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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Life history, population dynamics and conservation status of Oldenburgia grandis (Asteraceae), an endemic of the Eastern Cape of South Africa

Swart, Carin January 2008 (has links)
Oldenburgia grandis is a rare, long-lived woody paleoendemic of the Fynbos Biome of South Africa. Confined to quartzite outcrops, it has a small geographic range and narrow habitat specificity. O. grandis responds to its fire-prone environment by resprouting. Elasticity analysis of O. grandis reveals that growth and fecundity were traded off for persistence of adult, mature and sapling stages. Morphological adaptations such as a corky fire-resistant bark and the ability to resprout after fire are traits that O. grandis have evolved to persist in a frequently disturbed environment. Population growth rate for sites undisturbed by fire for a number of years (l = 1.01) and sites at various stages of recovery after fire (l = 1.00) were very similar. The highest variation in transition probabilities for all sites was seen in the persistence of the seedling stage and growth from seedling to sapling. Observed population structure and stable stage distribution determined by the matrix model show that sites recently undisturbed by fire had high abundances of the adult and sapling stages. A peak in sapling stages was seen for the stable stage distribution where similar peak in sapling numbers were seen for population structures of sites at various stages of recoveryafter fire. Favourable environmental conditions for the persistence of O. grandis populations include no fire with transition probabilities between the observed minimum and maximum and fire frequency at a 10 year interval where seedling protection from the fire is high and adult and mature mortalities during the fire are low. Stochastic environmental events that could put populations (particularly small populations) at an increased risk of extinction include high to moderate fire intensities where seedling protection from the fire is low and adult and mature mortalities are high as a result of the fire.
12

Perceptions of traditional healers regarding ethnobotanical importance and conservation status of indigenous medicinal plants of Thulamela, Limpopo

Nefhere, Khamusi Victor 03 1900 (has links)
Medicinal plants of Thulamela municipality are experiencing challenges due to human activities, resulting in some of the medicinal plants becoming difficult to find, declining, endangered or even extinct. Unsustainable harvesting is threatening the survival of certain medicinal plant species used as a source of primary healthcare in the area. This study investigates aspects related to traditional healers' perceptions with regard to collection, ethnobotanical importance and conservation status of indigenous medicinal plants used by traditional healers around Thulamela municipality. Information on medicinal plants was gathered by means of semi-structured interviews, field walks, personal observation and a literature review. A total of 90 medicinal plant species, which belong to 47 families, from a total of 82 genera commonly used by traditional healers to treat different ailments, were recorded. About 87% of traditional healers indicated that some medicinal plants are difficult to find; only 13% of healers did not experience difficulties in finding some medicinal plants. / Environmental Sciences / M. Sc. (Ornamental Horticulture)

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