The three micro-habitats used in this study were as described in Chapman and Tolhurst (2004): MH1-mud with leaf litter, visible patches of macro-algae and numerous pneumatophores, permanently shaded under the canopy, MH2 — similar habitat exposed to the sun during daytime low tides and MH3 — mud without any associated pneumatophores, visible macro-algae and leaf litter. Each habitat was sampled in 3 mangrove forests a few kilometres apart in Sydney Harbour (Fig. 1).