Sarah Kiger has completed her PhD dissertation on modeling carbon cycling and ecosystem services in the exurban residential landscape. The abstract from her dissertation follows:
“Ecosystem services (ES) are the physical goods and associated benefits that are provided to humans by the ecosystems of the planet. Assessment of ES requires knowledge of ecology and ecosystem processes and ES estimates can be improved when they include knowledge of nonlinearities, feedbacks, and interactions within ecosystems. A variety of assessment tools have been proposed to estimate the provision of ES and the economic benefits they provide to society. However, they fail to acknowledge the interconnectedness of services or the connection between ecosystem processes and services.
“This dissertation examines the connection of ecosystem processes and ES with the belief that knowledge of ecosystem ecology and ecosystem processes can be applied to improve the estimates of ES capacity over time and under a variety of management scenarios. To investigate this connection, I modified the ecosystem process model, Biome-BGC to simulate the provision of ES in exurban Southeastern Michigan. The modification resulted in a new version of the model, Biome-BGC-Ex, and involved detailed changes to the source code of the original model to include the ability to model turfgrass and open-grown trees in a single grid cell, incorporate residential management practices, and translate the model outputs into estimates of ES.
“My research was conducted as part of a larger collaboration, the SLUCE (Spatial Land Use Change and Ecological effects) project, and addresses the exurban residential landscape as a coupled human-natural system. It references and builds on previous elements of the SLUCE project including an empirical ecological field study, developer and homeowner interviews, web-based surveys, and modeling in a coupled human-natural system framework. My contributions to the project, specifically modifying Biome-BGC and linking it to ES, can be applied to future research on coupled human-natural systems.
“Chapter two describes how Biome-BGC was modified for the exurban landscape and then calibrated and parameterized for Southeastern Michigan. We examined which individual and combinations of yard management practices have the greatest effect on carbon sequestration and found fertilizer to be the strongest driver across the three major vegetation types. Chapter three describes how Biome-BGC-Ex was modified to provide outputs to estimate ES capacity of ten services in the residential landscape. We also evaluate the impact of yard management practices on ES capacity via Monte Carlo simulations. Model simulations show trade-offs between ES relating to high amounts of carbon or biomass and freshwater recharge. We find that analysis of ecological processes in novel ecosystems underscores the complexity of landscape management decisions. Chapter four takes a broader approach and evaluates terrestrial ecosystem process models as a potential tool for ES assessment and the integration of Biome-BGC-Ex with other tools to improve ES assessment. We find that while process models increase the complexity of knowledge needed to understand how services are being quantified, they also allow for more complex modeling that includes interconnected ecosystem processes and feedbacks.
“My dissertation research will be the first that has modified Biome-BGC to measure ES in a residential ecosystem. It is also novel because the focus of my work is on how human management of the landscape affects ES production as opposed to land use or land cover change. My dissertation research can be replicated in similar ecosystems to inform more complex ES modeling frameworks that rely on ES production modeling grounded in the understanding of ecosystem processes and their feedbacks.”
This dissertation will be available on the UM Deep Blue (deepblue.lib.umich.edu) repository soon, and manuscripts are currently being prepared for submission to peer-review journals.