AFP, published on Saturday, April 16, 2022 at 08:06
About 60% of cactus species will face less hospitable climates in the coming decades due to global warming, according to a study by University of Arizona researchers, which challenges the hypothesis that these plants will thrive as temperatures rise.
If we add other factors (disappearing habitats, degradation of the natural environment, etc.), up to 90% of cacti could be at risk of extinction by 2070, three times what is currently estimated, the researchers say in this study published in Nature on Thursday Plant.
About 1,500 species of cacti, distributed across the Americas, live in diverse climates, from sea-level deserts to high Andes, from arid ecosystems to tropical rainforests.
Species-rich biodiversity hotspots are central Mexico and the Atlantic rainforest along the coast of Brazil.
To test the hypothesis that cacti would benefit from a warmer, more drought-prone world, the researchers, led by University of Arizona’s Michiel Pillet, examined data from more than 400 species and used models to predict their evolution in the mid-20th century. century to predict. Century horizon and beyond, corresponding to different scenarios of greenhouse gas emissions.
The results “paint a more pessimistic future,” the study said.
Currently, cacti are threatened mainly by the expansion of agriculture, degradation of the natural environment, loss of biodiversity, and their harvesting for various purposes.
Even without climate change, cacti “represent one of the most threatened groups of organisms on the planet,” with more than 30% of them classified as critically endangered, the authors note.
And global warming will soon become a threat, too, unless emissions are drastically reduced.
“Our results suggest that climate change will become a major contributor to cactus extinctions, with 60-90% of species assessed being adversely affected,” the researchers said.
By 2070, around 25% of cactus species could face an unknown climate in a quarter of their current range.
Previous studies have shown that photosynthesis – the process by which plants use sunlight to grow from CO2 and water – is affected by warming.