Fifteen years ago my garden had a super-abundance of earthworms; leaf litter disappeared very rapidly; there were several in every shovel of earth.
I have not seen one this spring in all my digging. Seven miles away where I work, there are plenty.
IIRC, North America did not have any earthworms until the Europeans brought them. Fungus broke down plant debris and still does in the more boreal forests. Minnesota was ordering fishermen not to dump their bait worms but carry out the extras.