Brackenridgea zanguebarica Oliv.
|Brackenridgea bussei Gilg, Ochna alboserrata Engl., Ochna praecox Sleumer|
|Geellekkerbreek (a), Mutavhatsindi (v)|
Status and Criteria
Critically Endangered A2ad; B1ab(ii,v)
|V.L. Williams & D. Raimondo|
|At one known location in South Africa an 86% population reduction was observed from 1990-1997 due to debarking for the medicinal plant trade, fuel wood collection, and habitat destruction for agriculture. South African EOO and AOO <35 km², and decline continues. The South African national assessment is not downgraded as this population is isolated from other subpopulations in Africa.|
|Not endemic to South Africa|
|One known subpopulation in South Africa occurs in the Thengwe district in Venda. Also occurs in Zimbabwe, Mozambique and northwards to Tanzania.|
Habitat and Ecology
|Soutpansberg Mountain Bushveld|
|South Africa: stony, light grey and shallow sandy loam in woodland, 655m, also on the southern aspect of dry mountain bushveld. In east Africa, it is found in deciduous woodland and coastal bush. 0-1500 m.|
|In general, the threats to the species include: over-utilization by medicinal collectors; degradation of habitat through grazing and wood collecting; development of land for housing; and a lack of adequate funds to effectively manage and protect the site.
A past threat to the species includes road construction through the Thengwe area that damaged trees on two separate occasions. The first cited incidence of bulldozer damage is before 1980 (Netshiungani and van Wyk 1980). The second incidence was from 1989-1990 when an existing gravel road that ran through the area was re-routed and tarred (Todd 1999, Todd et al. 2004). The road bisected the B. zanguebarica population and damaged or destroyed more than 86 trees - this highlighted the need for stronger conservation measures to ensure the future survival of the species in the region and led to the first scientific study of the B. zanguebarica population in 1990 (Todd et al. 2004).
In 1992, 110ha (1.1 sq km) of land was proclaimed as the Mutavhatsindi Nature Reserve (Todd 1999). Hence part of the population was 'protected' within the reserve and the other part of the population was left vulnerable outside of the reserve. However, the Department of Environmental Affairs lacked adequate funds to effectively manage and patrol the reserve and this left the Brackenridge population very vulnerable (Todd 1999). A survey done in 1997 showed that the population size had decreased, even in the reserve, since the census of 1990 (Todd 1999). Trees were found to have been debarked and roots removed to such an extent that many trees died outside the reserve. Inside the reserve, where there was some control over who harvests and how much, survival of the adult trees was high (Todd 1999). The lack of control over harvesting led to a decrease in the number of trees outside the Mutavhatsindi Nature Reserve, whereas the lack of adequate management is attributed to declines within the reserve.
The harvesting of roots and bark (known as 'mutavhatsindi') for traditional medicine is a threat to the species. Netshiungani and van Wyk (1980) reported seeing an old man in the Sibasa market place selling the distinctive yellow roots. Netshiungani and van Wyk (1980) also speculated that the roots were the same ones mentioned in a report by Isaak Jan Lamotius around 1720 concerning Portuguese priests being in possession of yellow roots used as medicine and obtained from an area of Mozambique around .1691. In the Witwatersrand muthi shops during a 1994 survey of 50 traders, 12% sold the species and 20% cited it as scarce (Williams 2007; Williams et al 2000). Todd (1999) also reported that it was a popular traditional medicine that was still being used (despite the decline in availability), and that it could be bought in muthi shops in Thohoyandou for >R300/kg. Botha et al. (2001) reported it being sold in the Limpopo/Mpumalanga markets, and that the demand was "very high".
There is debate as to whether harvesting is sustainable because generation appears to be slow. Netshiungani and van Wyk (1980) reported that they found no plants <1 m high during their visit to a site in January 1980, whereas they had found trees up to 6 m in height with a dbh=64 cm. Trees that have been debarked and/or had their roots removed have shown signs of decreased recruitment from seedlings or suckers (Todd 1990). An anonymous source, however, stated that harvesting was sustainable and that the breakdown of customary taboos regarding the harvesting of the species has probably resulted in its slow decline.
Brackenridgea tends to establish itself in open areas with low grass cover where competition with other faster growing species is reduced. If bush becomes too dense (e.g. by removal of grazers and browsers such as cattle and goats), then re-establishment is difficult and the existing population size will fall below a level from which it could not recover without the intervention of a planting program (Todd 1999).|
Todd et al. (2004) reported that uncontrolled harvesting of the species has been high, leading to an 86% decline in density from 140 trees/ha in 1990, to 25 trees/ha in 1997. Furthermore, 100% of trees sampled outside the reserve had been debarked and their roots removed (Todd et al. 2004). Only 17% of trees outside the reserve were still living and >50% had had all their roots removed. Inside the reserve, 74% of trees showed evidence of harvesting, and of these 35% were dead (Todd et al. 2004). Harvesting has altered the population structure outside the reserve as well as within the reserve to a lesser extent. Outside the reserve, the population was dominated by relatively young plants (<15 cm basal diameter (bd); however, 50% were 1-5 cm) and trees with a basal diameter of 15-25 cm were absent. Within the reserve, 25% were 1-5 cm and 23% were 15-25 cm. No trees larger than 30 cm bd were recorded within the reserve or outside it during the 1990 and 1997 population surveys. This contrasts with the observations of Netshiungani and van Wyk (1980), who recorded trees up to 64 cm dbh.
|Protected in the Mutavhatsindi Nature Reserve (1992) of 110 ha (1.1 sq km). The cultural beliefs of the Vhavhenda is the main factor in the conservation of the species (Netshiungani and van Wyk 1980). Superstitions surrounding the consequences of people other than traditional healers harvesting the roots/bark tend to protect it from over-exploitation.|
|Williams, V.L. & Raimondo, D. 2008. Brackenridgea zanguebarica Oliv. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2020/04/06|