Substrate affinities of slime moulds (Eumycetozoa) and their potential use as forest ecological indicators
Abstract
Background. Slime moulds (Eumycetozoa) inhabit moisture-buffered microhabitats such as bark, dead wood, bryophyte mats and litter, where their assemblages are expected to track fine-scale forest structure. However, their potential as forest bioindicators has rarely been evaluated using harmonised data and study designs that explicitly account for sampling effort.
Methods . A taxonomically standardised, georeferenced occurrence archive spanning forests in Central and Eastern Europe was used to quantify substrate affinities of Eumycetozoa and to assess their suitability as ecological indicators. Records were assigned to a consolidated set of forest substrate classes and analysed in an effort-adjusted, presence-only framework that combined generalised linear mixed models of record composition with indicator value analyses across species and higher taxa. Complementary models described species responses to elevation, and measurements of pH were used for structured screening where available.
Results. After standardisation for sampling effort, diversity and evenness remained high and similar across substrates, while assemblage composition differed systematically among corticolous, lignicolous, bryophilous, terricolous and other substrates. Composition-adjusted models and indicator statistics highlighted distinct substrate signals that were shared across taxonomic ranks and yielded shortlists of candidate indicators, particularly for lignicolous and corticolous material. Species showed broad and interpretable elevational optima, whereas pH signals were weak and strongly constrained by sparse measurements.
Conclusions. These results support the use of Eumycetozoa as substrate-level indicators in effort-aware, regionally stratified bioassessment of European forests and identify systematic co-measurement of pH and improved coverage of under-represented substrates as priorities for strengthening Eumycetozoa-based bioindication.