But - it doesn't seem to say what we must do to save them ?
Or am I missing something ?
It's really about changing farming practices rather than anything that can be done at a micro-level.Crucially, its about getting farmers to understand how their soil works, how modern industrial farming is causing soil degradation and encouraging them to adopt less damaging practices. Here's quite a good article from DW.
James Wong suggests that, in the garden, we stop the age old practice of digging over the garden and instead adding a top layer of mulch in Winter for the earthworms to break down.
I think a bit of consciousness raising about soil management for the general public wouldn't go amiss either. Here's a useful publication from The Wildlife Trusts/RHS about how to help worms [pdf]
I've been using cardboard mulch on my allotment and the earthworms seem to like living under it more than plastic weed supressing fabric or bare soil.