The Karst region is a critical ecological barrier and functional zone in China. Understanding the spatiotemporal evolution of its ecosystem services and its relationship with human activities and climate change is of importance for achieving regional ecological protection and high-quality development. In this study, we used the InVEST model and CASA model to evaluate the spatiotemporal evolution pattern of ecosystem services in the study area from 2000 to 2020. The XGBoost–SHAP model was used to reveal the key indicators and thresholds of changes in major ecosystem services in the study area due to climate change and human activities. The results showed significant land use changes in the study area from 2000 to 2020, particularly the conversion of cropland to construction land, which was more intense in economically developed areas. The areas of forest and grassland increased initially but later decreased due to the impact of human activities and natural factors. Habitat quality (HQ) showed an overall declining trend, while soil retention (SR) and water yield (WY) services exhibited significant interannual variations due to climate change. The changes in rainfall had a particularly notable impact on these services; in years with excessive rainfall, soil erosion intensified, leading to a decline in SR services, whereas in years with moderate rainfall, SR and WY services improved. Carbon fixation (CF) services were enhanced with the expansion of forest areas. The XGBoost–SHAP model further revealed that the effects of rainfall and sunshine duration on ecosystem services were nonlinear, while population density and the proportion of construction land had a significant negative impact on habitat quality and soil retention. The expansion of construction land had the most significant negative impact on habitat quality, whereas the increase in forest land significantly improved carbon fixation and the soil retention capacity. By revealing the mechanisms of the impact of climate change and human activities on ecosystem services, we aimed to provide support for the promotion of ecological conservation and sustainable development strategies in the study area, as well as to provide an important reference for areas with geographic similarities to the study area.

Exploring the spatio-temporal differentiation characteristics and coupling coordination relationship of the composite ecosystem of urban agglomerations is of great significance for promoting the synergistic sustainable development and integration construction of urban agglomerations. This paper is based on LUCC (Land Use and Land Cover Change) data, a DEM (Digital Elevation Model), and temperature, precipitation, and other multi-source data, using the central Yunnan urban agglomeration as an example and constructing a multi-dimensional evaluation index system highlighting development quality and efficiency. The entropy weight method was first used to determine the comprehensive weights to evaluate the regional economic and social development level. Then, the InVEST (Integrated Valuation of Ecosystem Services and Trade-offs) model was used to quantitatively calculate and analyze the spatial and temporal evolution characteristics of the four key ecosystem services, evaluating the spatio-temporal evolution characteristics of the natural subsystem. The coupling coordination model was used to quantitatively analyze the evolution of the coupling coordination of the composite ecosystems in the central Yunnan urban agglomeration during the period of 2010–2020, and to reveal its development law. The results show the following: ➀ During the study period, the socio-economic subsystems in the central Yunnan urban agglomeration demonstrated an outward radiative growth from Kunming City, marked by underdeveloped sub-centers and prevalent low-level areas. ② Trends in ecosystem services varied, with water and soil conservation showing fluctuating increases, carbon sequestration remaining stable, and habitat quality declining. The critically important integrated ecosystem services zone of the natural subsystem is mainly located in the northeastern region and southwestern edge of the study area. ③ In 2020, the coupling coordination degree of the composite ecosystem was 0.9492. This showed that economic, social, and ecological subsystems are highly coupled, with consistent overall development trends and strong interactions. ④ The increase in the degree of harmonization amounted to 7.82%, with lagging subsystems varying in the degree of harmonization in subregions. This study can provide a scientific foundation for the development of policies for the Central Yunnan urban agglomeration, promoting regional sustainable development and optimizing the spatial pattern of the national territory.

With the popularity of spatiotemporal big data applications, more and more sensitive data are generated by users, and the sharing and secure storage of spatiotemporal big data are faced with many challenges. In response to these challenges, the present paper puts forward a new technology called CSSoB (Classified Secure Storage Technology over Blockchain) that leverages blockchain technology to enable classified secure storage of spatiotemporal big data. This paper introduces a twofold approach to tackle challenges associated with spatiotemporal big data. First, the paper proposes a strategy to fragment and distribute space–time big data while enabling both encryption and nonencryption operations based on different data types. The sharing of sensitive data is enabled via smart contract technology. Second, CSSoB’s single-node storage performance was assessed under local and local area network (LAN) conditions, and results indicate that the read performance of CSSoB surpasses its write performance. In addition, read and write performance were observed to increase significantly as the file size increased. Finally, the transactions per second (TPS) of CSSoB and the Hadoop Distributed File System (HDFS) were compared under varying thread numbers. In particular, when the thread number was set to 100, CSSoB demonstrated a TPS improvement of 7.8% in comparison with HDFS. Given the remarkable performance of CSSoB, its adoption can not only enhance storage performance, but also improve storage security to a great extent. Moreover, the fragmentation processing technology employed in this study enables secure storage and rapid data querying while greatly improving spatiotemporal data processing capabilities.

Rapid urbanization has greatly altered urban ecological spaces and habitat quality functions, threatening regional biodiversity and the sustainability of landscapes. Therefore, constructing a comprehensive ecological network and ecological safety patterns is crucial for ecosystem management and regional development. However, simple quantification of ecological networks fails to meet the construction needs of ecological safety patterns, and most studies focus solely on network quantification analysis, thus overlooking the importance of spatial analysis. This study proposes a method of ecological network quantification assessment combined with hotspot analysis and coupled with standard deviational ellipse spatial analysis, which not only satisfies quantitative analysis but also adds spatial analysis methods, facilitating a more comprehensive construction of safety patterns. Firstly, through morphological spatial pattern analysis (MSPA) and landscape connectivity indices, ecological source areas in the main urban area of Kunming were identified, integrating various resistance factors and corrective factors to construct an ecological resistance surface. The minimum cumulative resistance (MCR) model was used to identify potential ecological corridors, and their importance was evaluated using the gravity model, thus establishing an ecological network. Secondly, based on network structure indices, the ecological network was assessed and optimized. On this basis, combined with hotspot analysis coupled with standard deviational ellipse spatial analysis, an ecological safety pattern was constructed. The results show the following: the core area of the study region is 2402.28 km², accounting for 52.07% of the total area; there are 13 ecological source areas, totaling 2102.89 km², accounting for 45.58% of the total area; there are 178 potential ecological corridors, including 15 level-one ecological corridors and 19 level-two ecological corridors; and 103 ecological nodes, 70 “stepping stones”, and 48 ecological breakpoints were identified. In terms of ecological network optimization, six new ecological source areas were added, covering an area of 16.22 km², and the potential ecological corridors increased to 324, including 11 new level two ecological corridors, 51 new ecological nodes, 15 “stepping stones”, and 24 major ecological breakpoints. After optimization, the network closure index (α), network connectivity index (β), and network connectivity rate index (γ) improved by 15.16%, 24.56%, and 17.79%, respectively. Based on the network structure quantitative analysis and hotspot analysis coupled with the standard deviational ellipse’s spatial analysis, a “one axis, two belts, five zones” ecological safety pattern was constructed.

Exploring Land use and climate change-based multi-scenario simulation of ecosystem service trade-offs/synergies is of great importance to regional ecological security and sustainable development. Taking the Central Yunnan Urban Agglomeration (CYUA) as a case study, six different scenarios of LULC-RCP were established to quantitatively assess four key ecosystem services(ESs) of water yield (WY), carbon stock (CS), soil conservation (SR) and habitat quality (HQ) with multiple objective programming and patch-generating land use simulation(MOP-PLUS) and integrated valuation of ecosystem services and tradeoffs (InVEST) models. The ESs were revealed regarding spatio-temporal trade-offs/synergies using Spearman correlation and geographically weighted regression (GWR). It was found that: (1)the ESs in CYUA is characterized with high spatial heterogeneity in 2030; specifically, the distribution of WY and SR was low in the northwestern region and high in the southeastern region, while the distribution of HQ and CS was high in the western region and the periphery, and low in the eastern and central regions; (2) the trade-offs between WY-HQ, and WY-CS, and the synergies between WY-SR, HQ-SR, HQ-CS, HQ-CS, and HQ-SR; (3) under the six different scenarios, the spatial distribution of trade-offs/synergies between the four ESs was consistent: the SR-HQ, SR-CS, and WY-CS showed an overall weak synergistic relationship; the HQ-CS showed an overall weak trade-offs; the HQ-WY, CS-WY showed an overall weak synergistic relationship in the northern and southern areas and an overall weak trade-off relationship in the center. The findings of this study may provide a theoretical foundation for ecosystem management in CYUA and offer technical support for the evaluation of national land space.

Exploring the spatio-temporal differentiation characteristics and coupling coordination relationship of the composite ecosystem of urban agglomerations is of great significance for promoting the synergistic development and integration construction of urban agglomerations. This paper is based on LUCC data, DEM, temperature, precipitation and other multi-source data, taking the central Yunnan urban agglomeration as an example. The entropy weight method is first used to determine the comprehensive weights to evaluate the regional economic and social development level. Then, the InVEST (Integrated Valuation of Ecosystem Services and Trade-offs)model was used to quantitatively calculate and analyze the spatial and temporal evolution characteristics of the four ecosystem services, including water conservation, soil conservation, carbon sequestration services, and habitat quality. The coupling coordination model was used to quantitatively analyze the evolution of the coupling coordination of the composite ecosystems in the central Yunnan urban agglomeration during the period of 2010-2020, and to reveal its development law. The results show the following: ①During the study period, the socio-economic subsystems in central Yunnan urban agglomeration demonstrated an outward radiative growth from Kunming City, marked by underdeveloped sub-centers and prevalent low-level areas. ②Trends in ecosystem services varied, with water and soil conservation showing fluctuating increases, carbon sequestration remaining stable, and habitat quality declining. The integrated ecosystem services critically important zone is mainly located in the northeastern region and southwestern edge of the study area. ③Economic, social and ecological subsystems are highly coupled, with consistent overall development trends and strong interactions. ④The increase in the degree of harmonization amounted to 7.82%, with lagging subsystems varying in different degree of harmonization subregions. The study can provide a scientific basis for urban agglomerations to formulate scientific and reasonable development policies, promoting regional sustainable development and optimizing the spatial pattern of the national territory.