## 3 Results
### Ecosystem Health Assessment Results
#### 3.1.4 Ecological Stress Index (ESI)  
Using the ecologically sensitive area identification index system, four indicators--slope, elevation, land use, and vegetation cover--were applied to identify ecologically sensitive areas (Figure 3a-d). These indicators were weighted and superimposed, and areas classified as moderately sensitive, highly sensitive, and extraordinarily sensitive  
Figure 2: Spatial distribution pattern and calculation process of EHI sub-indicators: ecological pattern indicators include EL (**a1**), PC (**a2**), and Ecological Pattern Index (EPI) (**a**); ecological function indicators include Q\({}_{w}\) (**b1**), Q\({}_{s}\) (**b2**), WRC (**b3**), and Ecological Function Index (EFI) (**b**); biodiversity indicators included KS, (**c1**), HQI (**c2**), and Biodiversity Index (BI) (**c**); ecological stress indicators, including LDI (**d1**) and Ecological Stress Index (ESI) (**d**). Using weighted overlay to integrate EPI, EFI, BI, and ESI to obtain the spatial distribution pattern of Ecological Health Index (EHI) (**e**). **Note:** EHI stands for Ecological Health Index; EL stands for the ecological land area ratio index, PC stands for the connectivity of important ecological spaces index; Q\({}_{w}\) stands for the windbreak and sand fixation index, Q\({}_{s}\) stands for the soil and water conservation index, WRC stands for the water conservation index; KS, stand for the Priority Protection Organisms index, HQI stands for the Habitat Quality Index; LDI stands for the land-based development interference index. Secondary indicators are shown in black, primary indicators are shown in orange, and final indicators (i.e., EHI) are shown in red.  
were designated as sensitive regions. The analysis revealed approximately 376,500 km\({}^{2}\) of ecologically sensitive areas (Figure 3e), accounting for about 31.83% of the total study area. Spatially, ecologically sensitive areas exhibited a gradual decrease from northeast to southwest, with high concentrations in Inner Mongolia's forested regions, including the Daxinganling Primitive Forest Area, the Daqingshan Forest Area, and the Yinshan Mountains' forest ecosystems.  
By overlaying ecologically sensitive areas with national key nature reserve domains, a total of 465,600 km\({}^{2}\) of ecologically integrated protection areas was identified (Figure 3f), accounting for approximately 39.36% of the total study area. Based on these ecologically integrated protection areas, the spatial distribution of the land-based development interference index was determined (Figure 2d). This index evaluates the degree of pressure exerted on terrestrial ecosystems by human activities.  
High-value ecological stress areas were primarily concentrated in the agricultural and pastoral zones in southwestern Inner Mongolia, reflecting significant human exploitation of ecosystems and adverse impacts on ecological quality. Other medium- to high-value counties included Zhalainuoeer, Manzhouli, and Hailar Districts in northeastern Inner Mongolia; Huolinguole City in eastern Inner Mongolia; and Horgin, Ningcheng County, Hongshan District, and Yuanbaoshan District in southeastern Inner Mongolia. These areas demonstrated increased ecological pressure due to urban development and agricultural land use, which have heightened human interference in these ecosystems.