Taxonomy
Scientific Name
Conophytum depressum Lavis subsp. perdurans S.A.Hammer
Higher Classification
Dicotyledons
Family
AIZOACEAE
National Status
Status and Criteria
Endangered A4d
Assessment Date
2021/11/26
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 Northern Cape province of South Africa with an extent of occurrence (EOO) of 3,071 km² and area of occupancy (AOO) of 28 km². The plant is comparatively short-lived at 5-10 years compared to other species in the genus. The population is experiencing decline due to illegal collection for the ornamental succulent plant trade, with collection likely to increase as there has been a dramatic increase in the number of species and volume of plants targeted since 2019. This taxon can be very challenging in cultivation and the continued threat of illegal collection is therefore regarded as very high for this particular species. However, the highly cryptic nature of the plants and highly dispersed distribution across its range may limit future declines to 55% of the population within the next thirty years. It therefore qualifies as Endangered under criterion A4.
Distribution
Endemism
South African endemic
Provincial distribution
Northern Cape
Range
This succulent is endemic to the Northern Cape province of South Africa.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Namaqualand Blomveld, Namaqualand Klipkoppe Shrubland
Description
Plants are restricted to the Namaqualand Hardeveld bioregion of the Succulent Karoo biome. The plants occupy shallow grit and detritus-filled weathered pans on granite and gneiss. This succulent has a generation length of 10 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 succulent is currently threatened by illegal collection for the international trade in ornamental succulents with a large number of plants removed from habitat since 2019. This pressure 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 and this particular taxon is challenging in cultivation. Grazing and trampling by livestock is a localised threat to some populations. Anthropogenic climate change is a long-term threat to this succulent. 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 75% and 98% by 2080 for this taxon. Species in this genus have limited dispersal ability and migration to suitable habitats elsewhere is regarded as highly unlikely. However, this taxon occurs across several vegetation units and possesses certain morphological traits that are expected to provide a level of resilience to climate change. As a result the likely impact of climate change is expected to be reduced by 20% to 55% based on the uncertainty of the response given the expected resilience of this taxon. Given the uncertainty of this species' response to climate change and the fact that it has a generation length of only 10 years, climate predictions are not used to inform the overall assessment.
Population

It is small and highly cryptic making accurate estimates of population size extremely difficult. It has been recorded from numerous subpopulations usually consisting of just a handful of mature individuals. The total population is probably in excess of 2,000 mature individuals. The population is in decline due to illegal collection to supply the international trade in ornamental succulents.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Conophytum depressum Lavis subsp. perdurans S.A.HammerNT B1ab(v)+2ab(v)2020.1
Conophytum depressum Lavis subsp. perdurans 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.


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 depressum Lavis subsp. perdurans S.A.Hammer. National Assessment: Red List of South African Plants version . Accessed on 2024/06/21

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Distribution map

© A.J. Young


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