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The Structure, Limits, And Drivers Of Daphnid Diversity, Richard Joseph Knecht Sep 2018

The Structure, Limits, And Drivers Of Daphnid Diversity, Richard Joseph Knecht

Master's Theses and Capstones

In 1961 Hutchinson proposed the “Paradox of the Plankton” questioning how sympatric planktonic species can coexist for long periods of time while seemingly avoiding the competitive exclusion principle. As this ‘paradox’ became a focus of inquiry, one researcher conducted a 2-year study (1961-1962; Tappa 1965) on Aziscohos Lake Daphnia to address the question. While the study did not solve the enigma, it provided a detailed record of the dynamics and interactions of six coexisting species. Aziscohos Lake and its zooplankton have not been studied since. This study revisits the ‘paradox of the plankton’ by establishing the dynamics of extant Daphnid …


Four Years Of Unmanned Aerial System Imagery Reveals Vegetation Change In A Sub-Arctic Mire Due To Permafrost Thaw, Jessica Delgreco Jan 2018

Four Years Of Unmanned Aerial System Imagery Reveals Vegetation Change In A Sub-Arctic Mire Due To Permafrost Thaw, Jessica Delgreco

Master's Theses and Capstones

Warming trends in sub-arctic regions have resulted in thawing of permafrost which in turn induces change in vegetation across peatlands both in areal extent and composition. Collapse of palsas (i.e. permafrost plateaus) has also been correlated with increases in methane (CH4) emission to the atmosphere. Vegetation change provides new microenvironments that promote CH4 production and emission, specifically through plant interactions and structure. By quantifying the changes in vegetation at the landscape scale, we will be able to scale the impact of thaw on CH4 emissions in these complex climate-sensitive northern ecosystems. We combine field-based measurements of vegetation composition and Unmanned …