Taxonomy
Scientific Name
Conophytum minusculum (N.E.Br.) N.E.Br. subsp. leipoldtii (N.E.Br.) S.A.Hammer
Higher Classification
Dicotyledons
Family
AIZOACEAE
Synonyms
Conophytum leipoldtii N.E.Br.
National Status
Status and Criteria
Critically Endangered A4d
Assessment Date
2021/11/30
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 Western Cape of South Africa with an extent of occurrence (EOO) of 43 km2 and area of occupancy (AOO) of 36 km2. The population is in decline due to the collection for the illegal ornamental succulent plant trade, with collection pressures likely to increase. The threat of illegal collection is therefore regarded as very high for this particular taxon, with its proximity to habitation and relatively small population size rendering it very susceptible to this activity. A decline of up to 95% of the population is suspected within the next three generations (60 years) due to illegal collection. While climate change is also likely to impact this taxon the rapid declines to the population as a result of illegal collection means it qualifies as Critically Endangered under criterion A4.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
This succulent is endemic to the Western Cape Province of South Africa.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Citrusdal Vygieveld, Graafwater Sandstone Fynbos
Description
This succulent is primarily found in the Fynbos and Succulent Karoo biomes where it occurs in the Sandstone Fynbos and Knersvlakte bioregions, respectively. It is predominantly found on weathered quartzitic sandstone amongst moss and lichen or in shallow sandy-grit filled depressions. This succulent 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 taxon is currently threatened by illegal collection for the international trade in ornamental succulents. This is likely to increase in future as there has been a dramatic increase in the number of species and volume of plants targeted since 2019. This taxon is only known from a small number of locations and is believed to have a relatively small population size, making it susceptible to illegal collection. As a result a population decline of 80-95% is suspected over three generations (90 years). Anthropogenic climate change is a long-term threat to this taxon. There is no decline in habitat quality for this taxon as inferred by changes in vegetation cover determined from changes in Enhanced Vegetation Index (EVI) between 1984 and 2018 using Landsat data (Venter et al. 2020). 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 48% and 57% by 2080 for this succulent. However, as this taxon possesses certain traits likely to afford resilience to xerophytic conditions it is expected to have a level of resilience to climate change and the expected population loss is reduced by 20% to 28%. Species in this genus have limited dispersal ability and migration to suitable habitats elsewhere is regarded as highly unlikely. The majority of plants occur adjacent to or are located directly on farmland, typically Rooibos plantations, often within tens of metres of growing crops. Plants tend to be well protected from agricultural activities because they inhabit rocky outcrops which vary in size from a few square meters to several hundred metres. It is unlikely that land would be used for agricultural purposes but drift resulting from use of fertilizers, herbicides etc. could be potentially problematic. Some plants have been lost due to infrastructure (e.g., road) construction.
Population

It is known from a several subpopulations, where it is typically locally abundant. There are no formal estimates of population size for this dwarf succulent but the number of mature individuals is suspected to be between 10,000 and 20,000 individuals. The population is experiencing initial levels of decline due to illegal collection for the ornamental succulent plant trade.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Conophytum minusculum (N.E.Br.) N.E.Br. subsp. leipoldtii (N.E.Br.) S.A.HammerEN B1ab(v)+2ab(v)2020.1
Conophytum minusculum (N.E.Br.) N.E.Br. subsp. leipoldtii (N.E.Br.) S.A.HammerRare 2017.1
Conophytum minusculum (N.E.Br.) N.E.Br. subsp. leipoldtii (N.E.Br.) 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.


Hausfather, Z. and Peters, G.P. 2020. Emissions - the 'business as usual' story is misleading. Nature 577(618-620).


Opel, M.R. 2004. The rediscovery of Crassula alcicornis. Haseltonia 10:38-40.


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 minusculum (N.E.Br.) N.E.Br. subsp. leipoldtii (N.E.Br.) S.A.Hammer. National Assessment: Red List of South African Plants version . Accessed on 2024/07/14

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Distribution map

© A.J. Young


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