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Scientific Name | Conophytum acutum L.Bolus |
Higher Classification | Dicotyledons |
Family | AIZOACEAE |
Synonyms | Ophthalmophyllum acutum (L.Bolus) Tischer |
National Status |
Status and Criteria | Critically Endangered A4acd; B1ab(iii,v) |
Assessment Date | 2021/11/08 |
Assessor(s) | A.J. Young, I. Ebrahim, A. Harrower, L. Jabar, C. Rodgerson, P.C.V. Van Wyk, D. Guo, P.G. Desmet & N.N. Mhlongo |
Justification | This dwarf succulent is endemic to the Western Cape of South Africa where it is only found at a single location with an extent of occurrence (EOO) and area of occupancy (AOO) of 12 km². The plants are being specifically targeted for illegal collection for the ornamental succulent trade and a substantial proportion of the global population was illegally removed in 2020-21 alone. The remaining population size (2021) is thought to be less than 5,000 mature individuals but the highly cryptic, semi-subterranean, habit may result in an underestimation. The plants are severely range-restricted which renders them highly susceptible to further rapid declines in number through harvesting. This activity is likely to continue and a reduction in population size of up to 95% is suspected as a result of illegal collection and is expected within the next 30 years (one generation).
The single location and inability to disperse also makes the species very susceptible to the deleterious effects of climate change. 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 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 means it qualifies as Critically Endangered under criteria A4 and B1. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | This dwarf succulent is endemic to a small area within the winter-rainfall area of the Western Cape Province of South Africa where it is found in quartz fields. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Knersvlakte Quartz Vygieveld |
Description | This species is known from a small number of colonies in the quartz-rich fields in the Succulent Karoo biome. It is typically found on flat or gently sloping areas of quartz stones on open ground. It has a semi-subterranean habit in which most of the plant body shrinks beneath the soil level exposing only a tiny fraction. This makes the species highly cryptic in nature, possibly having the effect of restricting the number of recorded observations. 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 |
| Since 2019 this dwarf succulent has been subject to illegal harvesting for the ornamental succulent trade. This species is highly sought after by collectors as it is difficult to cultivate and remains relatively rare in cultivation. More than 9,000 mature individuals have been confiscated from poachers in 2021 alone, representing a substantial proportion and possibly the majority of the species. The single location coupled with very low numbers of individuals historically observed in the small area, not far from human habitation, makes the species very sensitive to such activity. This species has previously lost some habitat to infrastructure development, but habitat loss is not continuing. Other threats include livestock grazing and infrastructure maintenance.
There is an inferred decline in habitat quality at the only known locality for this species 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).
Anthropogenic climate change is a long-term threat to this species. 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 15 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 40% and 85% by 2080 for Conophytum taxa within the region. However, its morphological traits together with a semi-subterranean habitat indicates a likely level of resilience to climate change hence population decline is reduced by 20% to 20%. Species in this genus have limited dispersal ability and migration to suitable habitats elsewhere is regarded as highly unlikely. |
Population |
Rarely reported, the cryptic, part-subterranean, nature of this species makes population size quite difficult to assess but possibly fewer than 5,000 mature individuals remain (SANBI 2021). Generally found as scattered plants in discrete patches. When seen in habitat the numbers of plants are generally low and the species appears to be very restricted in its distribution. Two subpopulations are known with a third, historical report, not confirmed. The population is declining rapidly as a result of illegal collection.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Conophytum acutum L.Bolus | VU D2 | Raimondo et al. (2009) | | Conophytum acutum L.Bolus | VU D2 | Victor (2002) | | Conophytum acutum L.Bolus | Vulnerable | Hilton-Taylor (1996) | |
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).
IUCN. 1994. IUCN Red List Categories version 2.3. Prepared by the IUCN Species Survival Commission, IUCN, Gland, Switzerland.
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Citation |
| Young, A.J., Ebrahim, I., Harrower, A., Jabar, L., Rodgerson, C., Van Wyk, P.C.V., Guo, D., Desmet, P.G. & Mhlongo, N.N. 2021. Conophytum acutum L.Bolus. National Assessment: Red List of South African Plants version . Accessed on 2024/12/07 |
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