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Scientific Name | Geissorhiza monanthos Eckl. |
Higher Classification | Monocotyledons |
Family | IRIDACEAE |
National Status |
Status and Criteria | Vulnerable C2a(i) |
Assessment Date | 2023/06/07 |
Assessor(s) | P. Goldblatt, D. Raimondo, R.C. Turner & L. von Staden |
Justification | This species has an extent of occurrence (EOO) of 2502 km² and an area of occupancy (AOO) of 140 km². Nineteen fragmented subpopulations remain, and continue to decline due to ongoing habitat loss to crop cultivation and alien plant invasion. The overall population has fewer than 10 000 mature individuals and no subpopulation has been recorded to have more than 1000 mature individuals. It is therefore listed as Vulnerable under criterion C. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | It is restricted to the Atlantic coastal forelands of Western Cape, South Africa, extending from Darling in the north to Malmesbury in the east, Klipheuwel and Joostenberg in the south. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Swartland Shale Renosterveld, Swartland Granite Renosterveld, Swartland Silcrete Renosterveld, Boland Granite Fynbos, Atlantis Sand Fynbos, Swartland Alluvium Fynbos |
Description | It usually occurs on gravelly, granite derived soils. |
Threats |
| This species has lost 66% of its habitat (calculated using landcover data in GIS) to crop cultivation and urban expansion. This is a severe past and ongoing threat. Other threats include the effects of habitat fragmentation, alien invasive plants and inappropriate fire management. |
Population |
It is endemic to the Critically Endangered Swartland Granite Renosterveld, of which less than 20% remains and less than 1% is formally protected. Increased sampling by citizen scientists working as part of the Custodians of Rare and Endangered Wildflowers programme or independently on iNaturalist have increased the number of known subpopulations from 9 to 19. Most subpopulations are however small with fewer than 100 plants, the subpopulations at Darling Nature Reserve and Klipheuwel have between 250 and 500 individuals. The total population is therefore estimated to have fewer than 10 000 mature individuals and no subpopulation has been recorded to have more than 1000 individuals. The population is declining slowly as a result of ongoing habitat degradation due to invasive alien species.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Geissorhiza monanthos Eckl. | NT B1ab(i,ii,iii,iv,v) | Raimondo et al. (2009) | | Geissorhiza monanthos Eckl. | Indeterminate | 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.
Goldblatt, P., Manning, J.C. and Nänni, I. 2009. New species of Geissorhiza (Iridaceae:Crocoideae) from the southern African winter rainfall zone, range extensions, taxonomic changes, and notes on pollen morphology. Bothalia 39(2):123-152.
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., Turner, R.C. & von Staden, L. 2023. Geissorhiza monanthos Eckl. National Assessment: Red List of South African Plants version . Accessed on 2024/09/08 |
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