Evaluating success of an integrated control programme of Hakea sericea Schrader (Proteaceae) in the Western and Eastern Cape Provinces, South Africa through cartographic analysis

[摘要] ENGLISH ABSTRACT:One of the most threatening factors to the biodiversity of the Cape Floristic Region is that of invasive alienorganisms. A contestant for the most noxious of these fynbos threatening organisms isHakea sericea. When left to grow uncontrolled, this small Australian tree forms impenetrable stands that outcompete the natural vegetation. Due to the threat this plant poses, an extensive and integrated controlprogramme was initiated to reduce its numbers to a level where it can no longer compete successfully with theindigenous flora. This control programme consists of a carefully devised slash and burn method, chemicalherbicides and four biological control agents. Little literature surrounding the success of this control programmeis available. Two data sets, Fugler (1979) and Protea Atlas Project 2001, recording the distribution and densityof the plant at the height of its invasion and twenty two years later are compared to one another usingGeographical Information System techniques. Success of control measures is reflected by: (1) a reduction of340 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 dataprovide reward for all those involved in the control programme by justifying efforts associated with the controlof the invader. Furthermore, the findings of this project also highlight the value of the control programme aswell as indicate how future research should be concentrated in order to perfect the programme.

[发布机构] Stellenbosch University