Dissertation/Thesis Abstract

Generating space-time hypotheses in complex social-ecological systems
by Forbes, Dolores Jane, Ph.D., Florida Atlantic University, 2014, 190; 3691818
Abstract (Summary)

As ecosystems degrade globally, ecosystem services that support life are increasingly threatened. Indications of degradation are occurring in the Northern Indian River Lagoon (IRL) estuary in east central Florida. Factors associated with ecosystem degradation are complex, including climate and land use change. Ecosystem research needs identified by the Millennium Ecosystem Assessment (MA) include the need to: consider the social with the physical; account for dynamism and change; account for complexity; address issues of scale; and focus on ecosystem structure and process.

Ecosystems are complex, self-organizing, multi-equilibrial, non-linear, middle-number systems that exist in multiple stable states. Results found are relative to the observation and the frame of analysis, requiring multi-scaled analytical techniques. This study addresses the identified ecosystem research needs and the complexity of the associated factors given these additional constraints.

Relativity is addressed through univariate analysis of dissolved oxygen as a measure of the general health of the Northern IRL. Multiple spatial levels are employed to associate social process scales with physical process scales as basin, sub-basins, and watersheds. Scan statistics return extreme value clusters in space-time. Wavelet transforms decompose time-scales of cyclical data using varying window sizes to locate change in process scales in space over time. Wavelet transform comparative methods cluster temporal process scales across space. Combined these methods describe the space-time structure of process scales in a complex ecosystem relative to the variable examined, where the highly localized results allow for connection to unexamined variables.

The results describe discontinuities in seasonal cycles for dissolved oxygen observations, where discrete temporal intervals of interest are situated in space as indicators of external changing conditions or thresholds of internal change. Process scales are shown to be influenced by local, not global or regional effects, and indicate issues related to governance not management. Discontinuities in expected seasonal cycles are observed at most locations. These localized impairment indicators represent generated spacetime hypotheses through system reduction without summary or aggregation, and focus limited resources to generate additional knowledge and understanding. Similar analysis of other relevant variables is recommended to approach holistic understanding of the complex Northern IRL estuarine system.

Indexing (document details)
Advisor: Xie, Zhixiao
School: Florida Atlantic University
School Location: United States -- Florida
Source: DAI-B 76/08(E), Dissertation Abstracts International
Subjects: Geography, Geographic information science, Water Resource Management
Keywords: Complexity, Dissolved oxygen, Indian River Lagoon, Spacio-temporal, Wavelets
Publication Number: 3691818
ISBN: 9781321666007
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