Role of network topology in between-community beta diversity on river networks

The between-community beta diversity of fish species - characterized using the similarity of species between river basins shows a non-linear drop with topological distance on river networks. In this work, we investigate the pattern of this drop with network distances and the role of underlying topology. Using the framework of optimal channel networks, the species abundances are evolved under the neutral biodiversity model. We observe that the steady-state species-similarity shows a phase transition-like behaviour at a critical network distance. At this critical distance, the average degree over the nodes crosses the global average degree of the network. This study sheds light on the role of branching in dendritic networks in ecological community assembly rules.