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Scientific Name | Oxalis fragilis T.M.Salter |
Higher Classification | Dicotyledons |
Family | OXALIDACEAE |
National Status |
Status and Criteria | Critically Endangered A2c; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v) |
Assessment Date | 2022/07/31 |
Assessor(s) | L.L. Dreyer, K.C. Oberlander, N.A. Helme & H. Mtshali |
Justification | This Swartland endemic has an extent of occurrence (EOO) and an area of occupancy (AOO) of 8 km², and it is known from one location. It has experienced an estimated population reduction of 80% in the past three generations, based on 90% loss of suitable habitat in the past 90 years (generation length 30 years) and the loss continues. It is threatened by ongoing habitat degradation and loss to crop cultivation, alien plant invasion, livestock overgrazing and herbicide drift onto small fragments from surrounding agricultural fields. It therefore qualifies for listing as Critically Endangered under criterion A and B. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | This species has a restricted distribution in the Western Cape Province, South Africa, where it occurs between Piketburg and Moorreesburg. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Swartland Shale Renosterveld |
Description | It grows on damp, cooler aspects on shale, at 20-170 m.a.s.l. |
Threats |
| Across the Swartland Shale Renosterveld, this species has lost more than 90% of its habitat to crop cultivation (wheat), and loss continues. The Swartland where this species grows is furthermore threatened by herbicide drift onto small fragments from the surrounding agricultural fields and heavy browsing by cattle. Most of its habitat is also infested with alien invasive plants mainly acacias that are outcompeting native species.
Previously, it was thought that habitat loss had caused the extinction of this species, but a new subpopulation was discovered in 2020. Plants remain in a remnant of natural vegetation. The site where plants occur was threatened by the development of a proposed dam, however, the development of this dam is unlikely to go ahead as an alternate development site has been identified lower down near the Berg River where impacts will be significantly less. |
Population |
Previously this species had only a few historic collections made near Koringberg where the type collection was made by Salter in the 1930s. It was thought to be extinct until a new subpopulation with 3 stands was discovered northwest of the type locality at Berg Rivier farm (Bovenvlei) and was recorded on iNaturalist in 2020. This subpopulation is small consisting of a total of 1500 plants (the largest stand is on the east of the stream with 1000 plants, and the smallest with 200 plants). Based on loss of habitat to crop cultivation, the population is suspected to have declined by 80% in the past 90 years (generation length 30 years). The population continues to decline due to habitat degradation.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Oxalis fragilis T.M.Salter | Critically Endangered (Possibly Extinct) | Raimondo et al. (2009) | | Oxalis fragilis T.M.Salter | Indeterminate | Hilton-Taylor (1996) | | Oxalis fragilis T.M.Salter | Indeterminate | Hall et al. (1980) | |
Bibliography |
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.
Hall, A.V., De Winter, M., De Winter, B. and Van Oosterhout, S.A.M. 1980. Threatened plants of southern Africa. South African National Scienctific Programmes Report 45. CSIR, 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 |
| Dreyer, L.L., Oberlander, K.C., Helme, N.A. & Mtshali, H. 2022. Oxalis fragilis T.M.Salter. National Assessment: Red List of South African Plants version . Accessed on 2024/10/08 |
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