Mark’s expertise includes ecology, biological invasions and environmental risk analysis. He has been chief of CSIRO Entomology and CSIRO Ecosystem Sciences, and has served as Co-Chair of the Multidisciplinary Expert Panel (MEP) overseeing IPBES, the UN global biodiversity assessment platform. In 2016, he chaired the review of Wild Horses on Kosciuszko National Park. He is a member of the Ecosystem Science Council and the ACT Scientific Committee.