Summary
Spatial and temporal changes in the distribution of food organisms potentially available to curlew sandpipers Calidris ferruginea at Langebaan Lagoon (33 °S, 18 °E) are described for the period February 1974—March 1975. The inter-tidal benthic fauna at sandy sites showed spring and autumn peaks in biomass and numbers. The fauna was dominated by the gastropod Assiminea globulus, which comprised 62,5% of the total biomass. A Production: Biomass ratio of 4,96 was found for this species, and 1,36 for the amphipod Urothoe grimaldi. The fauna at sites containing macrophytes (Spartina, Zostera, Arthrocnemum) showed winter peaks in biomass and numbers. Classification and ordination confirmed the discreteness of macrophyte and non-macrophyte sites, each having its own characteristic benthos. There was a positive correlation between the distribution of benthos and sediment parameters at the different sites, macrophyte sites having a higher fine fraction and organic content.