Modelling seed dispersal in restoration and invasions

Simple item page
dc.contributor.advisorMilton, Suzanne J.
dc.contributor.authorKrug, Rainer Michaelen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.
dc.date.accessioned2008-06-18T10:27:53Zen_ZA
dc.date.accessioned2010-06-01T08:13:50Z
dc.date.available2008-06-18T10:27:53Zen_ZA
dc.date.available2010-06-01T08:13:50Z
dc.date.issued2008-03en_ZA
dc.descriptionThesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008.
dc.description.abstractDispersal 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 betweenen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/1155
dc.language.isoenen_ZA
dc.publisherStellenbosch : Stellenbosch University
dc.rights.holderStellenbosch University
dc.subjectSeed dispersalen_ZA
dc.subjectEcological restorationen_ZA
dc.subjectInvasion biologyen_ZA
dc.subjectEcological modellingen_ZA
dc.subjectDissertations -- Conservation ecology and entomologyen
dc.subjectTheses -- Conservation ecology and entomologyen
dc.titleModelling seed dispersal in restoration and invasionsen_ZA
dc.typeThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
krug_modelling_2008.pdf
Size:
7.71 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Doctoral Degrees (Conservation Ecology and Entomology)