## 3 Results
### Single Factor Analysis
#### 3.1.2 Human Disturbance Factors  
1. Land use types. Different land use patterns make for different land cover, and differences exist in their regional ecological service functions and response to human activity disturbances. Among the various types of land use in the Tumen River Basin, the woodland is absolutely dominant, followed by cultivated land, with a relatively low proportion of construction land, grassland, and other land areas. According to the principles of classifying the sensitivity levels of land use type factors (Table 2), the result of the ecological sensitivity levels in the study area is shown in Figure 4a and Table 5. The moderately sensitive area corresponding to the woodland accounts for 84.39% of the total area, covering most of the study area, with a clear dominance. In second place is the slightly sensitive area corresponding to cultivated land distributed in the valley plains and nearby areas with low slopes, accounting for 11.38%. The least abundant area is the extremely sensitive area, with only 0.46%, where the main types of land are water or wetland. 2. Distance to construction land. In general, the smaller the distance to construction land, the more frequent the human activities and the stronger the disturbance to the ecosystem (Table 2). Construction land in the Tumen River Basin is concentrated in the urban and township areas of the major cities in the study area, such as Yanji, Longjing, Tumen, and Wangqing, as well as in scattered rural settlements and industrial and mining sites. Therefore, the level of ecological sensitivity gradually decreases in these areas (Figure 4b). More than half of them are insensitive areas (57.07%). With the increase in sensitivity, the proportion of each sensitive area decreases (Table 5). 3. Distance to road: Similar to the impact of construction land on ecological disturbance in the nearby area, the closer to the road, the higher the ecological sensitivity. The results are shown in Figure 4c and Table 5, based on the principle of classifying ecological sensitivity according to the distance to the road (Table 2). It is obvious that the ecological sensitivity gradually decreases with the increase in distance from the center of all kinds of roads in the study area to both sides. The areas with a clear dominance of area remain insensitive areas. The proportion of slightly sensitive, moderately sensitive, and highly sensitive areas gradually decreases, with the least extremely sensitive area accounting for only 6.88%. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sensitivity Level**} & \multicolumn{2}{c}{**Mean Annual Temperature**} & \multicolumn{2}{c}{**Annual Precipitation**} & \multicolumn{2}{c}{**Elevation**} & \multicolumn{2}{c}{**Distance to Water**} \\ \cline{2-9}  & **Area (km2)** & **Proportion (\%)** & **Area (km2)** & **Proportion (\%)** & **Area (km2)** & **Proportion (\%)** & **Area (km2)** & **Proportion (\%)** \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Insensitive \\ Slightly sensitive \\ Moderately sensitive \\ Highly sensitive \\ Highly sensitive \\ Extremely sensitive \\ \end{tabular} } & 1389.19 & 6.12 & 2827.18 & 12.46 & 1801.31 & 7.94 & 6838.58 & 30.14 \\  & 5638.47 & 24.85 & 3804.25 & 16.77 & 8116.27 & 35.77 & 6926.50 & 30.53 \\  & 6626.97 & 29.21 & 4266.68 & 18.80 & 8624.22 & 38.01 & 4241.51 & 18.69 \\  & 5974.18 & 26.33 & 6646.86 & 29.29 & 3771.33 & 16.62 & 2741.64 & 12.08 \\  & 3061.89 & 13.49 & 5145.72 & 22.68 & 377.57 & 1.66 & 1942.47 & 8.56 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Area and proportion of ecological sensitivity classification of the natural environment.