patterns (Figure \[fig:balanced\]) are observed.

In non-regular dispersal patterns the existence of isolated patches not participating in dispersal has an impact on the effective density of dispersal connections in the metapopulations [see also @Bode08]. Moreover, in the case of asymmetric dispersal there exist patches that either only receive or only provide migrants, i.e.*sinks* or *sources*, and that cannot actively take part in the metapopulation dynamics [@Artzy-Randrup10]. Since both of these effects are most distinct at small densities of the random dispersal networks, we assume that these differences basically drive the minor differences at low $L/N$ between our results on regular and the general case of random dispersal. Arguments for *not* assigning this effects to asymmetry in dispersal but to examine them separately are made in Section \[sec:conclusions\].

\[sec:discussion:prev\]Relation to previous works
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In general our results suggest essentially no direct negative effect of asymmetric dispersal on metapopulation viability at intermediate and high densities of the dispersal network, at least as far as the stochastic patch occupancy model applied in this work is concerned. This is in contrast to the findings in [@Vuilleumier06] where it was concluded that extinction risk significantly increased when dispersal became asymmetric. The analysis in [@Vuilleumier06] is 