Study on the spatial-temporal evolution characteristics, patterns, and driving mechanisms of ecological environment of the Ecological Security Barriers on China's Land Borders

The national ecological security barrier holds a pivotal position within the framework of the national strategy for ecological conservation and restoration. Concurrently, the border areas, as a focal point of the national homeland security strategy, have garnered considerable attention. These two concepts collectively present a profound implication for upholding national security. To this end, monitoring the ecological changes of the ecological security barriers, and exploring the driving mechanisms of such changes constitutes the foremost imperative in comprehending and advancing the national ecological security barrier theory. However, current research has yet to extend the application of ecological security barrier theory to the national scale.This paper integrates the theory of ecological security barrier with China's land border cities belt, constructing the Ecological Security Barrier of China's Land Borders (ESBCLB). Then, this paper produces a Remote Sensing Ecological Index (RSEI) products for the early 21st century (2000-2021, 21 periods) by using Google Earth Engine (GEE). Based on pixel scale calculations and classifications, the spatial-temporal evolution characteristics and patterns of the ESBCLB are objectively obtained. Finally, this paper employs the Geographically and Temporally Weighted Regression (GTWR) model to explore driving mechanisms of six primary indicators, namely, economy, human activity, transportation, topography, hydrography and climate, which may have impacts on the ecological environment of the ESBCLB. Through analysis, this paper concludes that (1) On the whole, the ecological environment changes within the ESBCLB are not substantial, with regions where the ecological environment remains unchanged accounting for 73.78%. Among the regions where ecological changes have occurred, those north of the Aksu Prefecture and Kizilsu Kirgiz Autonomous Prefecture exhibit a predominantly improved trend, while those to the south show a degraded trend. (2) Among ten evolution patterns identified based on the evolution characteristics, the primary evolution patterns for the ESBCLB are pattern of no significant change and persistence as well as pattern of no significant change and counter persistence. Apart from these, pattern of very significant better and persistence and pattern of significant better and persistence dominate the majority of cases; (3) Overall, economy, human activity, transportation, topography, hydrography, and climate exhibit spatial heterogeneity in driving mechanisms of the RSEI. Among them, human activity, topography, hydrography, and climate show positive correlations with the RSEI of the ESBCLB. While economy and transportation show negative correlations. The significance of this paper lies in that it provides a scientific basis and theoretical support for the specific application of national ecological security barrier and the study of the evolution of regional ecological environment.