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Conservation of the insect assemblages of the Cape Peninsula biodiversity hotspot

  • James Stephen Pryke
  • Michael John Samways
Original Paper

Abstract

The Cape Peninsula is an area of outstanding biological importance, not only for to its high levels of floristic diversity and endemism, but also for its number of localised endemic invertebrates. Little is known of the spatial distribution of invertebrates across the Peninsula, or how best to conserve them. Sampling by visual searches assisted by aerial and aquatic hand-nets was undertaken throughout the Peninsula. The most important areas for insect diversity on the Peninsula, and associated environmental variables, were determined. The ‘Peninsula effect’ was also investigated. Nine Red Listed species and five new species for the Peninsula were recorded. This high number of Red Listed species (for those few groups that have been assessed) emphasises the biological importance of the Cape Peninsula. Table Mountain had the most Red Listed species, while Cape Point had many species not found in the other areas. Noordhoek Wetland is very important for aquatic Coleoptera. Small hills on the Peninsula are important for overall insect diversity. Elevation, slope, aspect, distance to water and vegetation structure were the most important environmental variables in determining the insect assemblages. The Peninsula effect appears to have no influence on these particular insect assemblages of the Cape Peninsula. The high number of new Peninsula records for well-known taxonomic groups indicates that still little is known of the insect assemblages across the Peninsula. Nevertheless, areas of conservation priority identified in this study are Table Mountain (for Red Listed species), Noordhoek (for aquatic Coleoptera) and Cape Point and the small hills across the Peninsula (for their unique invertebrate assemblages). Conservation of a variety of elevations, including steep and flat areas, all aspects of mountains, as well as both the wet and dry areas, overall will contribute to the conservation of the insects.

Keywords

Cape floristic region Conservation Environmental variables Insect assemblages Peninsula effect 

Notes

Acknowledgments

We thank the Table Mountain Fund (TMF) and the National Research Foundation (NRF) for financial support, South African National Parks (SANParks), South African National Biodiversity Institute (SANBI) and the City of Cape Town access to sites, as well as Clive Turner, Henk Geertsma and Corey Bazelet for helping with the identification of various insect groups.

Supplementary material

10841_2009_9213_MOESM1_ESM.jpg (3.6 mb)
Fig. 1 The Cape Peninsula, showing the locations of the Red Listed insect species (red circles) and range extensions (yellow circles) for the species sampled here. The map also gives the four quarters used to assess the possibility of the Peninsula effect, the areas of the Peninsula sampled and the various vegetation types. Vegetation information from Mucina and Rutherford (2006), topographical information from the Chief Directorate: Surveys and Mapping, South Africa © 2003. (JPG 3651 kb)
10841_2009_9213_MOESM2_ESM.jpg (2.1 mb)
Fig. 4 The Cape Peninsula, show the corrected average number of species per sampling station for each of the grids sampled. > 3.5, = 3–3.5, = 2.5–3, = 2–2.5, = 1.5–2, = 1–1.5, = 0.5–1 and < 0.5 species per sampling station, topographical information from the Chief Directorate: Surveys and Mapping, South Africa © 2003. (JPG 2104 kb)

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Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.Department of Conservation Ecology and Entomology, Centre for Agricultural Biodiversity, Faculty of AgriSciencesUniversity of StellenboschMatielandSouth Africa

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