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Modelling seed dispersal in restoration and invasions

Thesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008.

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Main Author: Krug, Rainer Michael
Other Authors: Milton, Suzanne J.
Format: Thesis
Language:English
Published: Stellenbosch : Stellenbosch University 2008
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access_status_str Open Access
author Krug, Rainer Michael
author2 Milton, Suzanne J.
author_browse Krug, Rainer Michael
Milton, Suzanne J.
author_facet Milton, Suzanne J.
Krug, Rainer Michael
author_sort Krug, Rainer Michael
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008.
format Thesis
id oai:scholar.sun.ac.za:10019.1/1155
institution Stellenbosch University (South Africa)
language English
last_indexed 2026-06-10T12:44:48.111Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2008
publishDateRange 2008
publishDateSort 2008
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/1155 Modelling seed dispersal in restoration and invasions Krug, Rainer Michael Milton, Suzanne J. Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. Seed dispersal Ecological restoration Invasion biology Ecological modelling Dissertations -- Conservation ecology and entomology Theses -- Conservation ecology and entomology Thesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008. Dispersal plays an essential role in determining the distribution of populations of species, especially species expanding their ranges. Two disciplines are concerned with gaining understanding of spread of species, namely restoration ecology and invasion biology. Con- ceptual understanding of dispersal, its mechanisms and its management is essential to both disciplines. Nevertheless, the disciplines have quite opposite objectives: in restoration ecol- ogy, spread of indigenous species into transformed landscapes is promoted, while invasion biology aims to prevent the (further) spread of alien species into pristine or restored habi- tats. Despite these two opposite objectives of facilitating spread and preventing spread of their respective target species, these disciplines have essentially the same requirements in terms of information needed for restoration. In this thesis, I will present two modelling studies—one looking at the impact of two different seed-feeding alien control agents on the spread of Hakea sericea, the other investigating the recolonisation by Dicerothamnus rhinocerotis of an old field dominated by Cynodon dactylon. Based on these studies, I will draw conclusions for the management in each case. In a second step, I will compare these two seemingly-different studies and draw conclusions on how these two disciplines can learn from each other, and how conclusions drawn and management recommendations developed for the one discipline can be translated for the other. The invasion biology study concluded that seed-feeding biocontrol agents do have a considerable impact on the velocity of the spread of the target species. In addition, management recommendations included the possibility of substituting seed-feeding biocontrol agents with an increased fire frequency where the negative impact on natural vegetation, on the site invaded by the target species, is acceptable. The restoration study concluded that the main impact on the velocity of spread, and the speed of the return of the shrub species onto the old fields, is the availability of micro-sites. A sensitivity analysis showed the even a slight change from 1% to 2% increases the velocity and pattern of spread dramatically. The other parameters playing an important role are the mean rate of establishment and the time span between Doctoral 2008-06-18T10:27:53Z 2010-06-01T08:13:50Z 2008-06-18T10:27:53Z 2010-06-01T08:13:50Z 2008-03 Thesis http://hdl.handle.net/10019.1/1155 en Stellenbosch University application/pdf Stellenbosch : Stellenbosch University
spellingShingle Seed dispersal
Ecological restoration
Invasion biology
Ecological modelling
Dissertations -- Conservation ecology and entomology
Theses -- Conservation ecology and entomology
Krug, Rainer Michael
Modelling seed dispersal in restoration and invasions
title Modelling seed dispersal in restoration and invasions
title_full Modelling seed dispersal in restoration and invasions
title_fullStr Modelling seed dispersal in restoration and invasions
title_full_unstemmed Modelling seed dispersal in restoration and invasions
title_short Modelling seed dispersal in restoration and invasions
title_sort modelling seed dispersal in restoration and invasions
topic Seed dispersal
Ecological restoration
Invasion biology
Ecological modelling
Dissertations -- Conservation ecology and entomology
Theses -- Conservation ecology and entomology
url http://hdl.handle.net/10019.1/1155
work_keys_str_mv AT krugrainermichael modellingseeddispersalinrestorationandinvasions