## 1 Introduction  
Ecosystem functions are increasingly used to assess the social and economic impacts of environmental changes and provide basic principles for resource and environment management [1, 2]. Water conservation is an important ecosystem function, which is of great significance for maintaining regional biodiversity and improving human well-being [3, 4]. Water conservation plays a key role in improving regional hydrological conditions and regulating the water cycle. It not only directly affects regional water supply, but also has an important impact on the regional ecosystem stability, agriculture, industry, human consumption, hydropower generation and fishery [5, 6]. Moreover, the regional natural environment and socio-economic factors also restrict the spatial and temporal distribution of water conservation functions [7, 8]. In recent years, researchers have conducted in-depth discussions on the water conservation functions of various ecosystems. The research on the impact of land use or land cover change on ecosystem services has become a research hotspot, especially the trade-off between ecosystem services, which objectively reveals the overall effect of implementing land use policies on the ecological environment [9, 10, 11, 12]. The research objects are mainly small and medium-sized regions, typical watersheds and other ecologically fragile areas [13, 14, 15, 16]. Regarding the essence of water conservation function,there has been a significant evolution in its interpretation. Initially, the emphasis was on safeguarding water resources through the concept of water conservation function [10]. However, the understanding of water conservation function has since broadened to encompass its wider role and significance within the ecological environment, marking a continuous expansion of its connotation. As an important ecological service function, water conservation has the characteristics of dynamics, complexity, space-time evolution, etc. [17; 18]. The discussion on how to scientifically evaluate the water conservation function has never been stopped. The assessment of regional water supply is expanded from the traditional soil water storage capacity method, comprehensive water storage capacity method and underground runoff growth method based on small watershed observation data to using the combination of remote sensing technology and hydrological model to quantitatively and visually analyze and assess the water conservation function of the ecosystem. At present, a large number of methods and tools have emerged to quantify and evaluate the provision of ecosystem services [19]. The main evaluation models such as the MIKE SHE model [20], TOPMODEL model, SWAT model [21; 22; 23] and InVEST model [11; 24] have been well applied in their respective research fields. Moreover, researchers identify the influencing factors affecting the water conservation function of various ecosystems using regression models. For example, multi factor Logistic regression analysis, structural equation model [25] and geographically weighted regression [22] are mainly aimed at the static impact analysis of single factors such as meteorological factors [26], hydrological factors [27], vegetation factors and soil factors [28]. These studies offer both quantitative and spatial insights that can inform decision-making related to regional land use and the utilization of water resources. Yunnan Province serves as a crucial ecological barrier in the upper reaches of the Yangtze River and holds a strategic position at the crossroads of the \"the Belt and Road\" initiative and the development of the Yangtze River Economic Belt. This region boasts abundant hydropower resources and is recognized as a significant area for biodiversity preservation and water conservation in China. However, recent decades have witnessed the exacerbation of regional water resource shortages due to rapid increase in climate change, socio-economic development, and population.