Ian is an ecosystem ecologist focusing on the development and application of molecular tools to determine the role of fungal communities in community and ecosystem-level outcomes. His main research interests spans the breadth of fungi, including mycorrhizas, wood decay fungi, and pathogens. He has also applied similar approaches to soil invertebrates, plant communities, bacteria, and oomycetes.

One application is in the invasion of woody plants, including the invasion of wilding conifers. Using molecular identifications of fungi on tree roots, he has shown that trees are largely co-invading with non-native fungi, transforming ecosystem function below ground.