The Pleistocene re-wilding gambit.

Re-wilding parts of North America with exotic Old-World species is an exciting but controversial conservation proposal hijacked by opinions over appropriate conservation baselines and details of implementation. Debate over its worth has become partisan. Here, I summarize the multifaceted issues surrounding Pleistocene re-wilding and edge debate from hazy conceptual arguments to empirical questions that can plug gaps in knowledge and begin to resolve this divisive conservation issue.