Species and trait compositions of freshwater nematodes as indicative descriptors of lake eutrophication

•We established the first trait database for abundant freshwater nematode species.•We compared the effects of eutrophication on the trait and species composition of lake nematode assemblages.•The trait composition was as effective as the species composition to mirror eutrophication.•Both, selected indicator trait modalities and species, allowed to discriminate among trophic lakes states.•In addition to macroinvertebrates also analyses of nematode assemblages provide suitable trait- and species-based indicators.