LESSON › ... › 9-12L1.pdf · 2013-06-13 · A Sand County Almanac(1949), a volume of sketches...

NUTSHELLIn this lesson, students learn aboutecosystem functions and the naturalprocesses that occur in forests. They readthe essay “Odyssey” from Aldo Leopold’sA Sand County Almanac and discuss theconcepts of change, interconnectivity, andsustainability. In small groups, studentsresearch a forest ecosystem in Wisconsinand then work in a large group to createecosystem food webs. Together, studentsuse the knowledge they have gained tocreate a story that describes the journey ofan atom through different forest ecosystems.

BACKGROUND INFORMATIONFORESTS AS ECOSYSTEMSA biologic community is a group of plantsand animals that live and interact with one another in a given area. The termecosystem is used to describe a biologiccommunity together with the abiotic(nonliving) components in it. An ecosystem’sabiotic components can include physicalcharacteristics (e.g., soils, topography),climatic factors (e.g., sunlight, temperature,moisture), and nutrients, elements andother chemical compounds (e.g., nitrogen,phosphorous, carbon dioxide, water, mercury,pesticides). Ecosystems can vary in sizefrom a large forest to a rotting log.

The living things in an ecosystem may beclassified as producers, consumers, anddecomposers. Producers, or autotrophs, areplants that make their own food. Consumers,or heterotrophs, are animals that need toconsume other organisms to obtain energyand nutrients. Decomposers (includingdetritivores, bacteria, and fungi) are a type of consumer that break down organic matter,making nutrients available for plants.

Lesson 1: The Forest Odyssey

LESSON 1The Forest Odyssey

LEAF Guide • 9-12 UNIT14

BIG IDEAS• An ecosystem is characterized by its composition,

structure, and function. (Subconcept 10)

• Ecosystem functions include the fixation ofenergy through the process of photosynthesis,the flow of energy through food chains andfood webs, and the cycling of matter. (Subconcept 12)

• Forest ecosystems are connected withother terrestrial (e.g., prairies) and aquatic(e.g., wetlands) ecosystems. (Subconcept 15)

OBJECTIVESUpon completion of this lesson, students will beable to:• Identify and describe ecosystem functions and

natural processes in forests.• Compare and contrast the ecology, natural

history, and human aspects of three differentforest ecosystems in Wisconsin.

• List specific examples of how ecosystems areinterrelated, how ecosystems change, and howecosystems are sustained.

SUBJECT AREASLanguage Arts, Science (Earth and Space Science,Life and Environmental Science)

PROCESS SKILLSLarge group analysis and consensus building,Research, Science-based creative writing

LESSON/ACTIVITY TIME• Total Lesson Time: 250 minutes• Time Breakdown:

Introduction .................................5 minutesActivity 1....................................45 minutesActivity 2....................................30 minutesActivity 3....................................70 minutesActivity 4....................................50 minutesConclusion ................................50 minutes

TEACHING SITEClassroom

Lesson 1: The Forest OdysseyLEAF Guide • 9-12 UNIT

Forest ecosystems are not isolated from otherecosystems. They are interconnected with otherterrestrial ecosystems (such as prairies) and with aquatic ecosystems (such as wetlands). For many of us, the biotic connections are mostobvious. For example, many animal and birdspecies, such as the eagle, osprey, and blackbear, find shelter in the forest but get much oftheir food from adjoining areas. Forest edgesreceive added sunlight, increasing the habitat for sun-loving plants, and providing importanthabitat for many birds and animals, includingdeer, turkey, and grouse. Some organisms(notably amphibians) need a wetland for part of their life cycle but live other parts of their life interrestrial areas, such as forests.

Forests are also connected to other ecosystemsby abiotic factors. Forests retain water andprotect surface and groundwater resources.Surface water and groundwater connect forestswith lakes, rivers, wetlands, farms, and cities.Fires spread from fields to forests. Erosion fromupland areas can cause siltation of waterwaysand create soil deposits in lowland areas.Forested areas can act as windbreaks andtemperature buffers. All of these are examples of the abiotic connections between forests andsurrounding ecosystems.

ECOSYSTEM FUNCTIONSEcosystems maintain functions that support life.These include the fixation of energy throughphotosynthesis, the cycling of matter, andthe flow of energy through food webs.

Ecosystem functions are driven by a host ofnatural processes. These processes can bebiological, chemical, or physical. The processesconnect biotic and abiotic components of anecosystem. Important natural processes inforest ecosystems include: respiration,assimilation, photosynthesis, decomposition,mineralization, weathering, erosion, nitrogenfixation, herbivory, competition, reproduction,succession, migration, carbon sequestration,and adaptation.

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MATERIALS LISTFOR EACH STUDENT• Copy of Student Pages 1A-B, Aldo

Leopold’s “Odyssey”• One copy of either Student Pages 2A-B,

Forest Ecosystem Profile: Oak Savanna OR3A-B, Forest Ecosystem Profile: Forested

Wetland OR 4A-B, Forest EcosystemProfile: Northern Hardwood Forest

• Copy of Teacher Page A2, Habitat andWildlife (optional)

• Copy of Student Page 5, Food WebsFOR THE TEACHER• Chalk/marker board• Cards made from Teacher Page A1, Natural

Process Cards (one card per pair of students)• Copy of Teacher Page A2, Habitat and

Wildlife

TEACHER PREPARATION• Familiarize yourself with Student Pages

1A-B, Aldo Leopold’s “Odyssey.”• Cut cards from Teacher Page A1, Natural

Process Cards.• Familiarize yourself with the information

on Student Pages 2A-B, 3A-B, and4A-B.

• Reserve a computer lab and library time forstudent research in Activity 3.

• Obtain the resources to facilitate groupresearch on forest ecosystem food webs(see Recommended Resources, page 27).

• Conduct the internet “key word” searchessuggested in Activity 3 and bookmark goodweb resources to find wildlife and habitatrelationships for the three forest ecosystemsstudied (forested wetlands, northernhardwoods, savannas).

Lesson 1: The Forest Odyssey LEAF Guide • 9-12 UNIT16

VOCABULARYAdaptation: Evolutionary adjustments instructure, form, or function that help individuals,populations, or species fit in their environment.Assimilation: The incorporation of energy andnutrients into the bodies of plants or animals.Carbon Sequestration: The capture and storageof carbon dioxide from the atmosphere into biotic(e.g., trees) or abiotic (e.g., coal) pools of carbon.Competition: The struggle that exists amongorganisms to acquire finite resources (e.g., light,space, nutrients, water).Cycling of Matter: An ecosystem functionin which elements are deposited, used byorganisms, and stored or exported.Decomposition: The breakdown of organicmatter (through a number of interrelatedprocesses) into simple compounds available for use by plants.Detritivores: Scavengers (e.g., millipedes, woodlice, slugs, snails, springtails, beetles) that feedon dead plants and animals or their waste;essential for the cycling of nutrients.Ecosystem: An area that contains organisms(e.g., plants, animals, bacteria) interacting withone another and their nonliving environment(e.g., climate, soil, topography). Ecosystem Functions: Functions thatsupport life including the fixation of energy,the cycling of matter, and the flow of energythrough food webs.Erosion: The wearing away of the land surfaceby water, wind, ice, gravity, or other natural orhuman forces.Fixation of Energy: An ecosystem function inwhich solar energy is changed into chemicalenergy (photosynthesis) and assimilated in plants.Flow of Energy: An ecosystem function inwhich chemical energy (found in carbohydrates,proteins, and fats) is moved through the foodwebs of an ecosystem.

Forest Ecosystem: An ecosystem characterizedby a dominance of tree cover.Herbivory: The consumption of living plantmaterial by plant-eating animals (herbivoresand omnivores).Interconnectivity: The relationships that existbetween ecosystems.Migration: The repeated movement of apopulation of organisms from one ecosystemto another.Mineralization: The conversion of an elementfrom an organic to an inorganic form; combustion,the act of burning, is a very rapid form ofmineralization.Natural Process: A specific biological, chemical,or physical interaction that occurs between thecomponents of an ecosystem (e.g., erosion,decomposition, photosynthesis, predation).Nitrogen Fixation: The process by whichatmospheric nitrogen is made available for use by plants in an ecosystem.Nutrient: The chemical elements that contributeto the growth and development of an organism.Odyssey: An extended wandering or journey.Photosynthesis: The process by which plantsconvert the electromagnetic energy of the suninto chemical energy usable by other organisms.Reproduction: The process by which organismsproduce offspring.Respiration (plant): A process involving theassimilation of carbon from the atmosphere.Succession: The change from one biologiccommunity to another over time.Sustainability: The ability of natural resourcesto provide ecologic, economic, and socialbenefits for present and future generations. Weathering: The process by which rocks arebroken down into minerals usable by plants.

One of the most important natural processes inan ecosystem is photosynthesis. Photosynthesisis the process by which plants harness theelectromagnetic energy of the sun and convert it into chemical energy (i.e., sugar). The chemicalenergy found in plant material can then bedigested, assimilated (as carbohydrates, protein,and/or fat) and used to perform processesthat the body needs to survive. The process of photosynthesis is essential to life on Earth.The appearance of green algae precededthe first explosion of life on this planet, andautotrophs continue to be a fundamentalcomponent of ecosystems.

Photosynthesizing organisms are calledproducers since, in all but a few ecosystems(e.g., hydrothermal vents on ocean floors),they provide all of the energy to the ecosystem.Organisms that do not photosynthesize arecalled consumers because they must consumeother organisms for their energy.

A complex web of feeding relationships ismaintained in an ecosystem. An organism’sfeeding position in an ecosystem is its trophiclevel. There are four main trophic levels:1) producers (photosynthetic plants, algae,bacteria); 2) primary consumers (herbivores);3) secondary consumers (carnivores andomnivores); and 4) tertiary consumers (topcarnivores). Ecosystems have a large numberof producers supporting a smaller number ofprimary consumers that support an even smallernumber of secondary consumers, which in turn support only a few top carnivores. Therelationship is often illustrated as a trophicpyramid to show the amount of energy storedand ultimately transferred to different levels inthe ecosystem.

Food chains explain simple feeding relationshipsbetween organisms (e.g., willow saplings areeaten by snowshoe hares, which are eaten byeastern timber wolves). Since most organismsfeed on a variety of different things, food chains

are often too simple to represent the variety of relationships that exist. As different feedingrelationships are added, food chains turn intofood webs that illustrate the variety of food sourcesthat organisms depend on (e.g., snowshoe hareseat grasses, willows, berries, conifer buds, aspenbark, etc.).

The feeding relationships between organisms are a component of the cycling of matter inecosystems. Matter is cycled through thebiotic and abiotic components of ecosystems.Matter consists of elements and makes upall the substances in an ecosystem. Elementssuch as calcium can be moved from rocks toplants, to animals, to soil, and to water. Themovement or cycling of matter is dependenton a variety of natural processes, includingdeposition, assimilation, erosion, mineralization,decomposition, carbon sequestration, andcompetition for nutrients by organisms.

The elements and elemental compoundsessential to plant and animal life are callednutrients. Nutrients known to be essentialto plants include hydrogen, oxygen, carbon,nitrogen, phosphorous, potassium, calcium,magnesium, sulfur, boron, copper, iron,manganese, molybdenum, and zinc. Nutrientsessential to animals include proteins,carbohydrates, fats and oils, and a variety of minerals and vitamins found in plant matter.

ALDO LEOPOLDAldo Leopold was born in Burlington, Iowa, in1887. He received a Master of Forestry fromYale University in 1909, and after earning hisdegree, went on to serve for 19 years in theU.S. Forest Service. Leopold worked in theSouthwest until he was transferred in 1924to the Forest Products Lab in Madison,Wisconsin. In 1933 he was appointed Professorof Game Management in the AgriculturalEconomics Department at the University ofWisconsin-Madison. Leopold taught at theUniversity of Wisconsin until his death in 1948.

Lesson 1: The Forest OdysseyLEAF Guide • 9-12 UNIT 17

Aldo Leopold is best known as the author ofA Sand County Almanac (1949), a volume of sketches and essays that helped define an ecological attitude toward people and theland. The notion of a land ethic was rooted in Leopold’s perception of the environment. He was an internationally respected scientist andconservationist instrumental in formulating policy,promoting wilderness, and building ecologicalfoundations for forestry and wildlife ecology.

Aldo Leopold died in 1948 but left an amazinglegacy. In 1930 he served as chairman of theGame Policy Institute, which developed theAmerican Game Policy. He assisted in thefoundation of both the Wilderness Society andthe Wildlife Society. Aldo Leopold also left us withone of the most eloquent and definitive collectionsof environmental writing in American history.

ODYSSEY CONCEPTSIn Leopold’s essay “Odyssey,” three mainconcepts emerge: change, interconnectivity, and sustainability. When A Sand CountyAlmanac was first published, the importance of these concepts was not widely recognized.Today, these concepts are widely studied andtheir significance understood. This occurred,in part, because writers like Leopold helpedpeople develop these concepts for themselvesby providing real life examples in interesting,meaningful, and personal stories.

Throughout the essay “Odyssey,” the readerrepeatedly encounters the concept of change in nature. Describing change in geologic terms,Leopold writes, “In the flash of a century, therock decayed.” He demonstrates the resilience of natural systems to disturbance as he explains,“But the prairie had two strings to its bow. Firesthinned its grasses, but they thickened its standof leguminous herbs…” He emphasizes naturalchange and death when he states, “The beaver

starved when his pond dried up during a bitterfrost.” He explains the cycles of prairie lifewhen he says, “The only certain truth is that itscreatures must suck hard, live fast, and die often,lest its losses exceed its gains.” He introducesthe human element of change as he concludesthe short story, “… a new animal had arrived andbegun redding up the prairie to fit his own notionsof law and order.”

Leopold strings the concept of interconnectivitythroughout “Odyssey.” Describing the life of anatom, he writes, “He helped build a flower, whichbecame an acorn, which fattened a deer, whichfed an Indian, all in a single year.” He describesthe web of life as “the bloodstream of the land.”And he illustrates the connection that organismshave even after death when he writes, “The dyingfox sensed the end of his chapter in foxdom, butnot the new beginning in the odyssey of an atom.”

Though Leopold does not use the term“sustainability” in his essay, he provides uswith examples of the fundamental principles usedto define the term. He refers to the resilience ofnatural systems and their ability to adapt to disturbance when he writes, “Thusthe prairie savings bank took in more nitrogenfrom its legumes than it paid out to its fires.That the prairie is rich is known to the humblestdeer mouse; why the prairie is rich is a questionseldom asked in all the still lapse of ages.” Hegives an example of ecosystem self-regulation(nature’s balance sheet) when he writes, “Forevery atom lost to the sea, the prairie pullsanother out of the decaying rocks.” He stressesthe importance of biodiversity in long-termecosystem stability as he states, “The oldprairie lived by the diversity of its plants andanimals, all of which were useful because thesum total of their co-operations and competitionsachieved continuity.”


Throughout the essay, Leopold discusses thehuman tendency to simplify and take a short-termperspective when he writes, “He failed to see thedownward wash of over-wheated loam, laid barein spring against the pelting rains.” Finally, herefers to growth and expansion and the problemsthat they present to sustainability when he writes,“But he used his alfalfa, and every other newweapon against wash, not only to hold his oldplowing, but also to exploit new ones which, inturn, needed holding.”

PROCEDUREINTRODUCTION – Aldo Leopold1. Have students raise their hand if they have

heard of Aldo Leopold. Ask them to keep theirhand raised if they have read anything he haswritten. If there are any students who haveread Leopold, have them explain what hewrites about. Guide the conversation toinclude nature, conservation, and society.

2. Tell the class that Aldo Leopold is one of themost famous North American nature writers, and his most acclaimed book, A Sand CountyAlmanac, is written about his life on a ruralhomestead in Wisconsin. Today they will reada short essay found in A Sand County Almanacand develop a similar science-based creativewriting about forest ecosystems.

ACTIVITY 1 – Ecosystem FunctionBrainstorm1. Hand out Student Pages 1A-B, Aldo

Leopold’s “Odyssey” to each student in theclass and tell them they are going to be readingthe essay as a homework assignment. Havestudents define the word “odyssey” (anextended wandering or journey) and explainthat the story describes the extended journeyof an atom through an ecosystem.

NOTE: Since the story is short, you mayalso wish to give students 10 minutes to readthe essay individually or out loud at the endof this activity.

2. Tell students that before they read “Odyssey”they should have a good understanding ofwhat forest ecosystems are, the functions theymaintain, and the natural processes that occurin them. Begin a brainstorming session todefine the word “ecosystem.” Further refinethe definition to describe a forest ecosystem.Use the students’ ideas to form a cleardefinition and write it on the board. (Ecosystem:An area that contains organisms [e.g., plants,animals, bacteria] interacting with one anotherand their nonliving environment [e.g., climate,soil, topography]. Forest: An ecosystemcharacterized by a dominance of tree cover.)

NOTE: This material may be a review foryour class, but the brainstorm will helpstudents organize and use the informationin later activities.

3. Once forest ecosystem is defined, explain tothe class that different ecosystems can havevery different communities of plants andanimals in them. Have students think of twovery different terrestrial ecosystems (e.g.,one in the tropical rainforest biome and onein the desert biome) and list the differentcharacteristics of each (e.g., moisture,temperature, type of vegetation, etc.) andthe types of animals and plants that mightbe found in each (cactus vs. tree, armadillovs. orangutan, etc.).

Once students have differentiated the twoecosystems, explain that even thoughecosystems have different species compositionand different species relationships, everyecosystem maintains specific functions thatkeep organisms alive.

Ask students to list things that organismsneed to stay alive. (Plants need sunlight,nutrients, air, space, and water. Animalsneed food, shelter, air, space, and water.)


4. Lead a discussion that helps studentsdistinguish between ecosystem functionsand natural processes and form a list of each.To best organize the discussion, divide theboard into three vertical sections.

Tell students that an ecosystem function isdefined as a system (a collection of interrelatednatural processes) that supports all of the lifein an ecosystem (allows organisms access tofood, water, space, nutrients, sunlight, shelter).Write one of the following three ecosystemfunctions in the top of each the three sectionsof the board:

• The fixation of energy through photosynthesis• The flow of energy through food webs• The cycling of matter

5. Once the functions are listed on the board,ask students to define each one and toexplain why the three functions are essentialto living organisms.

Facilitate the discussion by asking studentswhy organisms (e.g., animals, plants, people)need energy. (Organisms need energy topower all of the body’s processes. In humans,these processes include blood circulation,respiration, and body movement.) Askstudents where the energy comes from.(From food. More specifically from thecarbohydrates [e.g. sugar], proteins, andfats found in plants and animals.) Askstudents where the energy in food comesfrom. (All of the energy comes from theprocess of photosynthesis. Plants performthis process and change the electromagneticenergy of the sun into chemical energy thatis embodied in sugars. The sugars producedduring photosynthesis are modified by plantsand animals for different uses – creating more

complex forms called proteins and fats.) Askstudents what would happen without plants,or more specifically, without photosynthesis.(Energy would not be available for all ofthe other organisms in ecosystem, includinghumans!)

Help students define the flow of energy byasking if the producers (plants and algae)have all the energy, how does the energy getto other organisms. (Herbivores and omnivoreseat green plants and carnivores eat theherbivores, etc.) Ask students what the feedingrelationships are called. (Food webs.)Tell students that ecosystems maintaincomplex feeding relationships that distributefood energy to organisms through food webs.

Finally, help students discuss the cycling ofmatter by asking if producers (plants) geteverything that they need from the sun.(No, plants need nutrients.) Ask students howplants get nutrients. (Nutrients are found inthe atmosphere and soil. Trees absorb manynutrients such as phosphorous, potassium,and calcium through their roots as mineralsare weathered from rocks and organic matteris decomposed. They get other elements,such as carbon, from the carbon dioxide inthe atmosphere.) Ask students how animalsget nutrients. (They eat plants, animals,and other organisms. They assimilate thenutrients during digestion.) Tell studentsthat all of the processes that make nutrientsavailable to plants and animals are part ofthe cycling of matter.

NOTE: If you have covered the carbon cycle,water cycle, or other cycles with your class,you may wish to revisit them at this point.


6. Once the students are comfortable with thethree ecosystem functions, ask them if theyknow the difference between an ecosystemfunction and a natural process. Explain thatnatural processes are the biological, chemical,and physical interactions that occur betweenthe components of an ecosystem. Ecosystemfunctions involve many different processes.For example, the cycling of matter is anecosystem function that involves thedecomposition of organic matter and theweathering of minerals, both of which arenatural processes. Other natural processesinclude respiration, assimilation, growth,mineralization, erosion, nitrogen fixation,predation, herbivory, competition, reproduction,succession, migration, carbon sequestration,and adaptation.

7. Divide students into pairs and hand each pairone or two of the process cards found onTeacher Page A1, Natural Process Cards.

NOTE: If you have a large class, you maymake two copies of the cards, allowingdifferent groups to work on the same card.

Refer to the three ecosystem functions onthe board (the fixation of energy, the flow ofenergy, the cycling of matter). Tell the studentpairs that they will need to read the definitionof their term to the class, match their naturalprocess to one of the three ecosystemsfunctions, and explain how it is related.Groups with the same card should approachthe board together and work out any differencesin front of the class.

8. Guide the class through following example:

Who has the card “carbon sequestration?”What is the definition of carbon sequestration?(The capture and storage of carbon dioxidefrom the atmosphere into biotic [e.g., trees]or abiotic [e.g., coal] pools of carbon.) Whatis carbon used for in a tree? (It is the main

component of cellulose [wood].) Which functiondepends on the natural process of carbonsequestration? (The cycling of matter.) Doescarbon provide energy? (No. Carbon is matter,an element that trees need to survive.) Howis the process of carbon sequestration relatedto the cycling of matter in an ecosystem?(As trees convert solar energy into chemicalenergy [photosynthesis] they also absorbcarbon from the atmosphere [they grow].A tree’s biomass is primarily carbon in theform of cellulose [wood]. As organisms eat theplant matter or wood from a tree, they takeand use the carbon. As trees and animalsdie, the carbon in their bodies is added tothe soil. Insects, fungi, and microorganismsdecompose the plant and animal material,releasing the carbon back to the atmosphere.)

Tell students that some processes are part ofmore than one ecosystem function.

9. After you have helped the students write theprocess in the correct place(s) on the boardand explain why it is an important part of theecosystem function, have the rest of the classattempt to do the same with their cards. Oncestudents are ready, have them raise theirhands and proceed one at a time.

The relationships between natural processesand ecosystem functions should be similar tothe following:

• The fixation of energy: photosynthesis,assimilation

• The flow of energy through food webs:assimilation, competition, decomposition,predation/herbivory, migration, reproduction

• The cycling of matter: carbon sequestration,mineralization, decomposition, erosion,nitrogen fixation, weathering

10. Once the list is complete, tell students tocopy it down because they can use it whenwriting their short stories.


ACTIVITY 2 – Odyssey1. After students have read “Odyssey,” have them

work in small groups to map the odyssey ofatom X and atom Y (you may wish to havesome groups do X and others do Y). Have thegroups identify, in paragraph or diagram form,in which living and nonliving things X residedand describe how the atom got there (identifythe natural process). Once the groups arefinished, have them explain parts of theirinterpretation to the rest of the class.

2. After students have described the odysseyof atom X, lead a discussion on what thestudents thought about the way Aldo Leopoldpresented it. You may wish to ask thefollowing questions:

• What was different about your briefdescription of the atom’s journey andLeopold’s?

• Did you think the essay was interesting?• What did the essay make you think about?• Did you understand everything?• Did it leave any questions unanswered?• Do you think the essay is scientifically and

historically accurate?• Was it too technical to understand?

Further the discussion by asking about thecontent of the essay.

• What ecosystem(s) did Leopold write about?• What processes did Leopold write about?• What concepts or themes are emphasized

in the writing?

As students try to find concepts and themesin the writing, put all of their ideas on theboard. Guide them to the following concepts:change, interconnectivity, and sustainability.Use a few examples from the writing thatillustrate the concepts.

NOTE: Examples for each concept are foundin the section “Odyssey Concepts” of theBackground Information.

ACTIVITY 3 – Forest Ecosystem Research1. Ask students if it is apparent that Aldo Leopold

had an indepth understanding of the ecosystemshe was writing about. (Yes.) Tell students thatduring the next few class periods, they will bepreparing to write an essay similar to AldoLeopold’s “Odyssey.” They will write about theodyssey of an atom through a forest ecosystem.

Ask students what kind of preparation theywill need before writing the essay. (They willneed to study the natural history, ecology, andhuman aspects of forest ecosystems.) Tellstudents that they will do research about threedistinct forest ecosystems.

2. Write the following forested ecosystemnames on the board: Oak Savanna, ForestedWetland, and Northern Hardwood Forest.

Help students discuss what they know abouteach of the ecosystems. Have them makeinferences into what type of animals live thereand where the ecosystems are located inWisconsin. Have students attempt to compareand contrast the environmental conditions ofeach forest.

3. Once all three ecosystems are discussed,divide the class into three large groups. Tellthe groups that each of them will researchone of the ecosystems listed. Assign groupsto work on a specific ecosystem and hand allof the students in each group a copy of the corresponding student pages – either StudentPages 2A-B, Forest Ecosystem Profile:Oak Savanna OR 3A-B, Forest EcosystemProfile: Forested Wetland OR 4A-B, ForestEcosystem Profile: Northern Hardwood Forest.

Give the students 10 minutes to read theirprofile and highlight information that they feelwill be important when developing an essaysimilar to Leopold’s “Odyssey.” Remindthem that the story uses the concepts ofinterconnectivity, change, and sustainability.Answer any questions that students have.


4. Ask the class if the profiles are missing anyinformation that they might need. (They havea section on change and sustainability, but aremissing any mention of interconnectivity.) Askthe students to list ways that they think thatforest ecosystems are connected to otherecosystems. Help them come up with thefollowing ideas:

• Many animals move from ecosystemto ecosystem and depend on forestecosystems for different parts of theirlife cycle.

• Many ecosystems depend on waterresources that come from forest ecosystems.

• Fire can start in a forest ecosystem andmove to other ecosystems.

• Forest ecosystems can influence theclimate patterns and moisture levels ofneighboring ecosystems.

• Soil erosion from an ecosystem canaffect the water quality and landscapecharacteristics of neighboring ecosystems.

5. Tell the large groups that to finish their profilethey will need to do some research outsideof class. Have each student find a partnerwithin their large group to do researchwith. Explain that each student pair will doresearch on one specific aspect of ecosysteminterconnectivity – food webs. During theirresearch, each student pair should look forthe following information:

• Animals and plants common to theirecosystem

• Feeding relationships between the animalsand plants in their ecosystem

• Migration patterns, feeding habits, andother life cycle characteristics that connectanimals in their ecosystem to otherecosystems

Tell the students that they can use the internet,classroom resources, school library, and publiclibrary to find information. Students should

bring copies of the resources to class. Discussthe importance of citing resources when doingresearch. Explain to students the way youexpect resources to be cited for this project.

6. To better facilitate student research, youmay wish to give each student pair a copyof Teacher Page A2, Habitat and Wildlife.They can use the general habitat and wildlifedescription about their ecosystem to getstarted with their research.

You may also wish to have them brainstormsome good internet search terms. The listshould include the following: “Wisconsinwildlife,” “animal habitat,” “wildlife andhabitat and Wisconsin,” “forest ecosystemsin Wisconsin,” “forested wetlands andWisconsin,” “oak savannas and Wisconsin,”“northern hardwoods and Wisconsin.”

7. Once the student pairs understand theirresearch assignment, have the large groupsdiscuss and decide their research strategy.Tell the large groups that they will worktogether and use all of the research from eachstudent pair to form food webs that describethe wildlife relations in their ecosystem.

Tell them that it might be wise to divide thework so that students do not bring the sameinformation to class. You may wish to give thelarge groups the following suggestions:

• Divide research by animal group: predatorybirds, migratory birds, predatory mammals,large mammals, small mammals, reptiles,amphibians, detritivores, introducedspecies, etc.

• Divide research by location: internet,classroom resources, school library (books,magazines, digital), public library (books,magazines, digital)


Once the large groups have their researchplan, answer any questions they have aboutresearch methods. Tell students that they willmost likely come across a lot of “generic”wildlife information that is not specific to theirecosystem. Explain that a good strategywould be to find an organism that uses theirecosystem as habitat, and further researchthe habitat needs and feeding relationshipsof that organism.

NOTE: It may be helpful if you bring to classsome sample resources that students cansee (e.g., a printed page from an internetsite, a copy of a magazine article, a pagein a textbook). Resource ideas are listed onpage 27. You may also wish to give a minimumand maximum number of resources that eachstudent pair should bring.

ACTIVITY 4 – Forest Ecosystem Profiles1. Once the groups have done their research,

have them reconvene to review their findingsand form food webs for their ecosystem. Tellthe class that their large groups are going towork together to review the resources, identifyimportant information, and develop the foodwebs that explain the wildlife and habitatrelationships in their ecosystem.

Hand each student pair a copy of Student Page5, Food Webs. Review the food web shown

on the page, emphasizing how the relationshipsare identified and explained. Tell the class thateach large group should produce two to threefood webs similar to the example.

2. Direct students to the second part of thestudent page, “Group Assignment.” Tell thestudents that to complete the assignmenteach large group will need to assign thefollowing roles to its members:

• Group leader (1 student): lead largegroup discussions and help the groupagree on important information to includein the food webs

• Organizer (1-2 students): highlight andtake notes about the information that will beincluded in the food webs, create resourcecitation page

• Web designer (2-3 students): draw thefood web diagrams using the informationgathered by the notetaker

• Web profiler (2-3 students): write a shortparagraph describing each food web

• Presenter (1-2 students): use the foodweb diagrams and description to do afive-minute presentation to the rest ofthe class

Tell the class that each of the small groupsshould present their resources to the othermembers of their large group. The groupleader should help the large group review anddiscuss each of the materials and identify theimportant information in each.

Once the information is identified, webdesigners and web profilers should depictthe food webs in a drawing and describethem in writing. When all the work is complete,presenters from each group should use theirdiagrams to explain the food webs in theirecosystem to the rest of the class.

3. Before beginning the presentations, highlightsome main points in each of the ecosystemprofiles. As each group presents their foodwebs, correlate the wildlife and habitat todifferent aspects of the ecosystem. Emphasizethe points by asking questions and continuingdiscussion.

Once the presentations are finished, helpstudents compare and contrast some of theenvironmental conditions, major naturalprocesses, wildlife, and human elements ofeach of the ecosystems. You can use TeacherPage A2, Habitat and Wildlife to verify thestudents’ information.


CONCLUSION – Group Odyssey1. After the discussion is complete, arrange the

room so that the class can sit in a large circle.Be sure that students are segregated by group.

2. Explain to the class that just like in Leopold’s“Odyssey,” they are going to describethe journey of an atom. Each student willcontribute a part to the story. The storywill move from student to student until it completes the full circle.

Tell the students that the first person willdescribe where the atom is (e.g., as part ofa beaver’s front teeth), what happens to it(e.g., the teeth erode as the beaver usesthem to fell trees), and where it ends up(a mushroom grows on the wood chips andassimilates the atom). As the student identifiesthe beginning location, the natural process,and the destination of the atom, be sure theycan explain how it happens and how it ischaracteristic of their ecosystem. The atom’sjourney must be realistic.

The student next in line will need to inventwhat happens to the atom and where it endsup. This continues around the circle.

When the story is passed to a student with adifferent ecosystem profile, an interconnectionneeds to be identified and used. This is veryimportant since the character of the storyshould change as the atom moves to adifferent ecosystem. Play the role of thefacilitator by clarifying points, describingnatural processes, and distinguishing theecosystems from one another.

3. Start the circle as described above and haveeach student write down where the atomstarts, what happens to it, and where it endsup during their turn. This first round will formthe structure of the story.

4. After the first round is completed, tell studentsthat they have created the structure of a

story that is plausible, based in science andecology. Ask students what they will have todo to make it into an essay like Leopold’s“Odyssey.” (They need to make it readable,interesting, and creative. They need to givethe reader a reason to continue reading byrelating it to their life.)

Give students a few minutes to write aparagraph about their piece of the story.Tell them that they need to use the samestructure as they did in the first round butshould expand on their idea. Ask them touse creative writing element that make thejourney of the atom come to life for the reader.They can further explain the situation; smells,colors, time span, hidden meanings, etc.

You may wish to give students the followingexample:

5. Once the students have their paragraphsready, start the second round of the circle byhaving the students read their paragraphs oneafter the other. Once the story is read, allowstudents to discuss what they liked and didn’tlike, if it was realistic, and what they learned.You may want to record the story on tape forstudy or transcription later.


X rested in the wood chips at the base ofa fallen aspen tree. The beaver had beenindustrious. It had worn away a good bitof its teeth during the last week, allowingatom X a brief taste of freedom after themonths trapped in the tooth’s prison-likestructure. In a matter of weeks, a softbreeze and gentle rain brought a mushroomspore to the surface of the newly exposedwood. It grew quickly, incorporating atomX into its cap and preparing to continuethe cycle of life and death with which Xwas so familiar.

SUMMATIVE ASSESSMENT Tell students to use the information they learnedabout forest ecosystems and the developmentof science-based creative writings to create theirown essay (one to two pages) similar to AldoLeopold’s “Odyssey.” Have them, like Leopold,tell the story from the atom’s perspectiveand emphasize the concepts of change,interconnectivity, and sustainability.

You may want to allow the students to becreative when choosing the location and timethey choose to write about. Ideas might includeforests of the past, urban environments, themoon, and ecosystems of the future.

Explain to students that the key to writing agood science-based, creative essay is to bescientifically accurate, while at the same time,use common sense, broadly understoodrelationships, and well-known examples thatpeople can relate to. The essay should be easyto understand, interesting, and help the readerbetter understand the concepts of change,interconnectivity, and sustainability.

NOTE: Students may need a few days to properlydevelop the creative aspects of their essay. Asample of student work can be found on page 28.You may wish to share this with students to helpgenerate ideas.

REFERENCESThe Aldo Leopold Foundation. Aldo Leopold:Biography. World Wide Web: www.aldoleopold.org/Biography/Biography.htm

Anderson, R. C. et al. (1999). Savannas,Barrens, and Rock Outcrop Plant Communitiesof North America. New York: CambridgeUniversity Press.

Benyus, J. M. (1989). Northwoods Wildlife: AWatcher’s Guide to Habitats. Minocqua, WI:Northwoods Press.

Cochrane, T. S. & Iltis, H. H. (2000). Atlas of theWisconsin Prairie and Savanna Flora. Madison,WI: Wisconsin Department of Natural Resources.Technical Bulletin No. 191.

Cunningham, W. P. & Cunningham, M. (2002).Principles of Environmental Science: Inquiry andApplications. New York: McGraw Hill.

Curtis, J. T. (1959). The Vegetation of Wisconsin:An Ordination of Plant Communities. Madison,WI: University of Wisconsin Press.

Finan, A. S. (Ed). (2000). Wisconsin’s Forests atthe Millennium: an Assessment. Madison, WI:Wisconsin Department of Natural Resources.PUB-FR-161 2000.

Helms, J. A. (1998). The Dictionary of Forestry.The Society of American Foresters.

Hoffman, R. (2002). Wisconsin’s NaturalCommunities. Madison, WI: University ofWisconsin Press.

Kimmins, J. P. (1997). Forest Ecology: AFoundation for Sustainable Management. 2nded. New Jersey: Prentice-Hall, Inc.

Leopold, A. (1949). A Sand County Almanac.Oxford University Press.

Packham, F. R. & Harding, D. J. L. (1982).Ecology of Woodland Processes. London:Edward Arnold.

Trettin, C. C. et al. (1997). Northern ForestedWetlands: Ecology and Management. BocaRaton: CRC Press, Inc.

Wisconsin Ecological Landscapes Handbook.(2001). Madison, WI: Wisconsin Department ofNatural Resources. Handbook 1805.1.

Wisconsin Forest Management Guidelines.(2003). Madison, WI: Wisconsin Departmentof Natural Resources. PUB-FR-226 2003.



RECOMMENDED RESOURCES••• BOOKS •••

A Sand County Almanac by Aldo Leopold. (Oxford University Press, 1949.) Many essays in A SandCounty Almanac provide insight into the human aspects and sustainability of Wisconsin ecosystems.

Wisconsin’s Forests at the Millennium: an Assessment. (Ann-Marie S. Finan, Editor, WisconsinDepartment of Natural Resources, 2000, PUB-FR-161 2000.) This WDNR publication containsecological, social, and economic information about Wisconsin’s forests. It provides a goodframework to discuss challenges to forest sustainability.

Books Useful to Students as They Research and Develop Food Webs for Wisconsin’sNorthern Hardwood, Forested Wetland, and Savanna Ecosystems:Northwoods Wildlife: A Watcher’s Guide to Habitats by Janine M. Benyus. (Northwoods Press,Inc., 1989.)

Wisconsin’s Natural Communities by Randy Hoffman. (University of Wisconsin Press, 2002.)

Mammals of Wisconsin by Hartley H. T. Jackson. (University of Wisconsin Press, 1961.)

North American Owls: Biology and Natural History by Paul A. Johnsgard. (Smithsonian Institution, 1988.)

Hawks, Eagles, and Falcons of North America by Paul A. Johnsgard. (Smithsonian Institution, 1990.)

Mammals of the Great Lakes Region by Allen Kurta. (University of Michigan Press, 1995.)

A Guide to Bird Behavior Vol. 1 by Donald W. Stokes. (Little, Brown and Co., 1979.)



••• WEBSITE •••Natural Communities of Wisconsin ............................www.dnr.state.wi.us/landscapes/communityThis DNR website contains links to the natural communities in each of the ecosystem profiles usedin this lesson. Information includes natural history, wildlife, statistics, etc.


SAMPLE STUDENT ESSAY

THE ADVENTURES OF LEWIS

From an atom’s point of view, the world is a big place. There are many

things and places to see.

Lewis found himself in a leaf, resting atop a majestic black oak. He had

been there since spring but he could feel it getting colder and he knew he

would be on the move again. A couple months later, he broke free and was

swept away in a gust.After the snow had come and gone, he was part of the soil and became a

patch of ladder lichen. Lewis went straight to the top of one of the lobes as

he did in the black oak, but this time he was eaten by a deer mouse.

After finishing some more of the lichen, the deer mouse returned to her

hole only to find it overrun with snakes that had eaten her three offspring.

She turned and ran but was no match for the quickness of the snake. Soon

Lewis found himself part of the snake’s skin.

Three weeks later, Lewis was shed along with the skin. The skin then

decomposed and turned to rich soil that then became the bed of a small creek.

Lewis rode the current for many miles until the rich soil was washed ashore and

covered some seeds that sprouted into water reeds.

When the reeds were full-grown they stood about four feet tall. One day

Lewis could feel something tickling him but couldn’t figure out what is was.

He then found himself in the stomach of a caterpillar. After the reed meal,

the caterpillar hung himself up and turned into a chrysalis. Weeks later, it had

transformed into a monarch butterfly. As summer was ending, the monarch,

with thousands of its friends, traveled south to Mexico. Lewis and the monarch

never made it. During a strong windstorm in Northern Texas, the monarch lost

control and was thrown into the side of a cliff.

The monarch decomposed and Lewis sank deeper into the ground until he

found some graphite. He became friends with the other atoms so he bonded

with them.Many years later, he was dug up with all his friends and put on a truck.

Together they went to a factory where they were ground up and put into a

mold. Then they were pressed together and wrapped in a wooden blanket. Lewis

and the rest of the graphite-filled wooden rods were packaged and sent to the

store. I picked up Lewis and his friends and brought them to school. So, Lewis,

who began as a leaf on an oak tree, ended up in the last period on this page.


A1

NATURAL PROCESS CARDS

PHOTOSYNTHESIS

The process by whichplants convert the

electromagnetic energyof the sun into chemicalenergy usable by other

organisms.

WEATHERING

The process bywhich rocks are broken

down into mineralsusable by plants.

CARBONSEQUESTRATION

The capture and storageof carbon dioxide from

the atmosphere into biotic(e.g., trees) or abiotic

(e.g., coal) pools of carbon.

COMPETITION

The struggle that existsamong organisms to

acquire finite resources(e.g., light, space,nutrients, water).

REPRODUCTION

The process bywhich organismsproduce offspring.

MINERALIZATION

The conversion of anelement from an organic

to an inorganic form;combustion, the act ofburning, is a very rapidform of mineralization.

ASSIMILATION

The incorporation ofenergy and nutrients

into the bodies ofplants or animals.

EROSION

The wearing away of theland surface by rain,

running water, wind, ice,gravity, or other natural

or human forces.

HERBIVORY

The consumption ofliving plant material.

DECOMPOSITION

The breakdown oforganic matter intosimple compoundsavailable for use

by plants.

NITROGEN FIXATION

The process by whichatmospheric nitrogenis made available for

use by plantsin an ecosystem.

MIGRATION

The repeated movementof a population of

organisms from oneecosystem to another.

HABITAT AND WILDLIFEOAK SAVANNAProbably the most well-known wildlife speciesassociated with savanna is the American bison.Bison in Wisconsin were killed off by hunters inthe 1800s. In the Midwest, they are currentlyclassified as extirpated, meaning that there areno wild populations. In Wisconsin, all of thelarge mammals that once lived in the savannas(namely the elk, lynx, and bobcat) have sharedsimilar histories, yet, in recent years, the bobcathas shown signs of recovery.

The areas of savanna that remain provide habitatfor the coyote, fox squirrel, red fox, woodchuck,and striped ground squirrel. They provide crucialhabitat for the sharp-tailed grouse, swallow tailedkite, Karner blue butterfly, and the greater prairiechicken. Many important wildlife plants are foundin savannas, such as huckleberry and blueberry.Savannas are also home to some endangeredplants, including wild blue lupine, sand flameflower,and goat’s rue.

FORESTED WETLANDIn lowland broadleaf forests, the overstory ispartially open so that direct sunlight often reachesshrubs and plants. The open layers are used by birds such as flycatchers to catch insects.Standing and fallen dead trees supply abundantcrevices and cavities for raccoons and wood ducks.They also provide perfect perches for the barredowl that waits patiently to swoop down and feedon an unsuspecting mouse, frog, bird, or snake.Dense clumps of shrubs, such as dogwood, willow,and alder, provide cover for small birds, like theveery, and mammals, such as the woodlandjumping mouse. A rich assortment of ferns,sedges, and grasses grow in the cool moistground layer and provide habitat for heat- andmoisture-sensitive species, such as the four-toedsalamander and the wood frog. The grass is firstto green-up in spring and is heavily used byblack bears.

There are two distinct varieties of lowland coniferforest: black spruce bogs and white cedar swamps.Few animals make their homes in spruce bogs,and those that do, capitalize on the limited foodavailable. The spruce grouse feeds on conifer

needles and the leaves of healthy plants.Songbirds (like warblers, kinglets, andchickadees) and squirrels pry seeds out ofthe tiny spruce cones and the three toedwoodpecker chisels in dead trees for insectlarvae. The great grey owl scans the sphagnummoss for rodents and can plunge in up to18 inches below the bog surface to feed.

White cedar swamps are known to be mildenvironments in the winter because the densecedar canopy provides protection from wind andshelter from snow. Wildlife finds not only shelter,but plenty to eat. White-tailed deer strip whitecedar branches clean and porcupines often eatbark from the trunks. Snowshoe hares are prizedprey for the great horned owl and eastern timberwolf. Many insect-eating songbirds, like thenorthern parula, can be found in large numberswhen insects are present.

NORTHERN HARDWOOD FORESTSome of the most well-known wildlife species in northern hardwood forests are the northerngoshawk, ruffed grouse, neotropical birds (suchas the blue-headed vireo), the fisher, black bear,redneck salamander, and the ringneck snake.Wildlife species have both deciduous andconiferous trees at their disposal. The southernflying squirrel will often find habitat in birch treesnext to the ruby-crowned kinglet that depends onconiferous trees, like spruce, for its needs.

Neotropical birds migrate each spring from tropicalareas in Central America, South America, and theCaribbean. They reproduce in the northern forestsand return to the tropics as winter approaches.The birds depend on habitat in both regions tosurvive. The fisher, a type of weasel, is one ofthe top carnivores in northern hardwood forests.Since the fisher needs about one and a halfpounds of food a day, it has become a veryefficient predator of snowshoe hares, squirrels,mice, shrews, game birds, and even porcupines.Not long ago it was almost impossible to see afisher in the wild, but thanks to conservation andreintroduction efforts, the mammals have madea comeback in many areas.


A2


1A

ALDO LEOPOLD’S “ODYSSEY”X had marked time in the limestone ledgesince the Paleozoic seas covered the land.Time, to an atom locked in a rock, doesnot pass.

The break came when a bur oak root noseddown a crack and began prying and sucking.In the flash of a century the rock decayed, andX was pulled out and up into the world of livingthings. He helped build a flower, which becamean acorn, which fattened a deer, which fed anIndian, all in a single year.

From his birth in the Indian’s bones, X joinedagain in chase and flight, feast and famine,hope and fear. He felt these things as changesin the little chemical pushes and pulls that tugtimelessly at every atom. When the Indian tookhis leave of the prairie, X moldered brieflyunderground, only to embark on a second tripthrough the bloodstream of the land.

This time it was a rootlet of bluestem thatsucked him up and lodged him in a leaf thatrode the green billows of the prairie June,sharing the common task of hoarding sunlight.To this leaf also fell an uncommon task: flickingshadows across a plover’s eggs. The ecstaticplover, hovering overhead, poured praises onsomething perfect: perhaps the eggs, perhapsthe shadows, or perhaps the haze of pinkphlox that lay on the prairie.

When the departing plovers set wing for theArgentine, all the bluestems waved farewellwith tall new tassels. When the first geesecame out of the north and all the bluestemsglowed wine-red, a forehanded deer mouse cut the leaf in which X lay, and buried it in anunderground nest, as if to hide a bit of Indiansummer from the thieving frosts. But a foxdetained the mouse, molds and fungi took the nest apart, and X lay in the soil again, foot-loose and fancy-free.

Next he entered a tuft of side-oats grama, abuffalo, a buffalo chip, and again the soil. Nexta spiderwort, a rabbit, and an owl. Thence atuft of sporobolus.

All routines come to an end. This one endedwith a prairie fire, which reduced the prairieplants to smoke, gas, and ashes. Phosphorusand potash atoms stayed in the ash, but thenitrogen atoms were gone with the wind. Aspectator might, at this point, have predictedan early end of the biotic drama, for with firesexhausting the nitrogen, the soil might wellhave lost its plants and blown away.

But the prairie had two strings to its bow. Fires thinned its grasses, but they thickened its stand of leguminous herbs: prairie clover,bush clover, wild bean, vetch, lead-plant,trefoil, and Baptisia, each carrying its ownbacteria housed in nodules on its rootlets.Each nodule pumped nitrogen out of the airinto the plant, and then ultimately into the soil.Thus the prairie savings bank took in morenitrogen from its legumes than it paid out to its fires. That the prairie is rich is known to the humblest deer mouse; why the prairie isrich is a question seldom asked in all the stilllapse of ages.

Between each of his excursions through thebiota, X lay in the soil and was carried by therains, inch by inch, downhill. Living plantsretarded the wash by impounding atoms; dead plants by locking them to their decayedtissues. Animals ate the plants and carriedthem briefly uphill or downhill, depending onwhether they died or defecated higher or lowerthan they fed. No animal was aware that thealtitude of his death was more important thanhis manner of dying. Thus a fox caught agopher in a meadow, carrying X uphill to hisbed on the brow of a ledge, where an eaglelaid him low. The dying fox sensed the end of his chapter in foxdom, but not the newbeginning in the odyssey of an atom.


1B

ALDO LEOPOLD’S “ODYSSEY”(continued)

An Indian eventually inherited the eagle’splumes, and with them propitiated the Fates,whom he assumed had a special interest inIndians. It did not occur to him that they mightbe busy casting dice against gravity; that miceand men, soils and songs, might be merelyways to retard the march of atoms to the sea.

One year, while X lay in a cottonwood by theriver, he was eaten by a beaver, an animal thatalways feeds higher than he dies. The beaverstarved when his pond dried up during a bitterfrost. X rode the carcass down the springfreshet, losing more altitude each hour thanheretofore in a century. He ended up in the siltof a backwater bayou, where he fed a crayfish,a coon, and then and Indian, who laid himdown to his last sleep in a mound on the riverbank. One spring an oxbow caved the bank,and after one short week of freshet X lay againin his ancient prison, the sea.

An atom at large in the biota is too free toknow freedom; an atom back in the sea hasforgotten it. For every atom lost to the sea, theprairie pulls another out of the decaying rocks.The only certain truth is that its creatures must suck hard, live fast, and die often, lest its losses exceed its gains.

******************************************

It is the nature of roots to nose into cracks.When Y was thus released from the parentledge, a new animal had arrived and begunredding up the prairie to fit his own notions oflaw and order. An ox team turned the prairiesod, and Y began a succession of dizzy annualtrips through a new grass called wheat.

The old prairie lived by the diversity of itsplants and animals, all of which were usefulbecause the sum total of their co-operationsand competitions achieved continuity. But thewheat farmer was a builder of categories; tohim only wheat and oxen were useful. He sawthe useless pigeons settle in cloud upon his

wheat, and shortly cleared the skies of them.He saw the chinch bugs take over the stealingjob, and fumed because here was a uselessthing too small to kill. He failed to see thedownward wash of over-wheated loam, laidbare in spring against the pelting rains. Whensoil-wash and chinch bugs finally put an end to wheat farming, Y and his like had alreadytraveled far down the watershed.

When the empire of wheat collapsed, thesettler took a leaf from the old prairie book; he impounded his fertility in livestock, heaugmented it with nitrogen-pumping alfalfa,and he tapped the lower layers of the loamwith deep-rooted corn.

But he used his alfalfa, and every other newweapon against wash, not only to hold his oldplowing, but also to exploit new ones which, in turn, needed holding.

So, despite alfalfa, the black loam grewgradually thinner. Erosion engineers built damsand terraces to hold it. Army engineers builtlevees and wing-dams to flush it from the rivers.The rivers would not flush, but raised their beds instead, thus choking navigation. So theengineers built pools like gigantic beaver ponds,and Y landed in one of these, his trip from rockto river completed in one short century.

On first reaching the pool, Y made severaltrips through water plants, fish, and waterfowl.But engineers built sewers as well as dams,and down them comes the loot of all the farhills and the sea. The atoms that once grewpasque-flowers to greet the returning ploversnow lie inert, confused, imprisoned in oily sludge.

Roots still nose among the rocks. Rainsstill pelt the fields. Deer mice still hide theirsouvenirs of Indian summer. Old men whohelped destroy the pigeons still recount theglory of the fluttering hosts. Black and whitebuffalo pass in and out of red barns, offeringfree rides to itinerant atoms.

FOREST ECOSYSTEM PROFILE:OAK SAVANNA

GENERAL ECOSYSTEMDESCRIPTIONOak savannas in the Great Lakes region occurin Minnesota, Wisconsin, Michigan, Iowa,Illinois, Indiana, and Ohio. This ecosystem ischaracterized by dry soils, limited moisture,and periodic wildfire. Oak savannas generallycontain an understory of prairie grasses andplants but can have a variety of different treecompositions and structures.

The common forest structure and treecomposition for savannas is as follows:

• oak savanna: widely spaced oak trees• oak barren: an even-aged stand of small

oak trees• jack pine barren: an even-aged stand of

small jack pine trees• brush prairie: small scattered oak trees

and other shrubs

In this profile, the term “savanna” is used todescribe all of the above.

Savannas in Wisconsin are found on glaciallandscapes (moraines, outwash plains, andhistoric lake beds) and on the more nutrientrich soils of southwest Wisconsin. In northernWisconsin, northern pin oak, northern red oakand jack pine are the common trees present insavannas. In southern Wisconsin, bur oak, whiteoak, black oak, and Hill’s oak are common.

CHANGEThe formation of the Rocky Mountains,beginning 60 million years ago, created climate conditions suitable for grasslandsacross what is now the Great Plains and intothe tall grass prairies of Wisconsin. Savannaswere predominantly found on the fringe of thelarge grassland region, but could also be foundscattered throughout the area.

Savannas developed from other forestecosystems through time due to the dryclimate patterns and a variety of environmentalfactors. The most influential factor was periodicground fires. Naturally occurring ground fireskilled the undergrowth and small trees, leavingonly widely spaced, mature fire-resistant trees.Prairie plants and grasses that were adaptedto fire, like little and big bluestem, became anestablished component of the ecosystem.

When the first government land surveys were done in Wisconsin in the late 1800s, it was estimated that 4.2 million acres of thelandscape (12.1%) could be characterized as savanna. Today only 50,000 acres remain(0.15%). Though this is a small percentage, it is considerably more than the 0.02% of the presettlement savanna that is left in theMidwest as a whole.

Most of the original savannas were logged and abandoned in the early 1900s. Loggersleft behind many branches and dead trees that allowed fires to move to the crowns ofremaining trees and spread to other forestedareas. Many trees died due to intensewildfires. The abandoned lands were thenconverted to farmland, used as grazing areasfor cattle, or overtopped by urban areas. In some small, scattered undeveloped areasplant communities regenerated, but theperiodic ground fires that shaped the structureand composition of the savanna were absent.Human populations suppressed wildfires toprotect homes and property. The absence offire left many of the areas to form into oakwoodlands and mixed hardwood forests.


2A

FOREST ECOSYSTEM PROFILE:OAK SAVANNA

NATURAL PROCESSESLargely due to the influence of ground fires,savanna ecosystems cycle matter rapidly. As fires pass through the ecosystem, thechemical energy bound in the organic matter is transformed into heat energy and lost as the matter is broken down. Some minerals andnutrients are lost, but many remain in the soiland are used by the next generation of plantsand trees.

Fires speed up the process of mineralizationthat is needed to make minerals and nutrientsavailable to plants and trees. During normaldecomposition, this process can take years,decades, and even centuries, but fire cancomplete this process in hours or days. Somenutrients are available to plants after fires, butmuch of the nitrogen is lost to the atmosphere.

Some nitrogen is replaced in the ecosystem by lightning and certain species of soil fungi,but most nitrogen is replaced by plants thathave a symbiotic relationship with soil bacteria.Working with the bacteria, plants add nitrogento the soil through the process of nitrogenfixation. The majority of plants and trees do not have the ability to fix nitrogen and can onlyuse the nitrogen made available by nitrogenfixing plants. The rate of plant growth is mostoften limited by the rate that nitrogen is fixed in the soil.

SUSTAINABILITYTemperate savanna is one of the mostendangered ecosystems in the world. It iswidely understood that the restoration of oak savannas and prairie ecosystems to itspresettlement areas is not feasible. Thesavanna, once characteristic of the MidwesternU.S., is today only 0.02% of its original size.

The savannas that existed before settlementwere vast expanses of open land that hostedherds of buffalo, elk, and deer in a fashionsimilar to the herds of zebra, gazelle, andwildebeest of the African savanna. This is notlikely to be restored in today’s agricultural andhuman landscape, yet efforts to conserve theremnant savannas, barrens, and grasslandswill protect the wildlife that depend on them.

Major threats to the remnant savannas includefire suppression, development, and introducedspecies. Like many forested ecosystems faced with the conditions of today’s populatedlandscape, the savannas require active forestmanagement to maintain healthy biologicalcommunities characteristic of the ecosystem.Savannas will require controlled burns tomaintain the forest structure and composition,the control of introduced species to protectnative flora and fauna, and wildlife managementto ensure that native wildlife populationscontinue to thrive.

Even-aged: A group of trees that are allnearly the same age.

Moraine: A ridge or mound of boulders,gravel, sand, and clay left behind by a glacier.

Structure: The horizontal and verticaldistribution of layers in a forest, includingheight, diameter, and species present.

• V O C A B U L A R Y •


2B


3AFOREST ECOSYSTEM PROFILE:

FORESTED WETLANDGENERAL ECOSYSTEMDESCRIPTIONForested wetlands are defined as forestedareas that are transitional between terrestrialand aquatic systems. The water table isusually at or near the soil surface. Wetlandsare referred to by many names, including mire,bog, fen, swamp, and marsh. Two distincttypes of wetland forest exist in Wisconsin: the lowland conifer forest and the lowlandbroadleaf forest. In the lowland conifer forest,white cedar, tamarack, balsam fir, and blackspruce are common. In the lowland broadleafforest, black ash, red maple, yellow birch, andbasswood trees are common.

In Wisconsin, forested wetlands are found in the low-lying areas of glaciated landscapesand alongside rivers. They are often associatedwith ponds, kettle lakes, and streams. Theysupport unique plant and animal communities,help regulate water levels, and keep waterwaysfree of sediment and other pollutants.

CHANGEAlthough forested wetlands covered much ofthe Wisconsin landscape after the glaciersreceded 10,000 years ago, the majority ofthem supported only scattered, stunted trees.In most places in Wisconsin, the water tablewas too high to allow tree growth. A largeproportion of the total original wetland area has remained without trees, but in many areasthe water table has gradually lowered, allowingfor the expansion of forested wetlands acrossthe state.

During the period from 1830 to 1890, loggingand settlement activities began to drasticallyalter the northern forested regions ofWisconsin. Prior to 1900, white and red pines were the prized tree species for many

commercial loggers. Since these species werefound in upland forests, forested wetlandswere not severely affected until sometime after 1900. By the early 1900s, as the supplyof white and red pine were diminished, demandfor white cedar fence posts, railroad ties, andutility poles increased. Black spruce was cut asa substitute for white pine, and tamarack wascut for fence posts and log cabin construction.

Today, forested wetlands are used for timberand fiber products, hunting, fishing, trapping,recreation, and sanctuaries for plants andwildlife. Over the last half century, the majorityof forested wetlands in Wisconsin have beenlogged and some have been converted toagricultural or urban land use.

NATURAL PROCESSESWetlands are among the most important andbiologically diverse parts of forest ecosystems.They support a diversity of plants and wildlife,and they link aquatic and terrestrial ecosystems.Forested wetlands maintain shoreline stability,stream temperature, and water quality. Theystore water, provide nutrient and food input into aquatic systems, and provide habitat formany species of fish, mammals, birds, reptiles,amphibian, and insects.

Trees grow slowly in wetlands compared toother forest ecosystems in Wisconsin. Mostwetland soils are submerged under water for most or part of the year. The anoxic(without oxygen) soil conditions limit thenumber of microorganisms that are available to decompose organic matter. This slowsdecomposition, resulting in an accumulation of organic matter and a slow cycling ofnutrients through the ecosystem.

FOREST ECOSYSTEM PROFILE:FORESTED WETLAND

SUSTAINABILITYSince the widespread logging of Wisconsin’sforest in the early 1900s and the elimination of large predators from forest ecosystems (i.e., eastern timber wolf, bobcat), thepopulation of white-tailed deer has increaseddramatically. Deer eat tree saplings. Largepopulations of deer can severely affect the regeneration of forests. White cedarswamps are currently feeling these effects, andthe regeneration of white cedar trees has been difficult.

Clean water is essential to the quality of life.Forested wetlands play a very important role in the provision of clean water. Though manyforested wetlands have been logged andconverted to other land use, others have been managed for forestry or protected for environmental and/or social benefits.Management practices are used by manyforesters and private landowners across thestate to protect water resources. These

practices (such as logging when the wateris frozen in winter, leaving many standingtrees, and removing brush and other debris)reduce the environmental impacts of forestryby protecting shorelines, soils, and biologiccommunities.

Wetlands can be managed to provide bothecological and environmental benefits, butbecause of the wet soils, trees grow slowly,reducing the productivity of the site. Commonly,wetlands are drained before managing foreconomic benefits. This increases tree growthrates and allows greater access to the site, but severely alters the wetland ecosystem,ruining the habitat and environmental servicesthat wetlands provide. As logging pressureincreases on forested wetlands, theirsustainability will depend on our dedication to forestry practices that protect the physicalcharacteristics of the ecosystem.

Regeneration: Regrowth of trees naturally or by human means.



3B


4AFOREST ECOSYSTEM PROFILE:

NORTHERN HARDWOOD FORESTGENERAL ECOSYSTEMDESCRIPTIONThe term “hardwood” is often used to describebroadleaf, deciduous trees. This is becausetheir wood is typically harder than the wood of coniferous trees, which are often called“softwood” trees. Many northern hardwoodforests are composed of stands of deciduoustrees, including maple, aspen, birch, ash,basswood, and beech, but they also havemixed stands, which contain coniferous treessuch as hemlock, fir, white pine, and red pine.

Forests cover nearly 7,700,000 acres (12,000 square miles) in the northern part of Wisconsin. Due to disturbances such aslogging, fire, wind, and disease, a variety oftree ages are found in northern hardwoodforests. The vertical and horizontal contraststhat result tend to give the forest a patchworkappearance when viewed from the sky. Thisvariety provides a mixture of habitat for wildlife,making northern hardwood forests one of themost ecologically diverse on the continent.

Old growth forest areas are noticeably absentand make up less than 1% of northernhardwood forests in Wisconsin. Characteristicsof old growth forests in Wisconsin include largetrees, gaps in the canopy, multilayeredvegetation, large standing dead trees, andlarge fallen logs and limbs. Since the cutoverperiod in the early 1900s, forests have notyet had time to redevelop many of thesecharacteristics, yet more and more forests are approaching this stage.

CHANGEThe geologic history of the Great Lakes regionhas been dramatic. A billion years ago, amountain range similar to the Rocky Mountainsdominated the landscape. Hundreds of millionsof years of erosion, including glacial activity,

dulled the mountain peaks and reduced theirheight. When the last glaciers receded fromnorthern Wisconsin 12,000 years ago, they left a rolling landscape that is dotted with smallto medium-sized lakes. This glacial landscapesupports northern hardwood forests that weknow today.

Climate patterns have played major roles informing the northern hardwoods ecosystem.The convergence of warm gulf air and coldarctic air creates a zone that divides the stateof Wisconsin into a northern and southernregion. The “tension zone,” as it is called, is aclimate gradient that defines the northernmostrange of some trees (e.g., white oak, hickory)and southernmost range of others (e.g., northernhemlock, beech). Northern hardwood forestsare found entirely north of the tension zone.

Wind, fire, flooding, animals, human use, and disease have also shaped northernhardwood forests over time. Trees, plants, and animals adapt to the conditions createdfollowing the death of single trees and largeareas of trees. Trees are in constant competitionwith each other to make use of these areas.

By the early 1900s, nearly the entire expanseof northern hardwood forests was cut byloggers. Settlers attempted to turn much of what had been forest into farmland, but the majority went bankrupt due to the shortgrowing season and poor soil. High intensitywildfires burned through the slash left behindby the loggers, leaving many bare, charredlandscapes. As farms went bankrupt, woodsupplies ran dry, and the environmentaldamage became evident, the state began to reforest the cutover areas and provideincentives for landowners to replant and care for forests.


4B

NATURAL PROCESSESNorthern hardwood forests are productivecompared to other forest ecosystems inWisconsin due, in part, to the rich soil formedby the input of tree leaves, needles, andother plant matter. There is a diversity ofmicro-organisms in the soil due to a varietyof nutrient and pH conditions. Many northernhardwood forests contain a layer of rich,organic matter called humus just under theleaf layer. The rich topsoil layer supportsplant communities that are not found inother systems.

The most notable aspect of northern hardwoodforests is the great diversity of habitat thatexists and the complex food webs thatresult. Due to seasonal variations, localizeddisturbances, variety of tree ages, anddifferences in soil composition, habitatcan vary from place to place, season toseason, and year to year.

SUSTAINABILITYDue to the long disturbance history of northernhardwood forests (glaciers, fires, animalmigrations, disease outbreaks, windstorms,etc.), the plant and animal life was wellprepared for the near complete logging offorests starting in the late 1800s. It can be saidtoday that northern hardwood forests, with thehelp of many natural resource professionals,have recovered much of their originalbiodiversity. Forests have proven resilient, but many challenges still exist.

Many of the presettlement northern hardwoodforests are still designated as forestland, but old growth forest is scarce and thelandscape is fragmented by humandevelopment. The shift from a landscapedominated by old growth upland forests to one that has only scattered patches of old growth forested wetlands may haveunrecognized consequences for the region’splant and animal diversity. Introduced speciesand high population densities of white-tailed deer are also displacing plant and animalpopulations and placing pressure on somethreatened and endangered species.

FOREST ECOSYSTEM PROFILE:NORTHERN HARDWOOD FOREST

Slash: Branches, leaves, and twigs left after cutting down a tree.


FOOD WEBS


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The following food web represents the feedingrelationship between some of the organisms thatare widespread throughout different ecosystemsin Wisconsin. Many mammals, such as the skunkand raccoon, eat a variety of small mammals,reptiles, and plant materials. They can feed andreproduce in a variety of habitats and are knownto migrate over large areas. Predators like thered-tailed hawk are widely distributed because oftheir ability to hunt small animals and their abilityto move over large areas in short periods of time.They are the top predator in many ecosystemsand feed on a variety of small mammals, reptiles,and amphibians. The eastern garter snake can

survive in nearly every habitat including urbanareas, wetlands, and dry upland areas. It feedson frogs, salamanders, and mice, but has aprimary diet of earthworms and other detritivores.Earthworms, which are not native to Wisconsinforests, are spreading rapidly through forest soilsdue to transport by fishermen and the movementof soil to and from gardens and constructionsites. They digest plant material deposited on the forest floor by plants and trees. The nuts and seeds of both broadleaf and coniferous treesserve as a source of food for large mammalssuch as the raccoon, small mammals such as thedeer mouse, and many species of detritivores.

EXAMPLE FOOD WEB DESCRIPTION

• Group leader (1 student): lead large groupdiscussions and help the group agree onimportant information to include in thefood webs

• Organizer (1-2 students): highlight and takenotes about the information that will be includedin the food webs, create resource citation page

• Web designer (2-3 students): draw the foodweb diagrams using the information gatheredby the notetaker

• Web profiler (2-3 students): write a shortparagraph describing each food web

• Presenter (1-2 students): use the food webdiagrams and description to do a five-minutepresentation to the rest of the class

GROUP ASSIGNMENTTo create food web descriptions and food web diagrams for your forest ecosystem,

you will need to assume one of the following roles in your large group:

TERTIARYCONSUMER DECOMPOSERS PRODUCERSPRIMARY AND

SECONDARY CONSUMERS

Red-tailedhawk Skunk

Easterngartersnake

Tigersalamander

Deermouse

Raccoon

Springpeeper frog

Detritivores(earthworms,

wood lice,springtails,

snails,beetles, etc.) Plant

Material(bark, twigs,buds, leaves,

seeds,flowers, etc.)

EXAMPLE FOOD WEB DIAGRAM

LESSON › ... › 9-12L1.pdf · 2013-06-13 · A Sand County Almanac(1949), a volume of sketches...

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