Charles Darwin was right to laud the earthworm. It is a natural instrument for restoring degraded soils (see J. Davies Nature 543, 309–311; 2017). Yet several species are already on the Red List of the International Union for Conservation of Nature. In our view, the best way to save our diminishing earthworm workforce is to use routine vermicomposting of organic wastes and to manage soils in ways that respect permaculture principles and practices.
Earthworms are ecologically crucial in the creation of healthy soils. They mineralize nutrients, either directly or by stimulating microbial activity in synchrony with plant needs, thereby increasing crop yields by 25% (see J. W. van Groenigen et al. Sci. Rep. 4, 6365; 2014). And rain filtered through worm burrows gives rise to worm-worked humus that stores 40% more moisture to sustain crops through drought (see go.nature.com/2oofvfq).
Earthworms also help to remedy other global problems, such as biodiversity decline and climate change. They reduce the need for large quantities of agrochemicals and boost carbon storage in soil through ingestion of plant residues (see http://4p1000.org). The earthworm warrants more scientific attention and investment.