Life Sciences Commons^™

Nutrient Uptake And Water Quality In Great Salt Lake Wetland Impoundments, Rachel L. Buck

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Great Salt Lake (GSL) is the largest inland body of water on the Pacific flyway, a major pathway for migratory birds in the Americas that extends from Alaska to Patagonia. The lake is surrounded by approximately 360,000 acres of wetlands, providing critical food, shelter, cover, nesting areas, and protection to between 4–6 million birds that visit each year. Impounded wetlands were created as part of the GSL ecosystem to support waterfowl habitat. These large, shallow, submergent wetlands are diked to control water levels to sustain aquatic plants which are an important food source. Besides providing critical habitat, these impoundments …

Climate-Driven Impacts Of Warming And Grazing On Sub-Arctic Coastal Wetlands In Alaska, Ryan T. Choi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate change is rapidly warming the Arctic, especially at lower latitudes. Warmer temperatures and earlier springs are altering the timing of plants and animals, especially for long-distance migratory herbivores. Changes in the timing of both plants and herbivores have the potential to impact plant productivity and nutrient cycling, while also altering plant community diversity and composition.

In chapter 2, I conducted a field experiment to investigate how earlier growing seasons and differences in arrival times of migratory geese influence physical traits of sedge forage species. I found that both an earlier growing season and late grazing by geese had similar …

The Fate And Cycling Of Nitrogen, Phosphorous, And Trace Heavy Metals In Beaver-Altered Headwater Streams, Desneiges S. Murray

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Human land-use can increase the amount of non-point source (NPS) pollution in a stream, negatively affecting ecosystem health and beneficial services provided by an ecosystem. Unfortunately, NPS pollution remains high in many waterbodies. Beaver dams may be a passive, cost-effective strategy for removing NPS pollution in headwater streams because beaver dams slow stream flow and collect sediments. Impounded sediments can change how nutrients and pollutants are cycled in a stream through multiple pathways. In the first part of our study, we investigated whether beaver activity can reduce nitrogen, phosphorous and heavy metals from otherwise traveling downstream. Results suggest beaver ponds …

Forest Recovery, Nutrient Cycling And Carbon Sequestration In A Southern Appalachian Spruce-Fir Forest, Patrick T. Moore

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Our forests provide us with a variety of services from clean water, forest products and wildlife habitat to the lesser known functions of nutrient cycling and carbon
sequestration. This research helps to demonstrate the extent of some of these services in a heavily disturbed southern Appalachian spruce-fir forest within Great Smoky Mountain National Park, the most heavily visited National Park in the United States. Following a catastrophic infestation of the non-native balsam wooly adelgid, the future of this forest was unknown, causing some to speculate about the future of this sensitive forest type. Though predictions about this forest’s future varied …

15n Tracer And Modeling Analyses Of Nutrient Transport Through Lakes In A Subalpine Watershed, David M. Epstein

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lakes have historically been overlooked as important nutrient processors within their watersheds. In general ecologists have focused on streams as zones of uptake and transformation, while viewing lakes as simple nutrient traps. However, recent research has highlighted the large influence that lakes may have on water chemistry within their watersheds. Within the field of limnology, researchers have traditionally focused on the pelagic zone for in-lake production. Further research in shallow lakes has highlighted the role benthic production within the littoral zone plays in the lake ecosystem. The greater influence of lakes is highlighted when comparing watersheds containing lakes with watersheds …

Native Bunchgrass And Invasive Weed Establishment In Low Nutrient Rangeland Soils With Nitrogen And Phosphorus Manipulation, Jeffrey S. Burnham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Competition between native perennial grasses and Bromus tectorum has been studied for many years. Recently, soil nutrients have been immobilized in an effort to preferentially inhibit growth of B. tectorum relative to native species. Most of this work has focused on soil N, but interactions with soil P are less studied and may be important as well. Additionally, although competitive effects and nutrient responses of several Centaurea spp. are well documented, data are lacking on the competitive effects that Centaurea virgata exerts on the establishment of native and exotic communities. A field experiment and a greenhouse experiment were conducted to …

The Role Of Brown Bears (Ursus Arctos) In Nutrient Transport Into Forests Near A Salmon Stream In Coastal British Columbia, Canada, Arthur Morris

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nutrients from spawned salmon contribute to the fertility of rivers and riparian areas. Adjacent forests, even far from rivers, could receive substantial amounts of nitrogen and other nutrients from salmon. Since brown bears feed heavily on spawning salmon, bears probably influence the movement of nutrients from salmon into surrounding forests. Because salmon-derived nitrogen is high in ¹⁵N, increased isotopic enrichment is expected in forest soils and vegetation if this transport is occurring. Based on relative ¹⁵N enrichment of spawning areas, a quantitative estimate of marine-derived nitrogen (MDN) can be obtained using a linear two-source mixing model. To evaluate …