## 4 Discussion
### Ecological Network Evaluation and Optimization Suggestions  
Increasing ecological nodes and corridors is an effective way to optimize ecospatial networks [53], and optimizing ecospatial networks to improve the carbon sequestration capacity of ecosystems is an important way to achieve carbon neutrality [54]. The analysis of network structural characteristics is the basis of network optimization. At the same time, Inner Mongolia is a typical region with serious ecological damage and high carbon emission intensity. Therefore, it is of great practical significance to analyze the structural characteristics of the ecospatial network in Inner Mongolia and its relationship with carbon sequestration capacity.  
Combined with the analysis of ecospatial network robustness, the restoration robustness of nodes is slightly stronger than that of corridors, so we suggest that the basic principle of optimization is to primarily increase ecological corridors and increase ecological nodes as a supplement. We calculated the completeness and topological indexes of complex ecospatial networks, and the results mainly illustrated that in terms of spatial distribution, nodes with high topological indexes were mostly distributed in farm-forest ecotones, grasslands, and agro-pastoral ecotones, while nodes with low topological indexes were mostly distributed in woodlands and forest-grassland ecotones. Previous studies have shown that the topological index represents the importance of nodes in maintaining the ecological function of the network to a certain extent [40]. Therefore, in the study area of this paper, the ecological nodes in the farm-forest ecotones, grasslands, and agro-pastoral ecotones have a greater contribution to the network, which further confirms the conclusion in Section 4.1 that these areas are the key areas that can further exert ecological functions through human planning.  
At the same time, the distribution of NPP also showed a clear spatial heterogeneity, with higher values in woodlands, farm-forest ecotones, and agro-pastoral ecotones and slightly lower values in grasslands and unused land, which is consistent with the existing research results on the spatial distribution of NPP [55]. It can be found that the spatial distribution of ecological nodes based on topological indicators is similar to the spatial distribution based on NPP; for example, the higher farm-forest and agro-pastoral interlacing areas are also areas with higher NPP values, which indicates that the topological characteristics of ecological nodes within a specific land cover type are related to the carbon sequestration capacity. In other words, it is feasible to enhance the carbon sequestration capacity by optimizing the topological characteristics of ecospatial networks, which is one of the implications of this study. Through the analysis, we found that the degree of nodes in woodlands and grasslands had a significant negative correlation with NPP, and reducing the degree of ecological nodes in woodlands and grasslands is an effective means to improve the carbon sequestration capacity of ecosystems under the premise of ensuring network connectivity, that is, to rationally combine ecological nodes and corridors in these areas to an appropriate extent. This conclusion provides a theoretical basis for the subsequent optimization of ecospatial networks.