Earthworms Aren't as Good for the Soil as You Think

For many people, earthworms trigger memories of childhoods spent rooting around in the dirt or thoughts of a home garden 

Earthworms have long been considered a gardener's best friend since they can help aerate and enrich the soil

But for most earthworm species you find in North America, that's where their benefits end 

They used to be everywhere until around 10,000 years ago when the last ice age blanketed huge portions of the continent 

They tend to bring hitchhikers with them, and the first European settlers in North America were no exception 

But for nearly 10 millennia, the forests of North America have evolved to get along without earthworms 

Trees and smaller plants rely on the thick layer of dead and partially decomposed leaves that blankets the forest floor to help them grow