evolutionary rescue

Gomulkiewicz R & Holt RD 1995 When does evolution by natural selection prevent extinction? Evolution 49:201-207.

• many examples are known in which populations have evolved sufficiently to persist in changed environments, such as cases of evolved resistance to pesticides or heavy metal toxins
• an important problem for evolutionary biologists is thus to characterize those combinations of genetic and demographic conditions likely to result in persistence versus those expected to lead to extinction in a changed environment

• as a population adapts to a novel environment, its density may fall below a critically low level for a period of time, during which the population is highly vulnerable to extinction by demographic stochasticity
• if this occurs, the population is likely to vanish before it can be rescued by evolution

• evolution by natural selection can affect population persistence by influencing population mean fitness

• the major effect of evolution is to prevent a population from deterministically reaching critically low densities altogether

• our analyses reveal what we suspect are general features of the interplay between evolution and demography in novel environments