Arthropod diversity and functioning in mixed versus pure stands
PhD Student
Benjamin WildermuthResearch Outline
The aim of subproject 6 is to assess the community composition, functional diversity and trophic niche structure of epigeal arthropods in pure and mixed stands of European beech, Douglas fir and Norway spruce.During the first funding period, comprehensive sampling and analysis of the forest floor-associated arthropod community showed intermediate arthropod diversity levels and lower herbivory on beech saplings in mixed stands and high arthropod predation rates in stands with high proportions of Douglas fir.
In the second funding period, we will complement the data of the forest floor-associated community with data on the canopy stratum. Furthermore, we will analyze the natural abundance of stable isotopes (δ13C and δ15N) in generalist predator groups to examine the feeding niche structure (e.g. ground beetles and spiders).
Only when combining community data from the forest floor and the canopy, we will be able to draw general conclusions on how enriching native beech forests with (non-native) conifers affects arthropod diversity and functioning.
We sample canopy arthropods by applying a combined approach of flight interception traps and insecticidal fogging. The combination of both methods ensures assessment of both flying and more stationary taxa. In collaboration with subproject 8 we will record and analyze the canopy structure via laser scanning.
Sentinel prey will be placed in the canopy and checked for predation marks to complement the data on predation rates on the forest floor.
Stable isotope analysis of δ13C and δ15N will be implemented on the most abundant generalist predators from both the forest floor and the canopy to assess the feeding niche and main feeding channels. Collaboration with subproject 5 will allow us to include data on the isotopic signature of the forest floor and leaf litter.