## 3 Results
### Impact of Urban Expansion on Vegetation Distribution Dynamics  
During the study period, the negative impacts on vegetation caused by urban expansion far outweighed the positive impacts. Therefore, this research further analyzed the relationship between urban expansion and its impacts on vegetation from the perspective of land cover changes. On the basis of land cover data from 2001 to 2021, we conducted a detailed analysis at the pixel level to explore the changes in land cover types during these two decades. Furthermore, we generated a land cover type transition matrix for Lanxi (Table 3) and transition diagrams illustrating changes between various land cover types and built-up areas (Figure 6) to clearly demonstrate the changes in land cover types and the areas occupied by urban expansion during this period. Figure 6 shows the area of other land types occupied by urban expansion in the Lanzhou-Xining urban cluster and the area of urban land converted to other land types from 2001 to 2021. The transformation of urban land in the Lanxi urban cluster to other types of land, although present, is relatively small in scale, especially in terms of ecological land restoration, which shows a lack of sufficiency. Specifically, the area of urban land converted to cropland was 26.08 km\({}^{2}\), which may be related to the reclamation of urban land or the reintroduction of agricultural functions. However, compared with the cropland \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**2021** & **2001** & **Barren** & **Cropland** & **Forest** & **Grassland** & **Impervious** & **Shrub** & **Snow/Ice** & **Water** & **Wetland** & **Total** (km\({}^{2}\)) \\ \hline \hline \multirow{2}{*}{Barren} & 207.50 & 56.41 & 0.15 & 1534.25 & 5.71 & 0.05 & 3.44 & 6.17 & – & 368.68 \\  & 46.47 & 825.32 & 28.72 & 4889.49 & 26.08 & 0.42 & - & 31.37 & 0.04 & 13247.91 \\ Forest & 0.14 & 80.84 & 1870.16 & 1115.32 & 0.01 & 160.94 & - & 0.51 & - & 3227.91 \\ Grassland & 111.10 & 6153.20 & 765.40 & 65,289.73 & 44.43 & 608.53 & 0.26 & 44.45 & 0.22 & 7407.36 \\ Impervious & 12.30 & 87.78 & - & 85.82 & 103.45 & - & - & 5.82 & - & 295.17 \\ Shrub & - & 1.51 & 137.01 & 535.68 & - & 315.25 & - & - & 998.45 \\ Snow/Ice & 1.21 & - & 0.02 & 0.34 & - & 0.18 & - & - & 1.75 \\ Water & 179.25 & 59.57 & 1.79 & 221.61 & 4.70 & 0.12 & - & 3239.12 & 0.10 & 3706.26 \\ Wieland & - & 0.27 & 0.02 & 1.97 & - & - & - & 0.04 & 0.32 & 2.63 \\ Total & 3427.96 & 14,664.95 & 2803.26 & 73,674.21 & 184.38 & 1085.31 & 3.87 & 3327.48 & 0.69 & 99,172.12 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Land cover type transition table for the Lanxi urban cluster from 2001 to 2021 (km\({}^{2}\)). Figure 6: Land cover changes between the expansion zones of the Lanxi urban cluster and other land types from 2001 to 2021.  
occupied by urban expansion (87.78 km\({}^{2}\)), this area is still negligible, indicating that the loss of agricultural land during the urbanization process far exceeds its restoration. Furthermore, the area of urban land converted to grassland was 44.43 km\({}^{2}\), which, to some extent, shows attention to greening and ecological restoration during the urbanization process, but its effect is still limited. More noteworthy is that the conversion of urban land to forests is only 0.01 km\({}^{2}\), water bodies were 4.7 km\({}^{2}\), and barren land was 5.71 km\({}^{2}\). These figures indicate that the restoration and increase of land types with high ecological value during the urban expansion process are very limited and almost negligible. Table 3 represents the transfer quantities (km\({}^{2}\)) between different land use types in the Lanxi urban agglomeration. The rows represent the various land categories in 2001, while the columns indicate the land categories in 2021. The intersection of a row and a column represents the transfer quantity from a certain category in 2001 to another category in 2021, signifying the amount of a particular category that has transformed into another category by 2021.