Evaluating the Assumptions behind Pleistocene Rewilding

Over 40 years ago, the Overkill Hypothesis proposed that predation by human colonists to North America caused the extinction of the Pleistocene megafauna. This model has been extended to contexts world-wide to explain extinctions. Recently, this model has been linked to conservation biology concerning appropriate benchmarks for species reintroductions. Overkill has been used to justify Pleistocene rewilding of North America holding that related taxa of extinct species should be reintroduced to restore biodiversity. Much of the argument assumes that island extinctions are analogous to the North American context. These assumptions are examined here by comparing paleozoological data from New Zealand to the evidence from North America. Population declines and extinction following colonization are well documented in New Zealand. In addition, New Zealand has an extensive record of conservation efforts. Thus, the New Zealand case provides an appropriate point of comparison to assess the viability of Pleistocene rewilding in conservation efforts.