ENDOPARASITE CONTROL STRATEGIES - IMPLICATIONS FOR BIODIVERSITY OF NATIVE FAUNA

Efforts to control the spectrum of diseases that affect humans, our cr ops and our animals pose problems which need to be debated openly. Wid espread use of chemicals in such a broad sphere raises important conce rns not only about safety for the users, consumers and target species, but especially about the not so obvious effects upon the ecosystems i n which they are used. Some undetermined level of biological diversity is necessary to maintain ecological function and resilience. These, i n turn, are necessary for generating the biological resources (trees, fish, wildlife, crops) and ecological services (watershed protection, air cleansing, climate stabilisation, erosion control) on which econom ic activity and human welfare depend, The driving forces behind declin e of biodiversity stem entirely from human activities. Underlying caus es are those resulting from the cultural and social factors associated with economic activities and lead to direct depletion of species, and degradation or destruction of habitats. The broad spectrum and high e fficacy of the macrocyclic lactones against nematode and arthropod par asites of livestock and companion animals are unprecedented. Cattle, h orses, sheep, swine, dogs-to varying degrees all are utilised by human s for economic gain. Detrimental impact upon non-target animals is con sidered acceptable in eradicating parasites because of their economic importance to commercial livestock production. Production will increas e when these parasites are eliminated, but we remain oblivious to the long-term consequences of our actions, What are the ecological limits to rural economic activities? Decomposing animal faeces help to mainta in our ecosystem by returning valuable nutrients to the soil. Dung fau na-fungi, yeast, bacteria, nematodes, insects and earthworms-play a no n-conspicuous but important and varied role in this decomposition proc ess, a role dependent upon many factors, especially environmental ones , Anthelmintics and pesticides are of considerable value in agricultur e, but largely at an unevaluated cost to the greater environment, We h ave insufficient knowledge of the extent to which a spectrum of anthel mintics and pesticides affect ecological function and ecosystem resili ence in our commercial plant and animal production systems. It is time we developed a genuine interest in avoiding ''the dialogue of the dea f'' that in the past has minimised interdisciplinary research between environmental ecology and commercial plant and animal production. (C) 1997 Australian Society for Parasitology. Published by Elsevier Scienc e Ltd.