Taxonomy
Scientific Name
Conophytum concavum L.Bolus
Higher Classification
Dicotyledons
Family
AIZOACEAE
National Status
Status and Criteria
Critically Endangered A4d; B1ab(v)
Assessment Date
2021/11/17
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 restricted range species endemic to South Africa's Namaqualand Region has an extent of occurrence (EOO) of 67 km² and an area of occupancy (AOO) of 44 km². There has been an estimated population loss of 90% or more since 2019 due to illegal collection to supply the international trade in ornamental succulents and the remaining plants are threatened. The single location, proximity to human habitation and the continuing high demand for the species in cultivation means there is a high probability that this species will be collected to extinction within the next 10 years. Climate change is also highly likely to impact the population although there is uncertainty of the response given the expected resilience of this taxon. It therefore qualifies as Critically Endangered under criteria A3 and B1.
Distribution
Endemism
South African endemic
Provincial distribution
Northern Cape
Range
This species is endemic to South Africa where it is only found in a single location in the Northern Cape province. The plants are found in a single locality that lies within a protected area close to the coast and not far from human habitation.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Riethuis-Wallekraal Quartz Vygieveld
Description
This species is highly localised and is only recorded from a single location in South Africa. It is endemic to the Namaqualand Sandveld bioregion of the Succulent Karoo biome. Within this area it inhabits a restricted area of saline quartz fields but it can also be found in fringe areas that lack quartz. The plants are generally part-submerged in shallow areas of soft sand. 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
This species has been subject to very high levels of illegal collection for the trade in ornamental succulents since 2019 and this collection is ongoing. At the date of assessment over 50,000 mature individuals have been confiscated from poachers, with evidence of many thousands of plants reaching the markets in Asia. It is therefore thought that a majority of the population has been removed from habitat since 2019. Anthropogenic climate change is a long-term threat 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 85% and 100% by 2080 for this species. However, as this taxon possesses certain morphological 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 65% 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. As this taxon possesses traits that may provide some resilience, the likely impact of climate change is expected to be reduced and is not used to inform the overall assessment.
Population

A recent assessment by SANBI (field survey in 2021) recorded only 300 mature individuals in habitat. This may be an underestimate due to the cryptic nature of the plants but fewer than 2,500 mature individuals are likely still extant. There was no formal population assessment prior to this but estimates by authorities on the genus suggest at least 50,000 mature individuals were present at the location prior to 2019, a likely underestimate. More than 50,000 individuals have been confiscated from poachers in 2020-21 and there is evidence of habitat-collected plants being sold in Asia. It is estimated that the population has experienced a decline of over 90% since 2019.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Conophytum concavum L.BolusVU B1ab(v)+2ab(v)2020.1
Conophytum concavum L.BolusRare Raimondo et al. (2009)
Conophytum concavum L.BolusLower Risk - Least Concern Victor (2002)
Conophytum concavum L.BolusRare 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).


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 concavum L.Bolus. 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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