Assessing the local awareness and perception of invasive alien plants: A case study of Port St Johns Local Municipality, Eastern Cape Province, South Africa
- Authors: Somkala, Avela Abongile
- Date: 2021-10
- Subjects: Alien plants , Invasive plants
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22600 , vital:52595
- Description: Invasive alien plants (IAPs) are introduced species that constitute a self-sustaining population, consistently producing offspring in large numbers and at considerable distances from the parent plants with the potential to spread over a large area. Species invasions are one of the main conservation threats today and have caused modification of ecosystems, particularly in coastal areas. Therefore, Port St Johns Local Municipality (PSJ LM) was an appropriate study site to evaluate the local awareness and perceptions of IAPs. The study investigated the local community’s perceptions of invasive alien plants' uses and ecological impacts. Information about the local awareness and perceptions of invasive alien plant species in PSJ LM was gathered through semi-structured interviews, observation and guided field walks with 120 participants between February and April 2021. The participants included 30 people working on the alien plant eradication project in PSJ LM (Wards 1, 2 and 3) and 90 randomly selected community members. The data collected were entered in Microsoft Excel 2016 programme and analyzed for descriptive statistical patterns using Statistical Package for Social Studies (SPSS) version 22.0. Biological invasion by IAPs was ubiquitously perceived, with participants working on invasive alien plant eradication project in the area exhibiting more scientifically based knowledge on IAPs than ordinary community members. Invasive alien plants in the area appear to have adverse environmental and socio-economic impacts, as the participants are not benefiting from these plant species. Similarly, costs of eradicating these species were also acknowledged. The ability of local community members to identify IAPs is vital in effective management of the spread of these species. A total of seven invasive IAPs were recorded. Evaluating the perceptions of local people towards IAPs provides valuable insights for development planning and future management programmes focusing on biological invasions. The study will provide a basis for an enabling policy and institutional environment that provides a coherent framework for the sustainable management of IAPs in the Eastern Cape Province. , Thesis (MPhil) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Somkala, Avela Abongile
- Date: 2021-10
- Subjects: Alien plants , Invasive plants
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22600 , vital:52595
- Description: Invasive alien plants (IAPs) are introduced species that constitute a self-sustaining population, consistently producing offspring in large numbers and at considerable distances from the parent plants with the potential to spread over a large area. Species invasions are one of the main conservation threats today and have caused modification of ecosystems, particularly in coastal areas. Therefore, Port St Johns Local Municipality (PSJ LM) was an appropriate study site to evaluate the local awareness and perceptions of IAPs. The study investigated the local community’s perceptions of invasive alien plants' uses and ecological impacts. Information about the local awareness and perceptions of invasive alien plant species in PSJ LM was gathered through semi-structured interviews, observation and guided field walks with 120 participants between February and April 2021. The participants included 30 people working on the alien plant eradication project in PSJ LM (Wards 1, 2 and 3) and 90 randomly selected community members. The data collected were entered in Microsoft Excel 2016 programme and analyzed for descriptive statistical patterns using Statistical Package for Social Studies (SPSS) version 22.0. Biological invasion by IAPs was ubiquitously perceived, with participants working on invasive alien plant eradication project in the area exhibiting more scientifically based knowledge on IAPs than ordinary community members. Invasive alien plants in the area appear to have adverse environmental and socio-economic impacts, as the participants are not benefiting from these plant species. Similarly, costs of eradicating these species were also acknowledged. The ability of local community members to identify IAPs is vital in effective management of the spread of these species. A total of seven invasive IAPs were recorded. Evaluating the perceptions of local people towards IAPs provides valuable insights for development planning and future management programmes focusing on biological invasions. The study will provide a basis for an enabling policy and institutional environment that provides a coherent framework for the sustainable management of IAPs in the Eastern Cape Province. , Thesis (MPhil) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-10
Effects of elevated temperature, rainfall and soil nutrients on acacia mearnsii invasion
- Authors: Kharivha, Tshililo
- Date: 2021-10
- Subjects: Acacia mearnsii , Acacia mearnsii Effect of high temperatures on South Africa , Acacia mearnsii Climatic factors South Africa , Plant invasions South Africa , Invasive plants , Climatic changes South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/189997 , vital:44954
- Description: Climate change is associated with the risk of plant invasion hence a better understanding of the effects of elevated temperature, precipitation and soil nutrients on dominant invasive plants is needed for effective ecological planning. This study was set out to: (i) examine how elevated temperature (±2°C increase), (ii) high (above local average) and low (below local average) precipitation, (iii) elevated soil nutrient content (increase in soil N), and (iv) a combination of the above manipulations affects germination and growth of Acacia mearnsii, a dominant invasive plant in South Africa. The study further evaluated how the above-mentioned treatments affect soil chemical properties following A. mearnsii germination and growth. The above-mentioned specific objectives were tested under manipulated greenhouse conditions over six experimental months. The results indicated that the above-mentioned climate change scenarios have the potential to facilitate germination and growth of the invasive species A. mearnsii, and this is likely to proliferate its invasion in future. Results showed that seed germination was significantly high under all climate change manipulation treatments (˃50%) with highest seed germination recorded under high rainfall treatment (64%). Plant height was significantly higher under high temperature and high rainfall treatments throughout all the experimental months, though it was lowest under high nitrogen and combined treatment with high rainfall. The numbers of branches were high under higher temperature and low rainfall treatments than under high rainfall, high nitrogen and both combined treatments of low and high rainfall. Relative to the control, plants grown under climate change scenarios increased their root lengths, but this varied across different treatments. Total dry biomass was relatively high under high temperature treatment (0,7 g). Lower plant dry biomass was observed under low and high rainfall treatments (0,4 g), high nitrogen and combined treatments with both low and high rainfall treatments (0,1 g). Concerning the effects of climate change scenarios on soil chemical properties, soil pH levels were significantly higher after A. mearnsii germination and growth than before the experiment was setup. Soil resistivity was significantly higher in climate change treatments receiving nitrogen and combined treatments of low rainfall than other treatments and the soils before experiment. Soil total P was significantly higher in all the climate change treatments after A. mearnsii germination experiment than the before experiment soils. Soils receiving high temperature, high nitrogen, and combined treatment of low rainfall had significantly higher soil total N than other treatments and the before experiment soils. Soil total C was significantly higher in soils receiving high temperature, high nitrogen, and combined treatment of low rainfall after A. mearnsii germination than other treatments and before experiment soils. The findings suggest that future climate change scenarios of increased temperature and rainfall with soil nutrients could considerably enhance growth and germination success of the invasive plant A. mearnsii. Similarly, climate change scenarios could enhance some soil nutrient properties, which in turn, is likely to give the invasive plant A. mearnsii a germination and growth advantage. These results are the first in South Africa to show that future climate changes have the potential to facilitate A. mearnsii germination and growth, making it more invasive. The findings have implications for invasive plants management, especially action for managing the plant through clearing of the plant in sensitive ecosystems (e.g. riparian systems). , Thesis (MSc) -- Faculty of Science, Environmental Science, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Kharivha, Tshililo
- Date: 2021-10
- Subjects: Acacia mearnsii , Acacia mearnsii Effect of high temperatures on South Africa , Acacia mearnsii Climatic factors South Africa , Plant invasions South Africa , Invasive plants , Climatic changes South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/189997 , vital:44954
- Description: Climate change is associated with the risk of plant invasion hence a better understanding of the effects of elevated temperature, precipitation and soil nutrients on dominant invasive plants is needed for effective ecological planning. This study was set out to: (i) examine how elevated temperature (±2°C increase), (ii) high (above local average) and low (below local average) precipitation, (iii) elevated soil nutrient content (increase in soil N), and (iv) a combination of the above manipulations affects germination and growth of Acacia mearnsii, a dominant invasive plant in South Africa. The study further evaluated how the above-mentioned treatments affect soil chemical properties following A. mearnsii germination and growth. The above-mentioned specific objectives were tested under manipulated greenhouse conditions over six experimental months. The results indicated that the above-mentioned climate change scenarios have the potential to facilitate germination and growth of the invasive species A. mearnsii, and this is likely to proliferate its invasion in future. Results showed that seed germination was significantly high under all climate change manipulation treatments (˃50%) with highest seed germination recorded under high rainfall treatment (64%). Plant height was significantly higher under high temperature and high rainfall treatments throughout all the experimental months, though it was lowest under high nitrogen and combined treatment with high rainfall. The numbers of branches were high under higher temperature and low rainfall treatments than under high rainfall, high nitrogen and both combined treatments of low and high rainfall. Relative to the control, plants grown under climate change scenarios increased their root lengths, but this varied across different treatments. Total dry biomass was relatively high under high temperature treatment (0,7 g). Lower plant dry biomass was observed under low and high rainfall treatments (0,4 g), high nitrogen and combined treatments with both low and high rainfall treatments (0,1 g). Concerning the effects of climate change scenarios on soil chemical properties, soil pH levels were significantly higher after A. mearnsii germination and growth than before the experiment was setup. Soil resistivity was significantly higher in climate change treatments receiving nitrogen and combined treatments of low rainfall than other treatments and the soils before experiment. Soil total P was significantly higher in all the climate change treatments after A. mearnsii germination experiment than the before experiment soils. Soils receiving high temperature, high nitrogen, and combined treatment of low rainfall had significantly higher soil total N than other treatments and the before experiment soils. Soil total C was significantly higher in soils receiving high temperature, high nitrogen, and combined treatment of low rainfall after A. mearnsii germination than other treatments and before experiment soils. The findings suggest that future climate change scenarios of increased temperature and rainfall with soil nutrients could considerably enhance growth and germination success of the invasive plant A. mearnsii. Similarly, climate change scenarios could enhance some soil nutrient properties, which in turn, is likely to give the invasive plant A. mearnsii a germination and growth advantage. These results are the first in South Africa to show that future climate changes have the potential to facilitate A. mearnsii germination and growth, making it more invasive. The findings have implications for invasive plants management, especially action for managing the plant through clearing of the plant in sensitive ecosystems (e.g. riparian systems). , Thesis (MSc) -- Faculty of Science, Environmental Science, 2021
- Full Text:
- Date Issued: 2021-10
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