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Scientific Name | Conophytum angelicae (Dinter & Schwantes) N.E.Br. subsp. tetragonum Rawé & S.A.Hammer |
Higher Classification | Dicotyledons |
Family | AIZOACEAE |
National Status |
Status and Criteria | Vulnerable A3d+4c |
Assessment Date | 2021/11/08 |
Assessor(s) | A.J. Young, P.G. Desmet, D. Guo, A. Harrower, L. Knoetze, C. Rodgerson, P.C.V. Van Wyk & N.N. Mhlongo |
Justification | This succulent is restricted to the Karas region of southern Namibia and the Northern Cape province of South Africa with an extent of occurrence (EOO) of 3,055 km and area of occupancy (AOO) of 48 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 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 high. However, the remoteness and relative inaccessibility of many subpopulations coupled with the dispersed geographic distribution of the taxon is likely to limit such collection so a decline of 30% of the population is deemed likely over three generations (90 years). Climate change is also predicted to impact this taxon and loss of vegetation cover has already 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 there are high levels of uncertainty in how this species will respond to climate change, the rapid declines to the population as a result of illegal collection in future means it qualifies as Vulnerable under criterion A3. |
Distribution |
Endemism | Not endemic to South Africa |
Provincial distribution | Northern Cape |
Range | This taxon is restricted to a small area of the Northern Cape province of South Africa and the Karas region of Namibia. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Succulent Karoo |
Description | This taxon is found in both the Succulent Karoo and Desert biomes that experience winter rainfall. It is endemic to the Richtersveld and Gariep Desert bioregions. Plants, occur in small clusters, usually occupying shaded vertical fissures and cracks in large quartz outcrops, sometimes on mountain tops. 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 succulent is threatened by illegal collection of plants from habitat for the ornamental succulent trade. This particular taxon is already common in cultivation and while there is no evidence of illegal collection to date it is highly likely that it will become a target in coming years as the majority of other species in the genus have been targeted in recent years. As the plants are scattered over a very large area and often found in very remote inaccessible sites the likely impact of illegal collection will probably be restricted to individual subpopulations rather than threatening the taxon as a whole.
Mining and associated infrastructure have degraded the habitat of some of the isolated subpopulations inhabiting inselbergs.
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 25% and 85% by 2080 for this taxon. However, as this taxon occurs in a sheltered habitat and is fund across several vegetation units it is expected to have a level of resilience to climate change and the expected population loss is reduced by 20% to 5% 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 |
Plants often remain covered with the previous year's dried leaf (sheathed) throughout the year often making them very cryptic amongst the quartz. Plants are often solitary, dispersed across suitable, niche, habitat and rarely found in large numbers in a single area. Population size has not been determined due to the remoteness of most of the known sites but is estimated to be in the thousands. The population is declining as a result of decline in habitat quality. Loss of vegetation cover has been observed across this taxon's range via Landsat imagery comparisons between 1984 and 2018. This taxon is also predicted to decline in future due to illegal collection given the current horticultural popularity of the genus Conophytum.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Conophytum angelicae (Dinter & Schwantes) N.E.Br. subsp. tetragonum Rawé & 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., Guo, D., Harrower, A., Knoetze, L., Rodgerson, C., Van Wyk, P.C.V. & Mhlongo, N.N. 2021. Conophytum angelicae (Dinter & Schwantes) N.E.Br. subsp. tetragonum Rawé & S.A.Hammer. National Assessment: Red List of South African Plants version . Accessed on 2024/12/07 |
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