Wenglein, Ronja

Structure and functioning of soil animal communities in Douglas-Fir and Silver-Fir admixtures

The forest is changing, especially the coniferous forest. Increasing drought periods stress conifer stands and the outbreak of bark beetles damage the remaining stands resulting in bare slopes where once green spruce dominated. Therefore, alternative conifer trees are gaining increased interest, particularly the introduced Douglas-fir (Pseudotsuga menziesii) form North America and in small parts the introduced Silver-Fir (Abies procera) receive closer attention. However, instead of focusing on monocultures, admixtures with native beech (Fagus sylvatica) are to be considered as alternative in forest ecology and economy.
In my PhD project I focus on the influence of these admixtures on soil animal communities. From pure beech stands an increasing gradient of the two conifer admixtures are investigated and soil animal diversity as well as changes in structure and functioning of decomposer communities are studied.
Fatty acid analysis allows a functional and quantitative perspective of energy fluxes in forest soil food webs, from basal resources like leaf litter, fungi and microbes to animal consumers. Furthermore, trophic relationships can provide information on changes in soil animal communities in the different admixtures. This can help to understand the influence of Douglas-Fir and Silver-Fir on forests and soils, and help to find alternatives to conventional monoculture forest systems, which are improved both from an ecological but also economical perspective.