Cacti Face Climate Risks, Too
Cactus are quintessentially known as plants able to survive extreme heat and long dry spells. But a new study finds that 60% of cactus species are at greater risk of extinction because of the hotter, dryer conditions created by climate change. Not all cactuses live in the desert, some grow in rainforests or on limestone cliffs, which is partly why so many species are in danger.
The study found outcomes to be fairly consistent when examining different levels of temperature rise in relation to about a quarter of all known cactus species. Essentially, researchers found that climate change is likely to be a driver of extinction or negative impacts for 60-90% of cactus species.
BBC: Past seven years hottest on record, EU satellite data shows, January 10, 2022.
12News: Saguaros, other cacti at risk of extinction according to UArizona study, April 12, 2022.
Why This Matters
Like most living things in the natural world, including humans, cacti coexist in balance with the conditions and other species within their ecosystem. What may seem like a small or slight disruption has the potential to throw off that balance.
"There are a lot of these tipping points and thresholds and interactions that are very fragile and responsive to changes in the environment, land use, and climate change,” David G. Williams, a professor of botany at the University of Wyoming who was not involved in the study, told the New York Times.
WW0 COP26 Talks: Dr. Cécile Girardin, Science Lead, Oxford Biodiversity Network, November 10, 2021.
The Economist: See what three degrees of global warming looks like, October 30, 2021.
Another Prickly Risk: Wildfire
The study looked only at risk factors of warmer temperatures and increased drought caused by climate change. But wildfires are also a danger, especially for saguaros in the US Southwest. In 2020, the Bighorn Fire burned thousands of the old-growth saguaros. Fires also decrease plant species that can buffer flames and protect the cactus. The invasive buffelgrass plant -- referred to as the Sonoran Desert's archenemy by the National Park Service -- sucks in limited water and fuels hotter wildfires. Because it isn’t native to the region, the surrounding plant life has not adapted to survive the heat intensity of its fires.
"If you have a buffelgrass fire in an alley in Tucson, it will melt someone’s car or chain-link fence,” Patricia Estes, who used to run a lab at the University of Arizona and founded a volunteer group to combat the buffelgrass, told the New York Times. The biggest threat for saguaros in climate change isn’t the heat or the drought. It’s [the] fire that sweeps in and burns extremely hot.”
According to a National Park Service report on climate change and the saguaro species, there basically haven’t been any new ones since the ‘90s.
KGUN9: Saguaro's Resilience | Local scientists discuss climate change impact, January 14, 2022.