What Threats Do Giant Gippsland Earthworms (GGEs) Face?
Giant Gippsland Earthworms (GGEs) have a limited and patchy distribution throughout their range. The same characteristics that make giant worms somewhat unique in the earthworm world also make them more vulnerable to changes in their environment. A low reproductive rate, limited ability to move from one place to another and a fragile body means that the GGE cannot recover easily from changes to their environment or move to a better place if, for example, the soil dries out, floods or a toxin is added. Their large size also means they are more likely to be injured from digging activities whether that arises from a shovel or an excavator. Contrary to popular belief, these worms do not become two individuals when chopped in half and even slight injury may result in death. In the early settlement of Gippsland, farmers were paid by the government to clear the land allowing for agricultural production. There are many old stories in the literature that describe the fields after ploughing as “being red with blood” and that worms “hung from the tynes of the plough like spaghetti.” However, GGE have existed with agricultural practices and survived major changes to their habitat since European settlement of South Gippsland in the 1870s. It appears likely that GGEs can co-exist in the landscape with agriculture as long as certain activities are managed in ways that protect GGE habitat. Some of the known threats to GGE colonies include:Changes to soil moisture regimes both above ground and below ground (drying or flooding)Physical disturbances to their soil habitat (excavation, cultivation, compaction)Adding toxic substances to the soil – fungicides, some herbicides. The effects of fertilisers are unknown, although highly acidifying fertilisers such as ammonium sulfate are known to reduce worm numbers.These threats may arise from activities associated with changes in land-use e.g. pasture to crops or plantations, farmland to housing or industrial estates and inappropriate revegetation of GGE habitat. Other general farming activities such as ripping and spraying for establishing pastures, dam building and clearing drains may also impact on GGE habitat. It seems cows and worms can make good neighbours. Many farmers are aware of ways to protect the GGE habitat –Stay tuned for information about how you can manage your farm to protect GGE habitat.