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Full-Text Articles in Life Sciences
Impacts Of Changing Permafrost Conditions On Vegetation Productivity In The Northern Boreal Forest, Emily Ogden
Impacts Of Changing Permafrost Conditions On Vegetation Productivity In The Northern Boreal Forest, Emily Ogden
Theses and Dissertations (Comprehensive)
Vegetation productivity across the boreal forest has increased over the past several decades. However, at a regional scale there is large variation from increased (greening) to decreased (browning) productivity and large areas with no measured change. Some of this variation can be explained by disturbances, such as wildfire, or by increased climate variability. In northern regions underlain by permafrost, the interactions between climate, disturbance, and vegetation productivity may be more complex. For my thesis, I used a time-series of ground thermal data from permafrost monitoring sites established by the Geological Survey of Canada along a latitudinal transect of the Northwest …
Factors Influencing Zooplankton Communities In Small Arctic Lakes, Northwest Territories, Jasmina Vucic
Factors Influencing Zooplankton Communities In Small Arctic Lakes, Northwest Territories, Jasmina Vucic
Theses and Dissertations (Comprehensive)
The Canadian Arctic has been warming at an unprecedented rate, causing significant changes to the environment. At the same time, continued development in the north has increased the demand for gravel extraction used to construct and maintain infrastructure such as highways. The development of roadways and gradual loss of permafrost in Canada’s north has led to changes in water quality, including increased calcium, conductivity, and nutrients. In addition, gravel extraction has led to the formation of artificial gravel pit lakes. Research has yet to determine how physical and chemical changes associated with development and permafrost thaw might impact zooplankton, and …
Dispersal As A Buffer Against Zooplankton Community Change In Response To Fluctuating Salinity Levels On The Great Plains, Mercedes Huynh
Dispersal As A Buffer Against Zooplankton Community Change In Response To Fluctuating Salinity Levels On The Great Plains, Mercedes Huynh
Theses and Dissertations (Comprehensive)
The North American Great Plains is home to thousands of closed-basin lakes that are sensitive to changes in hydrology. Climate change models predict increased aridity in this region over the coming century, which is expected to lead to higher salinity levels in many freshwater lakes. Increases in salinity levels may impact zooplankton communities, as laboratory experiments show that many freshwater species have a low tolerance for elevated salinity levels, and field data demonstrate that salinity is the primary factor structuring aquatic communities on the Great Plains. Changes to zooplankton communities could lead to a trophic cascade based on their important …
Growth Dynamics Of Black Spruce (Picea Mariana) Across Northwestern North America, Anastasia E. Sniderhan
Growth Dynamics Of Black Spruce (Picea Mariana) Across Northwestern North America, Anastasia E. Sniderhan
Theses and Dissertations (Comprehensive)
The impacts of climate change have been widely documented around the world. One of the most rapidly changing areas is the boreal forest of North America. The extent of change has been such that there have been shifts in long-standing climate-growth relationships in many boreal tree species; while the growth of many of these high-latitude forests were formerly limited by temperature, warming has increased the evapotranspirative demands such that there is widespread drought stress limiting productivity in the boreal forest. With the importance of the boreal forest as a global carbon sink, it is imperative to understand the extent of …
Drivers Of Post-Fire Vascular Plant Regeneration In The Conifer-Dominated Boreal Forest Of Southern Northwest Territories, Alison White
Drivers Of Post-Fire Vascular Plant Regeneration In The Conifer-Dominated Boreal Forest Of Southern Northwest Territories, Alison White
Theses and Dissertations (Comprehensive)
In recent years, climate warming has led to an increase in the severity and frequency of naturally occurring fires in boreal ecosystems globally. In 2014, an unprecedented 3.4 million hectares of boreal forest burned in the Northwest Territories (NWT). While much research has focused on post-fire succession of serotinous tree species such as Picea mariana (black spruce) and Pinus banksiana (jack pine), the understory community of vascular plants play an important role in ecosystem functioning but less is known about the response of this component of the system to changing fire regimes. Regeneration strategies such as the ability to resprout …
Implications Of Galling Herbivory On Ground Thaw In Canada’S Northern Boreal Forest, Allison Mcmanus
Implications Of Galling Herbivory On Ground Thaw In Canada’S Northern Boreal Forest, Allison Mcmanus
Theses and Dissertations (Comprehensive)
Canada’s northern boreal forest has faced significant climate warming over the past century. This change can have direct and indirect effects on forest dynamics, including altering the disturbance patterns of herbivores and changing the abundance of natural enemies. Warmer air temperatures can impact the distribution and survival of arthropods, both novel species and resident natural enemies. Gall-inducing mites are a resident natural enemy in high latitude forests and have been shown to drive dramatic reductions in gas-exchange rates in infested plants. Physiological reductions in plants can directly affect the shrub energy balance and underlying soil processes. This can have major …
Musical Chairs In A Boreal Peatland: How Permafrost Thaw Reverses Successional Processes, Mélissa M. Fafard
Musical Chairs In A Boreal Peatland: How Permafrost Thaw Reverses Successional Processes, Mélissa M. Fafard
Theses and Dissertations (Comprehensive)
The current climate trends indicate amplified high latitude warming. Boreal peatlands can be found within those high latitudes and have important functions hydrologically, ecologically and also in terms of carbon cycling. Peatland’s are wetlands that have accumulated more than 40 cm of peat and can range from minerotrophic fens to ombrotrophic bogs. Naturally, a rich fen can be converted to a bog once groundwater sources are cut off by Sphagnum spp. In areas underlain by discontinuous permafrost, landscape changes are occurring particularly rapidly as the permafrost there is sensitive to both vertical and horizontal thaw. The purpose of this thesis …