Life Sciences Commons^™

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 …

Investigations Of Substrate Reduction By Nitrogenase: Light Powered Substrate Reduction By A Cds:Femoco System And Understanding Dinitrogen Inhibition Of Electron Transfer, Hayden Kallas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogen fixation is a key step of the nitrogen cycle which makes biologically inert N₂ gas available for organisms to use in the form of ammonia. Nitrogen fixing microorganisms all contain the same enzyme called nitrogenase which catalyzes the six electron transfers to N₂ required for conversion into ammonia. Nitrogenase is a two-component enzyme that contains a cofactor composed of iron and sulfur as well as heavier metals whose identity can be molybdenum, vanadium, or an additional iron atom depending on the variant. The two components of nitrogenase are the MFe protein and the Fe protein. The Fe …

Nitrogen Use Efficiency And Soil Bioavailable Nitrogen In Corn Silage Production In A Semi-Arid Environment, Phearen Miller

Student Research Symposium

As agriculture intensifies, the world faces a dual challenge of increasing food production while reducing impacts of excess reactive nitrogen (N) in the environment. A field study examining different N sources in corn silage under semi-arid conditions was conducted at the Greenville farm in northern Utah (41°45’ N, 1111°48’52 W) since 2012. The experimental design is a randomized complete block design with four blocks and four treatments: control (no nitrogen), low ammonium sulfate (AS 112 kg N/ha), high ammonium sulfate (AS 224 kg N/ha), and steer manure compost (224 kg total N/ha). We examined yield, nitrogen use efficiency (NUE), and …