Standard 7: "The physical processes that shape the patterns of Earth's surface"
Standard 8: "The characteristics and spatial distribution of ecosystems on Earth's surface"
Standard 16: "The changes that occur in the meaning, use, distribution, and importance of resources"
Each type of
prairie community has distinguishing characteristics. For example, the most common plants in each community are indicators, or markers, for that community.
Ask students how they would define "climate" and "microclimate," and discuss the differences between them. Explain that climate refers to all weather conditions for a given location over a period of time while microclimate refers to climatic conditions in a relatively small area, such as their schoolyard.
Tell students that they will be studying the characteristics of the microclimate in their schoolyard and comparing it to different types of prairie climates.
Provide students with the information about different types of prairie habitats below. If time permits, have them briefly research different prairie habitat characteristics on their own, too, at the following Web sites:
National Geographic: Geography Action! 2003—Habitats (Prairies)
Missouri Botanical Gardens: Grasslands
National Wildlife Federation: Types of Prairie
Here are some of the basic characteristics of each type of prairie:
Tallgrass Prairie:
- Precipitation averages 25 to 39 inches (63.5 to 99 cm) annually—enough for moisture to be available in the subsoil all year.
- Adequate moisture and nutrients in the soil make growing conditions very good for both native prairie plants and crops.
- Grasses grow to an average height of over 5 feet (1.5 m), with some varieties such as big bluestem or turkeyfoot (Andropogon gerardii) reaching heights of 12 feet (3.6 m).
- Shorter grasses and many species of flowering forbs also grow on tallgrass prairie.
- Trees grow primarily along streams, creeks, and rivers, or riparian corridors.
- Topsoil is very dark due to moisture, which promotes plant growth with the large amount of organic material it contains.
Mixed Grass Prairie:
Shortgrass Prairie:
Precipitation averages 10 to 15 inches (25.4 to 38.1 cm) annually—little enough that the subsoil is usually dry by late summer and plants may become dormant, reviving if there is adequate rainfall.
- Topsoil is even lighter in color and poorer in organic matter than that of the mixed grass community.
- Soils tend to be different from one another rather than uniform and may be considerably shallower than the soils of mixed grass and tallgrass prairie.
- Grasses reach an average height of under 2 feet (.61 m).
- Typical grasses here are buffalo grass (Buchloe dactyloides) and grama grass (Bouteloua sp.).
Choose three to five areas of your schoolyard where students can examine the plants and soil. Divide the class into small groups. Explain to students that they will be doing research in the classroom for part of the time, and observing microclimate conditions at each station in the schoolyard the rest of the time (if possible, have groups work simultaneously inside and outside, and then rotate).
Indoor groups:
Precipitation—Have students go to World Climate and look up the average annual rainfall for their town or city. Have them record this data.
Types of plants—Have students click on the links in the prairie descriptions above to read about and see pictures of typical prairie plants. They should browse pictures and information about prairie vegetation, including flowers and trees. [Note: If students see something in their schoolyard they do not recognize during the outside part of this lesson, have them go to National Geographic's Animals and Nature guide and enter their zip code into the U.S. Local Wildlife box in the center of the page. They will get pictures of the plants in their area to help them identify what they see.]
Outdoor groups:
Have one small group go to each schoolyard station. Review the procedures for each type of data collection (see below) prior to going outside. As each observation is made, data should be recorded; the class data will then be averaged for the final results.
[Note: With younger students, you may want to keep just one class observation sheet, with the whole class moving together from station to station.]
Types of plants—Have students look for the plants and trees they researched in the indoor part of the lesson. If they have not yet completed the indoor part of the lesson, have them sketch the vegetation they see, and try to identify them during their research.
Height of tallest plant—Measure from the ground to the top of the plant. Note if the plant has been pruned or mown. Ideally, finding plants that have not been altered is best, but if nothing else is available, use online resources like eNature to hypothesize how tall the grass would grow if left alone.
Soil moisture and color—Find a bare patch of soil. Fold up one paper towel until it is about the size of the student's hand. Press the paper towel to the soil. Check to see if there is moisture on the towel. (For recording this, students can quantify the moisture relative to the other stations—most moisture, least moisture, no moisture). Also, have students dig up a small amount of soil from under the surface with a trowel and test the soil moisture of this subsurface soil and compare it to their surface observation. Students should also comment about the color of the soil, describing whether they think it is light, medium, or dark, and how it differs from station to station.
[Note: These observations will be somewhat subjective, unless you want to pair with a science teacher to measure these characteristics more precisely. For example, the science department might have a copy of a soil color chart. More information about soil can be found at the Natural Resources Conservation Service's Soil Quality Institute.]
Have each small group go to each station and repeat observations and recording.
If possible, repeat observations at different times of the day (morning and afternoon) and over a period of several days or weeks. The data may then be averaged for the next part of the activity.
Determine the averages of the data for each station and record on the board. Briefly review the major characteristics common to prairies (listed at the beginning of this section). Compare students' data with prairie conditions. Which prairie community has conditions most like those you recorded? Are you in a prairie community? Why, or why not? What additional data might you need to decide?
Have students work in their groups and come up with additional questions they have about their data, and how they might go about answering these questions. Have them develop a hypothesis about one of their questions and design a detailed experiment to test it. If possible, allow students to carry out their experiments and comment on their results, and how they might have designed them differently.
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