The topology of ecological drift

Abstract Ecological drift, the random fluctuation of abundance in communities, can drastically affect the possibility of coexistence. However, ecological drift has mostly been considered at the macro-ecological scale, whereas its potential contribution to short-term ecological dynamics remains underexplored. Here, we propose a stage-structured ecological graph theory (ssEcoGT) to include complex life cycles and multiple ecological interactions to study the topology of ecological drift. ssEcoGT enables rigorous exploration of how topology of a community can affect the possibility of coexistence between two species. Using ssEcoGT, it is possible to compare the behavior of a range of models – e.g., random graphs, random graphs with intraguild predation, and random graphs with rewiring – against a complete graph of the same size. Thus, ssEcoGT provides a new tool to explore the interplay between ecological drift, competition, and stage-specific interactions.