Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: One of the most threatening factors to the biodiversity of the Cape Floristic Region is that of invasive alien
organisms. A contestant for the most noxious of these fynbos threatening organisms is
Hakea sericea. When left to grow uncontrolled, this small Australian tree forms impenetrable stands that out
compete the natural vegetation. Due to the threat this plant poses, an extensive and integrated control
programme was initiated to reduce its numbers to a level where it can no longer compete successfully with the
indigenous flora. This control programme consists of a carefully devised slash and burn method, chemical
herbicides and four biological control agents. Little literature surrounding the success of this control programme
is available. Two data sets, Fugler (1979) and Protea Atlas Project 2001, recording the distribution and density
of the plant at the height of its invasion and twenty two years later are compared to one another using
Geographical Information System techniques. Success of control measures is reflected by: (1) a reduction of
340 135 ha in total invaded by H sericea, (2) a reduction in density and (3) shifts in patterns of average rainfall,
altitude, slope and aspect of the areas associated with different density categories of this species. These data
provide reward for all those involved in the control programme by justifying efforts associated with the control
of the invader. Furthermore, the findings of this project also highlight the value of the control programme as
well as indicate how future research should be concentrated in order to perfect the programme. / AFRIKAANSE OPSOMMING: Uitheemse indringerplante is een van die enkele belangrikste faktore wat die Kaapse Fynbos biodiversiteit
bedreig. In hierdie geval is Hakea sericea een van die mees kompeterende spesies. Hierdie klein Australie
boompie ontwikkel, indien ongekontroleerd gelaat, tot 'n ondeurdringbare digte woud wat natuurlikke
plantegroei verdring. Dit is weens hierdie faktor dat ekstensiewe en geintegreerde kontroleringsprogramme
ontwikkel is om die getalle van bome na die vlakke te verlaag waar dit geen bedreiging vir inheemse flora sal
inhou nie. Die kontroleringsprogramme maak onder andere van chemiese onkruiddoders, vier biologiese
beheermiddels, ontbossing en beheerde brande gebruik. Min literatuur is beskikbaar oor die sukses wat verkry
word met die programme. Twee datastelle elk van Fugler (1979), bevattende data oor digtheid en verspreiding
van die plante 22 jaar tevore en die Protea Atlas Projek (2001) word vergelyk met behulp van Geografiese
Inligtingstelsel (GIS) tegnieke. Die sukses van die beheer maatreels word weerspieel in: (1) die totale afname
van 531 229 ha to 340 135 ha ingedring deur H. sericea, (2) afname in die digtheid en (3) verskuiwing in die
algemene reenval-, hoogte-, helling- en liggingspatrone wat geassosieer word met die verskillende
digtheidskatogoriee van die spesie. Die resultate bied regverdiging vir die kontroleringsprogramme van
indringerplante. Ook beklemtoon die projek die waarde van kontroleringsprogramme en dui aan waarop
toekomstige navorsing moet konsentreer om die programme te vervolmaak.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/49953 |
| Date | 04 1900 |
| Creators | Te Roller, Kerry Sharon |
| Contributors | Esler, K. J., Van der Merwe, J. H., Wood, A., Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology . |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 62 p. : ill. |
| Rights | Stellenbosch University |
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