Fig 5. Migration and size-dependent fragmentation rate allow multispecies communities to resist mutational meltdown.

Each panel shows, for each position in the strategy space, the maximum mutation rate a population can experience before going extinct (similar to Fig 3E). Columns (from left to right) depict increasing number of species. Rows depict: no size-dependent fragmentation and no migration (top); migration and no size-dependent fragmentation (center); size-dependent fragmentation and no migration (bottom). Grey squares correspond to communities for which the maximum mutation rate is outside the range of our simulations or numerical errors. For each value of mutation rate, we assessed ten replicates per fragmentation mode; we then calculated the mean (across replicates) of the logarithm of maximum mutation rate. Each point in the figure corresponds to a nearest-neighbour average of this quantity. Parameters: all parameters are set to the default values, unless otherwise indicated (Table A in S1 Text). Figs G and H in S4 Text comprise a wider range of values of σ and ν and depict raw values of maximum mutation rate (rather than nearest-neighbour averaged values).