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 …

Nutrient Enrichment Increases Invertebrate Herbivory And Pathogen Damage In Grasslands, Anne Ebeling, Alex T. Strauss, Peter B. Adler, Carlos A. Arnillas, Isabel C. Barrio, Lori A. Biederman, Elizabeth T. Borer, Miguel N. Bugalho, Maria C. Caldeira, Marc W. Cadotte, Pedro Daleo, Nico Eisenhauer, Anu Eskelinen, Philip A. Fay, Jennifer Firn, Pamela Graff, Nicole Hagenah, Sylvia Haider, Kimberly J. Komatsu, Rebecca L. Mcculley, Charles E. Mitchell, Joslin L. Moore, Jesus Pascual, Pablo L. Peri, Sally A. Power, Suzanne M. Prober, Anita C. Risch, Christiane Roscher, Mahesh Sankaran, Eric W. Seabloom, Holger Schielzeth, Martin Schütz, Karina L. Speziale, Michelle Tedder, Risto Virtanen, Dana M. Blumenthal

Wildland Resources Faculty Publications

1. Plant damage by invertebrate herbivores and pathogens influences the dynamics of grassland ecosystems, but anthropogenic changes in nitrogen and phosphorus availability can modify these relationships.
2. Using a globally distributed experiment, we describe leaf damage on 153 plant taxa from 27 grasslands worldwide, under ambient conditions and with experimentally elevated nitrogen and phosphorus.
3. Invertebrate damage significantly increased with nitrogen addition, especially in grasses and non-leguminous forbs. Pathogen damage increased with nitrogen in grasses and legumes but not forbs. Effects of phosphorus were generally weaker. Damage was higher in grasslands with more precipitation, but climatic conditions did not change effects of nutrients …

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 …

Stoichiometric And Stable Isotope Ratios Of Wild Lizards In An Urban Landscape Vary With Reproduction, Physiology, Space And Time, Andrew M. Durso, Geoffrey David Smith, Spencer B. Hudson, Susannah S. French

Ecology Center Publications

Spatial and temporal variation in stoichiometric and stable isotope ratios of animals contains ecological information that we are just beginning to understand. In both field and lab studies, stoichiometric or isotopic ratios are related to physiological mechanisms underlying nutrition or stress. Conservation and ecosystem ecology may be informed by isotopic data that can be rapidly and non-lethally collected from wild animals, especially where human activity leaves an isotopic signature (e.g. via introduction of chemical fertilizers, ornamental or other non-native plants or organic detritus). We examined spatial and temporal variation in stoichiometric and stable isotope ratios of the toes of Uta …

Early Goose Arrival Increases Soil Nitrogen Availability More Than An Advancing Spring In Coastal Western Alaska, Ryan T. Choi, Karen H. Beard, Katharine C. Kelsey, A. Joshua Leffler, Joel A. Schmutz, Jeffrey M. Welker

Ecology Center Publications

An understudied aspect of climate change-induced phenological mismatch is its effect on ecosystem functioning, such as nitrogen (N) cycling. Migratory herbivore arrival time may alter N inputs and plant–herbivore feedbacks, whereas earlier springs are predicted to increase N cycling rates through warmer temperatures. However, the relative importance of these shifts in timing and how they interact to affect N cycling are largely unknown. We conducted a 3-year factorial experiment in coastal western Alaska that simulated different timings of Pacific black brant (Branta bernicla nigricans) arrival (3 weeks early, typical, 3 weeks late, or no-grazing) and the growing season …

Plant Community Responses To Stand‐Level Nutrient Fertilization In A Secondary Tropical Dry Forest, Bonnie G. Waring, Daniel Pérez-Aviles, Jessica G. Murray, Jennifer S. Powers

Ecology Center Publications

The size of the terrestrial carbon (C) sink is mediated by the availability of nutrients that limit plant growth. However, nutrient controls on primary productivity are poorly understood in the geographically extensive yet understudied tropical dry forest biome. To examine how nutrients influence above‐ and belowground biomass production in a secondary, seasonally dry tropical forest, we conducted a replicated, fully factorial nitrogen (N) and phosphorus (P) fertilization experiment at the stand scale in Guanacaste, Costa Rica. The production of leaves, wood, and fine roots was monitored through time; root colonization by mycorrhizal fungi and the abundance of N‐fixing root nodules …

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 …

Nonnative Phragmites Australis Invasion Into Utah Wetlands, Andrew Kulmatiski, Karen H. Beard, Laura A. Meyerson, Jacob R. Gibson, Karen E. Mock

Wildland Resources Faculty Publications

Phragmites australis (Cav.) Trin. ex Steud. (common reed), already one of the world’s most widespread plant species, has realized rapid range expansion in coastal wetlands of North America in the past century, but little is known about P. australis range expansion in inland wetland systems. We used genetic analyses, aerial photographs, field surveys, and a greenhouse experiment to study the extent and mechanism of nonnative P. australis invasion of Utah wetlands. We collected and genetically analyzed 39 herbarium samples across the state and 225 present-day samples from northern Utah’s major wetland complexes. All samples collected before 1993 and all samples …

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 …