Taxonomy
Scientific Name
Conophytum calculus (A.Berger) N.E.Br. subsp. vanzylii (Lavis) S.A.Hammer
Higher Classification
Dicotyledons
Family
AIZOACEAE
Synonyms
Conophytum breve N.E.Br. var. vanzylii (Lavis) Rawé, Conophytum namiesicum L.Bolus, Conophytum vanzylii Lavis
National Status
Status and Criteria
Vulnerable A4cd
Assessment Date
2020/02/10
Assessor(s)
A.J. Young & D. Raimondo
Justification
This taxon is endemic to western Bushmanland in South Africa and has an extent of occurrence (EOO) of 3726 km². It is known from between 15 and 20 small scattered subpopulations. This slow growing taxon is under heavy demand by succulent collectors. A 30 to 40% decline over a moving three generation time period of thirty years starting from 2010 is projected based on observed loss of habitat and degradation of habitat at certain subpopulations and as a result of the marked increase in illegal collecting taking place since 2016. With this taxon being highly popular with collectors, ongoing declines are predicted to continue. This species therefore qualifies as Vulnerable under criterion A4.
Distribution
Endemism
South African endemic
Provincial distribution
Northern Cape
Range
Springbok to Pofadder, in the Northern Cape Province of South Africa.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Nama Karoo, Succulent Karoo
Description
Quartz patches within succulent karoo and nama karoo, often on Bushmanland Inselbergs.
Threats
Highly sought after by collectors in recent years, this slow-growing taxon, is threatened. While its more widespread and scattered distribution compared to subsp. calculus affords some protection from exploitation, ongoing decline is none the less taking place. Furthermore there are scattered mines within this taxon's range, and prospecting and mining expansion is ongoing affecting a number of subpopulations. It is also vulnerable to habitat degradation, particularly trampling by livestock when rangelands are overstocked. Some parts of its range, particularly low-lying flats, are heavily grazed.
Population

This taxon is widespread across western Bushmanland. It typically occurs as scattered individuals, or in small clumps of five or more individuals. There are at least 15 known subpopulations, and more are likely to exist. The population size is not known, but is suspected to exceed 1000 individuals. The population is declining due to illegal collecting, habitat loss to mining and habitat degradation from livestock overgrazing.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Conophytum calculus (A.Berger) N.E.Br. subsp. vanzylii (Lavis) S.A.HammerLeast 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. vanzylii (Lavis) S.A.Hammer. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2020/10/28

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Distribution map

© A.J. Young


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