Utah scientists get dirty to save threatened cactus

(Chris Caldwell | The Spectrum via AP) Botanists gather Siler pincushion cacti near the White Dome Nature Preserve on Wednesday, Oct. 21, 2020, in St. George. The species moved from endangered to threatened in 1993; however, the numbers are slow to increase as development moves in on their habitat.

St. George • Blake Wellard holds a middle-aged cactus in his hand, its long tendrilous roots dangling a foot and a half below the clod of desert dirt in which they are, purposefully, still enmeshed. The freelance botanist, as Wellard calls himself, knows that having these delicate and desiccated roots intact will be the key to this threatened Siler pincushion cactus’ survival in its new home, just a few miles down the road at the White Dome Nature Preserve south of St. George.

Fewer than 10,000 individuals remain worldwide of the Siler pincushion cactus, according to a 2006 survey that Wellard fears is now an overestimate. The species was listed by the U.S. Fish and Wildlife Service as endangered in 1979 and improved to threatened status as of 1993. But recent spates of drought and development in southern Utah have likely weakened its foothold on our planet once again.

One reason for its fragility is that the Siler pincushion cactus only grows on gypsiferous soils (soils high in the whitish mineral, gypsum) in southern Utah and northern Arizona. It cannot be cultivated in a nursery or grown from seed in a lab. As Kristine Crandall, a volunteer working with Wellard, put it, “This incredibly rare cactus just happens to love this exact place.”

Problem is, the particular patch of gypsiferous soil on which Wellard is standing has been slated for development. So it’s time for the cactus to go — something most plants need a little help doing.

On a quickly warming October morning, The Nature Conservancy arrived onsite to survey and excavate as many of these pincushion cacti as possible before the bulldozers arrive, the timeline for which remains unclear. So far, Wellard and others working with TNC have tagged 67 cacti for removal, marking each with a thin metal stake topped with a blue number tag. They expect to transport up to 75 of these spiky globes to a new home in the White Dome Nature Preserve, where protections enabled by TNC should prevent them from having to uproot again.

Although the federal Endangered Species Act usually protects critical habitat for listed species from development, the state of Utah has chosen to exempt land owned by the Utah School and Institutional Trust Lands Administration (SITLA) from this requirement, Wellard explained. That includes this gypsiferous expanse of gently rolling hills, crusted with biological soils and dotted with the woody shrub known as Mormon tea.

The cactus Wellard holds in his hand is pincushion number 15. He has extracted it from the place where it has spent its approximately decadelong life as carefully as if he was working on an archaeological dig. First the scientists dig a trench a few inches deep around the cactus in a circle about 2 feet in diameter. Next they use fingers and trowels to tease the brittle but vital roots free from the soil.

Utah state botanist Mindy Wheeler said she does occasionally get pricked by cactus spines. But she doesn’t seem to mind. For her, the chance to save one of Utah’s approximately 300 sensitive plant species is worth it.

“This is not easy work. Even thinking about this last night, I was stretching out a bit,” Wheeler said. “But biodiversity is really our friend. We’re all connected in terms of how we support each other. This cactus could have some really interesting DNA sequence or something that we have yet to learn, that could really boost science in a direction we never thought of.”

The team is aiming for a 60% success rate with these uprooted cacti thriving after relocation. In addition to having to tap into a new underground network of water, nutrients and beneficial fungi at the next site, the cacti will have to put down new roots to keep from blowing across the landscape like so many tumbleweeds. They will then face the hazard of rodents gnawing at their tissue for moisture and the risk that their pollinators may not get their forwarding address.

But the fact that the odds are stacked against the Siler pincushion is precisely the reason Wellard is spending his morning kneeling in the dirt trying to save it. He has been charmed by this species “hedging its evolutionary survival on these isolated gypsum soils.” Though he’s been working with cacti for over a decade, he hadn’t yet had a chance to get his hands on this beauty. For him, today is a passion project.

“It actually kind of hurts to have to dig these up at all,” Wellard said, blowing some dust off the top of cactus number 15 so he could examine and show off its faded yellow blooms. “But I’m so grateful that we have an opportunity to save these, because so often there’s not opportunities to save endangered plants before development.”

Wheeler hauls over a black plastic bin from the truck, already brimming with baseball-sized cacti that the botanists estimate are eight to 10 years old and football-sized cacti that might be up to 30 years old. Cactus number 15 is surprisingly heavy, having collapsed much of its tissue down to a denser state to cut back on its water needs over the winter.

It has also scaled back activities like photosynthesis and nutrient transport between its tissues, Wheeler explains. This ability to power down or go dormant through periods of drought is one strategy desert plants have adopted in order to survive St. George’s infamous hot and dry spells.

The hope is that, next spring, cactus number 15 will swell. Having had its roots surgically inserted into new gypsiferous soils by the careful hands of Wellard, Wheeler, Crandall and others, it will wake up in a new place and hopefully not know the difference. It will draw up spring moisture through its root network, plumping existing tissue and pushing out new flower buds. The bees that specialize on cactus pollination will visit the yellow blossoms atop spiky globes that dot this unique landscape. And the resulting seeds will then rise as the next generation of Siler pincushion cactus, observable from the public trails through the White Dome Nature Preserve.

Meiners is an Environment Reporter for The Spectrum & Daily News through Report for America, a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues.