Worm Attacks: Invading earthworms threaten rare U.S. fern
By Susan Milius
In the ecological equivalent of the dreaded Klez Worm burrowing into computers around the world, European earthworms are eating enough leaf litter in North American forests to put a rare fern at risk of extinction.
An unusual study reports that the goblin fern (Botrychium mormo), an elusive species that pokes up from thick leaf litter on a forest floor, has disappeared from 9 out of 28 patches surveyed in Minnesota’s Chippewa National Forest. Michael J. Gundale, now at the University of Montana in Missoula, also found that the normal forest carpet of fallen leaves was thin in all nine spots, and in eight of them, the forest floor was wriggling with the earthworm Lumbricus rubellus. In a lab test, these 3-to-4-centimeter-long worms proved capable of reducing a forest carpet to a balding remnant, Gundale reports in the December Conservation Biology.