Zhong, Linlin

Trophic ecology of earthworms: the relative role of litter- and root-derived resources

Detritus-based systems are resource limited. Earthworms are keystone detritivores that are regulated by resources. Earthworms occupy an important position in the soil food web and due to their high biomasses are often central to energy fluxes and nutrient cycling. Understanding the trophic ecology of earthworms under different resource condition is therefore of fundamental importance in order to better understand the role of different resource pools in fuelling soil food webs.

I am using earthworms as model soil animal group to explore resource pools and fluxes of carbon through the decomposer system as influenced by resource availability, quality and origin. My PhD project aims to investigate (1) how root-derived resources contribute to the diet of earthworms and how the channelling of root-derived resources is influenced by plants of different functional groups; (2) in turn, how are the facilitation and competition of plants regulated by different ecological groups of earthworms; (3) the relative importance of old organic matter versus resources based on recently fixed carbon by plants to the diet of earthworms; (4) how litter quality affects the trophic niche of earthworms. Compound-specific stable isotope analysis of amino acids and bulk stable isotope analyses will be carried out to quantify the trophic niche of earthworms and the relative importance of resource pools and energy channels. The PhD project contributes to improve our understanding of interactions between the belowground and aboveground system of terrestrial ecosystems.