Taxonomy
Scientific Name
Conophytum hammeri G.Will. & H.C.Kenn.
Higher Classification
Dicotyledons
Family
AIZOACEAE
National Status
Status and Criteria
Vulnerable A3d
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 323 km² and area of occupancy (AOO) of 52 km². It is known from more than 15 locations. The dwarf succulents that comprise this genus have been increasingly targeted by illegal collection in recent years and the vast majority of species are in high demand by collectors. Whilst there is no evidence of illegal collection at the time of this submission, closely related species, including some from the immediate area, have been illegally removed from habitat with a dramatic increase in the number of species and volume of plants targeted since 2019. While climate change is also likely to impact this species, illegal collection is the main future pressure and will result in a suspected decline of 30-45% within the next three generations (90 years). It therefore qualifies as Vulnerable under criterion A3.
Distribution
Endemism
South African endemic
Provincial distribution
Northern Cape
Range
This species is endemic to the Richtersveld region in the Northern Cape province of South Africa.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Kosiesberg Succulent Shrubland, Southern Nababiepsberge Mountain Desert, Northern Nababiepsberge Mountain Desert, Helskloof Canyon Desert, Lower Gariep Alluvial Vegetation
Description
This succulent primarily inhabits the Desert and Succulent Karoo biomes where it is found in the Gariep Desert and Richtersveld bioregions. Plants have a semi-subterranean habit on flat patches of quartz stones. 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 particular species is not currently subject to illegal collection but it is likely that it will become a target in coming years as there has been a dramatic increase in the number of species and volume of plants of this genus targeted since 2019. Related species within the immediate area have experienced severe declines in population number due to illegal collection. Anthropogenic climate change is a long-term threat to this species. Loss of vegetation cover has been observed across the geographic range occupied by this species via Landsat imagery between 1984 and 2018 indicating a decline in habitat quality. 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 42% and 96% by 2080 for this species. However, as this species occurs across several vegetation units, possess certain morphological traits and has a semi-subterranean habitat that together indicate a likely level of resilience to climate change the expected population loss is reduced by 20% to 22%. Species in this genus have limited dispersal ability and migration to suitable habitats elsewhere is regarded as highly unlikely.
Population

This species is highly cryptic in habitat as the plants have a semi-subterranean habit and grow amongst quartz stones. The retention of the old leaf-pair as a white sheath renders the plants almost invisible, even when in flower (small and sometimes white). The plants are probably widespread across quartz fields in much of the central Richtersveld and numerous subpopulations have been discovered in recent years. Whilst an accurate population count has not been performed there are probably well in excess of 100,000 mature individuals present in habitat. However in response to an extended drought in the Richtersveld that started in 2016 and is still ongoing at the time of assessment, the population is suspected to be declining. A future decline of between 30 and 45% is suspected due to climate change and illegal collection.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Conophytum hammeri G.Will. & H.C.Kenn.VU B1ab(v)+2ab(v)2020.1
Conophytum hammeri G.Will. & H.C.Kenn.Rare 2015.1
Conophytum hammeri G.Will. & H.C.Kenn.Critically Rare 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 hammeri G.Will. & H.C.Kenn. National Assessment: Red List of South African Plants version . Accessed on 2024/07/22

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Distribution map

© A.J. Young

© A.J. Young

© A.J. Young

© A.J. Young


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