the same conditions but antisymmetric dispersal ($\gamma=0$) was $62.7$. For $L/N=2$ the mean size of the largest cycles was $77.5$ for the symmetric dispersal matrices generated, whereas for the asymmetric case all dispersal matrices already extended to the entire metapopulation (i.e. their mean size was $100$). Hence we are faced with a percolation problem on random graphs [@Callaway00], where the percolation threshold depends on the symmetry properties of the dispersal pattern. Analysis of the eigenvalues of associated state transition matrices reveals, that the mean time to extinction of a set of patches participating in a closed cycle of dispersal increases with the size of the cycle. For this reason differences in viability at small $L/N$ are attributed to hierarchical differences of the generated matrices at only a few number of connections, namely $L/N\le
3$. This density is much smaller then relevant cases discussed e.g.in [@Vuilleumier06] as will be discussed in more detail in Section \[sec:discussion:prev\].

![\[fig:E50-itime\]Extinction statistics for the metapopulations with different values of the colonisation probability $c$ connected through dispersal matrices with $\gamma=0.5$ and $L/N=4$. The individual lines indicate the number of non-extinct simulations (out of $1,000$) as a function of the simulation time. The dashed line corresponds to 