Water conservation areas play an important role in regional ecological security patterns. The Funiu Mountain water conservation area is located in the densely populated central region of China, where human disturbance to the ecosystem is strong and ecosystem services are facing a very serious situation. Identifying and evaluating the factors leading to changes in the ecosystem service value (ESV) of the Funiu Mountain water conservation area can provide scientific guidance for ecological management and sustainable development. Using multi-source data and machine learning methods, our research reveals the characteristics of the spatio-temporal variation in the ESV, constructs a system of ESV influencing factors from the comprehensive perspectives of the natural environment and human activities, and discusses the comprehensive effects of the influencing factors on the Funiu Mountain area from 2000 to 2015. The results are as follows. (1) From 2000 to 2005, the ESV increased 375 million yuan, and from 2005 to 2015, it decreased 154 million yuan. (2) Hydrological regulation, biodiversity maintenance, soil conservation, gas regulation, and climate regulation were the main types of ecosystem services in the Funiu Mountain area. (3) The ESV was influenced by the comprehensive effects of the natural environment and human activities. Population was the most important influencing factor of the ESV; in addition, the normalized difference vegetation index (NDVI), precipitation, and economic factors had important influences on the ESV. (4) With the intensification of human activities, humanistic factors have surpassed the relatively stable natural factors, becoming the main factors of the ESV. With economic development, the effect of human activities on the ESV may be further intensified in the future.

Against the backdrop of urban–rural integrated development, special ecological function zones, as spatial carriers with significant regional ecological value and rural development functions, are confronted with a striking conflict between ecological conservation and regional advancement. This contradiction is comprehensively reflected in the interactions among land use functions (LUFs) that differ in nature and intensity. Therefore, exploring the trade-off and synergy (TOS) among regional LUFs is not only of great significance for optimizing territorial spatial patterns and advancing rural revitalization but also provides scientific evidence for the differentiated administration of regional land use. Taking 185 townships in the Funiu Mountain area of China as research units, this study constructs a land use assessment system based on the ‘Production–Living–Ecological’ (PLE) framework, utilizing multi-source datasets from 2000 to 2020. Spearman correlation analysis, geographically weighted regression (GWR), and bivariate local spatial autocorrelation methods are employed to examine the spatio-temporal dynamics of LUFs and the spatial non-stationarity of their TOSs. The findings indicate that, throughout the research period, the production function (PF) displayed a fluctuating declining trend, whereas the living function (LF) and ecological function (EF) demonstrated a fluctuating increasing trend. Notably, EF held an absolute dominant position in the overall structure of LUFs. This is highly consistent with the region’s positioning as a special ecological function zone and also a direct reflection of the effectiveness of continuous ecological construction over the past two decades. Spatially, PF is stronger in southern, eastern, and northern low-altitude townships, correlating with higher levels of economic development; LF is concentrated around townships near county centers; and high EF values are clustered in the central and western areas, showing an opposite spatial pattern to PF and LF. A synergistic relationship is observed between PF and LF, while both PF and LF exhibit trade-offs with EF. The TOSs between different function changes demonstrate significant spatial non-stationarity: linear synergy was the primary type for PF-LF, PF-EF, and LF-EF combinations, but each combination exhibited unique spatial characteristics in terms of non-stationarity. Notably, towns identified as having different types of trade-off relationships in the study of spatial non-stationarity are key areas for township spatial governance and optimization. Through the allocation of regional resources and targeted policy tools, the functional relationships can be adjusted and optimized to attain sustainable land use.

A major obstacle to sustainable land management in ecologically sensitive areas is our limited understanding of the complex nonlinear mechanisms and threshold effects that dictate trade-offs between land use functions (LUFs). This study takes the Funiu Mountain area, a typical ecologically sensitive area in China, as a case study. At the township scale, the spatiotemporal patterns of LUFs from 2000 to 2020 were assessed based on the “production-living-ecological” function framework. The root mean square error (RMSE) model was introduced to quantify inter-functional trade-off intensity. Furthermore, the optimal parameters geographical detector (OPGD) and generalized additive model (GAM) were innovatively coupled to systematically analyze their driving mechanisms and nonlinear threshold effects. The results indicate that: (1) LUFs show clear functional complementarity and spatial game characteristics. The production function (PF) exhibits a heterogeneous pattern of “locally high, overall low”; the living function (LF) shows a local central agglomeration feature; and the ecological function (EF) displays a continuous gradient distribution of “high in the northwest, low in the southeast”. (2) The trade-off intensities between PF&EF and LF&EF are relatively strong, with high-value areas mainly distributed in the high-altitude central regions; while the trade-off intensity of PF&LF is weaker, with high-value areas mostly appearing in the central urban areas of each county. (3) The spatial heterogeneity of the trade-off relationship of LUFs is a comprehensive manifestation of the combined effects of the natural environment, socio-economic factors, and landscape patterns. The driving mechanisms of trade-off intensity among different functions show significant heterogeneity. (4) Key driving factors have significant nonlinear threshold effects. POP shows a complex dynamic regulatory effect with multiple thresholds and strong nonlinearity, while SLOPE, PET, and NDVI continuously play a fundamental constraining role in the trade-offs related to ecological functions. The key thresholds identified in this study can provide a direct scientific basis for regional differentiated territorial space governance.