University of Western Ontario, BA, Honours
University of Guelph, MSc
York University, 1999, PhD


My research explores vegetation dynamics with a focus on the impacts of human activities, particularly ecosystem fragmentation, altered disturbance regimes, biological invasions and climate change. I am interested in finding solutions to manage these impacts. I study plant populations in ecosystems of eastern North America and the Karakoram Himalaya. My current and recent projects include examining potential range shifts among high alpine herb populations of the Central Karakoram; developing a mathematical model to predict tree species’ colonization potentials in fragmented eastern forests; assessing the policy of assisted migration to address the biodiversity threats of shifting bioclimatic limits; investigating invasive species’ responses to climate change; and studying fire history in eastern Black oak savanna to inform current fire management strategies.


HEWITT, N., LAROCQUE, G., GREENE, D. and KELLMAN, M. 2019 ‘A model of hardwood tree colonization among fragments: predicting migration across human-dominated landscapes’ Ecoscience 26(1), 35-51,



DINH, T., HEWITT, N. and DREZNER, T. D. 2015 ‘Fire history reconstruction in the Black oak (Quercus velutina) savanna of High Park, Toronto’ Natural Areas Journal 35(3), 468-475,


Winter 2019

GEOB102 Our Changing Environment: Climate and Ecosystems Sections

Energy and water in the Earth-Atmosphere system, global climates and climate change, ecosystem properties and processes, human impacts. Please consult the Faculty of Science Credit Exclusion Lists:,215,410,414.

Winter 2019

GEOB309 Geographical Sciences Field Course Sections

Field sampling, instrumentation, surveying, mapping techniques, and data analysis; mandatory multi-day field camp in April or May. Special fees and liability insurance are required.

Winter 2019

GEOG374 Statistics in Geography Sections

Introduction to statistical techniques and their application to geographical problems. Priority enrolment for honours and major students in Geography. Consult the Faculty of Science Credit Exclusion Lists:,215,410,414.

Winter 2019

GEOG319 Environmental Impact Assessment Sections

The principles, implementation, and role of environmental impact assessment in environmental management, in Canada and internationally.