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Full-Text Articles in Ecology and Evolutionary Biology
Short-Term Versus Long-Term Effects Of Nitrogen Addition And Warming On Ecosystem N Dynamics In A Grass-Dominated Temperate Old Field, Benjamin F. A. Souriol
Short-Term Versus Long-Term Effects Of Nitrogen Addition And Warming On Ecosystem N Dynamics In A Grass-Dominated Temperate Old Field, Benjamin F. A. Souriol
Electronic Thesis and Dissertation Repository
Increased atmospheric nitrogen (N) deposition and climate warming are both anticipated to influence the ecosystem N dynamics of northern temperate ecosystems substantially over the next century. Nevertheless, in field experiments with N addition and warming treatments, temporal scale can play an important role in determining the extent of treatment effects on N dynamics, and it is unclear to what extent the results of short-term studies can be extrapolated to responses over longer time scales. I compared the short-term versus long-term effects of N addition and warming on net N mineralization, N leaching, and N retention in a grass-dominated old field. …
From Individuals To Communities: The Effect Of Climate Change On Ectothermic Predators, Matthew Lawrence Meehan
From Individuals To Communities: The Effect Of Climate Change On Ectothermic Predators, Matthew Lawrence Meehan
Electronic Thesis and Dissertation Repository
The living components of ecological systems exist within a nested hierarchy, consisting of individuals, populations, and communities. Because of this nestedness, climate change can greatly impact ecological systems, as whole-organism metabolic and physiological demands change for ectotherms under warming, the effects of which may compound with every succeeding level. Therefore, a multi-level approach can better isolate how climate change will reshape ecological systems. In my doctoral research, I used feeding and mesocosm experiments to examine how climate change affects ectothermic predators at the individual-, population-, and community-level, using mesostigmatic mites (Arachnida: Parasitiformes) as my model predator. My research objectives were …
Carbon Cycling In Northern Fen Peatlands – Implications For Climate-Driven Changes Of Ecosystem Carbon Fluxes, Jing Tian
Electronic Thesis and Dissertation Repository
Northern peatlands are important long-term carbon (C) sinks with one-third of northern hemisphere soil organic carbon being stored there. Cool and wet environments at higher latitudes promote C accumulation in northern peatlands by limiting the C loss from decomposition. Northern latitudes are anticipated to experience disproportionately faster climate warming in the future, putting the vast C stores in northern peatlands at risk. There is a concern that northern peatlands are becoming net C sources and further accelerate climate warming. Using both laboratory and field experiments, this doctoral research aimed to explore the potential response of C cycling in northern peatlands …
Top-Down And Bottom-Up Effects On Collembola Communities In Soil Food Webs, Jordan Kustec
Top-Down And Bottom-Up Effects On Collembola Communities In Soil Food Webs, Jordan Kustec
Electronic Thesis and Dissertation Repository
Anthropogenic changes are causing shifts within soil food web communities, which may alter ecosystem processes such as nutrient cycling, carbon storage and decomposition. I quantified ecological stressor effects on the abundance, richness, community composition and body size of a soil-dwelling microarthropod (Collembola: Hexapoda). I quantified the effects of warming and nitrogen deposition in two separate field studies and demonstrated that warming shifts Collembola community structure and decreases community body size. I quantified the interactive effects of top-down and bottom-up forces mediated by warming as ecological stressors in Collembola communities. I found that bottom-up effects of nutrient addition did not affect …
Tree Seedling Establishment In Response To Warming And Nitrogen Addition In A Temperate Old Field, Bryana D. Mcwhirter
Tree Seedling Establishment In Response To Warming And Nitrogen Addition In A Temperate Old Field, Bryana D. Mcwhirter
Electronic Thesis and Dissertation Repository
Climate change and increased atmospheric nitrogen deposition over the next century may alter the ability of woody species to germinate and compete with grasses and forbs in temperate old fields. To investigate the responses of seed germination and seedling growth to warming and nitrogen addition, I transplanted seeds and seedlings into plots of a field experiment and conducted a greenhouse experiment. The combination of warming and nitrogen allowed seeds to germinate earlier, although there was no effect on final germination. In the greenhouse nitrogen increased seedling growth, and warming had little effect. However, in the field, warming significantly decreased the …