Florida’s Key Tree Cacti (Pilosocereus robinii and Pilosocereus millspaughii): Charismatic Megaflora at the Forefront of Sea Level Rise

Dense stands of columnar ‘tree cacti’ similar to those in the Greater Antilles were once found in the Florida Keys, but harvesting, habitat loss, damage from mammals, climate change, and sea level rise led to a population crash that landed the cactus on the US endangered species list in 1984.  Fairchild Tropical Botanic Garden’s conservation team began working with the species in the mid-2000s, under the tenure of Conservation Ecologist Dr. Joyce Maschinski. In the ensuing 15+ years, the team collaborated with other stakeholders to build a comprehensive conservation program for the species. Efforts included establishment of a “Key Tree Cactus Preserve;” annual, range-wide population monitoring; in situ ecological studies; an ex situ salinity study; development of horticultural methods; seed banking; plant rescues; genetic research; and several experimental reintroductions to (relatively speaking) higher elevation sites throughout the species’ natural range. Research revealed some surprises, and Mother Nature dealt some tough blows, but stakeholders are committed to working together in perpetuity, ex situ reserves are well-stocked, and hopes remain high for success of the recent round of reintroductions.