Extinction In Wild Of Florida Keys Cactus Confirmed; Wiped Out By Rising Sea Levels, Saltwater Intrusion

Scientists in Florida have recorded what they say is the first local extinction of a species caused by sea-level rise. The climate emergency has killed off the Key Largo tree cactus growing naturally in the US through saltwater inundation and soil depletion from hurricanes, according to researchers from the Florida Museum of Natural History, and Miami’s Fairchild Tropical Botanic Garden.

The species, which is now found only on a handful of remote Caribbean islands, northern Cuba and areas of the Bahamas, was already down to only a single population of six stems in the Florida Keys. Those were removed to a greenhouse in 2021 to ensure the species’ survival, and frequent searches since have revealed no naturally growing Key Largo cactuses. There is also little prospect of it re-establishing itself, despite “tentative plans” with the Florida department of environmental protection (DEP) for a small-scale replanting project.

About 90% of the low-lying Florida Keys island chain is at 5ft of elevation or less, with Nasa predicting future ocean rise of up to 7ft by 2100. “Unfortunately, the Key Largo tree cactus may be a bellwether for how other low-lying coastal plants will respond to climate change,” said Fairchild botanist Jennifer Possley, lead author of a study published Tuesday in the journal of the Botanical Research Institute of Texas that chronicled the species’ decline.

The scientists say they noticed the population of Pilosocereus millspaughii in the Keys was already ailing in 1992, when it was first discovered to be a separate species to the Key Tree cactus, which is similar in appearance and present elsewhere in the Keys, although also in declining numbers.

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https://www.theguardian.com/us-news/article/2024/jul/09/florida-key-largo-tree-cactus-extinct