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The impact of invasive alien trees on the monetary value of sediment loads in South African fynbos ecosystems
Thesis (MAgric)--Stellenbosch University, 2024.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867614016905412608 |
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| access_status_str | Open Access |
| author | Petnkeu, Jeronya Mbiatat |
| author2 | De Lange, Willem |
| author_browse | De Lange, Willem Petnkeu, Jeronya Mbiatat |
| author_facet | De Lange, Willem Petnkeu, Jeronya Mbiatat |
| author_sort | Petnkeu, Jeronya Mbiatat |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description |
Thesis (MAgric)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/131885 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:45:20.375Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/131885 The impact of invasive alien trees on the monetary value of sediment loads in South African fynbos ecosystems Petnkeu, Jeronya Mbiatat De Lange, Willem Stellenbosch University. Faculty of AgriSciences. Dept. of Agricultural Economics. Biodiversity conservation -- South Africa Invasive plants -- South Africa Alien plants -- South Africa Fynbos ecology -- South Africa UCTD Thesis (MAgric)--Stellenbosch University, 2024. ENGLISH SUMMARY: Invasive Alien Trees (IATs) have profound ecological and economic impacts on ecosystems where they have established themselves. These non-native species outcompete indigenous flora, alter fire regimes, and disrupt ecological processes, leading to biodiversity loss, habitat degradation, and increased wildfire intensity and severity. This, in turn, exacerbates sedimentation processes in fire-prone ecosystems, significantly affecting water quality and ecosystem health. This sedimentation impairs aquatic habitats and degrades water quality, posing water management and conservation challenges. Understanding the interplay between IATs and sediment dynamics supports effective ecosystem management. This study investigated the ecological and monetary impacts of IATs and wildfires on sedimentation processes and water quality in the fynbos ecosystems of South Africa, focusing on two catchments of the Jonkershoek Nature Reserve. The study employed the benefit transfer method incorporating a meta-analysis to quantify the monetary value (2023 Rands) of sediment loads deposited into water bodies following wildfire incidents in the fynbos ecosystems. This study performed a meta-analysis within the benefit transfer process, to ensure accurate and reliable sediment load valuation across both pristine fynbos ecosystems and ecosystems with a combination of fynbos and Invasive Alien Trees (IATs). Additionally, conducting outlier trimming and comparing the results with alternative valuation methods enhanced the robustness and reliability of the findings. This methodological framework lays the groundwork for a more reliable and systematic assessment of sediment load valuation, informing evidence-based decision-making in ecosystem management and conservation. Results revealed significant variations in sediment load values between invaded and pristine catchments, highlighting the detrimental effects of IATs and wildfires on sedimentation processes. Before the 1986 wildfire events, the monetary value of sediment loads in the pristine Langrivier catchment was R98/ha and remained the same in the first-year following the wildfire. The pre-fire monetary value of sediment loads in the invaded Bosboukloof catchment was estimated to be R1057/ha. In contrast, the post-fire value was R3963/ha signifying an increase of R2906/ha due to the presence of IATs. Given that the pristine Langrivier catchment showed no alterations after the wildfire, it can be inferred that IATs amplified fire intensity, consequently exacerbating sediment formation and deposition into water bodies within the Bosboukloof catchment. The impact of IATs and their influence on fire regimes amounted to a cost of R583,833 upon extrapolating these values to the respective catchment areas. This value represents the difference between the post-fire value of R796,136 and the pre-fire value of R212,303. This study specifically focused on suspended sediments, resulting in an estimated monetary cost of approximately R600,000 for the impact of invasive alien trees (IATs) on water quality in the first year following the wildfire. This study sheds light on the significant ecological and financial repercussions of IATs on South Africa's fynbos ecosystems. By analysing sedimentation rates after similar wildfire events, this research revealed significant differences in sediment load values between invaded and pristine catchments, highlighting the harmful impact of invasive alien species and wildfires. These findings underscore the importance of proactive management to mitigate the adverse effects of invasive species on ecosystem health and water resources. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2025-04-07T09:18:57Z 2025-04-07T09:18:57Z 2024-12 Thesis https://scholar.sun.ac.za/handle/10019.1/131885 Stellenbosch University xii, 87 pages : illustrations, maps, includes annexures application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Biodiversity conservation -- South Africa Invasive plants -- South Africa Alien plants -- South Africa Fynbos ecology -- South Africa UCTD Petnkeu, Jeronya Mbiatat The impact of invasive alien trees on the monetary value of sediment loads in South African fynbos ecosystems |
| title | The impact of invasive alien trees on the monetary value of sediment loads in South African fynbos ecosystems |
| title_full | The impact of invasive alien trees on the monetary value of sediment loads in South African fynbos ecosystems |
| title_fullStr | The impact of invasive alien trees on the monetary value of sediment loads in South African fynbos ecosystems |
| title_full_unstemmed | The impact of invasive alien trees on the monetary value of sediment loads in South African fynbos ecosystems |
| title_short | The impact of invasive alien trees on the monetary value of sediment loads in South African fynbos ecosystems |
| title_sort | impact of invasive alien trees on the monetary value of sediment loads in south african fynbos ecosystems |
| topic | Biodiversity conservation -- South Africa Invasive plants -- South Africa Alien plants -- South Africa Fynbos ecology -- South Africa UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/131885 |
| work_keys_str_mv | AT petnkeujeronyambiatat theimpactofinvasivealientreesonthemonetaryvalueofsedimentloadsinsouthafricanfynbosecosystems AT petnkeujeronyambiatat impactofinvasivealientreesonthemonetaryvalueofsedimentloadsinsouthafricanfynbosecosystems |