Green roofs (roofs with a vegetated surface and substrate) provide ecosystem services in urban areas, including improved storm-water management, better regulation of building temperatures, reduced urban heat-island effects, and increased urban wildlife habitat. This article reviews the evidence for these benefits and examines the biotic and abiotic components that contribute to overall ecosystem services. We emphasize the potential for improving green-roof function by understanding the interactions between its ecosystem elements, especially the relationships among growing media, soil biota, and vegetation, and the interactions between community structure and ecosystem functioning. Further research into green-roof technology should assess the efficacy of green roofs compared to other technologies with similar ends, and ultimately focus on estimates of aggregate benefits at landscape scales and on more holistic cost-benefit analyses.

Coastal barrens in Nova Scotia are heathlands characterised by short, predominantly ericaceous vegetation, sparse tree cover, exposed bedrock, pockets of Sphagnum bog, and stressful climatic conditions. Although coastal barrens are prominent in the physical and cultural landscape, they are largely unprotected. We selected six barrens along the Atlantic coast, and surveyed 20 1-m 2 plots at each barren for vascular plants, macrolichens, mosses and environmental factors. We recorded 173 species (105 vascular, 41 macrolichen, 27 moss), including six provincially rare vascular species found predominantly in nearshore areas with high levels of substrate salt and nutrients, variable substrate depth, and short vegetation. Although vascular plant and moss richness were similarly correlated with vegetation height, substrate depth, organic matter content, and rock exposure, there were no clear correlations between vascular plant, macrolichen and moss richness across all sites. Vascular plant rarity and species richness were not correlated, but had inverse relationships with key environmental gradients. Tailoring conservation efforts to protect areas of high richness may thus mean that rare species are missed, and vice versa. Ordination and ANOSIM show that barrens vegetation differs widely among sites; therefore, protecting any singular coastal barren will not protect the entire range of vegetation communities and species in this heathland type. Conservation planning should emphasize protecting environmental gradients correlated with richness, rarity and plant community structure, including substrate depth and moisture, and vegetation height. Additionally, protected areas should include a coastal-inland gradient and a diversity of substrate types, including exposed rock and trees.

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Green Roofs as Urban Ecosystems: Ecological Structures, Functions, and Services

People and plants live in complex networks of cultural and ecological relationships. In northern Canada, plants are important to cultural practices, just as cultural practices shape plant communities. This research responds to research priorities identified by Makkovimiut, residents of the Inuit Community of Makkovik, Nunatsiavut (Labrador, Canada), on people-plant relationships (2012)(2013)(2014)(2015)(2016). These priorities shaped the research objectives, which form the three central chapters of this integrated thesis: i) learning how to respectfully approach research on people-plant relationships in Makkovik; ii) learning about Makkovimiut relationships with plants; iii) learning about the effects of cultural practices on plant communities.Chapter 2 details and evaluates approaches in Indigenous methodologies that guide the research. As a non-Indigenous student, I rooted research questions in personal meaning and community relevancy, which I sought to understand through preliminary research, the ongoing guidance of community advisors, and by going as a learner to Makkovimiut plant mentors. An iterative approach to learning helped build relationships with Makkovimiut plant mentors and plants. Chapter 3 discusses Makkovimiut plant knowledge and practices. Plants support life and livelihood for Makkovimiut, and sustain cultural practices such as fishing, which reciprocally support plant communities. Plants are more than objects: plants are present in memory, well-being, and sharing, and have voices of their own. In actively managing-caring for-plants, Makkovimiut nurture the ecological and cultural values that create healthy communities for both people and plants. These values are expressed in the stories people tell about plants.My thanks start at the beginning, with my family. My parents Carol and Dieter Oberndorfer have taught by example through their respect, curiosity, care, and love for the natural world. These early lessons have been the gifts that have directed the course of my life. My brother Derek, my original outdoor companion, shares an appreciation for this great world that continues to bring our family closer. Thank you, Mom, Dad, and Derek, for all the gifts that are beyond measure and beyond thanks. v their warm welcome and friendship. There are so many kindnesses small and large that are so freely given. These are the lasting lessons of this work.