Re-introduction of the Miami blue butterfly, Florida, U.S.A.

Summary

The Miami blue butterfly (Cyclargus thomasi bethunebakeri), presumed extirpated by the early 1990s and now endangered in Florida, survives only in a few isolated Lower Florida Keys populations with limited dispersal ability that make natural gene flow between them unlikely. A captive propagation program at the University of Florida's McGuire Center, founded in 2003 with 100 eggs from Bahia Honda State Park and regularly infused with fresh genetic material, produced 45 generations and more than 32,000 viable organisms by 2009, with microsatellite monitoring confirming both wild and captive populations retained high genetic diversity without inbreeding depression. A taxon working group directed reintroduction efforts beginning in 2004, following habitat surveys across 47 mainland localities and 23 islands, but site approval was constrained by stakeholder conflict with local mosquito control operations over buffer distances, limiting initial releases to a small number of conservation lands, which were then hit hard by prolonged drought and hurricanes over the following two years. Additional releases continued in 2007-2009, with all populations monitored 5-12 times annually and dedicated post-release surveys for three to six months after each release. Despite releasing more than 7,000 captive-bred butterflies across three recipient sites, no prolonged population establishment was documented at any location. Major difficulties included unresolved stakeholder conflict over mosquito control impacts, a resulting shortage of approved release sites, and drought and hurricane damage to host and nectar plants. The project rates itself a Failure, though the broader recovery program's research and education components retain value beyond the reintroduction attempts.