EU Project ProPollSoil Investigates Solitary Ground-Nesting Bees and Soil Health

Last week, a walk through Derrycassan Wood in Longford, Ireland, revealed the aftermath of Storm Éowyn, which knocked down thousands of trees. Amidst this, signs of solitary bees were observed, highlighting their crucial role as pollinators and their dependence on soil.

Most of Ireland's 80 solitary bee species nest underground, digging tunnels up to a meter deep. Females provision cells with pollen and nectar for their larvae, which overwinter underground and emerge as adults in spring. Some species, like the gold-fringed mason bee, Osmia aurulenta, are highly specialized, nesting only in empty snail shells on coastal sand dunes.

Despite their importance, little is known about the underground lives of these pollinators. The EU Horizon Europe project ProPollSoil, launched last autumn with a €7.7 million budget and 20 partners, aims to bridge this knowledge gap. Led by Prof. Dara Stanley of University College Dublin, the project focuses on the link between soil health and pollinator health, a timely initiative given the EU Nature Restoration Law's requirement for coordinated pollinator monitoring.

ProPollSoil highlights that solitary bees are soil engineers, preferring drier soils and actively digging in summer, a contrast to earthworms. The project seeks to integrate pollinators into soil science, which has historically overlooked them. A citizen science component encourages the public to photograph and upload signs of ground-nesting bee activity to propollsoil.eu or iNaturalist (EuroBeeSoil project). This effort is critical as one-third of Ireland's wild bee species face extinction by 2030 due to habitat loss, chemical use, and intensive land management practices that disrupt their underground nesting conditions.