image: Cacti are renowned for their diverse forms and beautiful flowers. view more
Credit: Jardín Botánico Regional de Cadereyta
Thirty-one percent of cactus species are threatened with extinction, according to the first comprehensive, global assessment of the species group by IUCN and partners, published today in the journal Nature Plants. This places cacti among the most threatened taxonomic groups assessed on The IUCN Red List of Threatened Species™ - more threatened than mammals and birds.
According to the report, cacti are under increasing pressure from human activity, with more than half of the world's 1,480 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% of threatened 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," says Kevin Gaston, from the University of Exeter, who co-led the Global Cactus Assessment. "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."
"These findings are disturbing," said Inger Andersen, IUCN Director General. "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. 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."
Other threats to cacti include smallholder livestock ranching affecting 31% of threatened species, and smallholder annual agriculture affecting 24% of threatened species. Residential and commercial development, quarrying and aquaculture - particularly shrimp farming, which expands into cacti's habitats - are also among major threats faced by these species.
Cacti 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.
Cactus species are widely used by people in the horticultural trade, as well as for food and for medicine. Their fruit and highly nutritious stems are an important food source for rural communities. The nutritional value of one cactus stem of Opuntia ficus-indica - a 'prickly pear' cactus popular in Mexico, where it is known as 'nopal' - is often compared to that of a beef steak, and the roots of species such as Ariocarpus kotschoubeyanus which is listed as Near Threatened, are used as anti-inflammatories.
Trade in cactus species occurs at national and international levels and is often illegal, with 86% of threatened cacti used in horticulture taken from wild populations. European and Asian collectors are the biggest contributors to the illegal cactus trade. Specimens taken from the wild are particularly sought after due to their rarity.
"The results of this assessment come as a shock to us," says 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. 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."
"This study highlights the need for better and more sustainable management of cactus populations within range countries. With the current human population growth, these plants cannot sustain such high levels of collection and habitat loss."
The illegal trade in cacti has been reduced to a certain extent by the inclusion, since 1975, of most cactus species on CITES appendices and through the increased availability of plants grown from seed on the international market. However, the threat of collection prevails, especially in countries where the implementation of CITES has only recently been enforced.
For example, the once-abundant Echinopsis pampana, endemic to the puna desert of Peru, has been collected illegally for the ornamental plant trade at such high rates that at least 50% of the population has disappeared in the last 15 years. Its loss is irreversible as the areas that were once populated by the species have since undergone land use change for housing purposes. The species is now listed as Endangered.
Cacti are renowned for their diverse forms and beautiful flowers. They are endemic to New World arid lands except for one species, Rhipsalis baccifera, which is also found in southern Africa, Madagascar and Sri Lanka. Hotspots for threatened cactus species include arid areas of Brazil, Chile, Mexico and Uruguay. These areas are perceived as uncharismatic and unimportant, even though they are rich in biodiversity, hence arid-land species like cacti are often overlooked in conservation planning. The report's authors highlight the need to broaden arid land protected area coverage and raise awareness about the importance of sustainable collection of cacti from the wild in order to better conserve the species.
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IUCN
Ewa Magiera, IUCN Media Relations m +41 76 505 33 78 e ewa.magiera@iucn.org
Lynne Labanne, IUCN Global Species Programme, m +41 79 527 7221, e lynne.labanne@iucn.org
About the University of Exeter
The University of Exeter is a Russell Group university and in the top one percent of institutions globally. It combines world-class research with very high levels of student satisfaction. Exeter has over 19,000 students and is ranked 7th in The Times and The Sunday Times Good University Guide league table, 11th in The Complete University Guide and 12th in the Guardian University Guide 2014. In the 2014 Research Excellence Framework (REF), the University ranked 16th nationally, with 98% of its research rated as being of international quality. Exeter was The Sunday Times University of the Year 2012-13.
The University has four campuses. The Streatham and St Luke's campuses are in Exeter and there are two campuses in Cornwall, Penryn and Truro. The 2014-2015 academic year marks the 10-year anniversary of the two Cornwall campuses. In a pioneering arrangement in the UK, the Penryn Campus is jointly owned and managed with Falmouth University. At the campus, University of Exeter students can study programmes in the following areas: Animal Behaviour, Conservation Biology and Ecology, English, Environmental Science, Evolutionary Biology, Geography, Geology, History, Human Sciences, Marine Biology, Mining and Minerals Engineering, Politics and International Relations, Renewable Energy and Zoology.
The University has invested strategically to deliver more than £350 million worth of new facilities across its campuses in the past few years; including landmark new student services centres - the Forum in Exeter and The Exchange at Penryn - together with world-class new facilities for Biosciences, the Business School and the Environment and Sustainability Institute. There are plans for another £330 million of investment between now and 2016. http://www.exeter.ac.uk/cornwall
About the University of Exeter's Environment and Sustainability Institute (ESI)
The Environment and Sustainability Institute is a £30M interdisciplinary centre, based on the Penryn Campus, undertaking cutting-edge research into solutions to problems of environmental change; in so doing it is enhancing people's lives by improving their relationships with the environment. The ESI has three research themes: clean technologies, natural environment, and social science and sustainability. It is engaging with hundreds of businesses in Cornwall, the Isles of Scilly and beyond to translate its research and expertise across these themes into innovative business practice, products and services.
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The University of Exeter and Falmouth University are founding partners in the Combined Universities in Cornwall (CUC), a unique collaboration between six universities and colleges to promote regional economic regeneration through Higher Education, funded mainly by the European Union (Objective One and Convergence), the South West Regional Development Agency and the Higher Education Funding Council for England, with support from Cornwall Council.
About IUCN
IUCN, International Union for Conservation of Nature, helps the world find pragmatic solutions to our most pressing environment and development challenges.
IUCN's work focusses on valuing and conserving nature, ensuring effective and equitable governance of its use, and deploying nature-based solutions to global challenges in climate, food and development. IUCN supports scientific research, manages field projects all over the world, and brings governments, NGOs, the UN and companies together to develop policy, laws and best practice.
IUCN is the world's oldest and largest global environmental organisation, with almost 1,300 government and NGO Members and more than 15,000 volunteer experts in 185 countries. IUCN's work is supported by almost 1,000 staff in 45 offices and hundreds of partners in public, NGO and private sectors around the world. http://www.iucn.org
About The IUCN Red List of Threatened Species™
The IUCN Red List is the world's most comprehensive information source on the global conservation status of plant, animal and fungus species - an invaluable conservation resource, a health check for our planet - a 'Barometer of Life'. It is based on an objective system for assessing the risk of extinction of a species should no conservation action be taken.
Species are assigned to one of eight categories of threat based on whether they meet criteria linked to population trend, population size and structure and geographic range. Species listed as Critically Endangered, Endangered or Vulnerable are collectively described as 'threatened'.
The IUCN Red List is not just a register of names and associated threat categories. It is a rich compendium of information on the threats to the species, their ecological requirements, where they live, and information on conservation actions that can be used to reduce or prevent extinctions.
The IUCN Red List is a joint effort between IUCN and its Species Survival Commission, working with its IUCN Red List partners BirdLife International; Botanic Gardens Conservation International; Conservation International; NatureServe; Microsoft; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas A&M University; Wildscreen; and Zoological Society of London. http://www.iucnredlist.org http://www.facebook.com/iucn.red.list @iucnredlist http://support.iucnredlist.org
About the Species Survival Commission
The Species Survival Commission (SSC) is the largest of IUCN's six volunteer commissions with a global membership of around 10,000 experts. SSC advises IUCN and its members on the wide range of technical and scientific aspects of species conservation, and is dedicated to securing a future for biodiversity. SSC has significant input into the international agreements dealing with biodiversity conservation.
Journal
Nature Plants