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Scientific Name | Conophytum bilobum (Marloth) N.E.Br. subsp. claviferens S.A.Hammer |
Higher Classification | Dicotyledons |
Family | AIZOACEAE |
National Status |
Status and Criteria | Critically Endangered A4cd; B1ab(iii,v)+2ab(iii,v) |
Assessment Date | 2021/11/09 |
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 with an extent of occurrence (EOO) and area of occupancy (AOO) of 8 km², it is known from only one location. This subspecies has been subject to illegal collection of mature individuals for the international trade in ornamental succulents in 2020-21. The continued threat of illegal collection is therefore regarded as very high for this particular taxon and a decline of 100% is possible within the next ten years due to its highly restricted distribution and small population size. Anthropogenic climate change is another major future threat. Loss of vegetation cover has been observed via Landsat imagery between 1984 and 2018 and is used to infer that the habitat quality is already in decline. This taxon qualifies as Critically Endangered under criteria A4 and B1+2. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Northern Cape |
Range | This taxon is restricted to a small area within the Northern Cape province of South Africa. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Namaqualand Klipkoppe Shrubland |
Description | This taxon is endemic to the Namaqualand Hardeveld bioregion of the Succulent Karoo biome. Plants are restricted to a single quartz-rich mountain, often growing in partial shade. 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 taxon has been subject to illegal collection of mature individuals for the international trade in ornamental succulents in 2020-21. It has been sought after by collectors and is highly likely to remain so in future. The single site and small population size renders this taxon extremely susceptible to such activity. Another threat includes nomadic livestock grazing.
Anthropogenic climate change is a long-term threat to this taxon. 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 64% and 99% by 2080 for the species with the assumption that all subspecies will be similarly impacted. However, as this taxon possesses certain morphological traits likely to afford resilience to xerophytic conditions the expected population loss is reduced by 20% to 44% 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.
There is an inferred decline in habitat quality at the only known locality for this taxon based on the loss of vegetation cover determined from changes in Enhanced Vegetation Index (EVI) between 1984 and 2018 using Landsat data (Venter et al. 2020). |
Population |
Plants are only recorded from a single, range restricted population of 500-1,000 mature individuals. The population is declining rapidly due to illegal collection, with over 50% of the estimated population of 595 plants confiscated during 2021.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Conophytum bilobum (Marloth) N.E.Br. subsp. claviferens S.A.Hammer | VU D1+2 | 2017.1 | | Conophytum bilobum (Marloth) N.E.Br. subsp. claviferens S.A.Hammer | Least Concern | 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 bilobum (Marloth) N.E.Br. subsp. claviferens S.A.Hammer. National Assessment: Red List of South African Plants version . Accessed on 2024/12/07 |
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