Gerstner's Aloe

Taxonomy
Scientific Name
Aloe gerstneri Reynolds
Higher Classification
Monocotyledons
Family
ASPHODELACEAE
Common Names
Gerstner's Aloe (e), Isihlabana (z)
National Status
Status and Criteria
Endangered B1ab(i,ii,iii,v)+2ab(i,ii,iii,v)
Assessment Date
2018/10/02
Assessor(s)
H. Mtshali, J.E. Victor, E. van Wyk & G.F. Smith
Justification
Aloe gerstneri has a restricted distribution range (extent of occurrence 334 km², area of occupancy 12-24 km²), and is known from three to five locations. It continues to decline due to ongoing habitat loss and degradation.
Distribution
Endemism
South African endemic
Provincial distribution
KwaZulu-Natal
Range
This species is endemic to a small area in the Babanango District, central KwaZulu-Natal, South Africa.
Habitat and Ecology
Major system
Terrestrial
Major habitats
KwaZulu-Natal Highland Thornveld
Description
It occurs on rocky slopes and outcrops near streams in grassland and thornveld.
Threats
Aloe gerstneri is threatened by ongoing habitat loss and degradation due to expanding rural settlements, subsistence agriculture and overgrazing. Around 30% of its habitat is already irreversibly modified (calculated using recent land cover data), and there is likely to be ongoing degradation of the remaining natural areas due to overgrazing. According to C.R. Scott-Shaw (pers. comm.), Aloe gerstneri tends to persist in heavily overgrazed areas as it is not impacted by grazing. However, overgrazing has been causing widespread erosion, which is leading to ongoing population decline. Aloe gerstneri was also heavily collected in the past (Van Wyk and Smith 2003), which had a significant impact on the small and localized population, but the Aloe collecting frenzy of the 1960s and 1970s has largely ceased, and most species are now well established in cultivation.
Population

Aloe gerstneri has an extremely localized distribution, and is known from only a few records, most dating from the 1950s and earlier. It was last recorded as locally common just south of Nqutu in 2012, but other localities known from historical records need to be surveyed to gain a better understanding of the size of the population. According to Van Wyk and Smith (2003), Aloe gerstneri is declining.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Aloe gerstneri ReynoldsVU B1ab(i,ii,iii,v)Raimondo et al. (2009)
Aloe gerstneri ReynoldsVU B1B2abceVictor (2002)
Aloe gerstneri ReynoldsVU B1B2abcdScott-Shaw (1999)
Aloe gerstneri ReynoldsRare Hilton-Taylor (1996)
Aloe gerstneri ReynoldsVulnerable Hall et al. (1980)
Bibliography

Glen, H.F. and Hardy, D.S. 1990. Aloe gerstneri. Flowering Plants of Africa 51(1):t.2008.


Glen, H.F. and Hardy, D.S. 2000. Aloaceae (First part): Aloe. In: G. Germishuizen (ed). Flora of Southern Africa 5 Part 1, Fascicle 1:1-159. National Botanical Institute, Pretoria.


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.


Reynolds, G.W. 1937. Two new aloes from Zululand and two from the Transvaal. Journal of South African Botany 3:133-141.


Reynolds, G.W. 1969. The Aloes of South Africa. A.A. Balkema, Cape Town.


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


Smith, G.F., Steyn, E.M.A., Victor, J.E., Crouch, N.R., Golding, J.S. and Hilton-Taylor, C. 2000. Aloaceae: The conservation status of Aloe in South Africa: an updated synopsis. Bothalia 30(2):206-211.


Van Wyk, B.-E. and Smith, G. 1996. Guide to the aloes of South Africa. Briza Publications, Pretoria.


Van Wyk, B.-E. and Smith, G. 2003. Guide to aloes of South Africa. (2nd ed.). Briza Publications, 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.


Citation
Mtshali, H., Victor, J.E., van Wyk, E. & Smith, G.F. 2018. Aloe gerstneri Reynolds. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2020/07/10

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Distribution map

© L. Nkuna

© D.R. McKenzie


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