Research Dajana Radujkovic

Abstract

Soil food webs consist of intricate communities of soil organisms that play a vital role in supporting terrestrial life. While the importance of soil food webs has been acknowledged for several decades, the mechanisms controlling soil food web structure and function remain unclear. It has long been assumed that soil food webs are resource-controlled systems, meaning that detritus determines the structure of primary decomposer communities (bacteria and fungi) with cascading effects on other trophic levels. However, recent research demonstrating the strong influence of soil fauna (most of which are microbial consumers) on ecosystem functions, microbial richness and functional diversity, suggests a potentially important role of top-down control, where consumers determine the structure of primary decomposers and the processes they drive. This project aims to test the long-standing question about the relative importance of bottom-up vas top-down control on soil food webs and ecosystem functioning using metatranscriptomics. To this end, ten treatments with different microbial communities and varying levels of soil faunal abundance and diversity will be created and linked to ecosystem functions – nutrient cycling and plant productivity. Metatranscriptomics will be used to simultaneously study all active members of the soil food web, from viruses and bacteria to protists and soil fauna. Along with faunal DNA gut analyses, this approach will reveal the mechanisms by which soil fauna affect soil food web structure and it will enable the quantification of the relative importance of bottom-up vs top-down control. This project can provide fundamental insights into soil food web structure, its impact on ecosystem functions, and the key players in these processes. Understanding these aspects can help predict the effects of global changes on soil food webs and the processes they drive and pinpoint bioindicators of healthy soils.

Researcher(s)

• Promoter: Radujkovic Dajana

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Biodiversity underpins ecosystem functionality and stability. It is becoming increasingly clear that soil diversity and community complexity in particular (the presence of functionally diverse, interconnected organisms) are decisive for the maintenance of multiple ecosystem processes such as plant productivity and nutrient cycling. However, due to staggering soil diversity, difficulty to manipulate, and inadequacy of prior ecological concepts when applied to soil, we lack a thorough understanding of the link between soil biodiversity, ecosystem functioning, and environmental pressures across different soil types. This project will execute for the first time a series of microcosm experiments simulating contrasting European grasslands where soil community complexity will be manipulated to examine: 1) the effect of soil complexity on plant diversity, productivity and nutrient cycling across different grassland soils and their stability under different environmental pressures (drought, biomass removal, and intensified herbivory); 2) which key soil taxa and the interactions they form might be universally responsible for enhanced ecosystem stability across soils and stressors. The findings will not only advance our knowledge about the importance of soil biodiversity for grassland functioning and stability under disturbance but also delineate the biotic network properties and keystone taxa that are at the core of these processes and should be the focus of conservation efforts.

Researcher(s)

• Promoter: Verbruggen Erik
• Fellow: Radujkovic Dajana

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project