by A unique plant has become the first species in the United States to be driven from the wild by the compounding effects of rising seas, scientists say. It’s a bleak start, but not the last, as scientists fear the plant’s decline is a “bellwether” for other species as the climate crisis tightens its grip.
Due to the combined effects of sea level rise, rising tides and intense storms, the Key Largo wild tree cactus population became extinct in its only known location in the United States in the Florida Keys, according to the paper published this week in the Institute’s Journal Irish Botanical Research. Texas.
“This is just one example of what is happening to dozens of species, and people need to understand that if we don’t do something, this loss will accelerate,” said George Gann, study co-author and executive director. and president of the Regional Conservation Institute.
The Key Largo tree cactus still exists in parts of the Caribbean, including Cuba, Puerto Rico and the Bahamas, but the chances of it reestablishing naturally in the Florida Keys are essentially “zero,” Gann said.
There were about 150 individuals in 2011 on a barren intertidal rock atop a small limestone outcrop among an abundance of mangroves in John Pennekamp Coral Reef State Park. But by 2015, researchers noticed that the cactus was dying at an alarming rate, a consequence of a one-time animal attack, but also of its location on the low Florida Keys, most of which are just 5 feet above sea level. sea.
The plant’s habitat was being swallowed up by saltwater from storms and high tides were worsening due to rising seas. As fossil fuel pollution spreads up the planet, it also rises and expands the oceans and melts ice sheets and glaciers, raising water levels.
Sea levels around the Florida Keys are rising about 0.16 inches a year on average, or just over 8 inches since 1971, the researchers reported.
“Too much salt is just a stressful environment for most plants,” James Lange, study co-author and research botanist at Miami’s Fairchild Tropical Botanical Garden, told CNN.
Plants can tolerate brackish water for a few days, but when the timeline goes into weeks or longer, “their structures aren’t set up to deal with it because they’re not getting any fresh water anymore – they can’t feed their bodies. “
By 2021, after years of exposure, only a few cactuses remained. Researchers chose to remove them from the wild rather than let them die. The last wild straggler was removed in 2023 “because it was clear that the area will not continue to succumb to sea level rise,” the researchers said.
The loss of the species in the US is “a reflection of a larger problem,” Gann told CNN.
Sea levels are projected to rise by up to 7 feet by the end of the century around the Florida Keys, causing even worse tides and ocean water intrusion — an existential threat to many other species, he says scientists.
“Unfortunately, the Key Largo tree cactus may be the bellwether for how other coastal plants will respond to climate change,” said Jennifer Possley, lead author of the study and director of regional conservation at Fairchild.
Possley said more than 1-in-4 native plant species are critically threatened with regional extinction in South Florida. Among them are the rare flowering plant Spurge Garber, the small-flowered lilythorn, small-fruited varnish leaf and Grisebach’s morning glory.
And it’s not just plants. The encroaching saltwater is depriving local wildlife of fresh drinking water and forcing them to eat moisture-retaining plants such as cacti, exacerbating the problem for the threatened plants . To address this, biologists had to create small pools of fresh water to keep animals and plants alive.
But these solutions are only temporary. The amount of planet-cooking pollution already baked into the atmosphere is locked into decades of sea-level rise, making it challenging to protect biodiversity, researchers say.
The researchers rescued the last remaining cacti from the wild, covered them with towels for protection, and sent them away to an off-site greenhouse to ensure the survival of the plants.
Although there are plans to reintroduce the species to the Keys, researchers say it has been “difficult to find suitable habitat that can cope with the rapid climate changes”.
In the end, Key Largo’s tree cactus may not have a future in the wild made too wild by the climate crisis.
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