Exotic worm way into native soil
	Dirty work: Sue Emmentt with some newly-identified native worms
By Julian Lee Worms are not something that spring to mind when people think about conserving Australia's natural heritage. However they are an important resource that is in extreme danger, PhD student Sue Emmettt said. "Exotic worms are escaping into our natural environment all the time and may be displacing our native worms," she said. A United States study showed that exotic worms were killing native worms and creating more acidic soil conditions. Ms Emmett believes Australia faces the same danger. Ms Emmett, of the Department of Forestry, is one of only a handful of researchers in the country studying native worms. One of her study sites backs onto a National Heritage-listed area in southeast Tasmania where the almost extinct Huon pine grows. The value of the timber and the heritage listing led Ms Emmett to believe that she might find rare and unique worms there also. Although she started her research only this year, Ms Emmett has already identified five new worm species and suspects that there may be many more. "Native worms have high economic value, especially in agriculture, and yet almost nothing is known about them," she said. Initial examination of Australian native worms indicates that they are more evolved than worms found elsewhere. Our stable native forests, particularly in Tasmania, have enabled a steady and relatively uninterrupted evolution. Adapting to the particular conditions in Australia, native worms are unique in at least two ways. While all worms are hermaphrodites, the clitellum - the ring around a mature worm containing the sexual organs - on Australian worms is closer to the head than in most worms. Secondly, the guts in native worms are especially strong, enabling them to chew through more soil than other species. Both these features are probably due to having to cope with the dry, low nutrient conditions found in Australia, Ms Emmett said. Besides identifying new worms, the study aims to determine whether earthworms will be a good bioindicator - a living gauge of ecological health. Bioindicators are used in measuring sustainable forest management practices and are a booming international industry. A good bioindicator for soil will be related to many of the soil qualities - physical, chemical and biological. Thus worms which are affected by soil compaction, acidity and bacteria are good potential candidates. Another advantage of using earthworms as bioindicators is that they are territorial creatures, making them ideal for gauging soil health in a specific area.