Black-market collectors willing to pay hundreds of thousands of dollars for rare cactuses are putting more than 30 percent of the species at risk for extinction, according to a paper released Monday.

The first global assessment of the problem, completed by the International Union for Conservation of Nature, revealed that cactuses are the fifth-most-threatened group of species — topping mammals and birds. A small cactus with long thorns and brilliant flowers, the Echinopsis pampana, a native of Peru, has been stolen for the ornamental plant trade so much that at least half of the population has disappeared in the past 15 years. Photo by: Pete Cupial-Jones via Wikimedia Commons Download Full Image

Arizona State University conservation biologist and wildlife ecologist Jan Schipper contributed to the study. Deep-pocketed collectors hungry for the rarest of the rare are driving the trend, Schipper said.

“It’s not the quantity,” he said. “It’s like orchid collectors. They’re going after the rare stuff. They want the stuff no one else has. … Germany does a lot of this type of collecting. I’m not singling out a particular culture, but they do. People will fly to Mexico and go to some of these localities where cactus have been harvested in the past.”

The depletion is similar to what is seen in the theft, looting and trafficking of antiquities and archaeological treasures.

“Any time collectors after rarities are involved, you’re going to get that,” said Schipper, a conservation research postdoctoral fellow in a partnership between the ASU School of Life Sciences and the Phoenix Zoo-Arizona Center for Nature Conservation. “They pay hundreds of thousands of dollars, easily.”

Some species of cactus have tiny populations, as small as a single group on a hillside in remote areas, he said.

“Scientists have been studying populations for 10 years, and they go back and they’re all gone,” he said.

The seven-most-threatened taxonomic groups assessed on the IUCN Red List of Threatened Species are cycads, ancient seed plants that resemble palms (63 percent at risk for extinction); amphibians (41 percent); conifers (34 percent); warm-water reef-building corals (33 percent); cactuses (31 percent); mammals (25 percent); and birds (13 percent).

The findings are disturbing, said Inger Andersen, IUCN director general. The IUCN is the world’s oldest and largest global environmental organization.

“They confirm that the scale of the illegal wildlife trade — including trade in plants — is much greater than we had previously thought, and that wildlife trafficking concerns many more species than the charismatic rhinos and elephants which tend to receive global attention,” he said. “We must urgently step up international efforts to tackle the illegal wildlife trade and strengthen the implementation of the CITES Convention on International Trade in Endangered if we want to prevent the further decline of these species.”

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international agreement between governments aiming to ensure that international trade in specimens of wild animals and plants does not threaten their survival.

Eighty-six percent of threatened cactuses used in horticulture are taken from wild populations, the report said.

“European and Asian collectors are the biggest contributors to the illegal cactus trade,” the report read. “Specimens taken from the wild are particularly sought after due to their rarity.”

The results of the global health check came as a shock to Barbara Goettsch, lead author of the study and co-chair of IUCN’s Cactus and Succulent Plant Specialist Group.

“We did not expect cacti to be so highly threatened and for illegal trade to be such an important driver of their decline,” Goettsch said. “Their loss could have far-reaching consequences for the diversity and ecology of arid lands and for local communities dependent on wild-harvested fruit and stems.”

A small cactus with long thorns and brilliant red flowers, the Echinopsis pampana, native of the puna desert of Peru, has been stolen for the ornamental plant trade so much that at least half of the population has disappeared in the past 15 years. Places it could once be found in have now been covered by housing. The species is listed as endangered.

“I definitely didn’t expect cactus to come higher than mammals and birds in terms of threat, but it did,” Schipper said. “That kind of stuff can be controlled, it just needs legislative and legal framework and some law enforcement to back that up. … Most countries, especially in some of these areas, don’t have that capacity.”

“Recognition of the problem is the first step,” he added.

The study was released Monday in the journal Nature Plants.