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Scientific Name | Geissorhiza erosa (Salisb.) R.C.Foster |
Higher Classification | Monocotyledons |
Family | IRIDACEAE |
Synonyms | Geissorhiza erosa (Salisb.) R.C.Foster var. kermesina (Klatt) R.C.Foster, Geissorhiza hirta (Thunb.) Ker Gawl., Geissorhiza inflexa (D.Delaroche) Ker Gawl. var. erosa (Salisb.) Goldblatt, Geissorhiza rosea Eckl., Hesperantha kermesina Klatt, Ixia erosa Salisb., Ixia hirta Thunb., superfluous name for Ixia inflexa D.Delaroche |
National Status |
Status and Criteria | Endangered B2ab(i,ii,iii,iv,v) |
Assessment Date | 2021/10/12 |
Assessor(s) | L. von Staden & T. Patel |
Justification | This species has an extent of occurrence (EOO) of 6489 km² and an area of occupancy (AOO) of 180 km². The population is severely fragmented and declining due to ongoing habitat loss from vineyard and fruit orchard expansion, as well as urban and infrastructure development. It is therefore listed as Endangered under criteria B. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | An endemic to the southwestern corner of Western Cape province, South Africa, extending from Porterville and the Tulbagh Valley to Stellenbosch and Gordon's Bay. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Swartland Shale Renosterveld, Breede Shale Renosterveld, Western Ruens Shale Renosterveld, Swartland Granite Renosterveld, Elgin Shale Fynbos, Boland Granite Fynbos |
Description | It occurs on clay or stony sandstone slopes, usually in renosterveld. |
Threats |
| This species has lost 66% of its habitat (calculated using landcover data in GIS). Its lowland renosterveld and fynbos habitat has been severely transformed, primarily for the cultivation of vineyards and fruit. In the Tulbagh Valley, habitat loss due to expanding vineyards is ongoing. Around Stellenbosch, most historical records are from sites now lost to urban expansion. Around Theewaterskloof Dam, there has also been extensive habitat loss due to fruit orchards, dam construction, and housing/holiday resort development. |
Population |
Due to the extensive transformation and fragmentation of this species' habitat, all subpopulations remain on small, isolated fragments and continue to decline due to the ongoing loss and degradation of the remaining habitat. Monitoring data from iNaturalist and the Custodians of Rare and Endangered Wildflowers programme indicate that the majority of subpopulations are small (fewer than 50 plants), and more than 50% of the population occurs in small and isolated patches.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Geissorhiza erosa (Salisb.) R.C.Foster | EN B1ab(ii,iii,iv,v) | 2011.1 | |
Bibliography |
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.
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Citation |
| von Staden, L. & Patel, T. 2021. Geissorhiza erosa (Salisb.) R.C.Foster. National Assessment: Red List of South African Plants version . Accessed on 2024/09/08 |
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