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Scientific Name | Geissorhiza subrigida L.Bolus |
Higher Classification | Monocotyledons |
Family | IRIDACEAE |
National Status |
Status and Criteria | Critically Endangered C2a(ii) |
Assessment Date | 2023/06/19 |
Assessor(s) | P. Goldblatt, D. Raimondo, N.A. Helme & L. von Staden |
Justification | This species has an extent of occurrence (EOO) and area of occupancy (AOO) of 16 km². It is known from two locations. It consists of two small subpopulations of fewer than 250 mature individuals, with at least 90% of mature individuals found in one subpopulation. It is threatened by grazing, urban expansion and competition from alien invasive plants. It is therefore listed as Critically Endangered under criterion C. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Northern Cape |
Range | It is a narrow endemic of the Bokkeveld Mountains near Nieuwoudtville in Northern Cape, South Africa. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Bokkeveld Sandstone Fynbos |
Description | It occurs in dry montane fynbos in rocky soils derived from sandstone, flowering well after fire. |
Threats |
| This species has lost 44% of its habitat (calculated using landcover data in GIS) to rooibos tea cultivation in the past, but remaining plants occur on sites that are too rocky to plough. Much of the surrounding area is invaded by alien invasive wattles and pines, which is likely to spread into this species' habitat if left unmanaged. Should any of these sites be grazed, the population could very easily and quickly be wiped out (N.A. Helme, pers. comm.). Occurring on the urban edge of Nieuwoudtville, it is also threatened by habitat loss to urban expansion. |
Population |
It is currently known from two locations, possibly previously part of a single continuous subpopulation, now bisected by crop fields, one consists of fewer than 50 mature individuals, the other around 200 mature individuals. At least 90% of individuals occur in one subpopulation. The population has a declining trend as a result of habitat degradation.
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Population trend | Decreasing |
Conservation |
| It is not currently conserved in any formally protected area. |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Geissorhiza subrigida L.Bolus | CR B1ab(iii,v)+2ab(iii,v); C2a(i,ii); D | Raimondo et al. (2009) | | Geissorhiza subrigida L.Bolus | Rare | Hilton-Taylor (1996) | |
Bibliography |
Goldblatt, P. 1985. Systematics of the southern African genus Geissorhiza (Iridaceae-Ixioideae). Annals of the Missouri Botanical Garden 72(2):277-447.
Goldblatt, P. and Manning, J.C. 2000. Cape Plants: A conspectus of the Cape Flora of South Africa. Strelitzia 9. National Botanical Institute, Cape Town.
Goldblatt, P. and Manning, J.C. 2020. Iridaceae of southern Africa. Strelitzia 42. South African National Biodiversity Institute, Pretoria.
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.
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Citation |
| Goldblatt, P., Raimondo, D., Helme, N.A. & von Staden, L. 2023. Geissorhiza subrigida L.Bolus. National Assessment: Red List of South African Plants version . Accessed on 2024/09/08 |
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