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Scientific Name | Conophytum bolusiae Schwantes subsp. bolusiae |
Higher Classification | Dicotyledons |
Family | AIZOACEAE |
Synonyms | Conophytum intrepidum L.Bolus, Conophytum obscurum N.E.Br. var. alticola L.Bolus, Conophytum obscurum N.E.Br. var. puberulum L.Bolus |
National Status |
Status and Criteria | Critically Endangered A4d; B1ab(iii,v) |
Assessment Date | 2021/11/15 |
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 succulent is endemic to the Northern Cape province of South Africa where it is only recorded from a single locality with an extent of occurrence (EOO) and area of occupancy (AOO) of 20 km². The only known population is experiencing decline due to the illegal collection for the ornamental succulent plant trade, with collection pressures likely to increase. Large numbers of plants have been illegally removed from habitat since 2019. The continued threat of illegal collection is therefore regarded as very high for this particular taxon given its single location and small population size. A decline of up to 90% of the population is likely within the next ten years due to this activity. It therefore qualifies as Critically Endangered under criteria A4 and B1. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Northern Cape |
Range | This succulent is endemic to a small part of the Northern Cape province of South Africa where it is only found in a single location with a restricted geographic range. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Vyftienmyl se Berge Succulent Shrubland |
Description | This succulent is only found on a single hill where, often large plants, are plastered to large quartz rocks, 500-750 m. The plants are mainly found in partial shade in kloofs. This taxon is endemic to the Richtersveld Bioregion of the Succulent Karoo biome. It experiences sporadic winter rainfall and is regularly exposed to coastal fogs which is regarded as a critical source of moisture. This taxon 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 |
| This subspecies is currently threatened by illegal collection for the international trade in ornamental succulents. The plants are severely range-restricted which renders them highly susceptible to a rapid decline in number through collection or other adverse events. The single location is well known for its succulent diversity and richness and has been regularly targeted by poachers in recent years.
Anthropogenic climate change is a long-term threat to this taxon. While it is not possible to model the response of this succulent to climate change due to its restricted distribution, the average loss to climate change for 21 more widely distributed Conophytum species occurring within the same region 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 56% and 86% by 2080 for Conophytum taxa within the region. However, a combination of certain morphological traits and a sheltered habitat indicates a likely level of resilience to climate change and the expected population loss is reduced by 20% to 36% based on the uncertainty of the response given the expected resilience of this taxon. Species in this genus have limited dispersal ability and migration to suitable habitats elsewhere is regarded as highly unlikely. |
Population |
This subspecies is locally abundant, forming large mature clusters. Population size (SANParks survey 2021) estimated to be more than 20,000 mature individuals. It is declining as a result of illegal harvesting for the succulent ornamental plant trade, with several thousand plants removed illegally in 2021 alone. It is highly likely to continue to be targeted in coming years. The limited geographic range makes the taxon highly susceptible to a rapid future decline in the population.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Conophytum bolusiae Schwantes subsp. bolusiae | VU D2 | 2015.1 | | Conophytum bolusiae Schwantes subsp. bolusiae | Rare | 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).
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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 bolusiae Schwantes subsp. bolusiae. National Assessment: Red List of South African Plants version . Accessed on 2024/12/07 |
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