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Scientific Name | Conophytum subterraneum T.Smale & T.Jacobs |
Higher Classification | Dicotyledons |
Family | AIZOACEAE |
National Status |
Status and Criteria | Critically Endangered A3d; B1ab(iii)+2ab(iii) |
Assessment Date | 2021/12/09 |
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 4 km2. The dwarf succulents that comprise this genus have been increasingly targeted by illegal collection in recent years and the vast majority of species are in high demand by collectors. Whilst there is no evidence of illegal collection at the time of this submission, closely related species, including some from the immediate area, have been illegally removed from habitat with a dramatic increase in the number of species and volume of plants targeted since 2019. The threat of illegal collection is therefore regarded as very high for this particular species. The single location and very small population size of no more than 2,500 mature individuals makes the species very susceptible to very rapid declines. A complete decline of up to 100% of the population is very likely within the next thirty years (one generation). 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. While climate change is also highly likely to impact this taxon the rapid declines to the population as a result of illegal collection means it qualifies as Critically Endangered under criteria A3 and B1+2. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Northern Cape |
Range | This species is endemic to the Richtersveld region of the Northern Cape province of South Africa where it is only found in a single location with a very restricted geographic range. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Kahams Mountain Desert |
Description | This species is endemic to the Desert biome where it is found in the Gariep Desert bioregion. The plants occupy small gently sloping areas covered with quartz stones.
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 |
| This particular species is not currently threatened by illegal collection but it is likely that it will likely become a target in coming years as there has been a dramatic increase in the number of species and volume of plants of this genus targeted since 2019. Related species within the immediate area have experienced severe declines in population number due to illegal collection. Despite its remote location the single location and small population size makes the species highly susceptible to collection and a complete decline in the population is possible within a single generation (30 years).
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. 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 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, as this species possess certain morphological traits and has a semi-subterranean habitat that together indicate a likely level of resilience to climate change the expected population loss is reduced by 20% to 36%. Species in this genus have limited dispersal ability and migration to suitable habitats elsewhere is regarded as highly unlikely. |
Population |
This dwarf succulent species is only known from a single dense population of approx. 2,500 mature individuals (South African National Biodiversity Institute field survey 2021). Due to an extended drought in the Richtersveld that started in 2016 and is still ongoing at the time of assessment, the population is suspected to be declining.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Conophytum subterraneum T.Smale & T.Jacobs | VU D2 | 2020.1 | | Conophytum subterraneum T.Smale & T.Jacobs | Critically Rare | 2015.1 | | Conophytum subterraneum T.Smale & T.Jacobs | Rare | Raimondo et al. (2009) | |
Bibliography |
Desmet, P.G., Jacobs, T.L.K.F. and Smale, T.C. 2001. Conophytum subterraneum, a distinctive new species from the north-eastern Richtersveld, South Africa. Bradleya 19:15-18.
Hammer, S. 2002. Dumpling and his wife: New view of the genus Conophytum. EAE Creative Colour, Norwich.
Raimondo, D., von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. and Manyama, P.A. 2009. Red List of South African Plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
Snijman, D.A. 2013. Plants of the Greater Cape Floristic Region 2: The extra Cape flora. Strelitzia 30. South African National Biodiversity Institute, Pretoria.
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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 subterraneum T.Smale & T.Jacobs. National Assessment: Red List of South African Plants version . Accessed on 2024/12/06 |
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