Many complex networks extend in space and therefore have two types of connections, namely local connections between network nodes and spatial connections between different locations. A typical example are ecological food webs in a heterogeneous environment: The network nodes represent ecological populations interacting through predation. In addition to this (non-spatial) food web structure, the species live on a spatial network, since they occupy habitats embedded in physical space, with the possibility to migrate between different habitats. Using food webs as example systems, we investigate the structure and dynamics of such “networks on networks” and explore how the local trophic network structure, the structure of space, the distribution of species in space, and the population dynamics mutually influence each other. This involves characterizing the structure of such networks on networks, obtaining the correct spatial scaling of the dynamical terms, generating realistic networks in in silico simulations, and identifying criteria for the dynamical stability of such food webs and the persistence of species.

Work funded by: DFG Research Unit 1748