Populations of at-risk butterfly species are declining at an alarming rate. Conservation strategies emphasize a mix of restoration of butterfly habitat, captive propagation, and reintroduction of butterflies to repopulate sites at which populations have gone extinct and to augment declining populations. We review the use of these strategies to conserve butterflies for 25 British species with Species Action Plans and 25 American species listed as Endangered, Threatened, or Candidate under the US Endangered Species Act and found in the continental US. Based on a broad review of published and unpublished literature and 47 interviews with agency staff, we find that the majority of species require active restoration (n = 47 of 50) and that most species receive restoration enhancements (n = 45), but only for a few species are ecological responses to this management monitored (n = 15). In addition, we find that most conservation strategies recommend reintroduction (n = 34) and it has been attempted for 21 British species but for only 5 American ones. Captive propagation is recommended for 12 of 25 American species and has been attempted for 8. Documentation of both reintroduction and captive propagation is limited, with the number of founders known for just over half of the species. We conclude that advancing butterfly conservation will require systematic recording and communication of activities in readily accessible venues, improved experimental design and monitoring, enhanced use of ecological modeling, and improved knowledge of species-specific biology. Project designs that connect on-the-ground efforts to ecological responses of at-risk butterfly species would have tremendous impacts on our ability to use scarce resources to recover these species.

In: Israel Journal of Ecology and Evolution