Earthworms exert long lasting afterlife effects on soil microbial communities

Earthworms dominate the invertebrate biomass in soils. Although the effects of living earthworms on soil functioning have been extensively studied, the ecological impacts of earthworm cadavers on soil microbiota remain unclear. In a 10-weeks laboratory incubation experiment, we monitored the influence of decomposing earthworm cadavers on the diversity and composition of soil bacterial, fungal and protistan communities. We found that the decomposition of earthworm cadavers decreased alpha diversity and changed the composition of microbial communities in comparison to control soil and soil with living earthworms. Although the functional composition of bacterial communities was not significantly influenced by the presence of dead earthworms, both fungal and protistan communities significantly shifted toward r-selected copiotrophic strategists; fungal com-munities were significantly enriched in molds and yeasts while protistan communities were enriched in sapro-trophs. Our results suggest that dead earthworms play a distinct role in influencing soil microbial communities and associated functioning compared to their living counterparts. They further highlight that there is an increasing need to consider the afterlife effects of soil biota to better predict soil biogeochemical cycling in terrestrial ecosystems.

Automated summary

The decomposition of earthworm cadavers decreased the diversity and composition of soil microbial communities, with significant shifts in fungal and protistan communities towards r-selected copiotrophic strategists. The results suggest that dead earthworms play a distinct role in influencing soil microbial communities and associated functioning, highlighting the need to consider the afterlife effects of soil biota.