Spatial arrangement of size-different patches determines population dynamics in linear riverine systems

Despite years of attention, the dynamics of species constrained to disperse within riverine systems are not well captured by existing population models. Here we develop a population model subject to local population dynamics and regional dispersal process in a closed linear riverine system, which consists of three size-different patches (lakes) arranged at different positions in the chain. Generally, two-way dispersal, including down- and upstream, promotes global population density relative to one-way dispersal, but such dispersal superiority is weakened with increasing species relative mortality rate. Furthermore, unbiased dispersal (i.e., balanced down- and upstream) maximizes population viability in this closed linear system. Finally, which type of spatial arrangement of size-different patches is an optimal strategy for species persistence depends on both species inter-patch dispersal and local population dynamics, reflecting the balance between local demographic and regional dispersal processes.