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Scientific Name | Conophytum ratum S.A.Hammer |
Higher Classification | Dicotyledons |
Family | AIZOACEAE |
National Status |
Status and Criteria | Critically Endangered A4d; B1ab(iii,iv,v) |
Assessment Date | 2021/12/02 |
Assessor(s) | A.J. Young, P.G. Desmet, I. Ebrahim, D. Guo, A. Harrower, L. Jabar, L. Knoetze, C. Rodgerson, P.C.V. Van Wyk & N.N. Mhlongo |
Justification | This dwarf succulent species is endemic to the Northern Cape province of South Africa with an extent of occurrence (EOO) of 74 km2 and area of occupancy (AOO) of 36 km2. It is currently only known from a single location consisting of approx. 1,200 mature individuals with plants at a second location believed to have been removed by illegal collection. The population is experiencing ongoing decline due to mining and illegal collection for the ornamental succulent plant trade, with collection likely to increase as there has been a dramatic increase in the number of species and volume of plants targeted since 2019. Loss of vegetation cover has been observed at this site via Landsat imagery between 1984 and 2018 and is used to infer that the habitat quality is already in decline. The continued threat of illegal collection is regarded as very high for this particular species given its limited geographic distribution and very small population size. A complete decline of up to 100% of the population is likely within the next thirty years (one generation). It therefore qualifies as Critically Endangered under criteria A4 and B1. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Northern Cape |
Range | This species is endemic to the Northern Cape province of South Africa. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Aggeneys Gravel Vygieveld |
Description | This species is primarily known from a single quartz-rich inselberg in Bushmanland in the Nama-Karoo biome. The plants are found both on the top of the inselberg where they grow on firm quartz-covered soil alongside a number of other dwarf succulents, and on the surrounding quartz flats where the substrate is generally softer.
This species has a generation length of 30 years. It is expected to be sensitive to the impacts of climate change as it does not disperse and while adapted to arid conditions, is dependent on limited seasonal rainfall. Species in the genus are sensitive to long periods of drought. Drought related mortality has been observed for other closely related taxa within the genus. |
Threats |
| Mining activities are a serious threat to the survival of this succulent. The main subpopulation lies within and adjacent to the site of a major mine located at an inselberg in Bushmanland. Since the opening of the mine in 2015 these activities have resulted in severe and ongoing habitat loss and degradation and the associated loss of plants. Loss of habitat to mining remains a future threat to the majority of the remaining population. This species is increasingly popular in cultivation and highly sought after by collectors. Despite the cryptic nature of the plants illegal collecting is a potential problem. The species has disappeared from several sites known through historical records, which is suspected to be the result of illegal collecting. One subpopulation is known to have been cleared out by plant collectors. The small population size and limited geographic range make it very susceptible to illegal collection as it would be possible to remove most of the remaining plants in a very short period. As a result a population decline of 90-100% is suspected over one generation (30 years).
While it is not possible to model the response of this species to climate change due to its restricted distribution, the average loss to climate change for 14 more widely distributed Conophytum species occurring within the same area is used as an indication of likely impact to this species. Climate models for the likely emission scenarios where emissions stay at present day levels (RCP 2.6) (Hausfather and Peters 2020) and worst case scenarios where emissions continue to increase during the 21st century (RCP 8.5) indicate that there will be a loss of suitable bioclimatic envelope of between 32% and 81% by 2080 for Conophytum taxa within the region. However, as this taxon possesses certain traits likely to afford resilience to xerophytic conditions it is expected to have a level of resilience to climate change and the expected population loss is reduced by 20% to 12%. Species in this genus have limited dispersal ability and migration to suitable habitats elsewhere is regarded as highly unlikely. Loss of vegetation cover has been observed across the geographic range occupied by this species via Landsat imagery between 1984 and 2018 indicating a decline in habitat quality. |
Population |
The largest known subpopulation of this species consists of approx. 1,000 mature individuals. This subpopulation is in decline due to ongoing habitat loss and degradation due to mining. There are a few historical records from other sites local to the area, but several recent field surveys failed to relocate the species at any of these sites. These were probably small, unviable subpopulations. The semi-subterranean habit of the plants makes them highly cryptic and possibly undercounted.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Conophytum ratum S.A.Hammer | CR B1ab(iii,v)+2ab(iii,v) | 2017.1 | | Conophytum ratum S.A.Hammer | VU A4acde | Raimondo et al. (2009) | |
Bibliography |
Hammer, S. 2002. Dumpling and his wife: New view of the genus Conophytum. EAE Creative Colour, Norwich.
Hammer, S.A. 1993. The genus Conophytum: A conograph. Succulent Plant Publications, Pretoria.
Hausfather, Z. and Peters, G.P. 2020. Emissions - the 'business as usual' story is misleading. Nature 577(618-620).
Opel, M.R. 2004. The rediscovery of Crassula alcicornis. Haseltonia 10:38-40.
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Citation |
| Young, A.J., Desmet, P.G., Ebrahim, I., Guo, D., Harrower, A., Jabar, L., Knoetze, L., Rodgerson, C., Van Wyk, P.C.V. & Mhlongo, N.N. 2021. Conophytum ratum S.A.Hammer. National Assessment: Red List of South African Plants version . Accessed on 2025/04/22 |
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