Effects of colonization asymmetries

1 Ocean currents, prevailing winds, and the hierarchical structures of river networks are 2 known to create asymmetries in re-colonization between habitat patches. The impacts of 3 such asymmetries on metapopulation persistence are seldom considered, especially rarely 4 in theoretical studies. Considering three classical models (the island, the stepping stone 5 and the distance-dependent model), we explore how metapopulation persistence is af6 fected by (i) asymmetry in dispersal strength, in which the colonization rate between 7 two patches differs in direction, and (ii) asymmetry in connectivity in which the overall 8 colonization pattern displays asymmetry (circulating or dendritic networks). Viability 9 can be drastically reduced when directional bias in dispersal strength is higher than 25%. 10 Re-colonization patterns that allow for strong local connectivity provide the highest per11 sistence compared to systems that allow circulation. Finally, asymmetry has relatively 12 weak effects when metapopulations maintain strong general connectivity. 13 14