The topology of spatial networks affects stability in experimental metacommunities

Understanding the drivers of community stability has been a central goal
in ecology. Traditionally the emphasis has been placed on studying the
effects of biotic interactions on community variability, and less is
understood about how the spatial configuration of habitats promotes or
hinders metacommunity stability. To test the effects of contrasting
spatial configurations on metacommunity stability, I designed
metacommunities with patches connected as random or scale-free networks.
In these microcosms, two prey and one protist predator dispersed, and I
evaluated community persistence, tracked biomass variations, and measured
synchrony between local communities and their neighbors. After 30
generations, scale-free metacommunities had lower global biomass
variability and higher persistence, suggesting higher stability. At the
local scale, patches in scale-free metacommunities showed a positive
relationship between variability and patch connectivity, indicating higher
stability in isolated communities. No clear relationship was observed in
random networks.  These results suggest the increased
heterogeneity in connectivity of scale-free networks favors the prevalence
of isolated patches in the metacommunity, which likely act as refugia
against competition—the most dominant interaction in this system—resulting
in higher global stability. These results highlight the importance of
accounting for network topology in the study of spatial dynamics.