The ecological security pattern plays a crucial role in maintaining ecosystem health and ensuring ecological security. The establishment of the ecological security pattern in Mudanjiang City can provide a scientific basis and effective support for stabilizing the ecological environment, mitigating regional human–land conflicts, and rational land- use planning. This paper utilizes the theory of constructing an ecological security pattern using a source-resistance plane-corridor node to grade the importance of source areas based on the connectivity index. It combines morphological spatial pattern analysis and PLUS model to generate and identify the present value of 2022 in Mudanjiang City, as well as predict eight land types and seven landscape types under three development scenarios by 2032. A transfer matrix and transfer-intensity map are introduced to explore the structural characteristics of landscape transfer, while four fragmentation indexes are combined with principal component analysis and the coefficient of variation method to form comprehensive fragmentation indexes for different classes. Finally, based on constructing the ecological security pattern of Mudanjiang City in 2022, an analysis method is developed that establishes logical connections between land-use structure, a comprehensive fragmentation of land types, landscape transformation mechanism, and the importance of ecological sources. The results are as follows: (1) In Mudanjiang City, 23 ecological source areas, 65 corridors, and 66 ecological nodes were extracted. The overall ecological security pattern shows a “U” shape with openings to the northeast. (2) The cumulative weight of economic and social factors on the ecological resistance surface in Mudanjiang City reached 51.36%. (3) The response between the comprehensive fragmentation degree of forest land and the importance of primary and tertiary source areas was highly significant, with R values reaching 0.9675 and −0.8746, respectively. The comparative study comprehensively showed that the best scenario for the sustainable development of the ecological security pattern in the future is an ecological priority scenario, where the tertiary source area with the smallest area proportion but strongest disturbance fluctuation becomes a key area affecting connectivity and overall ecological security pattern in Mudanjiang City.

The Integrated Valuation of Ecosystem Services and Trade-Offs (InVEST) model with the distributed hydrological model Soil and Water Assessment Tool (SWAT) were implemented. The SWAT model quantifies and visualizes water production and groundwater reserves in the Mudanjiang River Basin, employing the groundwater runoff modulus method to calculate groundwater recharge in the basin. This study aims to assess the model’s applicability in cold basins and subsequently analyze groundwater distribution characteristics, water reserves, and the exploitable volume. It serves as a reference for the judicious allocation of groundwater resources and the preservation of the local aquatic ecosystem. The study indicates the following: (1) Utilizing the monthly runoff data from the Mudan River hydrologic station, SWAT simulation and calibration were conducted, yielding a determination coefficient (R²) of 0.75 and a Nash–Sutcliffe efficiency coefficient (NS) of 0.77, thereby satisfying fundamental scientific research criteria. The water yield predicted by the InVEST model aligns closely with the water resources bulletin of the research region. (2) The data from the water production module of the InVEST model indicate that the average annual water production during the research period was 6.725 billion m³, with an average annual water production depth of 148 mm. In 2018, characterized by ample water supply, the water output was at its peak, with a depth of 242 mm. In 2014, the water depth recorded was merely 16 mm. (3) Throughout the study period, the average annual flow of the Mudan River was 4.2 billion m³, whereas the groundwater reserve was 24.13 (10⁸ m³·a⁻¹). In 2013, the maximum groundwater reserve was 38.42 (10⁸ m³·a⁻¹), while the minimum reserve in 2014 was 2.36 (10⁸ m³·a⁻¹), suggesting that the region was predominantly experiencing sustainable exploitation. (4) The mean groundwater runoff modulus is 0.28 L/(s·km²), with a peak annual recharge of 15.4 (10⁸ m³·a⁻¹) in 2013 and a lowest recharge of just 3.2 (10⁸ m³·a⁻¹) in 2011.