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1. Ice worms emerge in pacific northwest glaciers Patch#
2. Ice worms emerge in pacific northwest glaciers plus#

The problem starts with the worms’ diet: the forest’s moisture-rich leaf litter, or duff layer.

Ice worms emerge in pacific northwest glaciers Patch#

Researchers identified a lush patch of forest floor in Wisconsin's Nicolet National Forest as a spot not yet invaded by earthworms and only lightly browsed by deer. And in northern hardwood forests and other natural environments that evolved without them, earthworms became a slow-moving disaster. But as hitchhikers in everything from wagon wheels to fishing bait to root balls, the newcomers became efficient, widespread invaders. On their own, the worms could theoretically move only half a mile in 100 years. That changed after European colonists began arriving en masse in the 1600s, their ships’ ballasts teeming with nightcrawlers, red wigglers and other European worm species. But farther north, glaciers once covered an area running roughly from New Jersey across the Upper Midwest to the Pacific Ocean, and as those glaciers retreated, they left behind an earthworm-free zone. Southeast and Pacific Northwest as well as Mexico, Central America and the Caribbean Basin. In areas that remained ice-free during the last glacial age, there are perhaps 300 native earthworm species, mainly in the U.S. “Invasive worms are changing things on a vast spatial scale.”Ĭonsider North America. “When you start moving native earthworms to a new continent, their populations tend to explode because they lack whatever controls them in their native habitat,” says Lee Frelich, director of the University of Minnesota Center for Forest Ecology. But today, nonnative earthworm species-introduced through human movement and activities-are rapidly and profoundly changing ecosystems on every continent except Antarctica. Gardeners and farmers laud these lowly, often unseen creatures for their ability to break down organic matter, add nutrients to soil and improve aeration. In 1881, Charles Darwin published an entire book on earthworms, writing, “It may be doubted whether there are many other animals which have played so important a part in the history of the world. THOUSANDS OF EARTHWORM SPECIES have shaped the planet’s soil chemistry, plant communities and even the atmosphere itself over hundreds of millions of years.

Ice worms emerge in pacific northwest glaciers plus#

Photos by Kim Taylor/NPL (left) and DaveAlan/iStock/Getty Images Plus (right). Spreading through northern forests that evolved without earthworms, these animals can degrade forest soils and devour the seeds of trees and native plants such as trillium (right) that help support native wildlife. The widespread, invasive European earthworm (left) is distinguished by a dark band near its middle. Invasive earthworms are spreading across the planet-transforming soils, gardens, forests and entire ecosystems in ways that may make you squirm.