Credit: Carol Melody and Olaf Schmidt
A survey on a farm near Dublin has turned up large numbers of a species of earthworm typically found in only southern France, more than 1000 kilometers farther south. Researchers found Prosellodrilus amplisetosus, the southern European earthworm (above), in soils at six of the 11 different habitats they surveyed, including large concentrations of the worms in a meadow and along the edge of a pasture that had been reseeded. Ratios of the carbon and nitrogen isotopes in the invasive worms' tissues indicate that the creatures—which consume soil to extract some of its organic material—are tapping into resources unused by native worms, possibly explaining their success, the researchers report today in Biology Letters. It isn't clear how these worms reached the farm, but they were probably stowaways in soil surrounding the roots of hedges or other plants brought to the farm decades ago. But isolated reports of the species from other sites—including northeastern Spain, east-central France, and northeastern Ireland—suggest that P. amplisetosus can become established far afield of its normal range. Although the worms don't seem to be reducing populations of native worms, if they become widespread they could exacerbate climate change by releasing large amounts of carbon currently locked away in soils, the researchers speculate.
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