Date: February 23, 2017
Presenter(s): Shawn T. McKinney
Description: Extinction under environmental change is a race between demography and adaptive evolution. Evolutionary rescue (ER) occurs when genetic adaptation allows a population to recover from near extinction following rapid environmental change, with evidence coming from laboratory experiments and simulation modeling. Is ER feasible in natural populations? We evaluated the effect of community context on the likelihood of ER by examining species interactions across a geographic gradient of stress-induced mortality in whitebark pine, a species experiencing severe population decline. As mortality increased, cone production declined, seed predation increased, and avian seed dispersal declined, reducing the likelihood of resistant types increasing over time; a key component of ER. Evolutionary Rescue is improbable in whitebark pine because the severity of stressors, coupled with higher-level trophic interactions, limits natural selection. Without management intervention it will be difficult to prevent extirpation of high mortality whitebark pine populations, and possibly other species confronted with novel stressors and complex community interactions.