Species richness of arachnids associated with Protea nitida (Proteaceae) in the Cape fynbos.

Regular counts of Arachnida on Protea nitida Mill. were made in three study areas in the western Cape over a period of one year. They were also investigated in the rest of the natural distribution area of I! nitida in the southern and western Cape, Collections were made according to three standardized methods. Five arachnid orders were collected, of which the araneae (spiders) were dominant. Thirty-two spider species (653 individuals) representing 18 families were collected, of which five families and eight genera (eight species) were recorded for the first time on the Proteaceae in the Cape fynbos. Four non-Araneae orders were collected. A micro-habitat preference was observed in some families. Numbers of immature spiders peaked in autumn. Adults and immatures did not always have the same habitat distribution and did not always peak during the same season. Families also showed differences in seasonal abundance. Plant architecture and distribution influenced the number of species collected. Protea nitida hosted more spider species than less complex plants with smaller distributions. The implications of these findings are discussed in terms of biodiversity and invertebrate conservation.