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The role of dispersal mechanisms in range shifts of plant species across sub-Antarctic Marion Island

Dissertation (MSc (Plant Science))--University of Pretoria, 2022.

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Other Authors: Le Roux, Peter Christiaan
Format: Thesis
Language:English
Published: University of Pretoria 2022
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access_status_str Open Access
author2 Le Roux, Peter Christiaan
author_browse Le Roux, Peter Christiaan
author_facet Le Roux, Peter Christiaan
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 (Plant Science))--University of Pretoria, 2022.
format Thesis
id oai:repository.up.ac.za:2263/87739
institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:37:38.698Z
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:2263/87739 The role of dispersal mechanisms in range shifts of plant species across sub-Antarctic Marion Island Le Roux, Peter Christiaan u13107021@tuks.co.za Greve, Michelle Mazibuko, Nompilo Dispersal Climate change Species range shifts Sub-Antarctic Marion Island UCTD Natural and agricultural sciences theses SDG-13 Natural and agricultural sciences theses SDG-15 Dissertation (MSc (Plant Science))--University of Pretoria, 2022. Dispersal is a key lifecycle event and is the means through which species spread geographically, across both fine and broad scales. Despite their ecological importance, dispersal events have proven challenging to quantify as they are often difficult to observe and measure accurately. An attempt to overcome this has been the use of mechanistic models and standardised experiments that combine theory and experimental data to simulate dispersal events that occur through wind, animals, water, and anthropogenic activity. The dispersal estimates obtained using such methods can be useful in multiple ways, including being incorporated into species distribution models to gain ecological and evolutionary insight into the current and future distributions of species across landscapes. Indeed, studies that include dispersal potential have developed more accurate predictions of how species and ecosystems respond to changing environmental conditions. Here, I use mechanistic modelling and standardised experiments to conduct the first quantification of the dispersal potential of the dominant vascular flora in the sub-Antarctic (via anemochory, thalassochory, zoochory, and anthropogenic activity) and test whether species’ dispersal capacity is correlated with inter-specific variation in recent changes in species’ ranges. My results show that species dispersal potential is not correlated with the magnitude of species range expansion for both native and alien species. Inter-specific variation in range expansion was also not related to species’ habitat specificity or functional traits, suggesting that other mechanisms (e.g. demography, competition, and/or the thermal requirements and nutrient demands of species) must be responsible for the variation observed in species range expansion rates. Since my findings contradict ecological theory and evidence from several other dispersal-focused studies, I conclude by reviewing the literature regarding methods for estimating dispersal and present suggestions about how these methods can be integrated to improve our understanding of the effects of dispersal at local scales. While there have been considerable advancements in methods for quantifying dispersal (especially where long-distance dispersal is concerned), this research shows that there is still room for improvement in how we study dispersal events and their effects at smaller scales. The National Research Foundation through the South African National Antarctic Program grant (grant number 110726) bs2026 Plant Science MSc (Plant Science) Unrestricted SDG-13: Climate action SDG-15: Life on land 2022-10-17T09:48:40Z 2022-10-17T09:48:40Z 2023-04 2022-09 Dissertation * A2023 https://repository.up.ac.za/handle/2263/87739 DOI: 10.25403/UPresearchdata.21258501 10.25403/UPresearchdata.21258501 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 Dispersal
Climate change
Species range shifts
Sub-Antarctic
Marion Island
UCTD
Natural and agricultural sciences theses SDG-13
Natural and agricultural sciences theses SDG-15
The role of dispersal mechanisms in range shifts of plant species across sub-Antarctic Marion Island
title The role of dispersal mechanisms in range shifts of plant species across sub-Antarctic Marion Island
title_full The role of dispersal mechanisms in range shifts of plant species across sub-Antarctic Marion Island
title_fullStr The role of dispersal mechanisms in range shifts of plant species across sub-Antarctic Marion Island
title_full_unstemmed The role of dispersal mechanisms in range shifts of plant species across sub-Antarctic Marion Island
title_short The role of dispersal mechanisms in range shifts of plant species across sub-Antarctic Marion Island
title_sort role of dispersal mechanisms in range shifts of plant species across sub antarctic marion island
topic Dispersal
Climate change
Species range shifts
Sub-Antarctic
Marion Island
UCTD
Natural and agricultural sciences theses SDG-13
Natural and agricultural sciences theses SDG-15
url https://repository.up.ac.za/handle/2263/87739