## 4 Discussion  
### EHI and EGI Assessment  
#### 4.1.1 EHI Assessment  
This study assessed the ecosystem health of the Inner Mongolia Autonomous Region, which is a key area of the Three-North Shelter Forest Program (TNSFP), using a bottom-up approach. The evaluation incorporated ecological patterns, ecological function, biodiversity, and ecological stress at three levels of sub-indicators. The results indicated that EHI values were higher in forest-grassland regions in the northeast and lower in deserts, Gobi areas, desert grasslands in the west, and agricultural-pastoral transition zones in the southeast and southwest. These findings align with those of previous studies [46].  
In terms of ecological patterns, the ecological agglomeration of county-level administrative regions reflected a distribution pattern similar to the AI and CONTAG indices reported in earlier studies [47]. Low-value areas were primarily concentrated in south-eastern and southwestern Inner Mongolia, while medium-value and high-value areas included forest, grassland, and western desert and Gobi regions. As a transitional zone  
Figure 6: Key area identification results, **(a)**: EQI reclassification results, **(b)**: variations in the number of rasters with longitude, **(c)**: variations in the number of rasters with latitude, **(d)**: the proportion of all rasters occupied by the five types of rasters. The spatial resolution of the rasters is 1 km \(\times\) 1 km; thus, the number of rasters is the area occupied by the rasters (in km\({}^{2}\)).  
between agriculture and animal husbandry [48], rapid population growth and increased demand for natural resources and animal products have expanded grazing and cultivated land [49]. This has disrupted ecosystem continuity and increased fragmentation across regions [47; 50].  
Regarding ecological function, this study evaluated windbreak, water conservation, and soil conservation. The results revealed a pattern of high values in the east, low values in the west, and medium values in the central regions. The windbreak and soil conservation indices positively correlated with vegetation cover, while high water conservation values were concentrated in forest and grassland areas, which is consistent with the greenness evaluation pattern. In other words, cities with larger woodlands and grasslands had higher EFI, which is similar to the findings of previous studies [50].  
For biodiversity, the distribution of key species was assessed using the National Key Species Protection Animals List and the National Key Species Protection Plants List. The HQI, which was calculated from land use data, showed a pattern of low biodiversity in desert and Gobi areas, central and eastern urban zones, farmland, and road networks and higher values elsewhere. These findings align with those of previous studies [51; 52]. Agricultural activities in agricultural-pastoral transition zones significantly fragmented habitats, adversely affecting biodiversity [33; 53].  
Regarding ecological stress, sensitive areas were primarily forested regions, which is consistent with the findings of [PERSON] et al. [29], who identified ecologically sensitive areas by superimposing them on nature reserves to define integrated ecological protection zones [54]. Counties with high ESI values were typically urban, where spatial expansion and human activities severely impacted the fragile ecological environment, contributing to medium-low ecological quality and threatening sustainable development [55; 56; 57].