Gasteria armstrongii

Taxonomy
Scientific Name
Gasteria armstrongii Schönland
Higher Classification
Monocotyledons
Family
ASPHODELACEAE
Synonyms
Gasteria nitida (Salm-Dyck) Haw. var. armstrongii (Schönland) Van Jaarsv.
National Status
Status and Criteria
Critically Endangered A4cd
Assessment Date
2015/09/20
Assessor(s)
E.J. van Jaarsveld, D. Raimondo, C. Logie & L. von Staden
Justification
A highly localized species (EOO 9 km²), known from a single, small population of about 500 plants, which is likely to decline by more than 80% within three generations if planned coastal development is to go ahead.
Distribution
Endemism
South African endemic
Provincial distribution
Eastern Cape
Range
Gamtoos Valley near Jeffreys Bay.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Humansdorp Shale Renosterveld, Gamtoos Thicket
Description
Coastal renosterveld.
Threats
At least 40% of this species' habitat has already been lost to agricultural expansion, and the population remains on a single, fairly extensive fragment of remaining coastal renosterveld. The population continues to decline due to ongoing habitat degradation due to quarrying, dumping, and spreading alien invasive plants. The site has been earmarked for coastal development, which is likely to have a severe impact on the population. Succulent collecting is also an ongoing threat.
Population

Gasteria armstrongii occurs in scattered, small clumps across a ±8 km² stretch of coastal renosterveld, spanning a number of properties. Surveys of the area over the past 10 years estimate the total population size to be around 500 mature individuals, which are all likely to be part of a single subpopulation, as habitat is still largely continuous over this area. The population is estimated to have already declined by at least 30%, predominantly due to habitat loss to agricultural expansion. If proposed coastal development plans are to go ahead, this species could decline by up to 80% in the next 20-40 years (1-2 generations).


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Gasteria nitida (Salm-Dyck) Haw. var. armstrongii (Schönland) Van Jaarsv.CR A4cd; B1ab(v)2012.1
Gasteria nitida (Salm-Dyck) Haw. var. armstrongii (Schönland) Van Jaarsv.CR A4cd; B1ab(v)Raimondo et al. (2009)
Gasteria nitida (Salm-Dyck) Haw. var. armstrongii (Schönland) Van Jaarsv.Insufficiently Known Hilton-Taylor (1996)
Gasteria armstrongii SchönlandUncertain Hall et al. (1980)
Bibliography

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.


Van Jaarsveld, E. 1992. The genus Gasteria, a synoptic review. Aloe 29(1):1-32.


Van Jaarsveld, E.J. 1992. The genus Gasteria, a synoptic review. Aloe 29(1):1-32.


Citation
van Jaarsveld, E.J., Raimondo, D., Logie, C. & von Staden, L. 2015. Gasteria armstrongii Schönland. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2018/12/14

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Distribution map

© E.J. van Jaarsveld


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