Invasive earthworms in northern Scandinavia; effects on soil microorganisms and carbon dynamics

Though earthworms are widely present in European forests, the northern regions of Scandinavia are still largely lacking burrowing earthworm species.

The expansion of such species into northern forests may have dramatic effects on their crucial soil carbon (C) storage function via cascading effects on soil microorganisms that control decomposition and nitrogen (N) availability, and by physical soil mixing.

The aim of this project is to quantify the impacts of burrowing earthworm expansion on soil C and N cycling in Scandinavia’s northern forests, and the mechanisms by which earthworms affect soil microorganisms.

Thereto, I plan (I) to quantify impacts of burrowing earthworms on soil microorganism abundances and communities and C and N dynamics of previously worm-free forests; (II) model past and current distribution patterns of earthworm species in Swedish forests in relation to soil properties, climate and forest management regime; (III) to provide estimates of the consequences of potential future burrowing earthworm establishment for soil C storage potential.

I will use controlled mesocosm experiments and identify natural invasion gradients using eDNA analysis of recent and decades old archived soil samples sampled in high spatial resolution across Sweden to quantify effects of earthworms on soil microorganims and C sequestration.

This project will identify whether climate-driven expansion of burrowing earthworm species is a threat for C storage in northern forest soils