But the International Union for the Conservation of Nature (IUCN)‘s first worldwide health check of the plants, published today in the journal Nature Plants, says that they are coming under unprecedented pressure from human activities such as land use conversions, commercial and residential developments and shrimp farming.
But the paper said the main driver of cacti species extinction was the: “unscrupulous collection of live plants and seeds for horticultural trade and private ornamental collections, smallholder livestock ranching and smallholder annual agriculture.”
The findings were described as “disturbing” by Inger Andersen, the IUCN’s director-general. “They confirm that the scale of the illegal wildlife trade – including the 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.”
The conservation group now judges cacti the fifth most threatened species on its red list of endangered flora and fauna, and is calling for an urgent ramping up of international efforts to tackle the illegal wildlife trade. Three of the IUCN’s five most threatened species to date are plants.
Cacti are almost always succulents but unlike most others, they store water in their stems alone, enabling them to survive extreme droughts. The plants can be as small as one centimetre in diameter and grow above 19 metres in height. Well over half of the species are used by humans for display ornamentation, food or medicine.
Almost 1,500 types of cactus were surveyed by the IUCN specialists over a five-year period, mostly in the Americas, where the plant is endemic.
Some, like the once-ubiquitous Echinopsis pampana, have seen population drops of at least 50% in Peru, due to plunder for the ornamental plant trade. The species is now listed as endangered.
“The results of this assessment came as a shock to us,” said Barbara Goettsch, the study’s lead author. “We did not expect cacti to be so highly threatened and for illegal trade to be such an important driver of their decline.”
Cacti are often dug up and exported off the books to Europe and Asia where rare species such as Ariocarpus can sell at prices of up to $1,000 (£660) a plant, Goettsch said.
Tackling the smugglers is a daunting task as the prickly cargo can be smuggled in suitcases or even socks. While countries such as Peru have made progress in blocking the illicit trade, the IUCN is calling for stricter implementation of the Convention on International Trade in Endangered Species (Cites) in the ‘hotspots’ of Uruguay, Brazil and Chile. Mexico has made advances but still has work to do, according to Goettsch.
Despite their charismatic flowers, and iconic status in popular culture, cacti are often overlooked in conservation planning. The report calls for a broadening of arid land protection to deal with human activities such as construction, quarrying and aquaculture.
Exeter University’s Professor Kevin Gaston, who co-led the assessment, said that the results showed how important funding for further scientific assessments is. “Only by so doing will we gain the overall picture of what is happening to them at a time when, as evidenced by the cacti, they may be under immense human pressures.”
