It took two years from proposal to acceptance. But apparently the Colorado hookless cactus is hardy fauna by nature, and so the delay in the U.S. Fish and Wildlife Service bureaucracy was not a prickly problem for the perennial plant.
After first being touted for removal from the endangered species list in 2023 because of a promising recovery, the little pink-blooming cactus is now officially “off.” The service said the upgrade “reflects ongoing conservation efforts,” and gave a shoutout to partners like Denver Botanic Gardens in the process.
Why “hookless” in the name? Most cactus’ central prongs are bent into some kind of hooked shape – while the Colorado hookless is just that, a cactus with very straight spines.
It also has blooms that plant experts declare to be enchanting, especially when encountered in the arid backcountry of the Upper Gunnison and Upper Colorado river basins.
The Botanic Gardens had been warning for years that oil and gas development in the West and other pressures were threatening the rare cactus. More “who knew”: There are also flora poachers who scoop up the hookless cactus and sell them on the internet to unscrupulous fanciers.
Researchers are celebrating the official cactus delisting as a success story. “It feels good,” Denver Botanic Gardens expert Michelle DePrenger-Levin said, to know that “yes, this beautiful cactus will be here to stay.”
DePrenger-Levin calls the Colorado hookless alternately an “adorable” or a “gorgeous” small cactus, usually found about 2 to 5 centimeters wide in the wild, and about that same height, though certain specimens can grow up to 20 centimeters.
What makes them “gorgeous,” she said, are the “lilac-purpley flowers, you might have two up to maybe 10 flowers right at the tip, that wait until it is about noon and the warmest and sunniest to open. And they open for only a few days in a row until they’re done, to try to get all the bees and get pollinated.”
The cactus variety was first listed as threatened in 1979, and is part of the Colorado Natural Heritage Program tracking locations and counts of all the threatened species. Denver Botanic Gardens has been going into the field since 2008 to help with counts and habitat studies for the hookless cactus, and also helping determine that there are near-twin varieties nearby in the Southwest.
A big part of the work is hiking out to stake sampling plots to get representative counts of the cactus. In that plotting, gardens researchers helped the BLM and others boost the known count of the cactus from about 20,000 individuals to “at least 68,000” for Sclerocactus glaucus in the southern range, and at least 17,000 individuals of a newly named additional species in the northern range.
Researchers track the plots through the plant’s lifecycle, including the demanding task of chipping cactus seeds the size of sesame seeds under a microscope in order to open them up for watering and propagation.
Over the years, the boosted count and a better understanding of how the hookless cactus survives severe drought helped everyone move toward delisting.
“The combination of knowing that there’s way more plants than we previously thought, and that they are responding OK when we’ve had some pretty severe drought, so we know we can make some predictions about how they will continue to respond into the future,” DePrenger-Levin said.
Gardens researchers say there were 15 other Colorado plant species in 2022 listed as threatened or endangered, and they help track and conserve many of them.
The delisting process includes long-term tracking of any species that manages to get off the more threatened categories, DePrenger-Levin said – it’s not just “good night, and good luck.”
“Even though the plant is no longer listed, we have a plan for continuing to monitor for the next 10 years, and then we have set thresholds of when we say, ‘Yes, it is still stable or increasing. Populations are fine. All this is working.’ Or,” she added, “if populations are declining and they drop below the threshold, then Fish and Wildlife should initiate another formal status review, and we will assess if relisting is appropriate. So we’re not ignoring the species.”
