Biology Theses and Dissertations

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Browsing Biology Theses and Dissertations by Subject "Agriculture"

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    Birds of a Feather: Spatial Relationships of Avifauna in Hazelnut Orchards
    (University of Oregon, 2024-01-09) Penkauskas, Calvin; Hallett, Lauren
    This thesis investigates how hazelnut orchard age and landscape variability influence wild bird communities on farms, with a focus on adjacent habitat and establishing a biodiversity baseline. I conducted field studies within the Willamette Valley, OR to assess avifaunal diversity across hazelnut farms of increasing matrix quality; and across orchard ages within the farm with the highest matrix quality, Dorris Ranch. My findings show that landscape heterogeneity has a significant impact on bird communities, with adjacent habitat being a key factor for functional community traits such as diet guild. Due to its proximity to large habitat areas and distributed wildlands, Dorris Ranch has high species richness – particularly near restored oak habitats. Although younger orchards supported a higher species diversity on average at this site, older orchards supported key species of conservation and service-provisioning value, highlighting the importance of landscape diversity and ecologically intensive practices in management plans.
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    Investigating the Influence of Management Practices on the Assembly and Function of Microbial Communities
    (University of Oregon, 2024-01-10) Spencer, Max; McGuire, Krista
    Microbial communities are integral to many ecosystem functions, including functions of interest to humans such as nutrient cycling and pathogenic infection. However, the influence of management intensity on microbial community assembly and functioning is poorly understood. High intensity management often reduces the overall diversity and biomass of fungi and bacteria; yet ecosystem function does not follow such a clear trend. Additionally, the timeframe in which management impacts microbial community and function is generally unknown. To address these gaps, I characterized microbial communities within logged and unlogged watersheds in the Western Cascade Mountain range and vineyards using different management intensities across a climate gradient in western Oregon, USA. Furthermore, I used wine fermentation as a proxy for microbial community functioning to measure functional differences between management intensities. I found that human management continued to have legacy effects upon microbial communities even five decades after cessation. I also found that management intensity had a clear influence on the organoleptic compounds found within Pinot noir wine samples. This work can deepen our understanding of the response of microbial communities and their functioning to human management.