Ex situ conservation of threatened plant species in island biodiversity hotspots: A case study from Hawai‘i

Abstract

Global plant extinction rates have increased dramatically over the past 50 years. Conservation efforts are especially challenging across the Hawaiian archipelago, where habitat loss and competition with invasive species threaten the existence of native plant species. Currently, 238 endemic Hawaiian plant species have fewer than 50 individuals remaining in the wild. To counteract this daunting statistic, conservationists apply a suite of ex situ techniques to effectively safeguard the many threatened plant species from imminent extinction. This perspective piece highlights how an integrated conservation approach that utilizes a co-located seed bank, micropropagation laboratory, and greenhouse, has led to the successful rescue and conservation of many threatened Hawaiian plant species. We draw on specific examples from the long history of Hawaiian plant conservation to detail successes and ongoing challenges associated with the implementation of ex situ conservation techniques. In doing so we discuss how plant micropropagation has emerged as a critical ex situ conservation tool, and how this underutilized tool fits into plant conservation as a whole. We also emphasize the essential roles that partnerships with external organizations play in ensuring that effective conservation efforts are implemented. Last, using lessons learned from these examples we detail and discuss an ex situ plant conservation decision tree that is widely applicable to other plant diversity hotspots of conservation concern, in order to help ensure regional and global zero-extinction goals are met.