Coexistence mechanism of alien species and local ecosystem based on network dimensionality reduction method

The interaction caused by nonnative species upset the balance of the existing ecosystem, the focus of previous studies is mainly on the survivability of alien species and their impact on the local ecosystem. However, the current research for the coexistence mechanism of alien species and resident species under different types of interactions are not very sufficient. Here, we apply an analysis framework that uses the weighted average neighbor activities to describe the state of local ecosystems, to map the multi-dimensional dynamic model to a one-dimensional equation, and simplify the structure and dynamics of the interaction between alien species and local ecosystems. Our work can help reveal the basic mechanism of species survival under the interaction of mutualism and competition. Remarkably, our results show that the species with fewer mutualistic interactions are prone to jump from high abundance to low abundance abruptly rather than continuous changes when encountering increased competition intensity. In addition, the local ecosystem with low species diversity is less tolerant to invasive alien species than the ecosystem with high species diversity.