Her PhD thesis titled Phytoliths, Late Quaternary Environment and Archaeology in Tropical Semi-arid Northwest Australia demonstrated the suitability of phytolith analysis to questions of palaeoenvironmental interest in the tropical semi-arid areas and, subsequently, produced the first detailed late Quaternary terrestrial vegetation record for northwest Australia.
[1] Her career spans both private and public sector cultural heritage management, university lecturing and research in both Indigenous and historical archaeology.
[5] Wallis' research interests focus on human-environment relationships through the late Quaternary period, coastal and island archaeology, phytolith analysis, and ethnobotany.
She specialises in palaeoenvironmental reconstruction through the analysis of phytoliths and remote area fieldwork, and maintains broad interests in community-based Indigenous archaeology.
[3] She has been worked on projects across most of Western Australia (WA), South Australia (SA), Northern Territory (NT), Australian Capital Territory (ACT) and Queensland (QLD) and has international experience working in Chile, Vietnam and Thailand.