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Abandoned homestead gardens as a source of plant invasions in rural South Africa

Dissertation (MSc)--University of Pretoria, 2021.

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Other Authors: Greve, Michelle
Format: Thesis
Language:English
Published: University of Pretoria 2022
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access_status_str Open Access
author2 Greve, Michelle
author_browse Greve, Michelle
author_facet Greve, Michelle
collection Thesis
dc_rights_str_mv © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MSc)--University of Pretoria, 2021.
format Thesis
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institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:37:55.807Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2022
publishDateRange 2022
publishDateSort 2022
publisher University of Pretoria
publisherStr University of Pretoria
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source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/83960 Abandoned homestead gardens as a source of plant invasions in rural South Africa Greve, Michelle molesengdoreenr@gmail.com Le Roux, Peter Christiaan Raseala, Moleseng Doreen UCTD Plant Invasions Species distribution modelling Rural landscapes Invasive species Abandoned homesteads Natural and agricultural sciences theses SDG-11 Natural and agricultural sciences theses SDG-15 Dissertation (MSc)--University of Pretoria, 2021. Alien invasions are a global concern, with impacts on native biodiversity. Invasive species may be introduced to new regions for many reasons, with ornamental horticulture being one of the major pathways for the entry of potentially invasive plant species. To prevent future alien invasions potentially invasive species should be detected early after their introduction. Newly introduced/naturalized alien plants can be identified during field surveys, and alien species with larger potential range sizes can be identified with the use of species distribution modelling techniques (SDMs). The aim of this study was to investigate if alien ornamental species were persisting and escaping from abandoned gardens in Limpopo and Mpumalanga provinces and to estimate their invasion potential. The first objective was to test which species have escaped cultivation from gardens since abandonment, and if these species’ distance of spread was related to the taxonomic group, NEM: BA category, reproduction mode, or growth form. The second objective was to test if potential range size of species was correlated with their distance of spread, or if potential range size differed between NEM: BA listed and non-listed species, and between spreading and non-spreading species. Alien ornamental plant species were recorded from 13 abandoned gardens in north-eastern South Africa. The family Proteaceae had the highest average maximum distance of spread and the families with a high number of alien ornamental representatives recorded were Solanaceae, Rosaceae, Lauraceae, Euphorbiaceae, and Bignoniaceae. Species’ maximum distance of spread from abandoned gardens was positively related to species’ NEM: BA status, with species that are required to be controlled showing the greatest spread distances. Species’ mode of reproduction and growth form were not related to spreading distances. Ensemble modelling of the potential distribution of the ornamental plants recorded from the abandoned homesteads showed that the ability of a species to invade larger areas is not related to species NEM: BA status or whether species were spreading or not. No significant positive correlation was found between the species average maximum distance of spread and the predicted potential range size. Potential range size maps were overlaid to generate species richness maps per group (NEM: BA spreading, NEM: BA not spreading, non-listed spreading, and non-listed not spreading), and areas of high potential richness were similar between the four groups of species. These results are at least partly contingent on the data for this study having been collected from areas with relatively high rainfall, and therefore may not be representative of more arid areas in South Africa. In conclusion, several invasive alien ornamental plants were found escaping cultivation from abandoned gardens to surrounding natural vegetation. The species which are currently listed on NEM: BA were found to have spread considerable distances although non-listed species were also were also recorded to spread. As a result, further studies need to investigate abandoned gardens in other biomes and climatic zones to better understand which species can persist and spread from abandoned gardens. The South African National Biodiversity Institute (SANBI) and the South African Department of Forestry, Fisheries and Environment, (DFFE). bs2026 Plant Science MSc Unrestricted SDG-11: Sustainable cities and communities SDG-15: Life on land 2022-02-16T07:43:55Z 2022-02-16T07:43:55Z 2022-04 2021-12-08 Dissertation * A2022 http://hdl.handle.net/2263/83960 en © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle UCTD
Plant Invasions
Species distribution modelling
Rural landscapes
Invasive species
Abandoned homesteads
Natural and agricultural sciences theses SDG-11
Natural and agricultural sciences theses SDG-15
Abandoned homestead gardens as a source of plant invasions in rural South Africa
title Abandoned homestead gardens as a source of plant invasions in rural South Africa
title_full Abandoned homestead gardens as a source of plant invasions in rural South Africa
title_fullStr Abandoned homestead gardens as a source of plant invasions in rural South Africa
title_full_unstemmed Abandoned homestead gardens as a source of plant invasions in rural South Africa
title_short Abandoned homestead gardens as a source of plant invasions in rural South Africa
title_sort abandoned homestead gardens as a source of plant invasions in rural south africa
topic UCTD
Plant Invasions
Species distribution modelling
Rural landscapes
Invasive species
Abandoned homesteads
Natural and agricultural sciences theses SDG-11
Natural and agricultural sciences theses SDG-15
url http://hdl.handle.net/2263/83960