Taxonomy
Scientific Name
Aloe craibii Gideon F.Sm.
Higher Classification
Monocotyledons
Family
ASPHODELACEAE
National Status
Status and Criteria
Endangered B1ab(iii,v)+2ab(iii,v)
Assessment Date
2018/10/16
Assessor(s)
L. von Staden, M. Lötter, J.E. Burrows & D. Raimondo
Justification
Aloe craibii has a restricted distribution range (EOO 134 km²), and the population has been fragmented through 50% habitat loss to timber plantations, and therefore it also has a small AOO of 44 km². Remaining subpopulations are small and isolated, the largest consisting of around 380 mature individuals. The species continues to decline due to competition from alien invasive plants and inappropriate fire management in small grassland fragments between plantations. It is also potentially threatened by succulent collecting.
Distribution
Endemism
South African endemic
Provincial distribution
Mpumalanga
Range
Aloe craibii has a very restricted distribution range in the mountains south of Barberton, Mpumalanga Province.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Barberton Montane Grassland
Description
Montane grassland, in well-drained, relatively deep soils on serpentine and sandstone substrates, in full sun on mountain summits, but not on rocky outcrops, 1500-1800 m.
Threats
Aloe craibii has lost 50% of its habitat to timber plantations, but comparable land cover data show no expansion of plantations between 1990 and 2014. The remainder of A. craibii's habitat is mainly in firebreaks, where there are only mature individuals (Condy and Craib 2003). The absence of juveniles and seedlings is suspected to be the result of too frequent burning. At the type locality, fire is excluded (Craib 2005, Smith and Craib 2005), which also appears to be impacting recruitment. This site is also infested with many alien invasive weeds (J.E. Burrows pers. comm., L. von Staden pers. obs.), that are outcompeting native species. The two largest subpopulations occur along the edges of timber plantations, areas that are also typically a source of invasive weeds. Recently (2014), the subpopulation at the type locality as well as a second subpopulation further along the same ridge have been contracted into the formal protected area network through biodiversity stewardship agreements, whereby privately owned land is included in the formal protected area network. Conservation management at this site will therefore include invasive species clearing in the future. The subpopulation at the type locality is vulnerable to illegal succulent collecting as it is easily accessible by road. There are many documented examples of aloe subpopulations having been completely cleared out by succulent collectors, particularly of newly described species that are not yet well established in cultivation. Succulent collecting has a significant impact on the risk of extinction of species with small wild populations such as A. craibii.
Population

Aloe craibii has a restricted distribution range and small population. Six subpopulations have been recorded, three of these consist of fewer than 100 mature individuals, while two larger subpopulations consist of at least 380 and at least 140 plants respectively. The size of the sixth subpopulation is not known. The subpopulations are isolated and fragmented by extensive stands of timber plantations.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Aloe craibii Gideon F.Sm.CR C2a(i)Raimondo et al. (2009)
Bibliography

Craib, C. 2005. Grass Aloes in the South African Veld. Umdaus Press, Hatfield.


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.


Smith, G.F. 2003. Aloe craibii Gideon F.Sm. (Asphodelaceae: Alooideae): a new species of grass aloe from the Barberton Centre of Endemism, Mpumalanga, South Africa. Bradleya 21:25-28.


Smith, G.F. and Craib, C. 2005. Aloe craibii and its environment. Cactus and Succulent Journal 77(4):202-204.


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


Citation
von Staden, L., Lötter, M., Burrows, J.E. & Raimondo, D. 2018. Aloe craibii Gideon F.Sm. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2020/10/20

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Distribution map

© P. Hardy

© M. Lötter

© Mpumalanga Parks and Tourism Agency (M.T.P.A.)


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