Abstract:
The research on typical ecosystem service functions, their spatio-temporal characteristics, and the associated tradeoffs and synergies is of great significance for national park development. With Nanshan National Park Candidate as the study area, this study employed InVEST model, hot/cold spot analysis, and coupled coordination degree model to analyze the spatio-temporal patterns, and interrelationships among three typical ecosystem service functions (carbon storage, nitrogen export, and water yield) from 2000 to 2020. The results showed that: (1) Three ecosystem service functions performed well. (2) The spatio-temporal patterns of nitrogen export and carbon storage were relatively stable, both exhibiting a slight U-shaped declining trend. Carbon storage displayed a pattern of higher values in the west and lower values in the east, while nitrogen export remained at low levels across both the east and west. Water yield showed significant spatio-temporal variation, with a U-shaped upward trend over time and a marked increase in the central area spatially, although the overall pattern remained higher in the west and lower in the east. (3) Different land use types contributed differently to these service functions. High-value areas for both carbon density and water yield corresponded to grassland, with values of 123.892 t/ha and 1519.355 mm, respectively. Cultivated land exhibited the highest nitrogen export (0.972 kg/hm
2), indicating its weakest water purification capacity. (4) The spatial distribution of cold and hot spots for carbon storage and nitrogen export was similar, with minimal temporal changes. In contrast, the cold and hot spots for water yield experienced significant shifts. (5) The coupled coordination degree among these three ecosystem service functions was at a good synergy level (0.719). The highest coordination was found between nitrogen export and water yield (0.729), while the lowest was between carbon storage and water yield (0.569). These findings can provide a scientific basis for enhancing the ecological product supply capacity and achieving sustainable management in Nanshan National Park Candidate.