The Southern African Plant Invaders Atlas (SAPIA) and its contribution to biological weed control

A precursor to the Southern African Plant Invaders Atlas (SAPIA) commenced in 1979 when alien invasive woody plants were surveyed along roadsides throughout Gauteng Province (formerly central Transvaal), South Africa (Wells et al. 1980). These surveys were later extended to the remainder of South Africa and were completed in 1993 (Henderson & Musil 1984; Henderson 1989, 1991a,b, 1992, 1998a). The momentum of these initiatives was maintained with the launch, in January 1994, of the first phase of the SAPIA project (Henderson 1998b). This inaugural phase, involving volunteer participants, was scheduled for a five-year period, ending in December 1998. SAPIA is primarily aimed at the collection of basic information on alien invasive plants and records their distribution, abundance and habitat types on a 15 minute square (quarter degree) scale. The atlas region for the first phase of SAPIA covers South Africa and the neighbouring countries of Lesotho and Swaziland. The second phase of the project will be extended to other countries of the Southern African Development region (SADC) and will include Angola, Botswana, Malawi, Mozambique, Namibia, Zambia and Zimbabwe. Information for the first phase of SAPIA is recorded on two standardized atlas sheets, with slightly different species lists, covering the western and eastern halves of the atlas region. One hundred plant taxa are listed on each sheet, with a combined total of 161 species. Provision has also been made for recording additional species, particularly new invaders. A pocket field guide that facilitates the identification of all listed species was also compiled as part of this initiative (Henderson 1995). The SAPIA database is computerized and currently includes some 40 000 records of more than 400 naturalized alien plant species (Henderson 1998b). Indeed, the distribution maps pertaining to all the weeds reviewed in this volume were generated by SAPIA. In this review, some of the ways in which this information can benefit biological control programmes in South Africa are considered.