In April/May 2019 the EcoTrack Experiment will get established in 12 of the 24 EcoUnits and will be 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 litter of the four focal tree species will 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) will be 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 this compartment.
- 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.