Taxonomy
Scientific Name
Dierama dubium N.E.Br.
Higher Classification
Monocotyledons
Family
IRIDACEAE
National Status
Status and Criteria
Vulnerable B1ab(ii,iii,v)
Assessment Date
2006/11/28
Assessor(s)
L. von Staden, J.E. Victor & C.R. Scott-Shaw
Justification
It has a restricted distribution in central KwaZulu-Natal (EOO 3800 km²) and is very rare, occurring in very low abundances and known from five to seven locations. Its habitat is severely transformed in the southern parts of the range. Across the known range of this species there is a continuing decline due to subsistence agriculture (crop cultivation and overgrazing of communal rangelands).
Distribution
Endemism
South African endemic
Provincial distribution
KwaZulu-Natal
Range
Mahlabatini to Mapumulo.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Midlands Mistbelt Grassland, Moist Coast Hinterland Grassland
Description
Grassland, 1200-1500 m.
Threats
Grassland transformation by agriculture and forestry has severely reduced suitable habitat (Scott-Shaw 1999). Of the two grasslands in which this species occurs, KwaZulu-Natal Sandstone Grasslands are the most highly transformed and have been classified as Endangered by the NSBA (Rouget et al. 2004). Grasslands between Kranskop and Mapumulo, where the most recent records of this species have been collected, was already 82% transformed by agriculture, forestry plantations and degradation due to severe overgrazing by 1996 (Calculated using GIS, NLC 1996 and Vegmap 2006), and this habitat has continued to decline since then due to overgrazing and subsistence farming (C.R. Scott-Shaw pers. comm.). Further north, the Northern Zululand Sourveld grasslands are somewhat less threatened, and this vegetation type has been classified as Vulnerable (Rouget et al. 2004). The main threat to this vegetation is severe, ongoing overgrazing of communal rangelands, and the soils are prone to erosion (Mucina & Rutherford 2006).
Population
Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Dierama dubium N.E.Br.VU B1ab(ii,iii,v)Raimondo et al. (2009)
Dierama dubium N.E.Br.Data Deficient Scott-Shaw (1999)
Dierama dubium N.E.Br.Rare Hilton-Taylor (1996)
Bibliography

Hilliard, O.M. and Burtt, B.L. 1991. Dierama: The hairbells of Africa. Acorn Books, Johannesburg and London.


Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical Institute, Pretoria.


Mucina, L. and Rutherford, M.C. (eds). 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. 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.


Rouget, M., Reyers, B., Jonas, Z., Desmet, P., Driver, A., Maze, K., Egoh, B. and Cowling, R.M. 2004. South African National Spatial Biodiversity Assessment 2004: Technical Report. Volume 1: Terrestrial component. South African National Biodiversity Institute, Pretoria.


Scott-Shaw, C.R. 1999. Rare and threatened plants of KwaZulu-Natal and neighbouring regions. KwaZulu-Natal Nature Conservation Service, Pietermaritzburg.


Citation
von Staden, L., Victor, J.E. & Scott-Shaw, C.R. 2006. Dierama dubium N.E.Br. National Assessment: Red List of South African Plants version . Accessed on 2025/01/18

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Distribution map


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