Earthworms and soil invertebrates are critical ecosystem engineers whose welfare is rarely considered despite being killed in vast numbers by tillage, pesticides, and soil compaction.
Earthworm welfare sits at the extreme frontier of animal welfare science. Evidence for subjective suffering in earthworms is weak, but they exhibit nociceptive responses and avoidance behavior suggesting at minimum basic pain-avoidance mechanisms. The precautionary principle applied to invertebrates would argue for minimizing unnecessary harm. From a practical standpoint, earthworm welfare aligns perfectly with ecological and agricultural goals — soil health practices that protect earthworms also improve carbon sequestration, water infiltration, and crop productivity.