Project ideas

Native seeds for prairie restoration. Most prairie restorations use seeds that ripen late in the season. Species that flower earlier are often more difficult to collect, but important for the prairie. For this project we want you to identify & characterize source populations for collecting seed of several early flowering native species. Then try one or several methods of hand collecting the seed when ripe. We are interested in two related questions: 1) Does density of flowering plants influence seed collection efficiency? and 2) Does density of flowering plants influence seed quality? This project will help us collect seed for our experimental research plots and the MN DNR will use the information (and seed) for their restoration efforts.

Hybrid Echinacea plants in native prairie. In western Minnesota, prairie restorations with the non-native Echinacea pallida have been planted near prairie remnants with the native Echinacea angustifolia. These two species are able to hybridize and this new restoration could threaten the native Echinacea by genetic swamping. We have three experimental plots with hybrids and non-hybrids planted in 2012, 2013 & 2014. We want you to measure these plants to look at differences in survival, growth, and any other trait that you can think of. We want to know how vigorous the hybrids are compared to the pure species. This work will build nicely on the projects of previous researchers. For example, the cohort planted in 2013 was germinated and measured by Jill Pastick for her spring semester internship then measured and analyzed by Marie Schaedel during the summer for her REU project. For more information, review the flog, especially post in the hybrid category.

Plant community diversity in remnant prairies. The Echinacea project has identified 27 remnant populations of Echinacea angustifolia, which we census annually. We have never surveyed plant diversity at these sites, even though we know that other plants in the community influence Echinacea directly via competition and indirectly via pollinators and other insects. For this project we would like you to design a sampling scheme for assessing plant species richness, take photos of plants, develop an online identification guide, and investigate the relationship between remnant size and plant diversity. We anticipate that this project will serve as the basis for future investigations of floral resources for pollinators. To this end, we want you to investigate techniques for assessing density of flowers using digital imagery.

A specialist aphid and Echinacea fitness. The most prevalent herbivore on Echinacea is a species of aphid that feeds exclusively on Echinacea. Theory predicts that specialist aphids have less detrimental effects on host than generalist aphids. Specialist aphids may not affect, or may even improve, host fitness. Katherine Muller set up an aphid addition and exclusion experiment in 2012 and treatments have been applied to the same plant annually since then. This summer we want you to assess fitness of the plants in the experiment and apply treatments. So far aphid effect have been subtle, but after the burn this spring we may have a much better opportunity to see how consistent aphid herbivory over the past three summers affects flowering this summer. This project will help us learn long-term effects of this aphid on Echinacea performance and will contribute generally to the understanding of specialist herbivores on hosts.

Echinacea plant survival after a spring burn. We been investigating fire & reproduction in Echinacea for a while. We have clear evidence that prescribed spring burns promote summer flowering in Echinacea plants.  For example, in summer 2014 at Staffanson Prairie Preserve (SPP) 76% of plants flowered in the East Unit, which burned in spring 2014, compared to only 23% in the West Unit, which last burned in 2012. We have less information about survival after fires. We want you to visit several hundred plants that were alive in SPP last year and see if they survived the winter. This information will help us gain a better understanding of effects of fire on the entire life-cycle of Echinacea.

Invasive species in prairie restorations. We want to eliminate or control several non-native species that persist in our experimental plots: birdsfoot trefoil (Lotus corniculatus), orange hawkweed (Hieracium aurantiacum), and reed canary grass (Phalaris arundinacea). For this summer project you would design an experiment with one or two feasible management treatments, apply the treatments, and assess effectiveness at the end of the season. In summer 2014, several team members made an initial foray into removing hawkweed. You could assess hawkeed in that experiment and use results to design another experiment. This project will help us better control invasive species in our experimental plots.

Pollen longevity. How long does Echinacea pollen survive? How much can refrigerating or freezing pollen prolong its survival? Answering these questions will contribute to a better understanding of pollination in natural conditions. In summer 2014 Will Reed began developing techniques to increase longevity. Being able to store live pollen will enable use to design clever crossing experiments to assess mating potential and to quantify quantitative genetic variation in traits such as fitness.

The costs of reproduction. We started an experiment to investigate the costs of reproduction on future fitness. 18 plants that flowered in 2012 were assigned at random to either a pollen exclusion or addition treatment. Treatments were applied regularly throughout the season. We expect that plants with added pollen expended more energy to produce seed than those with no pollen.  This energy expenditure may compromise future fitness by increasing mortality or reducing plant size or reproductive effort. We have annually applied the pollen treatments and we added 20 more plants in 2013. For this project you would measure fitness in the plants, apply the pollen treatments and, depending on how many plants flower this year, select more plants to add to the experiment. You would learn statistics and pollination techniques and make a contribution to understanding costs of reproduction. We are very curious to get some results.

SI or Style persistence in the Asteraceae. Many plants in fragmented prairie habitat experience reproductive failure. Self-incompatibility (SI) is the plant trait that is most consistently associated with reproductive susceptibility to habitat fragmentation. For this project you could assess susceptibility to habitat fragmentation in plants in the aster family using the style persistence method. Such experiments will involve pollen exclusion and pollen supplementation treatments. Investigating style persistence would really build on Lee Rodman’s work from 2011 and Karen‘s thesis work on Helianthus. Additionally, we really don’t know how many or which prairie plants are self-compatible or self-incompatible. We want to know! Worldwide, it is estimated that about 60% of plant species have some kind of SI system. The tallgrass prairie is one of the most fragmented habitats in the world, but the proportion of prairie plants with SI is unknown.A plan for sampling species could build on Megan’s project.

Mating incompatibility in remnant Echinacea populations. Rates of mating compatibility vary among remnants and depend on distances between pairs of potential mates (Wagenius et al 2007). It would be a great project to investigate mating compatibility within a remnant population. Simultaneously investigating pair-wise mating compatibility and pair-wise flowering asynchrony would be very cool.

Reproduction in fragmented purple prairie clover populations. Seed set is an important measure of a plant’s reproductive fitness and may affect persistence of fragmented plant populations. Dalea purpurea (purple prairie clover) is a perennial plant common to many prairie remnants, yet little is known about the status of these populations. In 2013, we collected Dalea seeds from 6 remnant populations of various sizes and assessed seed set and germination rates. We found that remnant size and population size did not predict seed set, therefore we seek to identify causes of reproductive failure. We would like to revisit these Dalea plants and systematically map neighboring flowering plants to test if proximity to potential mates influences seed set. This project could also include tracking Dalea seedlings from these remnant populations as well as exploring factors, such as pollinator visitation, that could also affect plant fitness.

Flowering phenology in remnant Echinacea populations. Asynchronous flowering between two remnants likely decreases geneflow between them. Asynchronous flowering within remnants likely reduces seed set. Quantifying phenology in several remnants would be a great project. This project would build on the work of Amber Z, Kelly K, Sarah B, and Alli G from 2011 – 2014. Read their flog entries (Amber’s, Kelly’s, Sarah’s), and be sure to check out Amber Z’s senior thesis.

Other projects

Seed dryer. We should build a seed dryer for drying Echinacea heads this fall.

Pole calibrator. We should build a station for calibrating the bubble levels on our survey poles.

Photo gallery. We need to develop a way to share research photos, showcase our activities, and document methods. There must be some plugin or app that works well with WordPress.

Video documentation of protocol. There are many protocols that we should document with videos. We need to take some videos and start sharing them on youTube.

Tagging heads. Every head in our experimental plot needs a unique id. These ids are used for data collection in the field, harvesting heads, inventorying at CBG, and collecting data in the lab. We now rely on twist-tie colors and unique plant locations to identify heads. It could be better to use bar code or RFID tags that can be read automatically by a device instead of a person. A good system would increase our efficiency and accuracy. We need help evaluating systems for trials and then developing a protocol to use high-tech tags in the field and lab.

Camera stand and fine-scale mapping. We need help developing an automated digital imaging method to map Echinacea seedlings. A new camera stand was being built for us, but it could use some improvements. Also, someone needs to perfect a method for using it.

Potential longer-term projects

Are bee communities changing over time? Do native bee communities differ among prairie remnants?

How can we use low-level (bee’s eye) aerial photography to quatify floral resources in roadside and other prairie remnants? There is great need for techniques to rapidly assess habitat quality for bees (especially floral resources and nesting locations. Aerial photography has great potential, but several critical obstacles. Challenges include getting images (boom on vehicle or drone), managing data, image analysis & interpretation.

Does porcupine grass fitness differ among prairie remnants? Quantify fitness of Hesperostipa (formerly Stipa) plants in ExPt1.

Is reproduction in dominant prairie grasses pollen-limited? Big bluestem, Indian grass, Side-oats grama, and prairie dropseed. Theory predicts no, but what’s really happening?

What cues flowering in Echinacea? Echinacea plants are more likely to flower after a spring or fall burn. It would be interesting to try a smoke treatment to test the hypothesis that chemicals in smoke cue flowering.

Movement of grass diaspores with hygroscopic awns. Several important prairie grasses (porcupine grass, big bluestem, little bluestem, indian grass, among others) have awns that move as humidity changes. This movement presumably helps seeds move through grass litter and duff to plant themselves in the soil. It would be a great study to quantify motility, assess individual variation in motility, and determine the fitness value of motility. Read about Hesperostipa (formerly Stipa) on the flog watch this video. Josh’s presentation has links to more videos.

Pollen-limitation and resource allocation. Hypothesis: Well pollinated plants will have reduced growth & reproduction compared to poorly pollinated plants. Read Dudash & Fenster 1997.

Functional leaf traits. Are functional leaf traits such as photosynthetic rates, water use efficiency, %C, and %N consistent from one year to the next in individual Echinacea plants? In summer 2013 Pamela Kittelson measured these traits in the inbreeding experiments, inb1 & inb2, and found differences between inbred plants and others. These traits are directly related to resource uptake, and can influence growth, survival and reproduction. It would be very interesting to find out how consistent they are from year to year and to quantify their heritability!

Does reproductive success differ among remnants or with isolation in species other than Echinacea? You could add another species to a common garden experimental plot! Plant species to consider: Coreopsis palmata, Liatris aspera, Solidago spp., Amorpha canescens, Dalea purpurea, Viola pedatifida, Asclepias spp.

Projects for another summer

Plant-herbivore interactions with hybrid Echinacea plants in native prairie. Hybrid Echinacea plants may not support as diverse an assemblage of insect herbivores as native plants. For instance, the native plant hosts a specialist aphid, Aphis echinaceae that cannot survive on E. pallida. It is unknown how well these aphids survive on hybrid plants. For this project you will collect and transfer aphids to native, non-native, and hybrid plants then measure aphid survival and reproduction. You will also measure performance of the plants to investigate the potential for aphids to affect plant fitness.

Tops and bottoms. Seed set is lower in tops of Echinacea heads compared to bottoms (Ison & Wagenius, in press). Why? Timing and nearby neighbors play a role, But what about the styles? Do longevity and receptivity of styles differ between bottoms (early) and tops (late) of Echinacea heads.

Ants and aphids on Echinacea. Katherine outlined several ideas for projects related to the aphids that specialize on Echinacea angustifolia and the ants that tend them. These projects build directly on Katherine thesis work: 1) continue the aphid addition & exclusion treatment to look at long-term effects of aphids on plant performance, 2) transfer aphids to inbred and non-inbred Echinacea plants and assess their fitness, 3) determine if aphids can survive on E. angustifolia x E. pallida hybrids plants (see below), 4) compare aphid phenology in burned and unburned units of Staffanson Prairie Preserve and relate it to plant phenology, and 5) look at population genetic structure of the aphid using molecular markers to gauge how much aphids might disperse among remnants (a nice sample of aphids is already in the freezer).

Pollinator efficiency. About 30 species of bees regularly visit Echinacea angustifolia to collect pollen and perhaps nectar. How good are they at pollinating? Katie Koch, Andrew Kaul, and Kory Kolis quantified pollination efficiency of some common visitors in 2010, 2012 & 2013. It would be great to build on their work. See their posters: Katie’s, Andrew’s, and Kory’s. Stay tuned for more updates on this project!

This is not an exhaustive list! Make sure to read the general background reading for this summer.