The CBD requires parties to develop protocols for assessing the invasive potential of species before their introduction. Such protocols include those by Tucker and Richardson (1995), Reichard and Hamilton (1997) and Rejmánek (1996). The protocols are based on such factors as: geographic origin and bioclimatic matches, climatic and latitudinal range, taxonomic relationships, past performance after introductions elsewhere, assessments of likely tolerance of an organism to features of such prevailing disturbance regimes, assessment of the reproductive biology and ecology. Such protocols have not been fully developed and implemented in southern Africa (van Wilgen et al., 2000). Without a protocol for screening potential invasive species before their introduction, the problem becomes a vicious cycle in which one set of problem is replaced by another, as new species enter the country taking over from those brought under control (van Wilgen et al., 2000). Australia and New Zealand already have such a policy in which all plant species are barred from importation unless they have been determined to be safe.