Habitat and Ecology
IUCN Red List Assessment
Red List Category
Red List Criteria
- 2003Near Threatened(IUCN 2003)
- 2003Near Threatened
- 1997Rare(Walter and Gillett 1998)
Abundance at known localities:
a) Past and current:
Since at least 1965, there have been reports of S. eriopus becoming scarce, rare and extirpated in many areas of its range. Vast numbers of plants were eradicated along the KwaZulu-Natal and Eastern Cape coast as sugar cane fields and the pineapple industry respectively replaced the natural vegetation. S. eriopus was once a usual sight in coastal and scarp forests and coastal grassland from Bathurst to Kosi Bay, but today it is far less common. Furthermore, plants within the borders of designated nature reserves are not altogether safe. Regular visitors to Ngoye have also reported drastic reductions in population numbers, and a recent half-day survey in the Gwaliweni forest north of Jozini in KwaZulu-Natal failed to locate any specimens. Between Durban and Hluhluwe, S. eriopus was lost at many localities due to habitat transformation for sugar cane and gum plantations. Very little natural vegetation exists in these areas today, and S. eriopus tends to be found in isolated pockets. Stangeria is therefore currently rare and of low abundance in this specific area.
The possible future construction of a coastal highway through the Eastern Cape would threaten many the subpopulations. Parts of the former Transkei are currently a refuge for Stangeria, but coastal urban development will threaten the habitat and the range as forest refugia become more accessible to collectors.
There are 34 known Quarter Degree Squares (QDS) records from PRECIS (the Pretoria Herbarium Specimen Database), the literature and personal observations. The following threats were noted:
a) In 14 known QDS (41%), habitat transformation and degradation has occurred from the Eastern Cape to KwaZulu-Natal for plantations (pineapple, sugar cane and pine trees). S. eriopus tends to occupy vegetation pockets within these areas or has been permanently extirpated (past decline).
b) 14 QDSs (41%) stand to be affected by the proposed new N2 highway through the Eastern Cape, hence destroying habitats and making previous S. eriopus refugia potentially accessible to collectors (future decline).
c) In at least 9 QDSs (26%), S. eriopus has been observed to be scarce, declining and actively targeted by collectors (current decline)
Therefore, in total, in at least 27 QDS (79%) that we know of (through personal observations and the literature), the S. eriopus population has experienced past declines OR is currently declining OR is facing potential decline due to past, current and future threats from habitat transformation and traditional medicine harvesting.
The tuber is sometimes branched into several growing points and because of this, it is usually not possible to uproot all of the plant without damaging and leaving behind some of the caudex. It is sometimes possible for regeneration to occur from the damaged caudex. It is therefore also possible that a portion of the caudex may be left behind during incomplete excavations for the traditional medicine (muti) trade, and that some regeneration may occur in areas that have been targeted by harvesters. Growth from seed is slow.
The possible future construction of the highway through the Eastern Cape will threaten many of the subpopulations. Parts of the former Transkei are currently a refuge for S. eriopus, but coastal urban development will threaten the habitat and the range as forest refugia become more accessible to collectors.
At least 20% of the habitat has been lost over the last three generations (150 years) (generation length is about 50 years) and harvesting for the traditional medicine trade has caused at least a further 10-20% decline in population size. The habitat is further threatened with future transformation and increased harvesting as a result of the N2 highway being extended through the Eastern Cape.
S. eriopus is a sought after medicinal plant which has been severely over-exploited over much of its distribution range. The habitat is rapidly being degraded because of woodcutting and the expansion of crop farming. The lignotuber is used for traditional medicine, hence harvesting is destructive and whole plants are usually killed. Estimates of an annual sale of 233 bags (50 kg-size) by 54 traders in the Durban markets have been made - possibly accounting for Â¼ of the total sales in the province. In a survey conducted in July 1992, 28 out of 170 gatherers (16.5%) in two Durban muti markets sold the tubers. The mean mass of caudices on sale = 0.7 kg; mean mass sold/month/trader = 85 kg; mean number of plants sold/month/trader = 122; total mass sold/month = 2380 kg; total number of plants sold/month = 3410 individual caudices (or, 40,920 plants per year). The unknown quantity of tubers sold by the muti shops in the city would have added considerably to the annual volume sold in the region. The plants were said to have been harvested from areas in the Transkei, southern and northern KwaZulu-Natal, and concerns were raised that the rate of exploitation would lead to a rapid demise of S. eriopus in the wild, especially if the herbal medicine trade continued to expand (as it has).
The popularity of S. eriopus is such that it is traded outside of its range in Mpumalanga and Gauteng. Trade figures for Johannesburg showed that 58% of muti shops stocked the species in 1994, 18% of which said it was scarce. The annual volume estimated to have been sold was 243 bags (50 kg-size). In the Faraday market in 2001, 9% of traders sold it with a combined volume of 38 bags.
More recently, evidence has been found of S. eriopus tubers having been excavated in the Manguzi, presumably for the traditional medicine trade. Possibly more than 50 plants had been removed from the site, and that conservatively hundreds had been excavated in the last few months. On a recent visit to the Faraday market, 20 traders with S. eriopus, each with about 20 plants per trader were found.
In terms of habitat destruction, vast numbers of plants have been eradicated along the KwaZulu-Natal coast as sugar cane fields replaced the natural vegetation, and the expansion of the pineapple industry in the Eastern Cape had caused similar diminution in the distribution of S. eriopus in that area.
Cycad collectors have also threatened the Stangeria population. A post-war anecdote has been cited in which a field botanist active along the Natal south coast was offered one pound per plant to send as many living Stangeria plants as could be collected to a Chicago museum. The botanist refused, and the field full of Stangeria that was mentioned in the anecdote was subsequently visited 30 years later to find that it had been over-grazed and not a single plant remained.
Stangeria eriopus is a cycad endemic to southern Africa It is the sole species in the genus Stangeria, most closely related to the Australian genus Bowenia, with which it forms the family Stangeriaceae. IUCN Red List Category & Criteria: Vulnerable, mainly due to habitat loss and over-exploiting for traditional medicine. It is listed under CITES Appendix I / EU Annex A, and CITES prohibits international trade in specimens of this species except when the purpose of the import is not commercial, for instance for scientific research.
Stangeria eriopus has pinnately-veined, fern-like leaves that distinguish it from all other cycads. The species occurs as two variable forms or varieties. The forest form, growing in regions with higher rainfall, is characterized by large, wide leaves that can reach up to 2 m in length. The grassland form, growing in regions subject to annual fire and drought, has shorter leaves with a thicker cuticle that may only be 30 cm long. In both varieties the petiole comprises one third to one half of the overall leaf length.
Stems are completely subterranean and the root is shaped like a carrot. As in other cycads, S. eriopus forms coralloid roots. These are specialized, plagiotropic (sideways-growing) roots housing colonies of cyanobacteria that fix nitrogen, much like the roots of legumes.
S. eriopus reaches maturity at 5–7 years of age, and has stalked cones as reproductive organs. As is typical of cycads, the species is dioecious, meaning that male and female cones are borne on different plants. The cones are insect-pollinated, giving off a faint odor to attract beetle pollinators. At maturity they fall apart to reveal the seeds, which are 2-3 cm in length.
The binomial name comes from the Greek prefix erio-, meaning "woolly", and suffix -pus, "footed", referring to the woolly petiole bases. It was named in honour of William Stanger, a former surveyor-general of Natal. Common names includes Natal Grass Cycad, Hottentot's Head and Stangeria.
It is native to the east coast of South Africa and southern Mozambique. It is found within 50 km, but not closer than 2 to 3 km, from the sea. This species of cycad is adaptable and is found in many habitats, from closed forest to grassland, but it is under increasing threat from habitat loss and unsustainable harvesting for traditional medicinal purposes.
- Donaldson (2003). Stangeria eriopus. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 11 May 2006.
- Whitelock, Loran M. (2002). The Cycads. Portland OR: Timber press. ISBN 0-88192-522-5.
- Tuckley, R. (1999). "A new significance for Stangeria?". The Cycad Newsletter 22 (4): 11–14.
- Osborne R, Grove A, Oh P, Mabry TJ, Ng JC, Seawright AA (July 1994). "The magical and medicinal usage of Stangeria eriopus in South Africa". J Ethnopharmacol 43 (2): 67–72. doi:10.1016/0378-8741(94)90005-1. PMID 7967657.
- Vorster, P., Vorster, E. (March 1985). "Stangeria eriopus". Encephalartos 2: 1–11.
- Douwes, E., Gillmer, M., Mattson, M., Dalzell, C. (2004). "Vegetative propagation of Stangeria eriopus from leaf material". Encephalartos 80: 28–30.
- The Cycad Pages: Stangeria eriopus
- Cycad Society of South Africa: Stangeria eriopus
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