Taxonomy
Scientific Name
Conophytum calculus (A.Berger) N.E.Br. subsp. calculus
Higher Classification
Dicotyledons
Family
AIZOACEAE
Synonyms
Conophytum calculus (A.Berger) N.E.Br. var. komkansicum (L.Bolus) Rawé, Conophytum komkansicum L.Bolus, Mesembryanthemum calculus A.Berger
National Status
Status and Criteria
Vulnerable A4bd
Assessment Date
2020/02/10
Assessor(s)
A.J. Young & D. Raimondo
Justification
An endemic to the Knersvlakte region of South Africa, that has an extent of occurrence (EOO) of 2637 km². While historically considered locally very common, this slow growing taxon is under heavy demand by succulent collectors. A 30 to 40% decline over a three generation time period of thirty years starting from 2016 is projected. This species therefore qualifies as Vulnerable due to recent observed declines and predicted future declines under criterion A4.
Distribution
Endemism
South African endemic
Provincial distribution
Northern Cape, Western Cape
Range
Knersvlakte, in the Western Cape and Northern Cape Provinces of South Africa.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Succulent Karoo
Description
Quartz patches.
Threats
This taxon has become highly sought after by collectors in recent years, as it is slow-growing it is under serious threat with large numbers being removed from some subpopulations. During 2019 three Koreans were arrested with 76 plants. They had on them spreadsheets showing hundreds of buyers interested in habitat collected plants of this species. This provides proof of the very high demand for these plants coming from Asia at the moment. In the past there has been mining applications on some of the sites where this taxon occurs, and habitat loss to mining remains a potential threat to some subpopulations. Overstocking, and particularly trampling by livestock, is also a potential threat, as it leads to habitat degradation. Some parts of the Knersvlakte are heavily grazed.
Population

It typically occurs in small, scattered colonies of 5-10 individuals, and occasionally it is also abundant in small quartz outcrops. There are many subpopulations, and the population was estimated to exceed 10 000 individuals in 2016, however with the current increase in illegal collection the population is in decline. Monitoring of the impact of collecting on wild populations is needed.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Conophytum calculus (A.Berger) N.E.Br. subsp. calculus 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.


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.


Citation
Young, A.J. & Raimondo, D. 2020. Conophytum calculus (A.Berger) N.E.Br. subsp. calculus. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2020/10/20

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Distribution map

© A.J. Young


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