Trekking along the rocky slopes of Tonto National Forest in March, a group of Desert Botanical Garden researchers and biologists from two federal agencies carried heavy-duty spelunking duffel bags filled with precious and spiky cargo.
Inside them were 60 federally endangered Arizona hedgehog cactus (Echinocereus arizonicus subspecies arizonicus). And for the first time in about a year, they’ve returned back home.
The Arizona hedgehog cactus is threatened with habitat loss and had a known wild population of about 7,000 before the 2021 Telegraph Fire burned more than 180,000 acres near Superior. That included large sections of its habitat. The devasting wildfire prompted U.S. Fish and Wildlife Service and the Forest Service as well as the Garden to save this endangered cactus.
In a concerted effort, the organizations developed a strategy to harvest 300 cuttings of this subspecies, root them and transplant them back to their known habitat in order to restore its population. The plan involved using common horticulture practices not previously used for restoration projects involving endangered species. And it’s one of the latest Garden endeavors to conserve and protect desert plants of the Sonoran Desert.
“The Forest Service greatly appreciates the hard work of partners like Desert Botanical Garden as together we address the impacts of the Telegraph Fire. This restoration effort is likely an important test to see the effectiveness of supplementing AHC [Arizona hedgehog cactus] with plantings, and so far, we are thrilled with the positive results. Successful plantings can help supplement AHC populations impacted by the Telegraph Fire and are likely an important step towards the ultimate goal of recovery for the species,” said U.S. Forest Service Wildlife Biologist Camden Bruner.
The project began in 2021 after Garden researchers Raul Puente and Lane Butler and USFWS staff Kathy Robertson collaborated in 2020 to gain funding for the restoration effort.
Even before the devouring blaze of the Telegraph Fire, the endangered cactus had been at risk for four decades. Most cactus are slow growers and restoring them from seeds takes years, if not decades. However, the easiest way to propagate cactus is from cutting — a process that involves removing a part of the plant that can form its own root system and continue to grow as an individual plant.
Researchers carefully cut off each cactus’ stem, or arm, at its base from the parent plant. Then, treated both sides of the cut with agricultural sulfur powder to prevent infection. The detached stems were then brought back to the Garden to heal and be potted to root into new plants. This method of rooting succulent plants from cuttings is a common horticultural practice.
On April 7, the group returned to Tonto National Forest to plant the final 40 hedgehog cactus, which was no easy task.
“It’s a challenging feat. The team must unpot each cactus, wrangle it into a paper lunch sack and stack all the prickly, cactus-filled lunch sacks in the duffels. Then, they have to fill up our shower packs and one-gallon bottles for watering, bag them, carry the cactus and water on our backs and fronts to the site, where we flagged each microhabitat for planting,” said Garden researcher Lane Butler. “Some sites require us to hike further than others.”
Garden researchers intentionally chose areas that did not require them to use climbing equipment or be on a safety line. However, the Arizona hedgehog cactus typically prefers steep, rocky slopes and cliffs. The transplant sites reflect this, and some flags inevitably ended up perched over sheer, near-vertical spaces. Staff walked and planted the cactus with care, using hand picks to excavate holes large enough to hold each plant with its root ball. After replacing the soil around the new transplant, they made a small trough in the soil and watered their roots, a practice that can help ease transplant shock for the plant.
Now, the group will monitor rainfall and, if necessary, provide the transplanted cactus supplemental watering over the summer in order to ensure the plants’ establishment.
If this project is successful, it can help inform Garden researchers how to proceed with other endangered cactus restoration efforts. Twelve different species of hedgehog cactus are endangered or threatened globally, as well as cactus like Copiapoa species native to Chile. These cactus have the same cespitose (forming multiple stems) growth habit as the Arizona hedgehog cactus, so the methodology of this project could be immediately applied to them to in order to increase their populations.
Contributing author: Lane Butler.