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Scientific Name | Erica onusta Guthrie & Bolus |
Higher Classification | Dicotyledons |
Family | ERICACEAE |
National Status |
Status and Criteria | Endangered B1ab(iii) |
Assessment Date | 2023/08/24 |
Assessor(s) | F. Munro, J.H. Vlok, D. Raimondo & J. Potgieter |
Justification | This species is restricted to a small area east of Knysna to Nature's Valley and has an extent of occurrence (EOO) of 84 km². Remaining subpopulations occur as isolated remnants among plantations. Habitat quality in fragments is declining due to a lack of fire and alien invasive infestations. This species therefore qualifies for listing as Endangered under criterion B. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | It occurs from the east of Knysna to Kurland near Nature's Valley in the Western Cape Province of South Africa. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Southern Afrotemperate Forest |
Description | Plants grow in coastal fynbos patches between forest. |
Threats |
| This species has suffered extensive habitat loss from forestry plantations in the past. Although forestry plantations are not expanding, all remaining subpopulations are restricted to small, isolated remnants of natural vegetation. Subpopulations continue to be degraded due to alien invasive plants, improper fire regimes, agricultural and urban development, and mismanagement of land where habitat may be suitable for this species. |
Population |
The most recent record for this species was collected in 2006 at a subpopulation in the Crags, north of Foresthall. There were fewer than 500 mature individuals in this subpopulation. All other records were collected prior to the year 2000. The overall size of the population is unknown, but it is inferred to be declining due to the ongoing degradation of its habitat by invasive alien plants.
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Population trend | Decreasing |
Notes |
| There is some concern regarding the taxonomic validity of this species, J.H. Vlok suspects that it may be a hybrid between the common and widespread Erica copiosa and Erica sparsa. Twenty subpopulations of a plant very similar in description to Erica onusta were recorded by the CREW Outramps group on iNaturalist between 2021 and 2022 but on close inspection of the stigma and ovaries, the plants turned out to be E. copiosa. Molecular work is required to determine the validity of E. onusta. |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Erica onusta Guthrie & Bolus | CR B1ab(iii,v) | Raimondo et al. (2009) | |
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.
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 |
| Munro, F., Vlok, J.H., Raimondo, D. & Potgieter, J. 2023. Erica onusta Guthrie & Bolus. National Assessment: Red List of South African Plants version . Accessed on 2024/12/06 |
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