An examination of thresholds and forest succession in the Acadian Forest of New Brunswick under a changing climate
University of New Brunswick
Climate change has warmed the atmosphere over scales relevant to modern society, causing widespread and rapid changes to the pedosphere, cryosphere, biosphere, and oceanic systems. Through our actions or inactions, we may be fundamentally altering the very nature of our environmental systems by forcing them beyond critical environmental thresholds. These environmental systems are complex and have many interconnected and interacting parts, so when a disturbance occurs the whole ecosystem can be impacted in ways that may not be readily apparent. To deal with this complexity, I have developed a conceptual framework to examine the historical simplifying assumptions foresters have used, from the simplest logistic curves to representations of forest dynamics as seen in hybrid process-based models, such as the Forest Landscape Model. The conceptual framework is separated into two parts, namely (i) ecological, and (ii) socio-economic constraints, each with their own results. Using this framework, this thesis seeks to unpack how the structure, composition, and function of forests will shift under anticipated climate change. My results led me to conclude that our simplifying assumptions of human-ecosystem interactions may point to competition as a driver of system thresholds and tipping points. I was able to identify various scenarios focusing on interspecific competition between southern and northern species that will require due consideration in the future. Nevertheless, a flexible response to dynamic system shifts in human-forest ecosystem interactions suggests that a flexible option would provide resilience to a complex system. My results lead me to conclude that a scenario with increasing species diversity will allow us to create more robust solutions for the future and reduce uncertainty.