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Cryostratigraphic mapping in the main shaft of the CRREL tunnel indicates secondary modification of original Pleistocene-age syngenetic permafrost. Layered, lenticular-layered and micro-lenticular cryostructures within undisturbed silt characterise the syngenetic permafrost. Thawed and refrozen deposits are characterised by massive and reticulate-chaotic cryostructures. The micro-morphology of typical cryostructures, as observed through an environmental scanning electron microscope (ESEM), is described. It is inferred that preferential cryogenic modification has occurred due to fluvio-thermal erosion operating along ice wedges. Soil and ice pseudomorphs are the manifestation of this process. Gravel, silt, ice and...
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Increased light reaching streams as a result of riparian vegetation management is often thought to be responsible for enhanced algal productivity. However, concomitant changes in nutrients and other physical processes confound that interpretation. We manipulated light in two separate experiments to test the role of light as a controlling factor for periphyton productivity and biomass, and to observe invertebrate responses in small streams in central British Columbia, Canada. We did this by adding artificial light to reaches of three forested streams, and in a second experiment we used shadecloth to cover reaches of two streams flowing through clearcuts. Periphyton growth, productivity and composition, and macroinvertebrate...
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In Canada, little is known about the governance of private protected areas (PPAs) and their contribution to the public interest. This dissertation evaluates the extent to which PPAs in Canada adhere to generally advanced principles of good governance---Direction, Legitimacy, Fairness, Performance and Accountability---and it assesses their contribution to the public interest. Findings from descriptive analysis of six case studies of Individual, Corporate, Non-Government and First Nation authorities indicate that principles are adhered to with relative vigor and visibility and that the public interest is generally advanced. The governance pattern is not strongly differentiated and it is generally uniform in strengths...
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Pattern and extent of treeline change using sequential vertical aerial photography in the northern section of the Kluane Ranges of southwest Yukon are examined. One of the most common predictions is that continued global temperature increases will cause the tree-line to advance in elevation and latitude. Comparison of aerial photographs of southwest Yukon indicates significant changes in the spruce forest-shrub tundra transition. Many areas exhibit increased growth of individual spruce without an increase in stand density or an advance in spruce distribution. Increase in the elevational distribution of spruce is observed in comparatively fewer areas, typically in combination with other two types of change.
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Aim? Using a new approach to analyse fossil pollen data, we investigate temporal and spatial patterns in Populus (poplar, cottonwood, aspen) from the Late Glacial to the present at regional to continental scales. Location? North America. Methods? We extracted data on the timing and magnitude of the maximum value of Populus pollen from each pollen diagram in the North American Pollen Database (NAPD). The information was plotted in histograms of 150-year bins to identify times when Populus was abundant on the landscape. We also mapped the maximum values to identify spatial patterns and their causes. Results? Our analyses show that there have been several periods since the Late Glacial when Populus was abundant on...
map background search result map search result map  Invasive Plant Management Guidance, McGrath, AK Governance of private protected areas in Canada: Advancing the public interest? Climate Change and Hazard Zonation in the Circum-Arctic Permafrost Regions The influence of coyote on Canada lynx populations assessed at two different spatial scales RELATIONSHIPS AMONG FIRES, FUNGI, AND SOIL DYNAMICS IN ALASKAN BOREAL FORESTS Stand-level Attributes of Snowshoe Hare (Lepus americanus) Habitat in a Post-Fire Trembling Aspen (Populus tremuloides) Chronosequence in Central Yukon Impact of doubled CO2 on the interaction between the global and regional water cycles in four study regions Experimental increases and reductions of light to streams: effects on periphyton and macroinvertebrate assemblages in a coniferous forest landscape The Ecological Future of the North American Bison: Conceiving Long-Term, Large-Scale Conservation of Wildlife Influence of repeated fertilization on forest ecosystems: relative habitat use by snowshoe hares (Lepus americanus) Uncertainty of 21st century growing stocks and GHG balance of forests in British Columbia, Canada resulting from potential climate change impacts on ecosystem processes [electronic resource] Trophic interactions, community organization, and the Kluane ecosystem Climate and snowpack monitoring progress report 2011: Arctic Network Is Alaska's Boreal Forest Now Crossing a Major Ecological Threshold? Rapid Cycling of Organic Nitrogen in Taiga Forest Ecosystems Evidence of Recent Treeline Dynamics in Southwest Yukon from Aerial Photographs Further cryostratigraphic observations in the CRREL permafrost tunnel, Fox, Alaska  Invasive Plant Management Guidance, McGrath, AK Further cryostratigraphic observations in the CRREL permafrost tunnel, Fox, Alaska Experimental increases and reductions of light to streams: effects on periphyton and macroinvertebrate assemblages in a coniferous forest landscape Rapid Cycling of Organic Nitrogen in Taiga Forest Ecosystems RELATIONSHIPS AMONG FIRES, FUNGI, AND SOIL DYNAMICS IN ALASKAN BOREAL FORESTS Governance of private protected areas in Canada: Advancing the public interest? Stand-level Attributes of Snowshoe Hare (Lepus americanus) Habitat in a Post-Fire Trembling Aspen (Populus tremuloides) Chronosequence in Central Yukon Trophic interactions, community organization, and the Kluane ecosystem Evidence of Recent Treeline Dynamics in Southwest Yukon from Aerial Photographs Climate and snowpack monitoring progress report 2011: Arctic Network Is Alaska's Boreal Forest Now Crossing a Major Ecological Threshold? Impact of doubled CO2 on the interaction between the global and regional water cycles in four study regions Influence of repeated fertilization on forest ecosystems: relative habitat use by snowshoe hares (Lepus americanus) Uncertainty of 21st century growing stocks and GHG balance of forests in British Columbia, Canada resulting from potential climate change impacts on ecosystem processes [electronic resource] The Ecological Future of the North American Bison: Conceiving Long-Term, Large-Scale Conservation of Wildlife Climate Change and Hazard Zonation in the Circum-Arctic Permafrost Regions The influence of coyote on Canada lynx populations assessed at two different spatial scales