Metacommunity robustness to invasion in mutualistic and antagonistic networks

One of the most significant threats to biodiversity is alien species invasion, and consequently understanding and predicting biological invasions has become an important issue in ecology. While numerous studies have explored the effect of community diversity and structure on invasion success, a systematic comparative analysis on system robustness to invasion between antagonistic and mutualistic networks from a metacommunity perspective is still lacking. Here we seek to address this gap using patch-dynamic models, which integrate local communities into the landscape metacommunity. We find that both mutualistic and antagonistic metacommunities displayed qualitatively similar responses to species invasion, except for animal invasion in antagonistic networks. Specifically, increasing network size and connectance generally promoted metacommunity persistence, while nestedness (negative) and modularity (positive) had contrasting effects on metacommunity robustness to invasion. However, these structural effects were strongly dependent on the generalization levels of both invader and the resident species it displaces. Overall, this study provides new and more general insights into how alien species are well integrated into native networks and how they affect metacommunity persistence.