Ant recolonisation of sand mines near Richards Bay, South Africa - an evaluation of progress with rehabilitation

Abstract

The ant fauna was sampled in eight rehabilitated, sand-mined area and three coastal dune forest control plots near Richards Bay, South Africa. Rehabilitation was achieved by seeding with cover crops and mixed indigenous species: the sample plots represented the cover crop, grassland scrub thicket and Acacia karroo-woodland stages of succession. A total of 76 ant species was recorded, of which 29 were found exclusively in the forest and 22 in the rehabilitation. Ant species richness increased over the first 2 years, declined thereafter and proceeded to increase further after 8 years of rehabilitation. Application of correspondence analysis to the ant community data indicated that the succession was following two trends, one represented by the 2-5 year-old plots and the other by the 8-13 year-old rehabilitation. These trends coincided with the massive increase in the density of Pheidole megacephala towards the fifth year of rehabilitation and by its subsequent decline. In terms of ant species richness and similarly, the 13-year-old rehabilitation had only partially attained a fauna which resembled that of the dune forest. The pattern of ant return is compared with results obtained elsewhere in the world and considered inr elation to rehabilitation procedures and prevailing climatic patterns.