. This study highlights the climatic consequences arising from century-long urbanization in a representative dryland urban agglomeration, which provides a robust foundation for future investigations into urban-climate interactions in arid and semi-arid regions.
Based on continuous monitoring of precipitation amount and meteorological factors and periodic collection of plant samples in the Poyang Lake plain from June 2017 to September 2020, this study investigated the spatiotemporal characteristics and formation mechanisms of Lake-effect precipitation events using a three-component isotopic mixing model and ERA5 reanalysis data. The contribution of Poyang Lake to regional precipitation was quantitatively evaluated. Results showed that: (1) The region exhibited a humid climate with weak below-cloud evaporation. Stable water isotopic compositions in precipitation were enriched in spring and winter but depleted in summer and autumn. The total amount of precipitation and frequency of extreme precipitation events decreased from northwest to southeast. (2) A total of 148 lake-effect precipitation events were observed, characterized by the higher frequency in winter than in summer. These events were classified into two spatial patterns of multi-core rainband and single-core vortex. (3) Lake-atmosphere interactions showed seasonal variations that intensive lake evaporation increased boundary-layer humidity saturation and thus intensified convective activity during spring and summer. By contrast, the elevated thermal gradients enhanced atmospheric instability and thus jointly promoted precipitation during autumn and winter. (4) The evaporative contribution rate of Poyang Lake to lakeside precipitation ranged from 1.65% to 37.93%. In winter, the coupling effect of cold-dry air masses and topographic uplift resulted in the peak contribution rate of 37.93% observed at Guling town. However, the evaporative contribution rate in the plain area remained below 15% characterized by low values in the west and high values in the east during summer, which was associated with the dilution effect of deep lake water levels and marine moisture. These findings provide a theoretical basis for optimizing precipitation forecasting models and flood disaster warnings in the Poyang lake plain region.
Runoff is a critical component of the water cycle. Traditional methods for measuring runoff are heavily influenced by the placement of monitoring stations, while physical runoff models require long-term, high-quality data series encompassing multiple elements. The use of remote images to invert the flow can get rid of the influence of natural, social and other factors, providing a new means for runoff simulation. At present, the relationship between remote sensing indicators and discharge is yet to be further explored. This study constructs seven optical remote sensing indicators using Sentinel-2 images (2017-2023), focusing on the river reach near the Qilijie hydrological station in the Jianxi River Basin. Through comparative analysis of runoff estimation results from three methodologies, the Calibration/Measurement (C/M) method, multiple linear regression, and random forest, across 180 pixel sets, the following findings were revealed: The accuracy of the C/M method is highly sensitive to the selection of M pixels, highlighting the necessity of choosing M pixels responsive to various flow magnitudes for reliable estimations. Key indicators, namely the CM signal, Normalized Difference Water Index (NDWI), Normalized Difference Vegetation Index (NDVI), Bare Soil Index (BSI), and Turbid Water Index (TWI), effectively capture key river characteristics such as water extent, vegetation cover, soil conditions, and water turbidity. Compared with the traditional C/M method, the multiple linear regression and random forest models that incorporate multi-source remote sensing indicators effectively mitigate the influence of M pixel scale and spatial distribution on runoff estimation. Among the three methods, the random forest algorithm demonstrates superior accuracy in runoff estimation, particularly for high-flow conditions. The findings of this study provide a scientific reference for river runoff simulation and offer valuable insights for the intelligent monitoring of river systems, helping to improve the efficiency and accuracy of water resource management.
As global climate change continues, the frequency and intensity of compound dry-heat events have significantly increased on both global and regional scales, exerting notable impacts on vegetation physiological activities. However, current studies mostly focus on the impacts of individual drought or heat events on vegetation while often neglecting the stress from compound dry-heat events. This study utilized monthly Standardized Precipitation Index (SPI), Standardized Temperature Index (STI), Compound Drought and Heat Index (CDHI), and Normalized Difference Vegetation Index (NDVI) from 1982 to 2015 to investigate the impacts and time-lag effects of different climatic conditions on vegetation during the growing season. The results revealed the following: (1) Compound dry-heat conditions generally promote vegetation growth at higher latitudes but suppresses it at mid-to-low latitudes. Additionally, as humidity increases, the effect of compound dry-heat conditions on vegetation shifts from suppression to promotion. Regarding different vegetation types, compound dry-heat conditions generally inhibit herbaceous plants while promoting woody plants. (2) The average lagged time of compound dry-heat and heat conditions events on vegetation is relatively short (1.1±1.8 and 1.1±1.9 months, respectively), whereas drought conditions exhibit a longer lagged time (2.8±2.1 months). The lagged time of all events varies with humidity levels. However, in different extreme climate events, the lagged time of compound dry-heat events is longer and comparable to that of drought events, while heat events have a relatively short lagged time, with no significant variation across different climate zones. In summary, this study comprehensively analyzes the impact of different climatic conditions on vegetation and their time-lag effects, providing a scientific basis for understanding vegetation dynamics under climate change.
The recently proposed Species-Area-Isolation hypothesis for global species richness distribution suggests that climate and climatic geography (i.e., the spatial distribution of climatic conditions, including climatic area and climatic isolation) can explain 90% of global species richness patterns, with larger and more isolated climatic conditions typically supporting higher species richness. However, it remains unclear whether this global pattern applies to regional species richness distributions. This study uses the Qinghai-Xizang Plateau, a unique geographic and climatic region, as a case study, employs generalized additive models (GAMs) based on climatic space to investigate the influence of climate and climatic geography on species richness patterns on the Qinghai-Xizang Plateau. The results indicate that: (1) The Species-Area-Isolation hypothesis applies to species richness distribution on the Qinghai-Xizang Plateau, suggesting its broader applicability. Considering climate and its geographic attributes, the model explains 85% of the animal species richness distribution and 80% of the plant species richness distribution on the Qinghai-Xizang Plateau. (2) Larger and moderately isolated climatic conditions support greater species richness, with climatic isolation showing a dual mechanism: moderate isolation (mean Euclidean distance between geographic fragments within climatic units < 500 km) increases richness, while high isolation (> 500 km) reduces it. (3) Climate is the primary factor influencing species richness distribution on the Qinghai-Xizang Plateau, while the independent effect of climatic geography is relatively minor. However, its interaction with climate is significant for certain taxa, explaining 25%, 12%, and 22% of the spatial variation in mammal, amphibian, and plant species richness, respectively. This study provides a regional empirical case for the Species-Area-Isolation hypothesis and offers a theoretical foundation for the conservation of regional species richness.
National Parks play a crucial role in achieving the scientific protection and rational utilization of natural resources. Under risks of climate change and human interference, detecting and monitoring the evolution of national park ecological resilience is a key cornerstone for ensuring regional sustainable development. Based on the construction of the ecological resilience assessment framework of "resistance-adaptivity-resilience" and the method framework of "highlands identification - resistance surface construction - corridor extraction", this study examines the spatio-temporal pattern and network of ecological resilience in Northeast China Tiger and Leopard National Park from 2017 to 2022. The results show that in this national park, each dimension of ecological resilience exhibits varied levels, with resilience dimension showing the highest and most stable level. The spatial heterogeneity of ecological resilience is significant, with the spatial characteristics closely related to geographical environment and human activities. The valley area, which accounts for 13.85% of the total area of the region, is the area with intense human activities and weak ecological resilience. A turning point appeared in the year of 2019, as the construction of national park promoted the change of ecological resilience from active interaction to non-interference adaptation pattern, signaling a prominent positive overall trend. The ecological resilience network system has significant hierarchical characteristics, with a total length of 4603 km of internal ecological corridors, and the radiating effect is gradually increasing. To enhance ecological resilience, it is fundamental to strengthen ecological corridor network connection and improve self-organizing adjustment ability of ecological resilience system to cope with risk interference. Through the construction of ecological resilience assessment framework, this study helps to effectively integrate the spatiotemporal processes of ecological resilience and ecological networks from a theoretical perspective, realize the organic connection of "surface-line" in the study of ecological resilience of national parks, and provide theoretical support for the formulation of ecological environmental development strategies for national parks, so as to promote regional sustainable development and efficient coordination of multiple factors.
