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Response of ant communities and ant–seed interactions to bush regeneration


  • Peter S. Grimbacher,

  • Lesley Hughes

  • Peter S. Grimbacher undertook this research as part of an Honours project conducted in the Department of Biological Sciences, Macquarie University, in collaboration with Lesley Hughes (NSW 2109, Australia. Tel: +61-2 9850 8195, Fax: +61-2 9850 8245, Email: Peter Grimbacher's current address is Australian School of Environmental Studies, Griffith University, Nathan, Qld, 4111.


Summary Bush regeneration programmes aim to restore native plant communities by interventions designed to assist natural recovery, supplemented by planting or direct seeding where necessary. The present study compared ground-dwelling ant communities and rates of seed removal by ants in weed-infested, regenerating and undamaged urban bushland in northern Sydney. Three replicate dry sclerophyll sites on sandstone were studied, each containing zones of weed-infested, regenerating and undamaged bushland. Canopy cover, midstorey cover, ground cover and litter depth were measured at each site. Each zone type showed distinctive vegetation and cover characteristics, particularly at the ground level. Ground foraging ants were sampled with pitfall traps, sorted to morphospecies and placed in functional groups. There were no significant differences in ant abundance, number of genera or number of morphospecies between site types. Ant diversity and equitability was highest in the undamaged zones, followed by regenerating zones, then weedy zones. There was a significant difference between zone types in the proportion of ant species in different functional groups. Weedy zones were dominated by Opportunist species whereas regenerating zones had a high proportion of Dominant Dolichoderinae. At undamaged zones, the distribution of ants across functional groups was more even. Differences in the ant communities between the three zone types were reflected by differences in interactions between ants and seeds. Seed removal rates of both native and exotic seeds were significantly lower at weedy zones than at undamaged zones, with the regenerating zones having intermediate rates. Sites subject to regeneration 4–10 years previously were intermediate between undamaged and weedy zones for ground cover, litter depth, ant species diversity and equitability, proportion of Opportunist ant species, and seed removal rates. Thus, the regeneration techniques used have been at least partially successful in restoring some aspects of the invertebrate fauna and ecological interactions typical of undamaged dry sclerophyll bushland.