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When the White Sage Fire swept the Kaibab Plateau last July, Clare Aslan and her students watched the satellite updates nervously as the flames encroached upon their monitoring sites. A rare, partially buried cactus the size of a French macaron grew in the direct line of fire.
Barred from checking on the botanical pincushions herself as the fire raged, Aslan grasped for a miracle — perhaps the highway, U.S. 89A, would intercept the flames before they got too close. Perhaps the heat would pass through quickly and leave behind mostly low-severity burns. Anything to help the Paradine plains cactuses ride out the fire.
“I didn't think that they would survive,” said the Northern Arizona University ecologist.
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Nearly three months later, Aslan finally returned to the fire scar north of the Grand Canyon to assess the damage. It was raining, and rivers of ash thundered over the landscape. A nearby rain gauge had partially melted in the blaze, its plastic body frozen into a wilt. Torched juniper and pinyon stood like wrought iron gates to a world turned cinder grey.x
Between the rivulets of ash, tiny flecks of green popped into view, the only signs of plant life around. Some of the Paradine plains cactus had survived. On the burnt terrain, the smattering of mute green might as well have been neon markers.
“I was blown away,” Aslan said. “They seemed to be doing far better than the things that were around them, which was pretty incredible.”
But the journey for the squat survivors is far from over. In a new study, Aslan and her team will monitor the recovery of the Paradine plains cactus for up to three years after the White Sage Fire. They’re concerned about whether it can still sustain pollinators and in turn produce new offspring the next year. Rebooting its lifecycle faces another challenge that might be more formidable than the fire itself: drought.
Cactus serves as early-spring pollinator hub
The most notable feature of the Paradine plains cactus is its puny stature. It belongs to the family of pediocactus — “pedio” means child-like, in reference to its small size — whose members are threatened by poachers feeding the cactus collection trade. Though not currently endangered, the Paradine plains cactus is a sensitive species that is closely monitored by government agencies so it doesn’t end up on the list with its other pediocactus cousins.
The cactus’s small build is only its tip. Like an iceberg, the rest of the plant body hunkers below the surface. Like a mole, the Paradine plains cactus can pull itself underground, which it does during the dry season and in the winter. It pokes its head out when monsoon rains inflate its roots, or during the spring to offer its flowers to pollinators.
Because of this subterranean lifestyle, Aslan thinks the cactus fared better than its taller neighbors in the White Sage Fire.
The tiny turtle cactus grows exclusively on the eastern face of the Kaibab Plateau near the Grand Canyon's North Rim. Starting from House Rock Valley 20 miles east of Marble Canyon, the terrain starts to climb, leaving sagebrush stronghold for ponderosa kingdom. Halfway up the incline, there among the liminal zone between the two ecosystems, nestles the Paradine plains cactus, numbering about 4,000 strong.
The Paradine plains cactus plays an important role in its environment. Come April, it’s the first to flower, decking itself with yellow hearts ringed by tall petals in all shades of ecru.
“When those pollinators are first coming out of their nests, this is one of the things that they can count on,” Aslan said. While the disappearance of the cactus wouldn’t crash the whole ecosystem, the solitary bees and hover flies that feed from its blooms would be the first to feel the pains.
Given its unique footprint, the cactus makes for a good indicator species for the health of the understory community in the aftermath of the White Sage Fire.
Aslan had been monitoring the cactus since 2021. Now, she has on hand the baseline data for comparing the effects of White Sage on the cactus population, and what the benchmark of recovery looks like.
Six parking lot–sized plots on the Kaibab plateau make up Aslan’s study. The goal is to track the lifecycle milestones of Paradine plains cactuses living there in the years after the fire. Her team will also use the results to make a judgment call on whether this species needs to be repopulated as part of the long-haul recovery efforts from the White Sage Fire.
Many steps toward a full recovery
In early July, Aslan traveled to the study site to peek at some of her cactuses just before they disappeared underground.
Finding these individuals was no small task. Under the shadows of charred juniper and pinyon pine groves, the Paradine plains cactus is easily the shortest thing around, if they haven’t already disappeared underground. Some new grasses had reasserted themselves, making the cactuses even harder to spot.
Starting this year, Aslan’s team will use high-resolution GPS with centimeter-scale precision to mark the location of individual cactuses to make them easier to track over time.
According to the post-fire assessment, most of the 59,000 acres in the White Sage Fire burned at low soil severity. The vegetation was harder hit, with certain slopes in mosaic fashion suffering full conifer mortality. Aslan estimates some 20% of the cactuses in her study sites perished.
Her study sites overall suffered mixed fire severity, and the damage among the cactus population was apparent. The injured had lobes or rings of sickly yellow. The dead were reminiscent of corn on the cob.
Splashes of green among the survivors were a promising sign. But it’s unclear how these individuals will fare in the long run. She’s also worried about the threat of erosion when the next rain hits, that these underground cactuses might be dislodged.
A month and a half ago, Aslan’s team made rounds, noting that the survivors flowered as usual per spring. Now, Aslan had expected to see some fruit, a sign of successful pollination. She found none.
The definition of post-fire recovery comes in many layers, requiring long-term studies to understand the full picture. And there’s a complication: A nearly-30-year megadrought looms in the background, threatening the rebound of the ecosystem.
Tree-ring studies have found that the American Southwest has been in its driest stretch since AD 800. The signs of drought have manifested as increasing wildfires, plunging water levels in rivers and lakes, dwindling groundwater supplies, leaving 91% of the American West in a drought.
The last megadrought to strike the region was in the late 1500s. Researchers point to climate change for throttling the current dry period to a mega status.
“The big question is, what comes back after a fire, when it also has to deal with extreme drought?” Aslan said.
The search for reproductive success among the Paradine plains cactus isn’t over. In the fall, Aslan plans to return for the “babies” that might have sprouted this season. Fruit production is a water-intensive process, so she suspects that the Paradine plains cactuses might be taking a hiatus after the tumult of the White Sage Fire, then restart their natural rhythms the following year.
Still, she is heartened that more than a handful of cactuses made it through the White Sage, a crucial first step. Did they just get lucky?
“I do suspect that they may actually be a little bit more resilient,” she said.
Fire is an ecologically important player in Arizona’s forests, helping recycle nutrients, prune the understory and spark the germination of seeds. But there’s a limit to what the Paradine plains cactus and its fire-adapted community can tolerate.
“When you put the two together, so fire being a disturbance and drought being a stress,” Aslan said, “sometimes that overwhelms what (plants) are able to do.”
Shi En Kim covers environmental issues for The Arizona Republic and azcentral. Send tips or questions to [email protected].
Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust.
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This article originally appeared on Arizona Republic: A tiny cactus holds clues to forest recovery after Arizona wildfire
