Phenology Trends and Climate Change in Minnesota
Seasonal events, for example flowering, fruiting, and the return of migrating birds, happen at particular times of the year. Some of these events happen in relation to climate, while others are dependent on other factors. Phenology is the study of these repeating events in the lifecycle of organisms. As the climate changes, the timing of some events may change in some species. This exercise will help students evaluate how climate change has already affected species in Minnesota.
The American elm (Ulmus americana) is a deciduous species, and its range includes most of the eastern United States and a bit of southeast Canada. This elm is a hardy species and can grow to a considerable size. It grows well in urban areas, so it is common in many cities. Unfortunately, the species is also susceptible to Dutch elm disease and the tree populations can suffer from massive die offs. All of these characteristics have led naturalists to be interested in this species, so we have lots of data about its phenophases (stages or events in its lifecycle).
In this module, students will practice answering a specific question about how climate change has affected flowering date in American elm trees. After students learn to manipulate the elm data set, build graphs, and analyze the data with a regression, they can then practice on a species of their own interest. Students can then share their species' information with the class for a larger discussion about what types of species may be affected by climate change.
Strengths of Module
Students with little experience with spreadsheets, data manipulation, and graphing find the module an accessible way to build confidence in these skills. It also allows them the chance to practice approximating trends and quantifying trends. Students practice quantitative skills and investigate the effects of climate change when they use figures they created.
What does success look like
Students should be able to:
- formulate an answerable question from a given data set
- demonstrate basic Excel skills (e.g. sort/filter, seek, graph)
- analyze phenological data to determine trends
- run a regression analysis between phenophase and temperature
- determine if, and if so, how, climate change has affected an organism of their choosing
Context for Use
This module is designed for an introductory-level course and can be used in majors or non-majors courses. The exercise assumes no prior knowledge of spreadsheet manipulation, work with large data sets, nor extensive climate change knowledge. The module was designed for an introductory course for biology majors that had covered the basics of climate change and reading figures. The students had not worked with any datasets and had not created any figures. We used the module to focus on the impact of climate change on biological systems.
The module is designed for one class period of 65 min with an additional take home assignment. The short pre-class homework assignment is meant to get students thinking about what phenology is, where the data come from, and what information is contained in the data sets. It also gives students a chance to manipulate spreadsheets at their own pace before working with them in class. If you are teaching a longer class period or lab, you could introduce the data set the same day and may not need the pre-class assignment (the worksheet can stand alone from the pre-class homework). If you are using the module for a shorter class period, an online course, or a hybrid course, you may need to use two class periods, one for Activities A and B, and the second class for reiteration of the results from the elm regression and then reporting and discussion from Activity C.
If your institution has a set of computers available for classroom use, you can use those to ensure all students have access to the same software editions. The exercise is functional for those students on a PC or Mac, and for those using Excel or Google Sheets.
Description and Teaching Materials
Why this Matters:
Students will build skills and confidence with spreadsheet manipulation, data analysis and quantitative thinking. The activities also demonstrate how long term data sets are important and can help us determine trends that result from climate change. A focus on species in the state of Minnesota will also highlight that the effects of climate change are visible locally, not only in far off locations.
Quick outline/overview of the activities in this module
- Pre-module work: Pre-homework may be assigned if class time is short (< 50-65 min). It introduces what phenology is, where the data come from, and what information is contained in the data sets. It also gives students practice with manipulating spreadsheets.
- Activity A: Determine changes in flowering date for American elm in Ramsey Co, MN
- Activity B: Determine significance of change in flowering date
- Activity C: Determine a phenophase ("event") pattern for a Minnesota organism of students' choice
A complete student handout containing the module components and guiding questions is available under Teaching Materials.
Activity A - Determine changes in flowering data for American elm in Ramsey Co
- Brief discussion of phenology, American elm, formation of answerable questions.
- Guided class activity to: use the data sheet, isolate data of interest, predict trends, determine trends, and create figures.
Activity B - Determine significance of changes in flowering date
- Determine if there is a dependent relationship between flowering date and temperature (run regression analysis).
- Determine how climate has affected the flowering date of American elm.
Activity C - Determine a phenophase (event) pattern for a Minnesota organism of your choice
- Identify an organism of interest in the database.
- Formulate a question that can be investigated given the available dataset.
- Identify and graph the phenophase of interest and the associated climate data.
- Determine the relationship between the phenophase and climate (run regression analysis).
- Share resulting figures with others and determine trends (or lack thereof).
- After comparison of trends, discuss what might limit an organism's ability to shift event (e.g. event based on light/dark hrs, temperatures, etc)
About the Data Sets:
The MN Phenological Network (https://mnpn.usanpn.org/home) downloadable data set is used with permission from the Minnesota Phenology Network (MNPN, 2020) and was available upon request. The full data set is available in the module. I thank the MNPN for supplying the data and the volunteer participants who gather data for the project.
The DNR website for historical observations from specific locations is: https://arcgis.dnr.state.mn.us/ewr/climatetrends/. Data for American elm and January temperatures (data for Activity A and B) is available in the module.
- Instructor's Manual: Phenology in MN Instructor notes.docx (Microsoft Word 2007 (.docx) 801kB Jun22 21) Phenology in MN Instructor notes.pdf (Acrobat (PDF) 554kB Jun22 21)
- Instructor's PowerPoint: Phenology in MN slides.pptx (PowerPoint 2007 (.pptx) 2.5MB Jun19 21)
- Student Pre-homework handout: Phenology Trends pre homework.docx (Microsoft Word 2007 (.docx) 29kB Jun19 21)Phenology Trends pre homework.pdf (Acrobat (PDF) 199kB Jun19 21)
- Student Handout: Phenology Trends class activity and homework - student handout.docx (Microsoft Word 2007 (.docx) 62kB Jun22 21)Phenology Trends class activity - student handout.pdf (Acrobat (PDF) 331kB Jun22 21)
- Datasets: MNPN master dataset 2018.xlsx (Excel 2007 (.xlsx) 3.1MB Jun22 21) and Am elm data for off-line work.xlsx (Excel 2007 (.xlsx) 27kB Jun19 21)
Teaching Notes and Tips
Workflow of this module:
- Assign the pre-class homework (if appropriate).
- Give students their handout when they arrive to class.
- Instructor gives brief PowerPoint presentation with background material. Discussion of the pre-homework can be integrated into this presentation.
- Students work through Activity A.
- Instructor gives a primer on regression and students work on Activity B
- Students choose a phenophase and work toward running a regression with their new data.
- Students report to the class their chosen phenophase results for a larger discussion about trends in phenophases due to climate change.
Notes on the student handout:
The handout may appear long and intimidating to students, but the process is laid out step by step and asks students to repeat/practice certain skills (e.g. building a figure). The handout is a bit dense because it has language for PC and Mac users as well as Excel and Google Sheet users, but it should be accessible to all.
Potential pre-class readings:
If you would like your students to have some additional perspective before the full activity, you could have them read Phenological changes reflect climate change in Wisconsin (Bradley et al., 1999). The paper uses a large data set from Wisconsin to investigate the relationship between phenophase changes and climate change. If you skip this reading it is fine, your students might then be more surprised by their own results.
As an extension to activity A, ask students to predict and describe the temperature data for the last 30 years (e.g. 1991-2021). Students can discuss their predictions with peers and then retrieve the data from the DNR website. After students plot the temperature trend, they can discuss the difference, if any, from their prediction and from the 1941-1991 trend. Students can also discuss the limitations of extrapolation, and predict if and how the flowering date may be affected.
Measures of Student Success
How do students self-assess?
Students can recognize their progress if they can:
- ask a question they can answer with the given data bases
- successfully locate and manipulate data in the data bases
- graph data and complete the figures
- run the regression analysis and articulate a decision about significance of the trend (if appropriate)
How do teachers assess?
Activity A: Students manipulate data in Excel to create a figure of American elm data, and then determine a trend in the flowering date.
Activity B: Students determine if there is a dependent relationship between flowering date and temperature.
Activity C: Students identify an answerable question, graph the appropriate data, test the relationship, and make a conclusion about their phenophase and climate effects.
References and Resources
Minnesota Department of Natural Resources (DNR). 2020. Minnesota Climate Trends. Accessed [7.10.2020]. Available: https://arcgis.dnr.state.mn.us/ewr/climatetrends/ .
Minnesota Phenology Network (MNPN). 2020. Datasets. Accessed: [7.10.2020]. Available: http://mnpn.usanpn.org.