| Scientific Name | Disa draconis (L.f.) Sw. | Higher Classification | Monocotyledons | Family | ORCHIDACEAE | Synonyms | Disa draconis in sense of other authors, not of (L.f.) Sw. (in part), Orchis draconis L.f., Satyrium draconis (L.f.) Thunb. | Common Names | White Disa (e) |
National Status | Status and Criteria | Endangered A3ce; B1ab(i,iii,iv,v)+2ab(ii,iii,iv,v) | Assessment Date | 2012/09/11 | Assessor(s) | L. von Staden, B. Bytebier & S.D. Johnson | Justification | EOO 744km², AOO <100 km², with only five remaining locations. More than 80% of its habitat has been transformed in the past 100 years due to urban and agricultural expansion. Only two subpopulations are in reserves. The largest subpopulation, which constitutes over 50% of the individuals in the total population, is highly likely to be lost to urban development in the near future (next 10 years, generation length 10- 15 years). Loss to coastal development and alien plant invasion is ongoing. |
Distribution | Endemism | South African endemic | Provincial distribution | Western Cape | Range | Yzerfontein to Cape Peninsula. |
Habitat and Ecology | Major system | Terrestrial | Major habitats | Cape Flats Dune Strandveld, Langebaan Dune Strandveld, Swartland Granite Renosterveld, Peninsula Granite Fynbos, Boland Granite Fynbos, Hangklip Sand Fynbos, Cape Flats Sand Fynbos, Atlantis Sand Fynbos, Hopefield Sand Fynbos | Description | Well-drained, deep sandy soils up to 150 m in strandveld coastal scrub. |
Threats | | Urban and agricultural expansion has caused extensive habitat loss in the past, and remaining subpopulations are isolated and fragmented. At least one known subpopulation is currently threatened by competition from alien invasive plants, however, even subpopulations in reserves are dependent on ongoing clearing and management of alien invasive plants to prevent reinvasion and further decline.
D. draconis forms part of a complex web of biological interactions, as it relies on the resemblance of its flower to Pelargonium suburbanum to attract its sole pollinator, a species of long-tongued fly. It is known that fragmentation of habitats into very small patches lead to the decline of species diversity on habitat fragments due to the disruption of biological interactions, such as plant-pollinator mutualisms (Harris and Johnson 2004), and it has been found that other Disa species occurring on similar habitats on the Cape Flats suffer from reduced seed set, as a result of poor pollination success (Bytebier 2004), which is quite possibly the result of specialist pollinators disappearing from habitat fragments with too small populations of host plants. However, this species is also able to reproduce vegetatively (A. Pauw pers. comm.), and therefore pollinator loss is not such a severe threat.
Flowering success in D. draconis is enhanced by high rainfall preceding the flowering season (Liltved and Johnson, unpubl.) and droughts, especially as has been predicted to occur more frequently in the Western Cape as a result of climate change, might be a potential further future threat to the successful reproduction and sustained population numbers of this species. |
Population | Population trend | Decreasing |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Disa draconis (L.f.) Sw. | EN A3ce; B1ab(i,iii,iv,v)+2ab(ii,iii,iv,v) | Raimondo et al. (2009) | | Disa draconis (L.f.) Sw. | VU B1B2abcd | Victor (2002) | | Disa draconis (L.f.) Sw. | Endangered | Hilton-Taylor (1996) | |
Bibliography | Bytebier, B. 2004. Disa barbata. PlantTalk 35:32-33.
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.
Hilton-Taylor, C. 1996. Red Data List of southern African plants. 1. Corrections and additions. Bothalia 26(2):177-182.
Johnson, S.D. and Linder, H.P. 1995. Systematics and evolution of the Disa draconis complex (Orchidaceae). Botanical Journal of the Linnean Society 118:289-307.
Liltved, W.R. and Johnson, S.D. Unpublished. The Cape Orchids - Wild orchids of the Cape Floral Kingdom.
Linder, H.P. 1981. Taxonomic studies in the Disinae. III. A revision of Disa Berg. excluding sect. Micranthae Lindl. Contributions from the Bolus Herbarium 9:1-370.
Linder, H.P. and Kurzweil, H. 1999. Orchids of southern Africa. A.A. Balkema, Rotterdam.
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.
Victor, J.E. 2002. South Africa. In: J.S. Golding (ed), Southern African plant Red Data Lists. Southern African Botanical Diversity Network Report 14 (pp. 93-120), SABONET, Pretoria.
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Citation | | von Staden, L., Bytebier, B. & Johnson, S.D. 2012. Disa draconis (L.f.) Sw. National Assessment: Red List of South African Plants version . Accessed on 2025/05/13 |
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