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Complex Adaptive Systems: Cross-Scale Structure and Resilience
This dissertation is focused on scaling and resilience of complex adaptive systems, including ecological and economic systems. In particular it is concerned with the textural discontinuity hypothesis (hereafter called the discontinuity hypothesis), which describes how the distinct spatial and temporal scales of processes that shape systems in turn generates distinct spatial and temporal scales in system structure and entities interacting with that structure; the cross-scale resilience model, which uses the discontinuity hypothesis as the foundation of a theory about specific system features that drive ecological resilience; panarchy and adaptive cycles, which articulate how system dynamics at the above-mentioned scales change over time and how feedbacks across those scales informs system behavior; and the notion of spatial regimes in ecological structure. I both expand existing frameworks to accommodate non-ecological complex systems, and test my hypotheses in a variety of economic and ecological systems. ^ Some general findings of my analyses are that the objective identification of scale domains in many types of complex systems can be useful for understanding how pattern and process shape structure and impact system-level resilience. Economic systems, for example, as expressed by Gross Domestic Product, fall into distinct, non-random size classes that suggest there are scale-specific processes generating basins of attraction. I expand the cross-scale resilience model to incorporate abundance, a species and community attribute that is mechanistically related to the provision of function and resilience. The coral reef fish communities of the Hawaiian archipelago were analysed to see if their cross-scale resilience differed amongst coral dominated and macroalgal and turf dominated reefs, with the surprising result that the macroalgal-turf communities were more resilient. In a twist on classic regime shift theory, which typically focuses on temporal shifts within a single ecosystem, I used a novel information theory method to successfully detect spatial boundaries and transition zones between types of ecological systems by using animal community data. Finally, I argue why the adaptive cycle may be a result of endogenous processes in complex adaptive systems, and is not just a convenient metaphor for cycling behavior and dynamics.^
Sundstrom, Shana M, "Complex Adaptive Systems: Cross-Scale Structure and Resilience" (2018). ETD collection for University of Nebraska - Lincoln. AAI10743915.