## 3 Results  
### Spatiotemporal Evolution of Vegetation NPP  
The overall trend of NPP in the Inner Mongolia Autonomous Region decreases from northeast to southwest to east to west, as shown in Figure 2. The vegetation NPP in the study area is divided into low 0-30 gC m\({}^{-2}\)-a\({}^{-1}\), low 30-60 gC m\({}^{-2}\)-a\({}^{-1}\), medium 60-90 gC m\({}^{-2}\)-a\({}^{-1}\), high 90-120 gC m\({}^{-2}\)-a\({}^{-1}\), and high 120-300 gC m\({}^{-2}\)-a\({}^{-1}\). The high-value areas are mainly distributed in mountainous areas such as the Greater Khingan Range in the northeast, with the largest proportion of forest land. In some areas, the NPP value exceeds 250 gC m\({}^{-2}\)-a\({}^{-1}\). The low-value areas are mainly distributed in the western Ordos Plateau and sandy areas of Aka. The terrain in this area is rugged, and the main vegetation includes windproof and sand-resistant plants and cultivated crops. The NPP \begin{table}
\begin{tabular}{c c c c} \hline
**Indicators** & **Name** & **Formula** & **Implication** \\ \hline PLAND & Patch area ratio & \(\frac{\sum_{i=1}^{n}t_{ij}}{A}\) & The proportion of a certain type of patch in the total landscape area determines important factors such as biodiversity, dominant species, and its quantity in the landscape \\ \hline LPI & Maximum patch index & \(\frac{\text{Max}(\mu_{i}-\mu_{i})}{A}\times 100\) & The maximum patch index helps determine the dominant type of landscape and can reflect the direction and strength of human activities \\ \hline LSI & Shape index & \(\frac{025E}{\sqrt{A}}\) & Measuring the complexity of patch shapes within a landscape, the larger the value, the more complex the landscape shape \\ \hline COHESION & Aggregation index & \(\left[1-\frac{\sum_{i=1}^{n}P_{ij}}{\sum_{i=1}^{n}P_{ij}\sqrt{a_{ij}}}\right] \times\left[1-\frac{1}{\sqrt{A}}\right]^{-1}\times 100\) & Reflecting the connectivity of different land use patch types within the landscape, the smaller the landscape, the higher the heterogeneity \\ \hline PAFRAC & Fractal dimension index & \(\frac{\sum_{i=1}^{N}\frac{11\ln(0.25p_{ij})}{\ln(a_{ij})}}{N}\) & The complexity of the shape of individual landscape patches \\ \hline AI & Aggregation index & \(\left[\frac{\pi_{i}}{\text{max}-5\delta_{i}}\right]\times 100\) & The relationship between adjacent types of landscape patches, with small values indicating high fragmentation levels and large values indicating good connectivity within the landscape patches \\ \hline CONTAG & Sprawl index & \(\left[1+\frac{\sum_{i=1}^{n}\sum_{i=1}^{n}P_{i}\ln P_{i}}{2\ln(n)}\right]\) & The degree of aggregation or extension trend of different patch types in the landscape is related to the spatial configuration relationship of landscape components \\ \hline JII & Dispersion and parallelism index & \(-\frac{\sum_{i=1}^{n}\left[\left(\frac{\pi_{i}}{\sum_{i=1}^{n}\epsilon_{ik}} \right)\ln(\frac{\pi_{i}}{\sum_{i=1}^{n}\epsilon_{ik}})\right]\times 100}{\ln(m-n)}\) & The overall dispersion and juxtaposition of patch types, calculated from the relationship between the length of each edge type (\(\epsilon_{ik}\)) and total edge of the landscape divided by a term based on the number of land use/land cover types (m) \\ \hline \end{tabular}
\end{table} 
Table 2: _Cont._value tends to 0, and the median area is located in the central part of Inner Mongolia, mainly consisting of grassland and cultivated land. There are significant differences in NPP values among different vegetation types. When analyzed based on vegetation ecosystem types, the trend of NPP changes among different vegetation types is forest > grassland > cultivated land > others. From a time scale perspective, there was an upward trend from 2000 to 2020. The high-value areas increased threefold from 2000 to 2010, and grew by 73% from 2010 to 2020, but overall, they remained below 300 gC m\({}^{-2}\)-a\({}^{-1}\). From this, it can be seen that the future trend of vegetation NPP changes in most regions is not significant.