Abstract

Assisted migration is a controversial conservation measure that includes moving species threatened by climate change beyond their indigenous range. Sandler argues that assisted migration exhausts most of the value of the species moved and that assisted migration, thus, fails to be a workable conservation measure. We show how accepting the moral relevance of species' indigenous range helps to reconcile Sandler's argument with earlier arguments about value loss in ecosystem restoration by Elliot and Katz. Contrary to Sandler, they do not favour losing a biological unit to retaining it in a human-influenced form. Drawing on the distinction between property- and history-based understandings of naturalness, we further argue that the outcomes of assisted migration to the predicted range are more natural in the property-based sense of the term, and thus retain more value, than the outcomes of "assisted migration" elsewhere.