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Scientific Name | Isoetes capensis A.V.Duthie |
Higher Classification | Ferns |
Family | ISOETACEAE |
Common Names | Cape Quillwort (e) |
National Status |
Status and Criteria | Endangered B1ab(iii)+2ab(iii) |
Assessment Date | 2018/11/26 |
Assessor(s) | J.P. Roux, D. Raimondo, I. Ebrahim, L. von Staden & H. Mtshali |
Justification | Isoetes capensis has an extent of occurrence (EOO) of 4612 km², and an area of occupancy (AOO) of 44-56 km². The remaining severely fragmented subpopulations continue to decline due to ongoing habitat loss and degradation. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Western Cape |
Range | This species has a limited distribution in the Western Cape lowlands between Worcester, Darling and Stellenbosch. |
Habitat and Ecology |
Major system | Freshwater |
Major habitats | Cape Flats Dune Strandveld, Swartland Shale Renosterveld, Breede Shale Renosterveld, Swartland Alluvium Renosterveld, Cape Flats Sand Fynbos, Swartland Alluvium Fynbos, Breede Alluvium Fynbos |
Description | It occurs in seasonally flooded depressions and in pools on flats with sandy clay soils. |
Threats |
| Habitat loss and degradation as a result of urban and agricultural expansion has caused the loss of many subpopulations on the Cape Flats and lowlands around Stellenbosch and Gordon's Bay. Remaining subpopulations are threatened by further habitat degradation as a result of disrupted water dynamics, eutrophication, alien plant invasion and ongoing habitat loss to urban expansion. |
Population |
Recent field observations recorded nine remaining subpopulations. All of these occur on small, isolated fragments of lowland fynbos and renosterveld vegetation. The largest recorded subpopulation has between500 and 1000 plants, but typically subpopulations consist of fewer than 100 mature individuals. This species is very cryptic and easily overlooked, but so little habitat remains, that it is unlikely that there are many undocumented subpopulations still remaining. The remaining population is estimated to consist of between 760 and 3740 mature individuals. At two localities where the species was last recorded in the 1970s, intact habitat still exist, but it is not certain whether the species still remains there. A continuing decline is inferred from ongoing habitat loss and degradation.
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Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Isoetes capensis A.V.Duthie | EN B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v) | Raimondo et al. (2009) | |
Bibliography |
Cook, C.D.K. 2004. Aquatic and wetland plants of southern Africa. Backhuys Publishers, Leiden, The Netherlands.
Crouch, N.R., Klopper, R.R., Burrows, J.E. and Burrows, S.M. 2011. Ferns of southern Africa: A comprehensive guide. Struik Nature, Cape Town.
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.
Manning, J.C. and Goldblatt, P. 2012. Plants of the Greater Cape Floristic Region 1: The Core Cape Flora. Strelitzia 29. 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.
Sieben, E.J.J. 2009. The status and distribution of vascular plants (Magnoliophyta, Lycophyta, Pteridophyta). In: W.R.T. Darwall, K.G. Smith, D. Tweddle and P. Skelton (eds.), The status and distribution of freshwater biodiversity in southern Africa (pp. 83-98), IUCN and SAIAB, Gland, Switzerland and Grahamstown, South Africa.
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Citation |
| Roux, J.P., Raimondo, D., Ebrahim, I., von Staden, L. & Mtshali, H. 2018. Isoetes capensis A.V.Duthie. National Assessment: Red List of South African Plants version . Accessed on 2025/05/14 |
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