Continental Changer: Earthworms were re-introduced to the Americas after a gap of 10,000 years by colonists from Europe
We all know that Christopher Columbus
and European pioneers brought back potatoes, tobacco and rubber from
the New World in the wake of his voyage of 1492, but a new book examines
the overlooked impact of the Old World on the newly discovered
Americas.
In fact so
great was one import from Europe that its impact is still being felt
today after having undermined the entire ecosystem of North America. And
that illegal alien is the lowly earthworm.
Wiped
out in North America since the Ice Age, the re-introduction of the
earthworm by the British colonists of Jamestown caused the landscape
that had formed for 10,000 years to radically alter and not for the
better.
Earthworms eat fallen foliage, the
problem is that northern trees and shrubs beneath the forest canopy
depend on that litter for food too.
In
its absence, water washes away the nutrients stored in the fallen
foliage and without this food plants die and the forest becomes more
open and dry – losing much of its firmness and fertility.
In
short, a forest with worms is vastly different to a forest without them
and that means, that as forests across North America's East Coast
become re-infested with earthworms the continent began to change.
