PhD Oral Exam - Isabella Richmond, Biology

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Cities are complex landscapes composed of natural, built, and social elements, resulting in high levels of spatial and temporal heterogeneity. Urban nature provides benefits to human residents, increasing their quality of life. The urban forest specifically provides many benefits to residents, yet these benefits are currently delivered inequitably. My thesis explores the spatial and temporal distribution of benefits provided by the urban forest in Canadian cities. In chapter one, I show that historical land-use of Montreal parks causes differences in forest composition and structure, and ultimately nighttime cooling capacity, disproportionately affecting immigrants and low-income residents. However, current park management can overcome historical differences, resulting in similar levels of daytime cooling in all parks. In chapter two, I provide evidence from two Quebec cities that while green alley programs provide higher levels of biodiversity support than traditional alleys, they do not consistently provide higher levels of nature’s benefits to residents – despite potential to do so. I suggest expert guidance on green alley design could lead to better outcomes for both nature’s benefits and biodiversity. Finally, in chapter 3, I show the importance of scale-specific context when predicting urban temperature and air pollution levels using a multi-scale, multi-city study that incorporates street tree, urban form, and sociodemographic data. I found that the most important predictors of temperature and air pollution vary across scales, highlighting the need for scale-specific approaches when attempting to manage temperature or air pollution. Ecological variables are important predictors of temperature, nitrogen dioxide, and ozone at the city and/or neighbourhood scales, which are key scales of management for decision-makers. Overall, my thesis uses under-studied frameworks of historical ecology, interdisciplinary methodology, and cross-city analysis to contribute knowledge about the benefits of urban greenspaces. I highlight that urban forests – including trees in parks, green alleys, and along streets – improve quality of life for residents across various spatial scales in Canadian cities. However, my thesis also contributes to the growing body of evidence highlighting distributional inequity of nature in Canadian cities.