Biodiversity loss due to habitat fragmentation is one of the biggest concerns in ecology. Biological populations are rarely isolated in space and interact with others via migration in metapopulations. Network connectivity patterns can have critical effects on network robustness, as some topologies can promote resilience after perturbations. However, at present, experimental evidence of how these patterns affect population persistence in a metapopulation framework is lacking. In this study, we used the aquatic protist Paramecium tetraurelia to determine how network topology influences its regional persistence. We created metapopulations engineered to be comparable in terms of linkage density, but differing in their degree distribution. We compared metapopulations arranged as random networks to power-law networks by evaluating local population persistence and abundance throughout ∼30 protist generations. In parallel, we ran simulations to explore differences between topologies.
Results/Conclusions
Random metapopulations of P. tetraurelia reached higher densities and higher occupancy (proportion of occupied patches) compared to power-law systems in both experimental and simulated systems. The two types of networks also showed opposite patterns of temporal occupancy or “incidence” when related to other node metrics. These contrasting results highlight the fact that node metrics alone are not good predictors of occupancy if topology is not accounted for.