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Scientific Name | Astridia citrina (L.Bolus) L.Bolus |
Higher Classification | Dicotyledons |
Family | AIZOACEAE |
Synonyms | Astridia rubra (L.Bolus) L.Bolus var. citrina L.Bolus |
National Status |
Status and Criteria | Critically Endangered A2ace+4ace; B1ab(i,ii,iii,iv,v) |
Assessment Date | 2022/09/15 |
Assessor(s) | D. Raimondo & P.C.V. Van Wyk |
Justification | A restricted range species with an extent of occurrence (EOO) and area of occupancy (AOO) of 24 km². All of this succulent's habitat falls within areas that have either already been mined or are earmarked for mining. It is known from one location, and the population has been observed to have declined by 80% since 1990 as a result of mining and mortality caused by drought. While some recovering following the drought is possible since this species can germinate with only small amounts of rainfall and has a long-lived seedbank, ongoing aridification of its range coupled with ongoing loss to mining is projected to result in a further 50% of the remaining population being lost by 2050 (generation length of 20 years). It therefore qualifies for listing as Critically Endangered under criteria A and B. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Northern Cape |
Range | This species occurs in the Richtersveld region of the Northern Cape Province, South Africa. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Western Gariep Hills Desert, Western Gariep Lowland Desert |
Description | It grows on low undulating hills, which are mostly alluvial. |
Threats |
| It is threatened by habitat loss and degradation due to severely destructive open-cast mining. All subpopulations fall within the Lower Orange River mining licensed area where there is ongoing habitat loss due to mining activities. Furthermore the population is declining due to climate change. Its entire range has experienced below average rainfall since 2012. Predictions of future climate change include further increases in annual average temperature of between 1.4°C and 2.4°C by 2050, which will result in unbearably hot temperatures and ongoing aridification throughout significant portions of the year (Van Wilgen et al. 2017). |
Population |
Only a handful of subpopulations of this species are known, ranging in size from a few individuals to several hundred plants. At least 50% of the population has been lost to mining activities since 1990 and a further 30% will be lost in the next 10 years. The recent extended drought has also caused significant decline with monitoring indicating 90% mortality. Fortunately this species has large seeds that have strong dormancy and should adequate rainfall be received it should be able to recover in areas where its habitat is left intact. Based on the proportion of this species' habitat that has been lost to mining and the observed loss of plants due to the severe drought, a decline of over 80% of the population has been observed to occur in the past 32 years. Loss is predicted to be ongoing with a further 50% of the remaining population likely to decline over the next 28 years. Less than 5000 mature individuals are suspected to be extant.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Astridia citrina (L.Bolus) L.Bolus | EN B1ab(ii,iii,v) | 2015.1 | | Astridia citrina (L.Bolus) L.Bolus | Least Concern | Raimondo et al. (2009) | | Astridia citrina (L.Bolus) L.Bolus | Rare | Hilton-Taylor (1996) | |
Bibliography |
Glen, H.F. 1986. Numerical taxonomic studies in the subtribe Ruschiinae (Mesembryanthemaceae) - Astridia, Acrodon and Ebracteola. Bothalia 16(2):203-226.
Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical Institute, 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.
Snijman, D.A. 2013. Plants of the Greater Cape Floristic Region 2: The extra Cape flora. Strelitzia 30. South African National Biodiversity Institute, Pretoria.
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Citation |
| Raimondo, D. & Van Wyk, P.C.V. 2022. Astridia citrina (L.Bolus) L.Bolus. National Assessment: Red List of South African Plants version . Accessed on 2024/12/07 |
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