Arthropods as indicators of the effects of fluoride pollution on the succession following sand mining.
This study examined the effect of fluoride pollution on arthropod recolonization of sites after sand mining at Tomago, New South Wales, Australia. This represented a simplified ecological system with a known history, enabling the authors to study the effects of fluoride pollution on arthropod succession without the complicating factor of previous fire regimes. Fluoride appeared to have an indirect effect on arthropods, with fluoride-induced changes in the vegetation structure being reflected in the relative abundance of arthropod groups. Additionally, fluoride pollution appeared to have a number of direct effects on arthropod populations. Arthropod diversity, beetles, spiders and possibly flies, appeared to demonstrate the effects of direct toxicity at the sites of highest foliar fluoride levels (>8 µmol/g). Ants decreased in abundance above low fluoride levels (>1.85 µmol/g). Mites and cockroaches, however, were found to increase in abundance in direct relation to fluoride. It was concluded that arthropod succession is significantly altered when fluoride fallout is imposed on the existing disturbance of sand mining. The repercussions of changes in the abundance of elements of the arthropod community on ecosystem processes are potentially great. The sensitivity to fluoride demonstrated by ants may make them particularly good candidates as bio-indicators of fluoride stress.