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Desertification Your Name: Jedidah Jackson Concepts Addressed: Causes of Desertification, Solutions for Desertification Lab Goals: Students will be able to describe how land turns into desert through Desertification. Students will be able to explain the role wind plays in Desertification. Students will be able to explain the role humans play in Desertification. Lab Objectives: Students will Discuss the importance of dealing with Desertification List the factors going into Desertification Brainstorm solutions for Desertification Benchmark(s) Addressed: 3.2P.1 Describe how forces cause changes in an object’s position, motion, and speed 4.1E.1 Identify properties, uses, and availability of Earth materials 4.2P.1 Describe physical changes in matter and explain how they occur 4.2E.1 Compare and contrast the changes in the surface of Earth that are due to slow and rapid processes 5.4D.1 Using science principles describe a solution to a need or problem given criteria and constraints 5.2L.1 Explain the interdependence of plants, animals, and environment, and how adaptation influences survival 6.4D.1 Define a problem that addresses a need and identify science principles that may be related to possible solutions 6.2L.2 Explain how individual organisms and populations in an ecosystem interact and how changes in populations are related to resources Materials and Costs: List the equipment and non-consumable material and estimated cost of each Large Flower Pinwheel (in season at Dollar Tree) ................................................$1.00 Brown or Black Tablecloth (Dollar Tree) ..............................................................$1.00 2 Bunches of Fake Grass (in season at Dollar Tree) ..............................................$1.00 Inflatable Palm Tree (in season at Dollar Tree) .....................................................$1.00 Animal Noses (1 each @ $3.00 x 15 – Finnegans) ..............................................$45.00 Handheld fan (in season at Dollar Tree) ................................................................$1.00 Estimated total, one-time, start-up cost: ..............................................................$50.00 List the consumable supplies and estimated cost for presenting to a class of 30 students 2 Pieces Poster Board ($.50 each at Dollar Tree) ..................................................$1.00 Markers (already in classroom) .............................................................................$0.00 Slips of paper (in classroom) .................................................................................$0.00 Copies of Desertification Worksheet .....................................................................$0.00 Estimated total, one-time, start-up cost: ................................................................$1.00 Time: Preparation time: about 20 minutes Instruction time: roughly 30 minutes Clean-up time: 5-7 minutes Assessment (include all assessment materials): See attached worksheet. Quiz Question: What is Desertification and why should we care about it? Background Desertification The world's great deserts were formed by natural processes interacting over long intervals of time. During most of these times, deserts have grown and shrunk independent of human activities. Paleodeserts, large sand seas now inactive because they are stabilized by vegetation, extend well beyond the present margins of core deserts, such as the Sahara. In some regions, deserts are separated sharply from surrounding, less arid areas by mountains and other contrasting landforms that reflect basic structural differences in the regional geology. In other areas, desert fringes form a gradual transition from a dry to a more humid environment, making it more difficult to define the desert border. These transition zones have very fragile, delicately balanced ecosystems. Desert fringes often are a mosaic of microclimates. Small hollows support vegetation that picks up heat from the hot winds and protects the land from the prevailing winds. After rainfall the vegetated areas are distinctly cooler than the surroundings. In these marginal areas, human activity may stress the ecosystem beyond its tolerance limit, resulting in degradation of the land. By pounding the soil with their hooves, livestock compact the substrate, increase the proportion of fine material, and reduce the percolation rate of the soil, thus encouraging erosion by wind and water. Grazing and the collection of firewood reduces or eliminates plants that help to bind the soil. This degradation of formerly productive land-- desertification--is a complex process. It involves multiple causes, and it proceeds at varying rates in different climates. Desertification may intensify a general climatic trend toward greater aridity, or it may initiate a change in local climate. Desertification does not occur in linear, easily mappable patterns. Deserts advance erratically, forming patches on their borders. Areas far from natural deserts can degrade quickly to barren soil, rock, or sand through poor land management. The presence of a nearby desert has no direct relationship to desertification. Unfortunately, an area undergoing desertification is brought to public attention only after the process is well underway. Often little or no data are available to indicate the previous state of the ecosystem or the rate of degradation. Scientists still question whether desertification, as a process of global change, is permanent or how and when it can be halted or reversed. Problem Desertification became well known in the 1930's, when parts of the Great Plains in the United States turned into the "Dust Bowl" as a result of drought and poor practices in farming, although the term itself was not used until almost 1950. During the dust bowl period, millions of people were forced to abandon their farms and livelihoods. Greatly improved methods of agriculture and land and water management in the Great Plains have prevented that disaster from recurring, but desertification presently affects millions of people in almost every continent. Increased population and livestock pressure on marginal lands has accelerated desertification. In some areas, nomads moving to less arid areas disrupt the local ecosystem and increase the rate of erosion of the land. Nomads are trying to escape the desert, but because of their land-use practices, they are bringing the desert with them. It is a misconception that droughts cause desertification. Droughts are common in arid and semiarid lands. Well-managed lands can recover from drought when the rains return. Continued land abuse during droughts, however, increases land degradation. By 1973, the drought that began in 1968 in the Sahel of West Africa and the land-use practices there had caused the deaths of more than 100,000 people and 12 million cattle, as well as the disruption of social organizations from villages to the national level. While desertification has received tremendous publicity by the political and news media, there are still many things that we don't know about the degradation of productive lands and the expansion of deserts. In 1988 Ridley Nelson pointed out in an important scientific paper that the desertification problem and processes are not clearly defined. There is no consensus among researchers as to the specific causes, extent, or degree of desertification. Contrary to many popular reports, desertification is actually a subtle and complex process of deterioration that may often be reversible. Global Monitoring In the last 25 years, satellites have begun to provide the global monitoring necessary for improving our understanding of desertification. Landsat images of the same area, taken several years apart but during the same point in the growing season, may indicate changes in the susceptibility of land to desertification. Studies using Landsat data help demonstrate the impact of people and animals on the Earth. However, other types of remote-sensing systems, land- monitoring networks, and global data bases of field observations are needed before the process and problems of desertification will be completely understood. Local Remedies At the local level, individuals and governments can help to reclaim and protect their lands. In areas of sand dunes, covering the dunes with large boulders or petroleum will interrupt the wind regime near the face of the dunes and prevent the sand from moving. Sand fences are used throughout the Middle East and the United States, in the same way snow fences are used in the north. Placement of straw grids, each up to a square meter in area, will also decrease the surface wind velocity. Shrubs and trees planted within the grids are protected by the straw until they take root. In areas where some water is available for irrigation, shrubs planted on the lower one-third of a dune's windward side will stabilize the dune. This vegetation decreases the wind velocity near the base of the dune and prevents much of the sand from moving. Higher velocity winds at the top of the dune level it off and trees can be planted atop these flattened surfaces. Oases and farmlands in windy regions can be protected by planting tree fences or grass belts. Sand that manages to pass through the grass belts can be caught in strips of trees planted as wind breaks 50 to 100 meters apart adjacent to the belts. Small plots of trees may also be scattered inside oases to stabilize the area. On a much larger scale, a "Green Wall," which will eventually stretch more than 5,700 kilometers in length, much longer than the famous Great Wall, is being planted in northeastern China to protect "sandy lands"--deserts believed to have been created by human activity. More efficient use of existing water resources and control of salinization are other effective tools for improving arid lands. New ways are being sought to use surface-water resources such as rain water harvesting or irrigating with seasonal runoff from adjacent highlands. New ways also being sought to find and tap groundwater resources and to develop more effective ways of irrigating arid and semiarid lands. Research on the reclamation of deserts also is focusing on discovering proper crop rotation to protect the fragile soil, on understanding how sand-fixing plants can be adapted to local environments, and on how grazing lands and water resources can be developed effectively without being overused. If we are to stop and reverse the degradation of arid and semiarid lands, we must understand how and why the rates of climate change, population growth, and food production adversely affect these environments. The most effective intervention can come only from the wise use of the best earth-science information available. http://pubs.usgs.gov/gip/deserts/desertification/ Procedures: Prep Work: - Before lesson, have these supplies ready: - Black tablecloth (to drape around “Top Soil” kid) - Inflated inflatable palm tree (for “Tree” kid) - Grass (for “Grass” kid) - Flower pinwheel (for “Flower” kid) - Animal noses (for “Animal” kids) - Axe or chainsaw cutout (for “Lumberjack” kid) - Spinny roller chair - Handheld fan (for “Wind” kid) - Copies of Desertification Worksheet In Class for 3rd and 4th grades: - Explain to students about the factors contributing to Desertification – wind, water, and humans. o Wind blows fertile top soil all over the place, making it difficult for plants to grow in an (usually) already arid area. Human consumption of plants contributes to the lack of plants, making it difficult for the plants’ root systems to hold the fertile top soil firmly in place and safe from the wind. - This can be explained through a demonstration that can also be used as a classroom activity. Have one student be the Top Soil, and sit in a spinny chair with wheels on it. The Top Soil kid should have the black or brown table cloth draped around them. Have other kids be Trees (hold up inflatable tree), Grass (hold up grass), Flowers (hold up flower pinwheel), Other kinds of plants Wind with the fan Lumberjacks with axe, chainsaw and Stihl hat Animals (with animal noses) o Have the plant kids stand around the Top Soil kid, and when the Wind comes along to try to blow the Top Soil around (using the handheld fan), the plants prohibit the Top Soil from moving around. o However, there are some kids that are Lumberjacks and they cut down the trees (lumberjacks and trees sit down. o Animals (wearing animal noses), and People who like flowers. Have these kids come up and “cut” the Tree down, “pick” the Flowers, and “eat” the Grass. Have the animals and flowers sit down. o Now, when the wind comes in to blow the Top Soil, the Wind is able to push the Top Soil in the chair ANYWHERE. The Wind might even spin the Top Soil in circles. o For the demonstration, simply use 6 or 7 kids, but for a classroom activity, use the whole class. You can get very elaborate with the “Play” with the whole class – have simple costumes and props, and create a narrative story that really brings the issue to light. o Have the students all sit down, and discuss what just happened. Explain that the Top Soil was safe from the Wind while the Plants were there, supporting the Soil with their root systems. However, due to human and animal consumption, when there were no plants, the Top Soil was pushed everywhere, and wasn’t there to help new plants grow. o You can use this “Dust Devil” to talk about the Dust Bowl in Oklahoma in the 1930s. o Explain that human and animal consumption is necessary – the animal has to eat, and it would be hard to build buildings without wood – but that we need to be careful about using more than we need. o Discuss the risk of Desertification – how it can happen anywhere that has little rainfall and a lot of human consumption. Ask the students if they think that Oregon is at risk for Desertification; they will probably say no. o Show them the Desertification Vulnerability map and the Risk of Human Induced Desertification map. Have them analyze the maps, and decide if Oregon is at risk. Remind them (if you are West of the Cascades) that while we have a fairly wet microclimate in Portland, that in Eastern Oregon, past the Cascade Mountains, they have a much drier microclimate. The maps indicate this. o Next, discuss what you and your students could do to prevent Desertification. o Go outside and look around. Maybe there is a patch of dirt somewhere around the school that has no grass, or plants. Your class might be able to plant something there to reduce the amount of topsoil lost to the wind. o Discuss different things that countries all over the world are doing to prevent and stop Desertification. In Class for 5th-6th grade: - For older students, you might or might not want to use the above-described demonstration or activity. For older students, explain everything that you would explain to 3rd-4th graders. Include a discussion about the effects of Desertification on the people that live in and near deserts – lack of food, dirty water, etc. - While the previous activity might be enjoyable, for this age group, another activity might work better. Have each student write on a piece of paper something that deals with Deserts and Desertification. For example, one might write “dry,” “wind,” top soil,” etc. - Put all the pieces of paper into a bowl, and play Pictionary or Charades with the pieces of paper. - Make t-shirts to create awareness in the community that say things like “ask me about Desertification” or “stop Desertification”. - For assessment, have the students write a small essay explaining Desertification and list 2 ways to prevent it. Additional Reading: The “Learning to Combat Desertification” Teacher’s Guide is a very valuable tool for anyone wanting to do an entire unit on Desertification. This guide is 261 pages long, and includes activities and all the information you could want on any topic relating to Desertification. This can be acquired at http://www.preventionweb.net/files/3986_VL102214.pdf Sources: http://pubs.usgs.gov/gip/deserts/desertification/ http://upload.wikimedia.org/wikipedia/commons/6/68/Desertification_map.png http://www.visumsurf.ch/jahr_der_wueste/images/klima.jpg http://static.howstuffworks.com/gif/desertification-4.jpg http://www.kew.org/science/tropamerica/images/peru/IMAGE-4-desertification.jpg http://portal.unesco.org/es/files/33055/11492610633desertification.jpg/desertification.jpg http://www.cpc.ncep.noaa.gov/products/predictions/tools/edb/sbfinal.gif http://www.worldproutassembly.org/images/desert_tunisia.jpg http://chinadigitaltimes.net/wp-content/uploads/2008/11/china-desert.jpg http://www.cite- sciences.fr/english/ala_cite/expositions/eau_pour_tous/img/maitriser_eau/desert_adritzz.jpg http://www.unccd.int/images/june17/june17-big.jpg http://sgp.undp.org/intranet//img/projects/7167/VN-03-002-6.jpg http://www.preventionweb.net/files/3986_VL102214.pdf Name: _______________________________ Date: ______________________ In the space below, draw a picture of your neighborhood if it was affected by Desertification What is one thing that Desertification would change about your life? Be specific! What is Desertification and why should we care about it?
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