Modeling land-use effects on forest soil food webs

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The proposed project aims at studying the effects of land-use types (coniferous forests, young, intermediate and mature beech forests, plenter forests) and the elemental stoichiometry of the basal litter on the diversity (i.e., species number) and topology (i.e., network structure) of forest soil food webs across the three Biodiversity Exploratories. The project comprises three work packages. The first work package will analyse a large data base on the 52 forest soil communities (> 800 species, > 5500 populations) that was established during the prior two funding periods. These analyses will address the interplay of food-web structures, land use, and elemental stoichiometry in determining diversity and structure of the communities. These analyses will provide specific hypotheses for the second work package addressing how the litter inhabiting animal communities (characterized by diversity and food webs) assemble depending on different surrounding habitats (the land-use types of the Biodiversity Exploratories) and environmental niches (litter types). This biodiversity assembly experiment will be established on 24 forest plots. On each plot, four treatments (three litter types: beech, ash, spruce, and a control with plot litter) will be established with three temporal replicates. Measurements will address the assembly of biodiversity (only specific animal groups), biomass distributions and functions in time series for micro-, meso-, and macrofauna. This experiment tests whether community assembly is driven by habitat characteristics (litter type, biogeochemistry) as predicted by niche theories or the surrounding communities (control treatments that differ according to plots) as predicted by neutral theory. The third work package will address how land-use types and the stoichiometry of the litter determine the distribution of biomasses across size classes (size spectrum analyses) and the diversity of size classes at the 75-forest-plot level of the Biodiversity Exploratories. This will generalize the findings of the data base analyses and the assembly experiment to the spatial level of the Biodiversity Exploratories.