Structured Landscapes Promote Persistence by Favoring Prudent Predators

AbstractEvolution can generate surprising outcomes. One such outcome is "adaptive decline," which occurs when a predator evolves to overexploit its prey, resulting in population decline of that predator and possibly even its extinction. Such a phenomenon has been theoretically demonstrated to occur in simple, well-mixed populations. However, in spatially explicit landscapes, a reduced population size may reduce the likelihood that one's progeny colonize a new patch. Thus, selection might directly favor larger population sizes, reducing adaptive decline. Here, we use a simulation model to investigate adaptive decline in multipatch landscapes. We find that landscape structure can have contrasting effects on adaptive decline: landscapes that comprise a greater number of interconnected patches exhibit less adaptive decline; however, reduced connectivity among patches increases the likelihood of extreme adaptive decline (i.e., adaptive decline leading to extinction). We highlight parallels between our work and both the evolution of virulence in host-parasite systems and the evolution of cooperation, where spatial structure typically facilitates reduced virulence and greater cooperation.