Effects of Nitrogen Addition Timing and Herbivory on Plant Diversity

Thumbnail Image
Date
2017-04-11
Authors
Bickley, Jordann
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Authors
Research Projects
Organizational Units
Journal Issue
Is Version Of
Versions
Series
Series
Symposium on Undergraduate Research and Creative Expression
Iowa State University Conferences and Symposia

The Symposium provides undergraduates from all academic disciplines with an opportunity to share their research with the university community and other guests through conference-style oral presentations. The Symposium represents part of a larger effort of Iowa State University to enhance, support, and celebrate undergraduate research activity.

Though coordinated by the University Honors Program, all undergraduate students are eligible and encouraged to participate in the Symposium. Undergraduates conducting research but not yet ready to present their work are encouraged to attend the Symposium to learn about the presentation process and students not currently involved in research are encouraged to attend the Symposium to learn about the broad range of undergraduate research activities that are taking place at ISU.

The first Symposium was held in April 2007. The 39 students who presented research and their mentors collectively represented all of ISU's Colleges: Agriculture and Life Sciences, Business, Design, Engineering, Human Sciences, Liberal Arts and Sciences, Veterinary Medicine, and the Graduate College. The event has grown to regularly include more than 100 students presenting on topics that span the broad range of disciplines studied at ISU.

Department
Ecology, Evolution and Organismal Biology
Abstract

Different factors such as nutrient addition or herbivore loss are known to decrease plant species richness in tallgrass prairies. However, little is known about how variation in timing affects these factors. For example, an intense, brief addition of nitrogen (N) could have a greater effect on species richness versus persistent, low levels of N addition because of the community’s prolonged exposure to N. Furthermore, herbivore activity may reverse the effects of N temporal variation by balancing out the differences. The purpose of this project was to determine if adding a set amount of N to soil over different timeframes would change species richness with herbivory. To accomplish this, we added a constant amount of N to pots containing six tallgrass prairie plant species, in different temporal regimes. Half received all of the N pulse in the beginning of the experiment, while the other half received the same amount in weekly doses over four weeks. We measured percentage cover before and after simulated herbivory. Final biomass was also collected at the end of the experiment by cutting plants at the soil surface. We expect that the addition of N in the absence of herbivory will decrease plant species richness when compared to the N treatment with herbivory. We also expect that quick, intense levels of N will cause species richness to decline faster compared to smaller, persistent levels of N. This research addresses factors that possibly alter plant diversity in tallgrass prairie ecosystems.

Comments
Description
Keywords
Citation
DOI
Source
Copyright