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Due to the recent warming trend, the arctic regions have experienced significant land cover and hydrology changes which include extended shrub coverage, shrinking water bodies and melting permafrost. All these changes have and will certainly continue to affect the carbon cycles of those regions which have the largest soil organic carbon pools in the world. Of these large soil organic carbon pools, we selected the portion of the Yukon River Basin in the state of Alaska to investigate the dynamic in land cover changes and methane (CH 4 ) emission from 1980s onwards. We also developed a dissolved organic carbon (DOC) transport model to analyze the DOC trends for a watershed in the Yukon River Basin. We used the newly-released...
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In the northern high latitudes, vegetation distribution and carbon cycling have been continuously changed in the past and could change more rapidly as the climate warming. The purpose of my PhD dissertation is to quantify the uncertainty in modeling vegetatidynamics and to assess the effect of permafrost on vegetation dynamics and carbon cycling in the northern high latitudes under different levels of warming conditions. The uncertainty in current modeling of vegetation dynamics is considerably large. The first part of this study is to assess how high-latitude vegetation may respond under various climate scenarios during the 21st Century with a focus on analyzing model parameters induced uncertainty and how this...
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An atlas detailing state and provincial distributions of 663 North American Ephemeroptera species is presented. Biogeographic affinities of 95 North American genera are discussed and their hypothesized origins reviewed. Historical events in regards to vicariance and dispersal were important factors influencing the evolution of the North American fauna. Lineages found in North America are a result of Northern Hemisphere vicariant events (e.g., plate tectonics) and periods of dispersalist invasion, notably via the Isthmus of Panama and Beringia. The North American fauna is composed predominantly of Nearctic endemics/relicts, and lineages with Laurasian or Neotropical affinities. Although Cloeodes and Ephoron are hypothesized...
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