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Accueil du site → Doctorat → Afrique du Sud → 2021 → Conserving living landscapes : investigating the impacts of livestock grazing and assessing rangeland restoration potential in Overberg Renosterveld, South Africa

University of Cape Town. (2021)

Conserving living landscapes : investigating the impacts of livestock grazing and assessing rangeland restoration potential in Overberg Renosterveld, South Africa

Poulsen, Zoë Chapman

Titre : Conserving living landscapes : investigating the impacts of livestock grazing and assessing rangeland restoration potential in Overberg Renosterveld, South Africa

Auteur : Poulsen, Zoë Chapman

Université de soutenance : University of Cape Town.

Grade : Doctor of Philosophy (PhD) Biological Sciences 2021

Résumé partiel
Biodiversity is declining faster than at any other time in the Earth’s history, driven mostly by land use change and degradation. Overberg Renosterveld, some of the most species diverse mediterranean type shrublands, are no exception with about 95% of their original extent lost to agriculture. Historically, large herds of indigenous grazing mammals roamed these landscapes. Today the Overberg’s agricultural lands are fragmented by land cover change and divided by fences. In the contemporary landscape animals, largely domestic livestock, and plant resources are closely coupled, and overgrazing of remaining renosterveld fragments a significant threat, with potential to cause irreversible damage. The Conservation of Agricultural Resources Act (CARA) (Act 43 of 1983) states that farmers must not exceed the grazing capacity of the veld unless it is protected against deterioration and destruction, and that any land that is degraded or denuded must be effectively restored or reclaimed. Despite this legislation, there is little empirical research on the impacts of livestock grazing on renosterveld, as well as on restoration of overgrazed areas. It was the aim of this thesis to contribute to this gap in understanding. The thesis assessed the role of grazing by different livestock types, namely cattle and sheep, on biodiversity, the soil seed bank, and the restoration potential of renosterveld vegetation from resting the veld. The effect of livestock grazing by sheep and cattle on plant species richness and diversity and growth form diversity was assessed using Modified Whittaker plots and presented in Chapter 3. It was hypothesised that livestock grazing by cattle would have less effect on species richness and diversity and growth form diversity than sheep grazing and that both cattle and sheep grazing would lead to a reduction in species richness and diversity in comparison to renosterveld sites with a treatment of no grazing. Thirty sites where either no grazing has taken place or that have been grazed by cattle or sheep were selected with sites being evenly distributed between Eastern, Central and Western Rûens Shale Renosterveld.

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Page publiée le 5 juin 2022