© 2002 Blackwell Science Ltd. http://www.blackwell-science.com/ddi 129 BIODIVERSITY RESEARCH Diversity and Distributions (2002) 8, 129–145 Blackwell Science Ltd Distribution of South African marine benthic invertebrates applied to the selection of priority conservation areas A. ADNAN AWAD 1 *, CHARLES L. GRIFFITHS 2 and JANE K. TURPIE 1 1 Percy Fitzpatrick Institute, University of Cape Town, Rondebosch, South Africa 2 Department of Zoology, University of Cape Town, Rondebosch 7701, South Africa Abstract. Available data on species distributions and endemicity were compiled and examined for 11 groups of South African marine invertebrates (2533 species). For five groups species richness adhered to a well-documented pattern, increasing from west to east, but for the other groups species richness was highest along the south coast. Endemicity was generally highest along the south coast, and lowest along the east coast. The data base was then analysed using several types of complementarity analyses, each produc- ing a minimum set of potential reserve areas, which cumulatively represent all invertebrate species analysed. Approaches based solely on rarity, species richness and endemicity demonstrated individual biases, suggesting a need to combine all three interests. Combining the three tech- niques produced similar results to the individual analyses, showing conservation priorities to be highest along the east coast. Specifically, the areas of Port Elizabeth and Durban were ranked high in all analyses. Consistently, a total of 16 sites was necessary to represent all species analysed. Comparisons with similar analyses on fish and seaweeds revealed similar findings. Existing inver- tebrate records were shown to be biased towards centres of high sampling activity, demonstrating a need of future sampling attention in under- represented areas. Key words. Marine invertebrates, South Africa, endemism, biogeography, marine reserves. INTRODUCTION Following the early works of Thompson (1917, 1921, 1924), Clark (1923) and Stephenson (1939, 1944, 1948), much attention has been focused on documenting the distribution patterns of South African marine invertebrates (Day, 1967a,b, 1974; Millard, 1975; Clark & Courtman-Stock, 1976; Griffiths, 1976; Kensley, 1978, 1981; Gosliner, 1987; Williams, 1992a,b; Monniot et al. in press). The wealth of available species records continues to grow, providing a powerful tool for conservation- orientated analyses. The overall pattern and trends of invertebrate distributions have been well described (Emanuel et al., 1992; Field & Griffiths, 1991), but direct comparisons between the distributions of different invertebrate taxa are lacking. The South African coast is divided into three bio- geographical provinces, influenced by the flow of the Benguela upwelling system (west coast), and the south-flowing Agulhas current (east coast) (Ekman, 1953; Branch & Branch, 1981). Water temperatures have the strongest influence on the biogeographical division into the cool temperate west coast province, the warm temperate south coast province, and the subtropical east coast province (Ekman, 1953; Stephenson & Stephenson, 1972). Conventionally, and for the purposes of this study, the south coast is delimited by Cape Point to the west and Port Elizabeth to the east. A splitting of the east coast into two subprovinces * Correspondence: GloBallast Programme, International Maritime Organization, c/o Department of Environmental Affairs & Tourism, Private Bag X2, Roggebaai 8012, South Africa. E-mail: Adawad@mcm.wcape.gov.za