One tiny cactus could be key to understanding post-wildfire recovery

“When the Dragon Bravo and White Sage fires roared through northern Arizona last summer, they didn’t just destroy the Grand Canyon Lodge and hundreds of thousands of ponderosa pine trees. They also affected a humble yet ecologically important native succulent: the paradine plains cactus. It’s not a plant many Four Corners visitors are likely to notice. Shaped like a tiny green hedgehog, the paradine plains cactus grows just an inch or two above the ground and could fit in the palm of your hand. In winter, when it’s cold and dry, the entire plant often recedes underground, lying dormant until warmer and wetter conditions return. When Clare Aslan , an associate professor in NAU’s School of Earth and Sustainability, heard the White Sage Fire had spread across much of the plant’s native range, she worried the species would suffer irreparable damage. “I knew some really high-severity burns had occurred right where these cacti grow,” Aslan said. “I went up there in October, right after the fire was 100% contained. I saw that lots of them were very charred, but to my surprise, some areas were totally black except for these little green dots. It was the cacti. I thought, ‘How is this even possible?’” Thanks to a grant from the U.S. Forest Service, Aslan is about to find out just how resilient these succulents can be. Over the next three years, Aslan and assistant professor Sara Souther will venture out to a series of White Sage Fire burn sites on Forest Service land and monitor the lifecycles of every cactus they find. While they’ll take note of cacti that were completely charred by the fire and cacti that remain completely green, they’re most interested in the plants that have burned outer spines but remain green in the center. “We’re studying those most closely to find out whether they make it in the long term—whether they regrow or not,” Aslan said. “We’ll also track reproduction. Some plants look like they’re not reproducing this year, but we’ll see if that changes in the future. If it does, we’ll be able to see new baby plants appear.” Aslan said the work will help the Forest Service understand which fire-burned areas need restoration work and which are better left to regenerate on their own, allowing them to allocate taxpayer dollars more wisely. “They have to be careful with limited resources,” Aslan said. “If we’re seeing sites that are more resilient, that seem to be recovering just fine, they might skip restoration in those areas and save it for other sites that need it more.” But the study’s impact could extend far beyond succulents in the Southwest. About a quarter of the U.S. has been in a megadrought since the year 2000. Ecologists like Aslan have measured the effects on plants in a wide variety of biomes, from the coast to the desert—and they’re worried. “There’s a strong drought response in these plants,” Aslan said. “Plant diversity has taken a hit. There are fewer pollinators. A lot of the ecosystem is at its limit now; the plants don’t have many free resources. To add a big fire on top of that is incredibly damaging and could make it really hard for plants to recover.” And yet, as Aslan has seen, some plants do recover—including some small succulents like the paradine plains cactus. If ecologists can monitor plants across all fire-prone areas and track which species do and do not recover well without human intervention, governments can do a more effective, efficient job at preserving these environments in the future. “In lots of places, from California to Minnesota, we’re getting bigger fires and more prolonged droughts,” Aslan said. “Understanding how our plant communities can make it through those kinds of shocks is a huge question in restoration. If we can identify sources of resilience, we could help improve resilience across all our ecosystems.” Jill Kimball | NAU Communications (928) 523-2282 | jill.kimball@nau.edu

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