DISSERTATION RESEARCH: Application of Phytolith Analysis to Infer Vegetation and Disturbance Regime Changes Over the Past 200 Years.

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Historical ecology is a field of study that seeks to describe changes in ecosystems over time by synthesizing information from historical records (i.e., the human archive) and biological data. Methods used in historical ecology cover a wide range of time scales; however, biological evidence for the last 200 years is limited and new approaches are needed. This research seeks to expand the use of biological data for inferring vegetation changes in the last 200 years by combining the human archive with soil phytolith analysis. Phytoliths are microscopic fossils of plant cells that are deposited into soils when plants decay. This research will use phytoliths to characterize plant community changes in western rangelands and document the frequency of fires that occurred within the past 200 years. These new techniques will benefit land managers and researchers working in sagebrush steppe and pinyon-juniper woodlands, two widespread and highly degraded rangeland types in the West, by providing historical information on vegetation change as related to land use and climate change. An understanding of historical conditions helps guide management decisions and restoration efforts. In addition, this research will contribute significantly to the scientific field of historical ecology.