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Scientific Name | Geissorhiza tulbaghensis F.Bolus |
Higher Classification | Monocotyledons |
Family | IRIDACEAE |
National Status |
Status and Criteria | Endangered B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v) |
Assessment Date | 2023/06/20 |
Assessor(s) | I. Ebrahim, D. Raimondo & R.C. Turner |
Justification | This species has an extent of occurrence (EOO) of 909 km² and an area of occupancy (AOO) of 92 km². Between 15 and 20 small, severely fragmented subpopulations remain, mostly on road verges and in remnant patches of renosterveld. It has lost extensive habitat to wheat and vineyard expansion. It is suspected that there are fewer than 10 000 mature individuals extant. It continues to decline due to alien plant invasion, pesticide spraying and agricultural and urban expansion. It is therefore listed as Endangered under criterion B. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | It is endemic to Western Cape, South Africa, and is found from Porterville to Wellington. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Swartland Shale Renosterveld, Breede Shale Renosterveld, Breede Shale Fynbos, Swartland Alluvium Fynbos, Breede Alluvium Fynbos |
Description | It occurs on heavy, often stony clay soil in renosterveld. |
Threats |
| This species has lost 71% of its habitat (calculated using landcover data in GIS). Agricultural transformation for wheat and vineyard farming has caused the loss of three subpopulations known from herbarium records. One subpopulation in the Tulbagh valley is likely to be ploughed in the near future (landowner pers. comm. with I. Ebrahim 2005). Half of the subpopulations are being impacted by alien grass invasion. There is also loss of pollinators due to pesticide spraying, two subpopulations are adjacent to farmlands and volunteers of the Custodians of Rare and Endangered Wildflowers (CREW) Programme have documented a decline in numbers of individuals due to pesticide spraying. |
Population |
The population has a decreasing trend and is known from between 15 and 20 subpopulations which are severely fragmented. One large subpopulation of 5000 individuals has been recorded, all other subpopulations are small with fewer that 250 mature individuals and many with fewer than 50.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Geissorhiza tulbaghensis F.Bolus | EN B1ab(ii,iii,iv,v) | Raimondo et al. (2009) | |
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.
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 |
| Ebrahim, I., Raimondo, D. & Turner, R.C. 2023. Geissorhiza tulbaghensis F.Bolus. National Assessment: Red List of South African Plants version . Accessed on 2025/02/18 |
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