The effects of short-duration overnight kraaling on herbaceous vegetation and soils in mesic grassland
- Authors: Mgwali, Nompendulo
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424721 , vital:72178
- Description: Land degradation is widespread in communal rangelands in the grassland biome of South Africa, and often attributed to overstocking and lack of coordinated management. Excessive pressure on the herbaceous component has contributed to the uncontrolled spread of opportunistic invasive alien woody species e.g. Acacia mearnsii in many degraded areas, resulting in significant loss of ecosystem service capacity, along with soil and land productivity. Short-duration overnight kraaling has been suggested as a tool for restoring degraded rangelands. Recent studies in semi-arid savannas and shrublands have reported increased grass cover, soil nutrients and palatability and concluded that short-duration kraaling is a low-cost and effective way of restoring degraded rangelands using livestock. However, the response of different plant functional types and communities to such intense livestock impact may vary depending on local context. This study used twelve paired kraal and control sites to investigate the effects of short-duration (7-24 days) overnight kraaling of livestock on herbaceous vegetation and soils in a mesic grassland. The study area is generally considered to be overgrazed but has considerable variation in grass composition and basal cover. Sites included relatively intact natural grassland and sites where wattle infestations had been cleared and where mostly bare ground remained. I tested the hypotheses that overnight kraaling would result in (1) increased basal cover due to introduction of grass seed and stimulation of germination through hoof action, (2) increased infiltration due to hoof action, and (3) increased soil nutrients and organic matter due to dung and urine deposition. I also hypothesized that factors such as a site’s initial grass cover, its slope, the occurrence and amount of rainfall before and during kraaling, and the kraaling intensity (number of livestock and duration of the kraaling event) would influence the magnitude and direction of the kraaling effect. The effect of kraaling on vegetation was strongly dependent on initial condition. Kraaling increased basal cover of grasses when sites had low initial basal cover, but decreased basal cover if initial values were over 50%. Infiltration increased if kraaling took place during or after rain but decreased if kraaling took place when soils were dry. Kraaling increased soil P and K. In mesic grasslands, short-duration overnight kraaling is promising as a tool for rehabilitating degraded sites but should be avoided where the grass sward is relatively intact. I recommend that the suitability of kraaling be further evaluated per vegetation type and local context. , Thesis (MSc) -- Faculty of Science, Botany, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Mgwali, Nompendulo
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424721 , vital:72178
- Description: Land degradation is widespread in communal rangelands in the grassland biome of South Africa, and often attributed to overstocking and lack of coordinated management. Excessive pressure on the herbaceous component has contributed to the uncontrolled spread of opportunistic invasive alien woody species e.g. Acacia mearnsii in many degraded areas, resulting in significant loss of ecosystem service capacity, along with soil and land productivity. Short-duration overnight kraaling has been suggested as a tool for restoring degraded rangelands. Recent studies in semi-arid savannas and shrublands have reported increased grass cover, soil nutrients and palatability and concluded that short-duration kraaling is a low-cost and effective way of restoring degraded rangelands using livestock. However, the response of different plant functional types and communities to such intense livestock impact may vary depending on local context. This study used twelve paired kraal and control sites to investigate the effects of short-duration (7-24 days) overnight kraaling of livestock on herbaceous vegetation and soils in a mesic grassland. The study area is generally considered to be overgrazed but has considerable variation in grass composition and basal cover. Sites included relatively intact natural grassland and sites where wattle infestations had been cleared and where mostly bare ground remained. I tested the hypotheses that overnight kraaling would result in (1) increased basal cover due to introduction of grass seed and stimulation of germination through hoof action, (2) increased infiltration due to hoof action, and (3) increased soil nutrients and organic matter due to dung and urine deposition. I also hypothesized that factors such as a site’s initial grass cover, its slope, the occurrence and amount of rainfall before and during kraaling, and the kraaling intensity (number of livestock and duration of the kraaling event) would influence the magnitude and direction of the kraaling effect. The effect of kraaling on vegetation was strongly dependent on initial condition. Kraaling increased basal cover of grasses when sites had low initial basal cover, but decreased basal cover if initial values were over 50%. Infiltration increased if kraaling took place during or after rain but decreased if kraaling took place when soils were dry. Kraaling increased soil P and K. In mesic grasslands, short-duration overnight kraaling is promising as a tool for rehabilitating degraded sites but should be avoided where the grass sward is relatively intact. I recommend that the suitability of kraaling be further evaluated per vegetation type and local context. , Thesis (MSc) -- Faculty of Science, Botany, 2023
- Full Text:
- Date Issued: 2023-10-13
Population dynamics, fire, and reproductive ecology of Oldenburgia grandis (Asteraceae), an unusual fynbos tree endemic to the Eastern Cape
- Authors: Mostert, Emma Charlotte
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365268 , vital:65722
- Description: Thesis embargoed. Possible release date set for early 2024. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Mostert, Emma Charlotte
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365268 , vital:65722
- Description: Thesis embargoed. Possible release date set for early 2024. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
- Date Issued: 2022-10-14
CO2-induced woody thickening depends strongly on interacting abiotic and biotic factors
- Authors: Raubenheimer, Sarah Lynn
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164646 , vital:41151 , doi:10.21504/10962/164646
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Botany, 2020
- Full Text:
- Date Issued: 2020
- Authors: Raubenheimer, Sarah Lynn
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164646 , vital:41151 , doi:10.21504/10962/164646
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Botany, 2020
- Full Text:
- Date Issued: 2020
Some elements of the arthropod fauna of the soil in South Africa
- Authors: Farquhar, M J
- Date: 1947
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193691 , vital:45386
- Description: In a paper entitled "Bacteria of the Soil", Dr. Russell of Rothamsted is quoted as saying, ”The top six lashes might almost be called a separate world? 80 great is the number and variety of its inhabitants”• It is with a few forms belonging to this enormous biological complex that the author intends to deal, viz*, representatives of the Orders Pauropoda, Symphyla, Protura, Coleoptera and Hemiptera. Time does not permit the inclusion of a study of the multitude of Arthropod, species that occur in the soil, but a more complete work on these soil groups is intended in the future. McCullogh and Hayes (1922,p.288) state that the soil is an integral factor In the study of biological problems. Hence an understanding of the organic life of the soil, which is of great importance in relation to the other aspects of pedology, is a necessary adjunct to the study of the soil ae a whole. , Thesis (MSc) -- Faculty of Science, Botany, 1947
- Full Text:
- Date Issued: 1947
- Authors: Farquhar, M J
- Date: 1947
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193691 , vital:45386
- Description: In a paper entitled "Bacteria of the Soil", Dr. Russell of Rothamsted is quoted as saying, ”The top six lashes might almost be called a separate world? 80 great is the number and variety of its inhabitants”• It is with a few forms belonging to this enormous biological complex that the author intends to deal, viz*, representatives of the Orders Pauropoda, Symphyla, Protura, Coleoptera and Hemiptera. Time does not permit the inclusion of a study of the multitude of Arthropod, species that occur in the soil, but a more complete work on these soil groups is intended in the future. McCullogh and Hayes (1922,p.288) state that the soil is an integral factor In the study of biological problems. Hence an understanding of the organic life of the soil, which is of great importance in relation to the other aspects of pedology, is a necessary adjunct to the study of the soil ae a whole. , Thesis (MSc) -- Faculty of Science, Botany, 1947
- Full Text:
- Date Issued: 1947
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