Project description A4 - Project completed

Scientific advisor
Prof. Dr. M. Schaefer

Project

Soil macrofauna community structure in deciduous forests with increasing tree species diversity

The influence of tree species diversity (1, 3, 5 species) on the abundance and diversity of the soil fauna, in particular of the decomposer fauna, was studied. Although canopy litter diversity affected the composition of the soil fauna community, no general relationship between increasing tree species diversity and diversity and abundance of the investigated animal taxa was found. Trophic groups responded differently to tree species diversity: key groups of primary decomposers such as isopods and earthworms were favoured by a high diversity of litter resources whereas numbers of snails and predators such as spiders or carabid beetles decreased in the highly diverse plots due to the fast decomposition of the litter in the ground zone.
In addition, litter decomposition rates (indicating the activity of the decomposer fauna) of six major tree species (beech, ash, lime, hornbeam, Norway and sycamore maple) were studied. Besides a marked difference in the decomposition rate of the individual tree species, overall decomposition was highest in the most diverse forests. The influence of litter diversity versus abiotic soil factors was studied in a litter exchange experiment.
The stable isotope content of the soil animals was analysed to gain insight into the trophic structure of the soil food webs.

Methods

• Heat extraction and hand sorting of the soil fauna from litter and soil samples
• Extraction of earthworms with mustard solution
• Pitfall traps
• Litter bags
• Litter exchange
• Analysis of stable isotopes (15N, 13C) of the soil fauna