Aloe nubigena

Taxonomy
Scientific Name
Aloe nubigena Groenew.
Higher Classification
Monocotyledons
Family
ASPHODELACEAE
National Status
Status and Criteria
Rare
Assessment Date
2014/06/17
Assessor(s)
M. Lötter, J.E. Burrows & L. von Staden
Justification
A range-restricted (EOO 150 km²), but locally abundant species that is not threatened.
Distribution
Endemism
South African endemic
Provincial distribution
Mpumalanga
Range
Mpumalanga Escarpment, from Mariepskop to Graskop.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Grassland
Description
Mistbelt grassland, upper steep south to east facing cliffs above forested gorges.
Threats
Much of the surrounding grasslands within the distribution range of A. nubigena has been converted to forestry plantations (Craib 2005). This is unlikely to have directly impacted on much of the habitat of A. nubigena, except for subpopulations occurring on flat areas at the top of cliffs. However, invading pine seedlings dispersed from nearby plantations onto the cliff faces could potentially lead to degradation of the habitat (Craib 2005), but is unlikely to rapidly affect all individuals of this common species. Pine plantations as well as grazing cattle could disrupt and degrade the drainage of seepages onto the cliffs, especially above Graskop Gorge, which may alter the moisture regime of the habitat (Craib 2005). However, the main source of moisture to A. nubigena is probably precipitation from mist, and this is unlikely to be affected by habitat degradation. Plants in easily accessible sites at the cliff tops such as God's Window, a popular tourist destination, are potentially threatened by illegal collecting. According to field observations by local botanist M. Lötter, the largest part of the population occurs on inaccessible, steep cliff faces where there are no potential threats of either habitat degradation or collecting and, therefore, the threats listed by Craib (2005) are not significant enough to rapidly affect the population so that it could become critically endangered or extinct within a very short time period.
Population

Aloe nubigena has a restricted range (EOO 150 km²), with highly specific habitat requirements (AOO <10 km²). However, within areas of suitable habitat it is locally abundant (M. Lötter pers. comm.). A small proportion (less than 10%) of the population occurs in sites on top of cliffs while the rest occurs on the steep cliff faces below. There has been some decline in the past at the more accessible sites on top of cliffs due to habitat degradation and collecting of plants for horticultural purposes, but the remaining population is not declining or threatened (M. Lötter pers. comm. 2014).


Population trend
Stable
Conservation
Most of the population between Graskop and Mariepskop is protected within the Blyde River Canyon Nature Reserve.
Notes
A disjunct population of Aloe nubigena from the mountains south of Barberton was recently described as a separate species, Aloe condyae (Van Jaarsveld 2012).
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Aloe nubigena Groenew.Rare 2015.1
Aloe nubigena Groenew.VU D22014.1
Aloe nubigena Groenew.Least Concern 2013.1
Aloe nubigena Groenew.Least Concern Raimondo et al. (2009)
Aloe nubigena Groenew.VU D2Victor (2002)
Aloe nubigena Groenew.Not Threatened Hilton-Taylor (1996)
Bibliography

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


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


Van Jaarsveld, E.J. 2012. Aloe condyae, a new cliff-dwelling aloe from Mpumalanga, Republic of South Africa. Bradleya 30:167-172.


Van Wyk, B.-E. and Smith, G. 1996. Guide to the aloes of South Africa. 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
Lötter, M., Burrows, J.E. & von Staden, L. 2014. Aloe nubigena Groenew. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2018/12/12

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Distribution map

© D.R. McKenzie


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