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UArizona-led study warns worsening drought could push saguaros and other cacti toward the brink
Researchers modeled heat and drought stress on nearly 1,000 cactus species across the Americas and found that adding severe drought to climate projections sharply worsens the outlook â with saguaros among the species at risk. Lead author Michiel Pillet says he expects some species will be lost in the wild.
A new study led by researchers at the University of Arizona and the University of South Florida warns that continued extreme drought could leave future generations with far fewer cacti across the Southwest â including the saguaro, the towering icon of the Sonoran Desert.
The research team, led by Michiel Pillet, modeled how long-term extreme heat and drought could affect nearly 1,000 cactus species across the Americas. When the scientists factored severe drought into their climate models, the outlook grew markedly worse.
Pillet described the shift with a medical analogy: under drought conditions, the share of cactus species he characterized as "patients" â plants showing signs of sickness â rises from roughly six in 10 to seven in 10. The affected species are also "quite a bit sicker than we previously thought," he said.
In the field, researchers have observed cacti blooming less and ailing plants showing more severe symptoms than expected. Arizona researchers reported seeing more heat-related illness in cacti around the Valley last year.
Pillet was blunt about what the findings suggest for wild populations. "I am certain that we will lose some of these species in the wild," he said. "That is my personal opinion, but informed by science, unfortunately."
The stakes extend beyond the plants themselves. Cacti provide shelter and food for desert wildlife, and Pillet said the consequences of prolonged heat and drought ripple through the ecosystem. "It's not just the cacti that are important, but it's also animals that depend on those plants for survival through shelter and providing food," he said.
The findings land as Arizona confronts a deepening water crisis. Phoenix has been preparing for tighter water supplies and recently moved toward Stage 2 drought measures as officials warn that Colorado River cutbacks could further squeeze the region. Recent storms have lifted reservoir levels at Lake Powell and Lake Mead, but water managers caution that the gains do little to erase years of chronic drought.
For desert communities, the study adds a new dimension to those concerns: the possibility that the saguaro and other cactus species â long treated as symbols of resilience in an arid landscape â may themselves be vulnerable to the hotter, drier conditions scientists project.