Vivienne L Williams

Dr. Vivienne L Williams

University of the Witwatersrand, Johannesburg, Gauteng, South Africa
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Research Focus & Metrics

Academic Career Length

30Years (1997-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 July 2000 in Economic Botany
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Vivienne L WilliamsVivienne L Williams
Vivienne L Williams
KBKevin Balkwill
Kevin Balkwill
EWEdward Witkowski
Edward Witkowski

1 May 2013 in South African Journal of Botany
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Vivienne L WilliamsVivienne L Williams
Vivienne L Williams
JVJ.E. Victor
J.E. Victor
NCN.R. Crouch
N.R. Crouch
In 2009, South Africa completed the IUCN Red List assessments of 20,456 indigenous vascular plant taxa. During that process, medicinal plant species (especially those sold in informal muthi markets) were identified so that potential extinction risks posed to these species could be assessed. The present study examines and analyses the recently documented threat statuses of South African ethnomedicinal taxa, including the number of species used, revealing family richness and the degree of endemism, and calculates the Red List Index (RLI) of species survival to measure the relative degree of threat to medicinal species. Approximately 2062 indigenous plant species (10% of the total flora) have been recorded as being used for traditional medicine in South Africa, of which it has been determined that 82 species (0.4% of the total national flora) are threatened with extinction at a national level in the short and medium terms and a further 100 species are of conservation concern (including two species already extinct in the wild). Thirty-two percent of the taxa have been recorded in traditional medicine markets in the provinces of KwaZulu-Natal, Gauteng, Eastern Cape, Mpumalanga and Limpopo. The study also reflects on the challenges associated with Red List evaluations of medicinal species, many of which, based on market reports, are extracted at a seemingly unsustainable rate. In contrast to the majority of species enumerated in the Red List of South African plants, medicinal taxa are often widespread, with large extents of occurrence. Accordingly, the population decline criteria have necessarily been applied to assess threats to their existence, even though accurate figures for numbers of remaining individuals, areas of occupancy, quantities harvested, and regeneration times are often found lacking. Factors leading to susceptibility of plant species to extinction as a result of harvesting pressure are discussed. The current findings reveal a need for greater emphasis on focussed population level research on prioritised medicinal plant species

27 August 2014 in PLOS ONE
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Vivienne L WilliamsVivienne L Williams
Vivienne L Williams
ACAnthony B. Cunningham
Anthony B. Cunningham
AKAlan C. Kemp
Alan C. Kemp
RBRobin K. Bruyns
Robin K. Bruyns
Few regional or continent-wide assessments of bird use for traditional medicine have been attempted anywhere in the world. Africa has the highest known diversity of bird species used for this purpose. This study assesses the vulnerability of 354 bird species used for traditional medicine in 25 African countries, from 205 genera, 70 families, and 25 orders. The orders most represented were Passeriformes (107 species), Falconiformes (45 species), and Coraciiformes (24 species), and the families Accipitridae (37 species), Ardeidae (15 species), and Bucerotidae (12 species). The Barn owl (Tyto alba) was the most widely sold species (seven countries). The similarity of avifaunal orders traded is high (analogous to “morphospecies”, and using Sørensen's index), which suggests opportunities for a common understanding of cultural factors driving demand. The highest similarity was between bird orders sold in markets of Benin vs. Burkina Faso (90%), but even bird orders sold in two geographically separated countries (Benin vs. South Africa and Nigeria vs. South Africa) were 87% and 81% similar, respectively. Rabinowitz's “7 forms of rarity” model, used to group species according to commonness or rarity, indicated that 24% of traded bird species are very common, locally abundant in several habitats, and occur over a large geographical area, but 10% are rare, occur in low numbers in specific habitats, and over a small geographical area. The order with the highest proportion of rare species was the Musophagiformes. An analysis of species mass (as a proxy for size) indicated that large and/or conspicuous species tend to be targeted by harvesters for the traditional medicine trade. Furthermore, based on cluster analyses for species groups of similar risk, vultures, hornbills, and other large avifauna, such as bustards, are most threatened by selective harvesting and should be prioritised for conservation action.

17 September 2001 in Bothalia, African Biodiversity & Conservation
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Vivienne L WilliamsVivienne L Williams
Vivienne L Williams
KBK. Balkwill
K. Balkwill
EWEdward Witkowski
Edward Witkowski
At least 511 medicinal plant species are traded commercially in 50 Witwatersrand umuthi shops. The plants are listedalphabetically by genus and common (vernacular) name. The orthographic vernacular names, as well as the orthographicvariations in these names, are incorporated into the list. Annotations include the plant family, the number of umuthi shopsstocking the species, the language of the common name, and the plant part traded. The plant family in the region which hasthe highest number of species and infraspecific taxa in trade is Liliaceae sensu lato., followed in descending order by Fabaceae, Asteraceae. Euphorbiaceae and Amaryllidaceae. Approximately 88.6% of the vernacular names are in Zulu. Themean number of umuthi shops per species is 12.3. ranging from 1 to 41. Three hundred and fifty three species (69.2%) occurin the four northern provinces, and 23 species are listed as threatened on the Red Data List.

1 February 2016 in Journal of Ethnopharmacology
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Vivienne L WilliamsVivienne L Williams
Vivienne L Williams
MWMartin John Whiting
Martin John Whiting

7 February 2011 in Journal of Zoology
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MWM. J. Whiting
M. J. Whiting
Vivienne L WilliamsVivienne L Williams
Vivienne L Williams
THT. J. Hibbitts
T. J. Hibbitts
In South Africa, animals and plants are commonly used as traditional medicine for both the healing of ailments and for symbolic purposes such as improving relationships and attaining good fortune. The aim of this study was twofold: to quantify the species richness and diversity of traded animal species and to assess the trade in species of conservation concern. We surveyed the Faraday traditional medicine market in Johannesburg and conducted 45 interviews of 32 traders during 23 visits. We identified 147 vertebrate species representing about 9% of the total number of vertebrate species in South Africa and about 63% of the total number of documented species (excluding domestic animals) traded in all South African traditional medicine markets. The vertebrates included 60 mammal species, 33 reptile species, 53 bird species and one amphibian species. Overall, species diversity in the Faraday market was moderately high and highest for mammals and birds, respectively. Evenness values indicated that relatively few species were dominant. Mammal body parts and bones were the most commonly sold items (n=2453, excluding porcupine quills and pangolin scales), followed by reptiles (n=394, excluding osteoderms), birds (n=193, excluding feathers and ostrich eggs) and amphibians (n=6). Most (87.5%) species traded were of least concern using IUCN criteria, although 17 species were of conservation concern. However, a higher than expected proportion of traders (62.5%) were selling listed species, which is a matter for concern and should be monitored in the future.