The Point of No Return

Animal extinctions get lots of attention, but a recent study reminds us that many of the earth’s plants are on the brink of oblivion, too—specifically, cacti.

That’s right, our favorite scene-setters for Western films are going the way of the dodo. New research, published earlier this month in the journal Nature Plants, found that extinction threatens nearly 500 cactus species, including the highly cultivated Schlumbergera bridgessii from southeastern Brazil, a.k.a. the Christmas cactus.

“[Cacti] are fascinating plants with amazing adaptations to arid lands,” says lead author Barbara Goettsch, a researcher at the International Union for Conservation of Nature, or IUCN. “We assumed that many of them were threatened with extinction, but we didn’t know to what extent.”

Basing their findings on IUCN’s conservation-status criteria, Goettsch and her team found that almost one-third of the 1,500 cactus species are in danger of extinction. That makes these succulents the fifth most-threatened group ever assessed—behind cycad plants (63 percent), amphibians (41 percent), conifers (34 percent), and corals (33 percent).

Humans are a big part of the problem (shocking, I know). The conversion of dry lands into farms and housing developments bulldozes a lot of cacti habitat, but the major culprit, the researchers found, is the illegal collection of plants and seeds for the horticultural industry. Goettsch says cacti are often taken to Europe and Asia, where a single rare plant can be sold for up to $1,000. The study found that the illegal trade of plants and seeds affects a whopping 47 percent of the threatened cacti species.

The problem is so concerning that only a few experts know the location of one species, Mammillaria luethyi, to protect it from collecting.

While a 1975 international trade agreement has curbed the illegal cacti trade in some countries, Goettsch thinks governments—especially those with many threatened species, like Peru, Uruguay, Brazil, and Chile—could do more to keep these pointy plants out of the hands of smugglers. She also believes education programs can help communities protect their prickly plants.

Some cacti, especially those sold as decorative indoor plants, can grow relatively easy in farm-like environments, taking the pressure off of their wild counterparts. But farming cacti isn’t a panacea for all, says Goettsch. “Given the very adverse conditions of arid lands, I think many of the species propagated [off-site] and then planted in their natural environment would have a very small chance of survival,” she said.

And it’s not just cacti that are being trafficked into extinction. Wild orchids, big-leaf mahogany trees, and American ginseng are also becoming increasingly rare. “These results are shocking, and in order to understand what’s really happening with biodiversity, we should be generating this information for more plant groups,” says Goettsch. While the IUCN has assessed the conservation statuses for plenty of mammals, birds, and amphibians, only 6 percent of the more than 300,000 total plant species have been evaluated so far.

Plant lovers may covet the look of cacti, their spines often guarding bright, delicate flowers, but if we don’t take the steps to guard them, their beauty might be lost to everyone forever.