Browsing by Subject "Facilitation"

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    Blinded by the Light: The Functional Ecology of Plant-Light Interactions
    (2020-07) Kothari, Shan
    The capture of sunlight by plants and other primary producers is the greatest driver of the world’s carbon cycle. The photosynthetic machinery that plants use to fix carbon dioxide and light energy into storable carbohydrates must be able to handle intense fluxes of energy, and both lack and excess of light put plants at a disadvantage—either from starvation or from damage. Plant leaves evolve in how they absorb, reflect, or avoid light in ways that can be explained as functional adaptations to their environment. Here, I present four studies on the interactions between plant tissue and the light environment—two of which concern the functional role of light capture or avoidance in ecological strategies, and two of which are methodological studies that explain how we can use plants’ interactions with light to understand their strategies more broadly. Chapter 1 reports on a study in the Big Biodiversity (BioDIV) experiment that seeks to characterize the range of strategies that plants have to cope with excess light under stressful conditions. In a survey of prairie plants, we find that species may either primarily use biochemical or structural strategies to protect themselves from excess light. The position along this continuum is phylogenetically conserved. Communities with more species relying on biochemical mechanisms are more resilient aboveground during water-limited periods. Chapter 2 uses growth surveys and physiological measurements in the Forests and Biodiversity (FAB) experiment to show how broadleaf trees respond to shade from faster-growing conifer neighbors. While most species were harmed by shade, growing slower and assimilating less carbon, two species showed the opposite trend. These two species were the most shade-tolerant in the experiment and were exceptionally susceptible to photoinhibition, such that shade from their neighbors facilitated their growth. All species relied on photoprotection more in sunnier environments. Chapters 3 and 4 use reflectance spectroscopy to estimate traits in different kinds of leaf tissue. Chapter 3 focuses on leaf litter, whose chemical traits are often measured to gain insight into components of nutrient cycle such as nutrient resorption and decomposition. We show that we can estimate a fiber content and elemental composition using pressed-leaf spectra and, with somewhat higher accuracy, ground-leaf spectra. Chapter 4 is about pressed leaves, such as herbarium specimens, whose functional traits ecologists increasingly seek to measure in order to fill in trait databases or understand the impacts of global anthropogenic changes. We show that reflectance spectroscopy can provide non-destructive estimates of several leaf functional traits from pressed leaves, which may extend the possibility of using a wider variety of herbarium specimens in functional ecology.
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    The effects of facilitation management on interorganizational coordination and trust in an Anti-Iraq War political advocacy nonprofit network in the Twin Cities.
    (2010-04) Hansen, Toran Jay
    This study is a communications network evaluation of the organizations in the Twin Cities opposing the current Iraq War. The theoretical framework, testable hypotheses, and research questions drew from social network, social movement, empowerment, and group facilitation scholarship. Multiple linear regression analyses were used to test the hypotheses that relationships existed between the independent variable `facilitation management' (including the facilitation functions of: logistical arrangements for communications, social support, participatory discussion, conflict resolution, and participatory decision-making) and the dependent variables trust and coordination. These relationships were confirmed, though facilitation management had a larger effect on coordination. The study also investigated how concentrated responsibility was for the various facilitation functions among the network members. Facilitation functions that were found to be more concentrated (logistical arrangements (including: organizing and information dissemination), participatory discussion, and participatory decision-making) were considered facilitated in the network. Data were collected for this study in three phases. A background questionnaire collected information about the organizations that were represented in this study, as well as the study participants' perceptions of whether they felt that their network was expanding or contracting over the year prior to the study. A primary questionnaire was then utilized to collect data concerning the study participants' demographic information, their perceptions of their facilitation functions, trust, and coordination, their perceptions of their accomplishments and challenges, their perceptions of the worthwhileness and effectiveness of their activities, and their perceptions of the network's context over the previous three-month period. Finally, the study participants were invited to a focus group meeting to discuss their impressions of the research process and the study's findings, after they were given a report detailing the findings and insights that emerged from the literature review. The report included a discussion of findings coming from formative evaluation questions designed to determine specific ways that the communications network could be enhanced. Thus, this study was also a form of action research that accorded with the principles of empowerment theory.