Will fire forever change Arizona’s desert ecosystem?
A University of Arizona researcher is studying how fire affects the Sonoran Desert to help our rural / urban interface communities avoid increasing fire risks in the future.
Dr Ben Wilder is the director of the Desert Laboratory on Tumamoc Hill. From his office, Wilder had a panoramic view of last summer’s devastating Bighorn fire in the Santa Catalina Mountains.
The Tucson native is particularly concerned about the way non-native grasses, such as buxel, burn.
“Previously, until this invasive species attack that is really causing this increase in fires, you would only have fires in desert ecosystems like this after very wet winter rains or heavy rains. brought on by El Nino, ”Wilder said.
Wilder explained that when desert plants are so scattered, wildfires tend to be smaller and short-lived.
Some recent desert fires have affected massive and threatened homes, major highways and other structures. They include the 2005 Cave Creek Complex Fire, the 2020 Bush Fire in the Tonto National Forest, and the Bighorn Fire in the Tucson area.
“This is part of the bigger problem of climate change, because there will be a lot of climate-prone spaces that are very risky to live in and we have to adapt accordingly,” Wilder said.
FULL SECTION: Impact Earth
Dr. Wilder and his team started at Catalina State Park and climbed to an elevation of around 4,000 feet. In October, they set up 10 research plots, which were almost 50 feet by 50 feet squares. Half are in the burnt areas of Bighorn. The other half are in unburned control areas.
They will study plant recovery in these research plots for years to come.
“We’re going to repeat the photograph – matching the same images over time,” Wilder said. “A picture says 1000 words.”
The biggest question the UA team hopes to answer is whether fires, especially repeated fires, will change the ecosystem. Plants native to the Sonoran Desert, such as saguaro cacti and palo verde trees, can struggle to recover from a wildfire. However, buxel is fire tolerant and can invade the landscape.
Wilder wonders if the combination would create savannah-like conditions. If a forest fire were to start, grass fires could burn quickly and hot. This could endanger homes and lives at the desert-urban interface more quickly.
In the first few months after the Bighorn fire, Wilder saw some promising developments in the storylines.
“Some [native species], like the kind of limberbush right there and some palo verde have already had really high percentages of regrowth, which really surprised us, ”said Wilder.
Dr Wilder will be taking his next set of photos after the monsoon this summer.
The results of this study could guide public land managers and community leaders in Arizona to make better decisions about desert edge construction, invasive grass species, and fire protection.