by Tonya and Richard Mandl
Introduction: Riparian zones, the green ribbons of life found on the edges of streams and lakes, are valuable ecosystems. You are going to learn about these important ecosystems by conducting actual field research and drawing conclusions from your data.
The following is a series of connected lessons, utilizing all learning modalities, to be taught either as part of a larger natural science unit on biomes or as a single unit of study. Students will learn about ecosystems, and the elements that make up the riparian ecosystem. Students will also learn how to conduct habitat surveys and collect field data. Finally, students will culminate by visiting an actual riparian zone and conducting their own research.
Lesson 1: Habitat surveys
Materials: butcher paper, marking pens, paper for recording observations, trowel or stick, photographic light meter or photosensitive paper, thermometer, small strip of paper, compass
Overview: An ecosystem is a community of different species interacting with each other and with the chemical and physical factors making up its nonliving environment. It is a system of interrelationships among organisms, and between organisms and the physical environment. In this activity students will examine three different environments as they focus on sunlight, soil moisture, temperature, wind, plants, and animals in each environment. By comparing different environments, students will begin to consider how nonliving elements influence living elements in an ecosystem.
Preparation: Find three study sites that are somewhat different from each other in terms of sunlight, air temperature, soil moisture, wind, and number and types of plants and animals living there. If possible, select one site that is open, like a field or lawn; one that has trees; and one that contains water.
Plan to visit the sites on the same day, or at about the same time on different days. Using butcher paper and marking pens, prepare a large chart for compiling each team's data.
1. Ask students to think of a place they enjoy visiting. This can be done quite effectively using a visualization exercise (closing eyes and mentally traveling to a favorite place). Ask them to think about these questions:
- What did you particularly enjoy about the place: Was it the people? The physical space?
- What did you do?
- What living things made your place enjoyable?
- Name any nonliving things that made your place enjoyable.
Help students see that any place has both living and nonliving parts that work together to make an ecosystem. Explain that students will investigate ecosystems at three different study sites to find out how living and nonliving elements affect each other.
2. Divide the group into six teams. Each team will investigate and record observations of a different component of three different study sites. Give students instructions, a copy of the team chart, and materials described below. Later, teams will transfer their observations to the class data chart.
Team 1: Soil
Ask this team to determine the soil moisture at the study sites. Students can use a trowel or stick to scrape the surface of the ground and to obtain a small sample of soil from underneath the surface. By feeling the soil, they should be able to tell whether it is wet, moist, or dry. They should examine the soil for other characteristics such as texture, color, and smell. They should also note plant material or organisms in the soil.
Team 2: Sunlight
Ask this team to determine how much sunlight penetrates the ground at each study site. Students may determine light intensity at each site by using a photographic light meter or photosensitive paper. If these items are not available, they can use relative terms such as shady, dark, medium light, or bright.
Team 3: Wind
Ask this team to use the small strip of paper to determine the wind movement at each site. One student can hold the paper away from the body, while the others observe whether it hangs straight down or blows at an angle. Ask students to use the compass to determine from which direction the wind seems to be blowing.
Team 4: Temperature
Ask this team to measure each site's temperature at aground level, 1" deep in the soil, and at 1 yard above ground. If one site contains water, have the team measure the temperature at just above the water, at 1" deep, and at 1 yard above.
Team 5: Plant life
Ask this team to observe the various kinds of plants at each site (large trees, small trees, shrubs, small plants, grasses, grasses). Suggest that students record the most common types of plants found in each location and that they note especially where each grows relative to the others.
Team 6: Animal life
Ask this team to note the various kinds of animals at each site (insects, birds, reptiles, fish, etc.). Students should note evidence of animals such as scat, tracks, burrows, or leaves that have been chewed.
3. After teams have had sufficient time to investigate each location, have them all come together to present their findings and share what they have learned.
4. Each team should listen to the reports of the other teams, and use the information to complete their team chart.
5. Ask teams to enter their data on the large class chart you prepared. Use this chart as a basis for discussing differences between the locations and any interactions students observed among the elements. Ask the following questions:
- Which ecosystems had the greatest number of plants? Animals? Which has the least of each? How do you explain this difference?
- How are plants and animals the same at different sites? How are they different?
- Which has the wettest soil? The driest?
- Do plants seem to affect the light intensity, air temperature, and soil temperature in an area?
- How does water seem to influence the soil temperature, air temperature, and soil moisture?
- What relationship does light seem to have with air temperature? With soil moisture? With plants?
- Which of the six elements we studied seems most important for determining the character of the environment at each site? What makes you say so?
Ask students if they noticed any evidence of human actions that affected the areas. Discuss the potential negative or non-negative impacts of this on the ecosystems.
: This activity can be repeated at the end of the entire unit on biomes, comparing three different biomes/ecosystems visited on a field trip. Or it can be repeated at the end of the mini-unit on a trip to a natural riparian zone.