Nearly 30 percent of 1,478 known cactus species are on the verge of extinction, according to a new report published yesterday in the journal Nature Plants.
Cacti in the Sonoran Desert. Image credit: Bob Wick / Bureau of Land Management / CC BY 2.0.
Cacti are members of the plant family Cactaceae. They are key components of New World arid ecosystems and are critical to the survival of many animal species.
They provide a source of food and water for many species including deer, woodrats, rabbits, coyotes, turkeys, quails, lizards and tortoises, all of which help with cactus seed dispersal in return. Cactus flowers provide nectar to hummingbirds and bats, as well as bees, moths and other insects, which, in turn, pollinate the plants.
According to the new report, cacti are under increasing pressure from human activity, with more than 50 percent of all cactus species used by people.
The illegal trade of live plants and seeds for the horticultural industry and private collections, as well as their unsustainable harvesting are the main threats to cacti, affecting 47 percent of threatened species.
Collectors from Europe and Asia are the biggest contributors to the illegal cactus trade. Specimens taken from the wild are particularly sought after due to their rarity.
“These findings are disturbing. 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,” said Inger Andersen, Director General of IUCN, who was not involved in the study.
“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 Species, if we want to prevent the further decline of these species.”
“The startling results reflect the vital importance of funding and conducting assessments of the threatened status of all of the species in major groups of plants, such as the cacti,” said co-author Dr Kevin Gaston from the University of Exeter, UK.
“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.”
Dr Gaston and his colleagues gathered data for each of 1,478 cactus species on their distribution, population trend, habitat preference and ecology, conservation actions, use and trade
“This included over 38,000 occurrence point records, which were used to generate preliminary range maps,” the scientists explained.
“This information was evaluated at a series of nine formal expert workshops, and then used by the participants to evaluate the extinction risk of each species using the IUCN Red List Categories and Criteria.”
“This study highlights the need for better and more sustainable management of cactus populations within range countries,” said study lead author Dr Barbara Goettsch, Co-Chair of IUCN’s Cactus and Succulent Plant Specialist Group.
“With the current human population growth, these plants cannot sustain such high levels of collection and habitat loss.”
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Barbara Goettsch et al. 2015. High proportion of cactus species threatened with extinction. Nature Plants 1, article number: 15142; doi: 10.1038/nplants.2015.142
