The spatial position of dispersal corridors connecting subpopulations in a metapopulation can affect persistence and growth. Such corridors may be distributed very evenly such that all subpopulations are equally connected to their neighbors, or they could be clumped, leaving most subpopulations connected to only one or two neighbors while a few hub subpopulations are more highly connected. Following local extinction, highly connected subpopulations are more likely to be rescued by migration from neighbors, and therefore a metapopulation containing highly connected subpopulations is predicted to have a higher probability of recovery following disturbance than a metapopulation with fewer highly connected subpopulations. However, the role of connectivity of the extinct subpopulation remains largely unexplored.
Here I tested the prediction that metapopulations would recover from the extinction of highly connected subpopulations faster than from the extinction of poorly connected subpopulations by comparing replicate metapopulations of the bacterium Pseudomonas syringae cultured in Metapopulation Microcosm Plates, devices I design and build which resemble 96-well microtiter plates with corridors connecting the wells to form metapopulations with 96 subpopulations. I compared the time to recovery of metapopulations following the extinction of highly connected subpopulations to those following the extinction of poorly connected subpopulations.
Results/Conclusions
Following extinctions in highly connected subpopulations, P. syringae metapopulations recovered to their pre-disturbance abundances faster than following extinctions in evenly-connected metapopulations, while metapopulations recovered from extinctions in poorly connected subpopulations more slowly than those in evenly-connected metapopulations. Likely due to the high probability that they would remain connected to an occupied subpopulation, extinct highly connected subpopulations were quickly re-colonized while those that were poorly connected had a much longer and more variable time to re-colonization.