Browsing by Author "Te Roller, Kerry Sharon"

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    Evaluating success of an integrated control programme of Hakea sericea Schrader (Proteaceae) in the Western and Eastern Cape Provinces, South Africa through cartographic analysis
    (Stellenbosch : Stellenbosch University, 2004-04) Te Roller, Kerry Sharon; Esler, Karen J.; Van der Merwe, J. H.; Wood, A.; Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology .
    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.