RESEARCH PROJECTS

Boreal Ecosystem Resiliency

The factors and drivers governing ecosystem resiliency are arguably the most important ecological knowledge-gaps faced by humanity for the coming century, given the observed and predicted increases in anthropogenic disturbance globally. My research program characterizes how boreal forests respond and recover from the independent and interactive effects of climate change and industrial development, focusing on shifts in the plant community structure and the implications for carbon stocks.

My current work examines the resiliency of boreal forests to emergent disturbances prompted by changing temperature and precipitation regimes, including increasing wildfire and permafrost thaw frequency.

The Role of Wildfire 

 Boreal wildfires are predicted to be one of the strongest feedbacks to ongoing climate change over the 21st century, amplifying stored carbon release. During mega-fire years wildfires already emit approximately the same amount of carbon as annual fossil fuel combustion rates in Canada. However, the magnitude of the fire-carbon feedback varies across the boreal landscape. Working as part of NASA's Arctic Boreal Vulnerability Experiment (ABoVE) I am working to empirically quantify wildfire carbon combustion rates and identify the landscape-level predictors of combustive carbon losses throughout the North American boreal biome. These efforts inform Earth System Modelling products used to anticipate the future of global scale wildfire-carbon dynamics.  

The Role of Permafrost Thaw

Permafrost soils contain approximately half of the world's terrestrial carbon, surpassing the amount of carbon in the atmosphere. Warming soil conditions is prompting permafrost decay globally, which releases labile carbon and nitrogen resources to both the microbial and vegetative communities. These resources may prime the microbial communities for enhanced decomposition of 'legacy carbon' stores, creating a positive feedback to climate change. However, the plant community may also be stimulated by the increased availability of labile nitrogen, increasing the photosynthetic uptake of modern carbon from the atmosphere, offsetting or even surpassing the carbon lost due to microbial processes. The uncertainties associated with permafrost carbon store resiliencies represent a critical knowledge gap in current Earth System modelling efforts. My research works to close this gap by providing the empirical data needed to parameterize the permafrost-climate change feedback, and accurately predict its effect on atmospheric carbon loading. 

Plant-Soil Linkages

The plant community represents one of the most important linkages between the atmosphere and the lithosphere. By simultaneously undertaking photosynthetic and respiratory processes, while impacting microbial community structure and activity the plant community represents a critical regulatory pathway governing the flow of carbon, nutrients, and energy within a boreal forest ecosystem. However, contrasting plant growth forms use different competitive tactics to modify their local environment to increase their own fitness, with cascading impacts on processes like decomposition. My research mechanistically links plant growth form strategies and soil biogeochemical conditions to advance our understanding of carbon cycling and storage in boreal systems. Specifically, I empirically quantify the links between vegetation growth form, the microbial community (rhizosphere) activity, porewater chemistry, organic soil structures, as well as gaseous phase products (i.e. CO2, CH4) to determine how vegetation community assemblages impact soil carbon storage and microbially mediated soil carbon loss. 

Boreal Soil Decomposition Processes

The micro-scale biogeochemical processes that govern carbon compound transformation underpin global carbon cycling and ongoing climate change impacts. A deep knowledge of carbon-microbial feedbacks advances our capacity to understand and anticipate the emergent trends that form at larger scales of carbon cycling. My work in this field identifies the role of carbon quantity and quality in governing decomposition processes under contrasting environmental conditions and soil histories. I have considered and tested microbial priming effects as well as microbial carbon use efficiencies in soils throughout the boreal biome under varying climate change conditions. My current work is pushing the field to consider co-cycling feedbacks between both carbon and nitrogen quantity and quality as it moves between soil, porewater, and gas phase products. This research will advance our understanding of microbial resources as drivers of CO2 release following permafrost thaw under standardized laboratory conditions.