  Metapopulation theory for a long time has assumed dispersal to be symmetric,
i.e. patches are connected through migrants dispersing bi-directionally without
a preferred direction. However, for natural populations symmetry is often
broken, e.g. for species in the marine environment dispersing through the
transport of pelagic larvae with ocean currents. The few recent studies of
asymmetric dispersal concluded, that asymmetry has a distinct negative impact
on the persistence of metapopulations. Detailed analysis however revealed, that
these previous studies might have been unable to properly disentangle the
effect of symmetry from other potentially confounding properties of dispersal
patterns. We resolve this issue by systematically investigating the symmetry of
dispersal patterns and its impact on metapopulation persistence. Our main
analysis based on a metapopulation model equivalent to previous studies but now
applied on regular dispersal patterns aims to isolate the effect of dispersal
symmetry on metapopulation persistence. Our results suggest, that asymmetry in
itself does not imply negative effects on metapopulation persistence. For this
reason we recommend to investigate it in connection with other properties of
dispersal instead of in isolation.
