Research

My main research focus is concerned with how global climate change influences ecosystem interactions, and in particular above ground-below ground linkages. This research explores multi-trophic interactions, especially those incorporating below-ground insect herbivores. Many of these plant-mediated interactions shape insect herbivore behaviour and dynamics and our goal is to identify the underpinning mechanisms. This insight provides the potential for exploiting these mechanisms to maintain sustainable production systems in a changing climate.

I am particularly interested in how chemical ecology and plant traits underpin such interactions and work with researchers from many different fields to identify the causal mechanisms from the level of the gene to the field. I am also interested in the development of novel techniques for investigating insect–root interactions belowground, and in particular have used X-ray micro-tomography to answer some of these research questions.

Figure 1 (right): Visualisation of white clover root, root nodules and Sitona lepidus larva (bottom left) using X-ray micro-tomography.

Currently, we have several research projects investigating:

  • how elevated CO2 and changes in precipitation patterns affect trophic cascades spanning above-ground and below-ground sub-systems
  • the role of plant-mediated interactions between insect herbivores and plant microbes (e.g. viruses and AM fungi)
  • the chemical ecology underpinning host plant selection and aggregation by vine weevils
  • the genetic control of physical resistance traits in plants to insect herbivory

A recent example of my climate change research illustrated how changes in precipitation patterns affect plant communities and trophic groups through nine direct and indirect mechanisms.

Figure 2: Major direct and indirect mechanisms affecting plants and trophic groups under different precipitation scenarios. See Johnson et al. Journal of Ecology.

My current research team comprises:

  • PhD students: Katy Clark (awarded 2010), Scott McKenzie, Will Hentley, Lindsay McMenemy and Andrew Burgess
  • Postdocotoral Researcher: Dr Carolyn Mitchell
  • Technical support: Sheena Lamond