[en] The belowground food web represents a major part of associated biodiversity in forest
ecosystems, and plays a significant role in the ecosystem processes of litter decomposition and
nutrient turnover. Past research has demonstrated overwhelming evidence of strong tree
species identity effects on earthworm communities. It has been proposed that increased plant
community diversity would be beneficial to the abundance and diversity of the belowground food
web, but effects of tree species diversity on earthworm communities have seldom been
reported, and are inconclusive.
In this study at continental scale we evaluated whether tree species diversity positively affects
earthworm biomass and diversity. For this purpose the FunDivEUROPE Exploratory Platform
was used with 209 plots in 6 regions well spread over Europe with a low within-region site
variability, but a within-region tree species diversity gradient from monocultures to 3 or 4
species plots. In every plot earthworms were sampled using a combined method of mustard
extraction and hand sorting of litter and a soil monolith. Data are being analysed with
multivariate tools and mixed effects models.
First results suggest only limited influence of tree diversity on the biomass of earthworm
communities at continental scale. Tree diversity effects are weak, context specific and
interacting with tree identity. In nutrient poor soils we found a negative tree diversity effect on
earthworm biomass when deciduous monocultures are enriched with coniferous species, while
in rich soils we found a positive tree diversity effect which could be related with the food security
this provides to the earthworm community.