## 4 Results
### Human-Environment Coordinated Development Zoning Management of HF and EQ  
#### 4.3.1 Static Quadrant Zoning of HF-EQ  
The interactive relationship between HF and EQ highlights the necessity of human-environment coordinated management. This section presents static quadrant zoning for various periods. Figure 8a illustrates the scatter plot distribution of the static relationship between HF and EQ across three time points. Overall, the sample points exhibited a reverse distribution trend in China's lake-ring urban agglomerations, suggesting a strong negative correlation between HF and EQ. The density of points in SII consistently remained the highest. The density of points in SIV continued to increase, with the boundary expanding outward to the lower right, reflecting the intensifying stress caused by human activities on the ecosystem and the gradual expansion of non-coordinated areas. For each urban agglomeration, (1) in DTU and PYU, the sample points were concentrated in the SII quadrant. SII and SIII exhibited continuous clustering near the EQ critical value over time. (2) In CHU and HZU, numerous points initially clustered in SIII. From 2010 onwards, SIII gradually transformed into SII and SIV, emphasizing the increasingly intense antagonistic development trend within the human-environment system. (3) In THU, SIV consistently dominated throughout the three periods, with dense points and a wide range. Simultaneously, the boundaries of SIII continuously clustered toward the lower right, indicating that degraded ecological areas are transforming into regions with high human disturbance, further exacerbating non-coordination characteristics.  
Figure 8b presents the raster-based visualization of the static quadrant zoning. From an overall spatial pattern perspective, the dominant quadrants of the lake-ring urban agglomerations from west to east are SII (88.68%), SII (76.62%), SII (63.57%), SII (61.85%), and SIV (39.35%), respectively. The overall coordination level of the human-environment system appeared mismatched. For each category, (1) SI had the lowest proportion, forming a peripheral ring around urban built-up areas, indicating a few areas where development and ecological coexistence were achieved. During the study period, SI showed a  
slight expansion around the built-up areas of DTU, PYU, CHU, and HZU but generally remained low. This suggests that achieving coordination in areas with high development intensity remains challenging. (2) SII had the highest proportion among the five urban agglomerations, primarily in low-interference areas distant from the urban core. Initially, due to surface vegetation and humidity improvements, SII transitioned from SIII in the northern part of CHU and the western part of HZU. Subsequently, as HF increased, SII gradually transformed into SIV, most notably in THU. (3) SIII emerged in a patchy and scattered pattern between SII and SIV, largely overlapping with degraded forest land and low-efficiency cropland. During the study period, SIII mostly transformed into SII or SIV, with only a slight increase in localized irrigation areas in DTU. (4) SIV was predominantly concentrated in each urban agglomeration's central urban areas, transportation corridors, and lakeside development zones. This quadrant exhibited continuous expansion across all urban agglomerations, most notably in THU, where the area proportion increased from 18.75% to 54.62%. The expansion trend indicates the significant intensification of ecological stress driven by urbanization.  
Figure 8: Static quadrant zoning of HF-EQ. (**a**) Scatter distribution of static relationships; (**b**) Proportion and spatiotemporal distribution patterns of static quadrants.