The Effects of Competition for Water and Light on the Establishment of Prairie Wildflower Seedlings Project Description Background: Ecological restoration is the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed (SER, 2004). Less than 2% of unplowed tallgrass prairies remain in Nebraska, (Samson et al. 2004), and the loss of prairie habitat has caused a loss of plant diversity. The tallgrass prairie plant ecosystem can be broken into two main plant categories; grasses and wildflowers. Wildflower species are far more diverse than grass species, thus the overall diversity of the prairie relies heavily on wildflower establishment. As land managers seek to restore lost plant diversity, one of the main challenges is successful establishment of newly planted wildflower seeds. There are three main resources that control plant growth; light, nutrients, and water. It is unknown what resource is the most important for initial seed growth and establishment in native tall grass prairies. Unfortunately the budget is a significant hindrance when attempting to assist the recovery of a degraded ecosystem. Native prairie seeds can be difficult and quite expensive to obtain in large quantities. The lack of availability is primarily driven by the lack of habitat to collect seeds from, which in turn drives the prices up. Therefore it is important that a restoration can obtain high levels of seedling establishment in the early stages of planting. I predict that light is the main factor for initial sprouting of the seedlings but water will be the main factor in their survival. Studies have shown that there is higher wildflower presence with a seed mix containing lower grass density (Dickson & Busby 2009). This would imply there is a high level of competition between grasses and wildflowers for establishment. Current research suggests mowing the taller vegetation will increases the light hitting the soil and is most likely the main factor in wildflower emergence and survival (Williams et al 2007). Typically prairies are densely packed with several different species of grasses and wildflowers. When new seedlings attempt to emerge in an already flourishing prairie they can be completely shaded from the sun. One of the main prairie grasses, Big Bluestem, can grow as tall as seven feet. This would lead you to suggest light is the main factor determining seedling germination. However, Abbott and Roundy (2003) found that in certain plant species germination was widely variable and highly dependent on water availability. Sheley and Half (2006) also discovered that increasing water frequency increased their wildflower establishment. There are conflicting results between several studies, but most have yet to look at the effects of water and light at the same time exclusively. Significance: I will look at water and light availability and their contributions to seedling establishment and survival within a tallgrass prairie community. This study will attempt to narrow down the mechanisms that control prairie wildflower seedling establishment and survival. Wildflowers are the most important factor in determining pollinator (bees, butterflies, etc.) abundance (Gilgert and Vaughan 2011). Pollinators are crucial to maintaining a healthy and functioning ecosystem. This information would also be critical for land managers attempting to restore tallgrass prairie habitat. This study will also be an excellent learning experience for me as I prepare to complete my bachelor s degree and plan to further my education at the master s level.
Methodology: Ten wildflower species native to Nebraska have been chosen for this experiment. All have very specific and easily identifiable characteristics. I have been given permission to conduct my research at the Glacier Creek Preserve from Dr. Tom Bragg, the Preserves Director. I will set up research plots in a factorial design of irrigation (irrigation / no irrigation), mowing (mowing / no mowing), and tying back vegetation (tie back / no tie back) (Table 1). Each of these treatments will be replicated 5 times for a total of 30 plots. The plots will measure approximately 50 cm by 50 cm. I will also set up test plantings to place in the UNO greenhouse as a control to test seedling germination rates to compare to field results. I will look at the difference in seedling germination rates as well as survival rates under a variety of treatments. Treatments Mow Tie Back Vegetation Control (No mow/ tieback) Irrigation 5 Plots 5 Plots 5 Plots No Irrigation 5 Plots 5 Plots 5 Plots Table 1: A brief outline of the treatment variables and number of plots associated with the treatments. (Ex: 5 plots will be mowed and irrigated; 5 plots will be mowed and not irrigated, etc.) Mowing the plots will increase the amount of light hitting the soil, but may alter the nutrient uptake by established vegetation. Tying back vegetation will allow for more light to hit the soil while not altering the nutrient uptake of established vegetation. The tie backs will be constructed for the study using stakes and mesh netting. Water will be added to the irrigated plots if there has been less than an inch of rainfall within three days. In the highly unlikely event we have a very wet summer I will only be able to look at the difference in mowing, tieback, and control treatments without the effects of irrigation. I will count the seedlings, measure growth, and percent coverage for each species on a weekly basis. The study will go through the entire summer (May-Sept) to allow sufficient time for seedlings to sprout. Some seedlings tend to sprout later in the year so this would ensure I do not miss out on crucial data by cutting the study short. Project Timeline: Spring 2015 Measure out seedlings to be planted in each plot. Set up plots and plant seedlings. Set up test batch of seedlings for greenhouse germination tests. Summer 2015 Measure seedling growth, count, and percent coverage at least once a week. Add water to necessary plots whenever rainfall is not sufficient. Fall 2015 Analyze data and write scientific paper to be submitted to peer review undergraduate journals for publishing. Spring 2016 Present results at the 2016 Student Research and Creative Activity Fair Table 2: A timeline of events that will be occurring throughout the study. Roles of Student and Mentor Dr. Timothy Dickson will be my mentor for this project. I will perform all the experimental set up, data collection and data analysis with his guidance. I will commit a minimum of 200 hours to this project between field and lab work. I will be sharing my results with Dr. Dickson and other members of his lab throughout my project. I will also present the results of the project in a final scientific paper and submit it to various undergraduate journals for it to be published.
Budget Justification Budget Item Cost Seeds $200 Planting Materials / Misc. Materials $300 Stipend $2000 Total: $2500 Half of the required seeds are being provided by Dr. Tom Bragg and the Glacier Creek Preserve. The other half will be purchased from local seed suppliers. The planting materials include: Hand trimmer to mow the plot areas, Water jugs to carry to plots, soil / containers for greenhouse germination tests, and materials to build the plant tie back mechanisms. The stipend is figured by: (200 hours of work * $10/hr = $2000)
References: Abbott, L.B., and B.A. Roundy. 2003. Available water influences field germination and recruitment of seeded grasses. Journal of Range Management 56:56-64 Dickson, T.L., and W.H. Busby. 2009. Forb species establishment increases with decreased grass seeding density and with increased forb seeding density in a northeast Kansas, U.S.A., experimental prairie restoration. Restoration Ecology 17:597-605 Gilgert, W., and M. Vaughan. 2011. The value of pollinators and pollinator habitat to rangelands: Connections among pollinators, insects, plant communities, fish, and wildlife. Rangelands 33:14-19 Samson, F.B., F.L. Knopf, and W.R. Ostlie. 2004. Great Plains ecosystems: past, present, and future. Wildlife Society Bulletin 32:6 15 Sheley, R.L., and M.L. Half. 2006. Enhancing native forb establishment and persistence using a rich seed mixture. Restoration Ecology 14:627-635 Society for Ecological Restoration, Science & Police Working Group, SER International Primer on Ecological Restoration (2004) Accessed on January 7, 2015. http://www.ser.org/resources/resourcesdetail-view/ser-international-primer-on-ecological-restoration Williams, D.W., L.L. Jackson, and D.D. Smith. 2007. Effects of frequent mowing on survival and persistence of forbs seeded into a species-poor grassland. Restoration Ecology 15:24-33.
BIOLOGY DEPARTMENT February 16, 2015 To the Reviewers of Geoff Coughlin s FUSE Grant, I am enthusiastic to collaborate with Geoff Coughlin on his research examining the effects of light and water competition on prairie wildflower establishment. Geoff worked for me last summer as an undergraduate research assistant and he gained skills in plant identification and experimental design. During the summer Geoff expressed his interest in performing independent research and we worked to develop a research project during the summer and fall. The idea for his FUSE project builds upon published research that I have completed on factors affecting wildflower establishment, but Geoff s project would be the first to experimentally separate the effects of competition for light and water on wildflower establishment. Geoff has read through primary literature and refined the ideas. We have worked on the hypotheses and the experimental design together, but he wrote the proposal on his own with minor editing as my contribution. Geoff has also secured permission to perform the research at UNO s Glacier Creek Preserve (formerly Allwine Prairie) and to utilize their irrigation equipment. Geoff will work independently with assistance from me as needed. He will be the person in charge of data collection and analysis, and I will teach him methods and approaches to use. I anticipate that we will be able to publish the data and he would be the first author on the publication. Sincerely, Timothy L. Dickson, Ph.D. Assistant Professor tdickson@unomaha.edu http://grasslandecology.com/ 6001 Dodge Street Omaha, NE 68182 (402) 554.2800 www.unomaha.edu