A Closer Look
Suggest that students study carefully the illustration on the poster in relation to the various components of an ecosystem.
Count the number of food chains present in the illustration. Think about the microscopic food chains that are invisible to the naked eye. Brainstorm the benefits and disadvantages to the plants and animals living together in this ecosystem. Examples might be the potential for conflict between the nesting birds and the cat and the advantage (for humans and their garden) of ladybugs controlling the aphids.
Identify smaller and larger ecosystems that abut a backyard ecosystem. What is upstream? Downstream? Think about the airshed, watershed, and underlying geology. How do outside factors influence your backyard ecosystem? Consider such things as acid rain, leaves fallen into your yard from the neighbors' trees, groundwater and air current movements, weather patterns, and socially accepted human practices, such as spraying insecticides to reduce mosquito problems and seeding clouds for rain.
Find all of the living and nonliving parts of the ecosystem pictured. Which are consumers? Producers? Decomposers? What role does each one play in the ecosystem, and what is your relationship with each of them? Describe all of the habitats represented; don't forget the human habitat. Note that the light fixture provides a nesting perch, and the fallen log above the stream creates a small dam.
Research the characteristics of a healthy ecosystem. Is the backyard ecosystem pictured healthy? Create a skit or game where characters represent the various living and nonliving components of the ecosystem, including predators and prey. Write about what would happen to your backyard ecosystem if :
- your neighbor adopts two free-roaming cats;
- you quit composting and begin using chemical fertilizers;
- rain becomes acidic;
- or there is an early frost.
In each of the scenarios, consider what actions you could take individually, collectively, regionally, and globally.
Research what would happen to the ecosystem pictured (including the plants, animals, and nonliving components) during the winter months. Determine the original material from which the manufactured items pictured on the poster were produced. How might the ecosystems where these materials originate have been changed by their extraction? For example, the copper metal used for the manufacture of parts of the light fixture was extracted from an open pit mine in the Southwest. Open pit mines developed in natural areas are often reclaimed to alternative uses, such as recreation.
Draw a picture of how you think your own backyard ecosystem looked 100 years ago, 10,000 years ago, 100,000 years ago, and a million years ago. How might a backyard of the future look if human habits remain as they are today? How about if humans became more aware of the importance of maintaining healthy ecosystems? If a natural disaster (earthquake, hurricane, flood, or severe thunderstorm) wiped out your existing backyard ecosystem, and you did nothing to restore it, what would happen? What plants might grow there? What animals might come to live in your yard?
The Question in Smithdale
Some people see undeveloped areas of the natural environment as little more than raw material for human use. Other people believe that the natural environment should be preserved without regard for human needs. Still others yearn for a balance between economic growth and a healthy and vigorous natural environment, but there remains a great difference of opinion regarding how to achieve that balance.
To give students a feel for the complexity of resolving competing interests and turning a potential conflict into a collaborative effort, conduct the following exercise, which will take several days for student preparation and two or three hours for the "public meeting."
Begin by photocopying the cards (each group of three to five students will receive one) and the background passage (one per student.) Have your class read the background passage and then form small groups. Give each group a "position card." Then, instruct them to prepare their arguments. Over the next few days, the children should do research, interview people in the community, investigate how other communities might have handled similar situations, and generally prepare themselves to the utmost before they present their case to the council. Also, each group should choose a spokesperson.
When you are ready to conduct the "public meeting," have the city council group sit in front of the class. Give each group five minutes in which to state its position to the council, who then can question the spokesperson. Once every group has presented its opinion, lead students in a general discussion. Then, the council must vote on the use they want to make of the land.
Make sure students see that each group does have a valid concern, and that there is no "right" or "wrong" in this situation. After the public meeting, have students reassemble in groups made up of one person from each of the interest groups, with the exception of the city council. Challenge each of these new groups to collaboratively come up with a recommendation about how to manage the tract of land, with the guiding principle being the sustained health of the ecosystem.
During their discussion, encourage students to consider the following questions:
- What else would you like to know about this ecosystem? It might be helpful to have, for example, an inventory of the ecosystem's threatened and endangered plants and animals.
- What are some things about the human dimension that would be useful to know? Examples might be economic studies of cattle grazing or the hotel-marina proposal.
- How do the values of the various interest groups differ?
- Do you trust one group more than another? Why?
- What is the best use of this land in regard to human interests? What about in regard to promoting biological diversity? What solution could satisfy the needs of both?
- What can you give up or alter about your position?
- What if you knew the economic values for some of the choices? Would that make a difference in your decision?
- How does the historical and archaeological information influence what you may think of as appropriate uses for the land?
Each of the multi-interest groups should then present their solutions. The city council group must then vote on what to do with the land. After the vote, discuss the pros and cons of the suggested solutions. Identify and list the benefits, if any, and the cost and liabilities, if any, that will occur as a result of the council's decision. Include effects on people, plants, and animals.
To extend learning further, follow the same procedure for a similar issue currently under debate in your community. Contact constituent groups and ask them to give you prepared statements (500-1,000 words) summarizing their positions on the issue, or invite them to a debate in your classroom and continue to research the issue so that students can ask relevant questions.
The community of Smithdale, population 50,000, abuts a large tract of land. The land includes a river and riparian areas, uplands, steep cliffsides, the highest peak near the city. Most of the tract is in a natural state, but there are areas where hazardous waste has been dumped and where the streamside vegetation has been eradicated by cattle grazing earlier this century. The river boasts the best fly-fishing in the region . The federal land managing agency, in charge of the area, is the Bureau of Land Management (BLM).
Data from a nearby archaeological site reveal that the prehistoric inhabitants had deforested the area, eventually causing heavy erosion. Historic photographs show that 100 years ago the river was wider, more shallow, and braided, an indication of a heavy sediment load. At that time, large numbers of livestock were grazed in the uplands, resulting in a loss of vegetative cover. One result of a stream carrying a heavy sediment load is a reduction in the native fish populations. These data show this ecosystem to be quite vulnerable to disturbance.
The BLM has been approached to trade the tract to the city in return for a piece of land that the city owns inside another, nearby wilderness area, Acquiring the city-owned tract would enable the BLM to consolidate its land holdings and make it easier to manage the wilderness as a habitat for mule deer in the winter. Smithdale is holding a hearing to engage citizens in a public dialogue about the best use for the BLM tract.
These people want to
- graze cattle along the river in the tract,
- build a pipeline to three new livestock watering holes,
- maintain the traditional economic base of the community,
- and control the coyote population.
Friends of Biodiversity
These people want to
- have the tract remain in its natural state,
- begin a streamside revegetation project,
- have the hazardous materials cleaned up,
- eliminate cattle grazing,
- and encourage the greatest possible diversity of native plant and animal species.
Sportsmen (Hunters and Fishermen)
These people want to
- have better access to the river and uplands by upgrading a jeep trail and installing a boat launch,
- have a nearby shop selling bait and other sporting equipment,
- have a nearby picnic area,
- and limit cattle grazing so it doesn't conflict with hunting seasons.
Local Native American Tribe
These people want to
- preserve native vegetation for use as basketry materials and herbal remedies,
- have the jeep trail upgraded to provide access for elderly religious practitioners,
- restrict access to the jeep trail in order to protect the sacred mountaintop area,
- and eliminate development and cattle grazing.
Chamber of Commerce
These people want to
- promote economic growth through development,
- encourage the construction of a large hotel-marina complex,
- and accommodate limited cattle grazing and hunting.
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