In April/May 2019 the EcoTrack experiment got established in 12 of the 24 EcoUnits based on the design of the MyDiv experiment. It aims at investigating the movement patterns of epigeic macro-invertebrate species - predators and prey - and how they are influenced by the spatial arrangement of tree litter and temperature. The four focal tree species, whose leave litter was used, differ in mycorrhizal interaction partners (ectomycorrhizae versus arbuscular mycorrhizal fungi) and stoichiometry (high versus low C-to-N ratio). The upper soil layer (just below the litter layer) got equipped with RFID sensors to track the animals.
Our hypotheses are:
(A) Movement ecology
- In heterogeneous habitats, prey predominantly move into patches of high stoichiometric litter quality.
- In homogeneous, well-mixed habitats prey follow more random movement paths.
- Predators efficiently track their prey and follow them into the same habitat compartments.
- Predator aggregation in habitat compartments causes prey movement out of these compartments.
- The speed of these movements increases with warming.
(B) Biodiversity-ecosystem functioning
- Small-scale litter mixing will support higher levels of decomposer activity and population sizes that may cascade up to higher predator fitness.