Tshisikhawe, M. P.Swanepoel, L. H.Rahlo, S. J.Tlaamela, Dikonketso Margaret2026-06-302026-06-302026-05-19Tlaamela, D.M. 2026. Understanding the negative impacts and benefits of invasive alien populus Alba L: implications for management in South Africa. . .https://univendspace.univen.ac.za/handle/11602/3322Ph. D. in BotanyDepartment of Biological SciencesPopulus alba is an alien tree species that has become invasive in South Africa. Its native region ranges from Asia, Europe, and North Africa, and it was introduced to South Africa as an ornamental plant. However, the species has been reported to escape cultivation, posing threats to native biodiversity and agricultural productivity in the country. This study aimed to address several challenges related to control methods for P. alba. Firstly, a systematic review was conducted to collate information on the ecology of P. alba from peer-reviewed published literature using Web of Science, Google Scholar, and ScienceDirect. The review revealed 2767 records with 254 relevant publications included for retrieval. This encompassed nine parameters, including different taxonomic levels, environmental conditions, distributions, and threats. Most publications focused on habitat conditions (25.61%), followed by benefits (24.94%). The systematic review revealed that P. alba can establish in varying climate and habitat conditions and has both negative and positive impacts in some regions. Secondly, a species distribution model (SDM) was developed to determine the potential suitability of P. alba in South Africa under current and future climate scenarios (2041-2060 and 2061-2080). The model predictions under current climate data projected high suitability across the country, except for Northern Cape Province. The predictions of P. alba under the future climate for 2050 indicate higher suitability levels across Gauteng, Northwest, and Mpumalanga provinces. There was a reduction in suitability in the Eastern Cape and Gauteng provinces in 2070. Ground-truthing was conducted to validate model predictions and identify new infestations in Limpopo Province. It revealed 26 new P. alba populations that were hence incorporated in the distribution map. Thirdly, semi-structured interviews were conducted to gather data on its introduction and dispersal pathways, benefits, negative impacts, and management efforts. Interviews with varying stakeholders, including experts and indigenous and local communities (IPLCs), were conducted in-person and on Google Forms platforms with the aid of a questionnaire. The number of responses per question was 13 for introduction pathways, 15 for dispersal pathways, 13 for negative impacts, 33 for benefits, and 5 for management attempts. The most dominant pathways for introduction and dispersal were intentional use (10) and natural dispersal (11), respectively. Some participants perceived P. alba as an important species with no negative impacts in their regions (12), while others mentioned its competitive behaviour (12) and high-water use (11). The most dominant benefits of P. alba were firewood production (9), roofing, and matchstick production (7 each). Fourthly, the current distribution of P. alba was mapped using the occurrence records from online databases [Global Biodiversity Information Facility (GBIF), Southern African Plant Invaders Atlas (SAPIA)], herbarium records, and records obtained from ground truthing. Most populations were reported in Mpumalanga, Gauteng and Limpopo provinces. These records ranged from 1968 to 2024, with most records reported in 1969 (65). In terms of biomes, most populations were distributed in the Grassland (167), followed by the Savanna (141). Lastly, possible control methods were discussed to develop an adaptive management plan for Populus alba in South Africa. The possible control methods, in compliance with the legal framework, inter alia, the Conservation of Agricultural Resources Act (Act No. 43, 1983), National Environment Management: Biodiversity Act (Act No. 10, 2004), The Fertiliser, Farm Feeds, Agricultural Remedies and Stick Remedies Act, 1947 (Act No. 36,1947), were discussed. These resulted in four control methods, including mechanical, chemical, burning, and biological control. There are no registered pesticides and biological agents to control P. alba in South Africa. Mechanical control results in resprouts, but it becomes effective when used in combination with chemical control.1 online resource (xviii, 237 leaves): color illustrationsenUniversity of VendaUCTD583.650968Populus albaPoplarSalicaceaeThesisTlaamela DM. Understanding the negative impacts and benefits of invasive alien populus Alba L: implications for management in South Africa. []. , 2026 [cited yyyy month dd]. Available from:Tlaamela, D. M. (2026). <i>Understanding the negative impacts and benefits of invasive alien populus Alba L: implications for management in South Africa</i>. (). . Retrieved fromTlaamela, Dikonketso Margaret. <i>"Understanding the negative impacts and benefits of invasive alien populus Alba L: implications for management in South Africa."</i> ., , 2026.TY - Thesis AU - Tlaamela, Dikonketso Margaret AB - Populus alba is an alien tree species that has become invasive in South Africa. Its native region ranges from Asia, Europe, and North Africa, and it was introduced to South Africa as an ornamental plant. However, the species has been reported to escape cultivation, posing threats to native biodiversity and agricultural productivity in the country. This study aimed to address several challenges related to control methods for P. alba. Firstly, a systematic review was conducted to collate information on the ecology of P. alba from peer-reviewed published literature using Web of Science, Google Scholar, and ScienceDirect. The review revealed 2767 records with 254 relevant publications included for retrieval. This encompassed nine parameters, including different taxonomic levels, environmental conditions, distributions, and threats. Most publications focused on habitat conditions (25.61%), followed by benefits (24.94%). The systematic review revealed that P. alba can establish in varying climate and habitat conditions and has both negative and positive impacts in some regions. Secondly, a species distribution model (SDM) was developed to determine the potential suitability of P. alba in South Africa under current and future climate scenarios (2041-2060 and 2061-2080). The model predictions under current climate data projected high suitability across the country, except for Northern Cape Province. The predictions of P. alba under the future climate for 2050 indicate higher suitability levels across Gauteng, Northwest, and Mpumalanga provinces. There was a reduction in suitability in the Eastern Cape and Gauteng provinces in 2070. Ground-truthing was conducted to validate model predictions and identify new infestations in Limpopo Province. It revealed 26 new P. alba populations that were hence incorporated in the distribution map. Thirdly, semi-structured interviews were conducted to gather data on its introduction and dispersal pathways, benefits, negative impacts, and management efforts. Interviews with varying stakeholders, including experts and indigenous and local communities (IPLCs), were conducted in-person and on Google Forms platforms with the aid of a questionnaire. The number of responses per question was 13 for introduction pathways, 15 for dispersal pathways, 13 for negative impacts, 33 for benefits, and 5 for management attempts. The most dominant pathways for introduction and dispersal were intentional use (10) and natural dispersal (11), respectively. Some participants perceived P. alba as an important species with no negative impacts in their regions (12), while others mentioned its competitive behaviour (12) and high-water use (11). The most dominant benefits of P. alba were firewood production (9), roofing, and matchstick production (7 each). Fourthly, the current distribution of P. alba was mapped using the occurrence records from online databases [Global Biodiversity Information Facility (GBIF), Southern African Plant Invaders Atlas (SAPIA)], herbarium records, and records obtained from ground truthing. Most populations were reported in Mpumalanga, Gauteng and Limpopo provinces. These records ranged from 1968 to 2024, with most records reported in 1969 (65). In terms of biomes, most populations were distributed in the Grassland (167), followed by the Savanna (141). Lastly, possible control methods were discussed to develop an adaptive management plan for Populus alba in South Africa. The possible control methods, in compliance with the legal framework, inter alia, the Conservation of Agricultural Resources Act (Act No. 43, 1983), National Environment Management: Biodiversity Act (Act No. 10, 2004), The Fertiliser, Farm Feeds, Agricultural Remedies and Stick Remedies Act, 1947 (Act No. 36,1947), were discussed. These resulted in four control methods, including mechanical, chemical, burning, and biological control. There are no registered pesticides and biological agents to control P. alba in South Africa. Mechanical control results in resprouts, but it becomes effective when used in combination with chemical control. DA - 2026-05-19 DB - ResearchSpace DP - Univen LK - https://univendspace.univen.ac.za PY - 2026 T1 - Understanding the negative impacts and benefits of invasive alien populus Alba L: implications for management in South Africa TI - Understanding the negative impacts and benefits of invasive alien populus Alba L: implications for management in South Africa UR - ER -