C H A P TER 33 depends on...

Human survivaldepends on sustainableecosystems.

Biodiversity keepsecosystems strong andstable.

Indigenous knowledgecan help us achievesustainability.

Human activities candecrease biodiversity.

Humans can preserve,conserve, and restoreecosystems.

Humans can lessen theirecological footprint.

KEY IDEAS

Ribbit! These rare tailed frogs were lucky to have someone to speak upfor them. Some students in West Vancouver found tailed frogs in anarea where developers planned to build houses. The students’ interestencouraged the property owners to plan for the frogs’ survival. Theowners supported a five-year study to determine where tailed frogsexisted in the area. This is an example of how humans can worktogether to plan for the future of an ecosystem.

Endangered spaces usually mean endangered species. Is therea species of plant or animal in your community that needs yourvoice? Is there a space—a stream, a field, or a schoolyard—in yourcommunity that needs your voice? You, like the students in WestVancouver, can be a voice for endangered spaces and species.

Unit A Ecosystems58 NEL

• CHAPTER •

33

3.1 The Role of Humans in Ecosystems 59NEL

What is your place in your ecosystem? Do you visit nature, or do youthink of it as your home? Do you worry about your effect on otherspecies, or do you think non-human species are less important thanyou? Should people control ecosystems, or should people controltheir use of ecosystems? These are very complicated questions. Howpeople live in ecosystems depends on how they see themselves andtheir world (Figure 1).

The ecosystems of the natural world support the web of life.Energy flows from the Sun, and one species’ waste is another species’food. Matter cycles through ecosystems, creating a balance. Like allother living things, humans depend on ecosystems to provide theirneeds for survival and to recycle wastes.

The Role of Humans inEcosystems 3.13.1

Figure 1Do you think you can “conquer” nature?

LEARNING TIPWork with a partner anddiscuss the questions in thefirst paragraph. Compareyour reactions to those ofyour partner.

For most of human history, ecosystems were able to sustain, or bearthe weight of, their human populations over thousands and thousandsof years. This ability of ecosystems is called A sustainable ecosystem is able to replace the resources that peopleremove, and recycle the wastes that people put in.

Humans are a very successful species. As our populationcontinues to grow, so does our need for food, air, water, and shelter.Also, we produce more waste. Today, we often remove resourcesfaster than ecosystems can replace them. We often put wastes intoecosystems faster than the natural cycles can deal with them. As aresult, some ecosystems can no longer provide for other species.The other species die or leave.

Each time a species is lost from the web of life, the ecosystem isweakened. A strong ecosystem has a variety of species and complexinteractions. The variety of species in an ecosystem is called

Scientists know that a loss of biodiversity can threaten thesustainability of our ecosystems. This is such an importantproblem in our world today that the United Nations has developeda Convention on Biodiversity. It asks all the countries of the worldto pay more attention to the knowledge and ways of indigenouspeoples, the peoples who originally lived in an area (Figure 2).

biodiversity.

sustainability.


Figure 2The UN Convention on Biodiversity recognizes the important role of indigenousknowledge.

3.1 The Role of Humans in Ecosystems 61NEL

The longer you observe something, the more you learn about it.Aboriginal peoples have observed local ecosystems for thousandsof years. They have passed their knowledge from generation togeneration, often in the form of stories (Figure 3). Stories areuseful models for complex relationships, like those found innature. Aboriginal stories emphasize the relationships amongliving things and their non-living environment. As a result,Aboriginal peoples often have a very good understanding of howinterconnected all things are, and how important it is for humansto live in harmony with other living things and the environment.The United Nations has decided that this is the type of understandingwe need to have to ensure the sustainability of our ecosystems.

If you listen to Aboriginal stories, you will notice that natureusually has something to teach people. The stories emphasize thatnature is in control, not people. Scientists who study ecosystemshave learned the same thing.

CHECK YOUR UNDERSTANDING1. What do humans remove from ecosystems, and what do they put in?

How is this the same as what other species do? How is this different?

2. Would you expect to find greater biodiversity in a natural ecosystemor a human-made ecosystem, such as a farm or a garden? Explainyour answer.

3. How can indigenous knowledge help all British Columbians today?

Figure 3Aboriginal Elders pass on their knowledge through stories.

LEARNING TIPThink of other examples inwhich people use stories tocommunicate scientificinformation.

A comedian once said that pollution is a dirty word. Pollutionrefers to things that are not normally found in the environment, orthings that are present in such large amounts they overload thenatural cycles in an ecosystem. Do you often get the feeling thatothers, such as manufacturers, farmers, and people driving towork, are polluting your environment (Figure 1)? We all, however,pollute the environment. Think of your food and home, and howyou travel each day.

Pollutants in the land, air, or water can enter food webs and endup in the bodies of plants and animals.


Pollution of Ecosystems 3.23.2

LEARNING TIPLook at the headings in thissection. What three typesof pollution will you bestudying? Make a three-column chart using theseheadings and recordexamples as you read.

Figure 1Do you see evidence of pollution?

3.2 Pollution of Ecosystems 63NEL

Landfill sites contain many decomposers. As well, they sometimesattract detrivores, such as bears, seagulls, and rats. There is usuallyless biodiversity, however, than in the original ecosystem. The moregarbage people throw out, the more land that is used for landfill sites,and the more biodiversity that is lost. Composting and recycling aretwo ways to reduce the amount of waste that we put in landfills(Figure 3).

Figure 3How can recycling andcomposting protect biodiversityin your ecosystem?

Figure 2These seagulls are feeding at the Vancouver Landfill in Delta.

Polluting the LandMost of the household garbage that you produce ends up in landfillsites (Figure 2). A landfill is created by digging a very large hole and,over a period of time, filling it with garbage. The original ecosystemof the field or forest is replaced by the ecosystem of the landfill site.If electronics waste (such as computers and batteries) and poisonouschemicals are put in a landfill, these harmful substances can pollutethe soil and water. The environment changes and the plant and animalspecies that used to live in the ecosystem die or leave.

Polluting the AirHave you looked at the labels on your food, clothing, and electronics?If these products were made far from your home, how did they travel?Most of them have likely been on a ship, plane, train, or transporttruck and have travelled hundreds or even thousands of kilometres.The leading cause of air pollution is the transportation of goods andpeople.

Air pollution can cause health problems for humans, other animals,and even plants. It can also cause acid rain. Acid rain can harm the soilthat plants need to survive. Acid rain can also increase the acidity inlakes. This reduces biodiversity, since most plants and animals cannotsurvive in acidic lakes.

Air pollution can even change the climate. A certain amount ofcarbon dioxide in the atmosphere is needed for photosynthesis. Ithelps to trap the Sun’s heat energy, just like greenhouse glass trapsthe Sun’s heat energy, warming the greenhouse. Scientists call thisthe greenhouse effect. Without the greenhouse effect, Earth wouldbe too cold for life as we know it. The burning of coal, oil, andnatural gas changes the balance in the carbon cycle so that there ismore carbon dioxide in the atmosphere. Scientists hypothesize thatthe extra carbon dioxide is causing global warming. Even a slightincrease in the average temperature can affect climates worldwide,changing the water levels in oceans and creating extreme weatherpatterns of heat and cold, and droughts and floods (Figure 4). Whateffects might these changes have on people, crops, and animals?


Figure 4Sachs Harbour is located on BanksIsland in Canada’s Western Arctic.Warmer temperatures are meltingthe permafrost, causing theground to sink and shift. This canbe clearly seen at the edge of thislake near the coast of Banks Island.

3.2 Pollution of Ecosystems 65NEL

Polluting the WaterWhen you flush your toilet or drain your sink, the wastewater has togo somewhere. It may go to a sewage treatment plant on its way to ariver and eventually to the ocean. Every year, billions of litres (L) ofuntreated sewage from cities and communities pour into waterwaysand then into the oceans worldwide. About 80% of ocean pollutionis caused by human activities on land. Agriculture and industry alsocontribute to water pollution during the processes that produce thefood you eat and the products you buy. Water pollution kills manyplants and animals, reducing the biodiversity in our lakes, rivers, andoceans (Figure 5).

CHECK YOUR UNDERSTANDING1. Which types of pollution affect you personally? Explain how you have

been affected by each.

2. Explain how your household garbage can reduce biodiversity.

3. Explain how your shopping habits could contribute to air pollution.

4. Estuaries are important ecosystems for migratory birds. Explain howpollution in your community could affect an estuary ecosystemhundreds of kilometres away.

5. Which types of pollution mentioned in this section do you think areoccurring in your community?

Figure 5How do you think the garbage in this photo is affecting the water?

SKILLS MENU

Questioning Observing

Predicting Measuring

Hypothesizing Classifying

Designing InferringExperiments

Controlling InterpretingVariables Data

Creating CommunicatingModels

Conduct an InvestigationConduct an Investigation


Polluted WatersWhen streams and lakes are polluted, the organisms that live in thewater are affected. Can you think of some ways that a plant oranimal may be affected by a change in its watery home? Can someorganisms still live in polluted water?

Earlier in this unit, you learned that yeast (a living thing) lives bestin warm, sugary water. In this investigation, you will observe howyeast is affected when a pollutant is added to its non-livingenvironment. The pollutant you will add is lemon juice, an acid.

QuestionHow will different amounts of a pollutant affect the growth of anorganism that lives in water?

HypothesisWrite a hypothesis that answers the question above. Use thefollowing form for your hypothesis: “If … then ….”

Materials• 10 250-mL clear glass jars or beakers• masking tape• pen or marker• apron• safety goggles• measuring spoons• measuring cup• 5 mL of sugar for each small container• graduated cylinder• very warm (not hot) water for each small container• lemon juice at room temperature• 2 soup spoons• 1 large jar (500 mL)• 100 mL of very warm (not hot) water for larger jar• 25 mL of instant rise

baker’s yeast• clock or watch

3.33.3

Wear safety goggles forthis investigation.

beaker

maskingtape

penapron

gogglesmeasuringspoons

measuring cupsugar

waterlemonjuice

soup spoons

largejar baker’s

yeast

watch

Procedure

3.3 Conduct an Investigation 67NEL

3 Put 5 mL of sugar in eachcontainer. Using a

graduated cylinder, add 50 mLof very warm water to the firstcontainer, 45 mL to thesecond, and 40 mL to thethird. Continue to decreasethe amount of water added by5 mL until the tenth container

4 In the large jar, put100 mL of very warm

water. Sprinkle the 25 mL ofyeast into this jar, a little at a

Effects of Lemon Juice on Yeast Growth

3 min 5 min 7 min 9 min 11 min 13 min 15 minnone

5 mL

1 In your notebook, make a table like the one below.

2 Working with a partner,set up your containers in

a line. Label the first container“none.” Then, label the restby fives: 5 mL, 10 mL, 15 mL,and so on until you havelabelled all of them.

has only 5 mL of water addedto it. Then, put lemon juice ineach container, as indicated onthe label. In other words, putno lemon juice in the containerlabelled “none,” put 5 mL in thecontainer labelled “5 mL,” andso on. Using a soup spoon, stireach container to dissolve thesugar. Work quickly butcarefully.

time. Stir with the other soupspoon after each addition.

5 Add 10 mL of this yeastmixture to each

container. Swirl eachcontainer to mix. Note thetime on the watch or clock.

6 Make your firstobservation 3 min after

you add the yeast mixtureto the containers. Continueto make observations every2 min, until 15 min havepassed. Record yourobservations in your table.


Analyze 1. Each container has a different amount of lemon juice. Was there

a difference between any two containers that you think wasimportant?

2. What did you learn from this investigation about the amount ofa pollutant in water and the effect on the organisms that live inthe water?

Write a Conclusion3. Write a conclusion that explains the results of your investigation.

Your conclusion should refer back to your hypothesis. Was yourhypothesis correct, partly correct, or incorrect? Explain how youarrived at your conclusion.

Apply and Extend4. Examine the photos in Figure 1. Which lake do you think has

more acid in the water?

CHECK YOUR UNDERSTANDING1. What could you call the container with no lemon juice? Why was it

important to have this container?

2. Why was it important to have the same amount of yeast, sugar, andwater in each container?

3. What was the dependent variable in this investigation?

www.science.nelson.com GOGO

5. What do you know about acid rain? Write a brief paragraphabout what it is and how it is currently affecting easternCanada. You may need to do some research in a library oron the Internet.

Figure 1

LEARNING TIPFor more informationon variables, see the“Controlling Variables”section in the SkillsHandbook.

3.4 Land Use and Habitat Loss 69NEL

Humans use land in many ways. Human activities, such as farming,building cities, and logging, can change or eliminate the conditionsthat are needed for other living things to survive. Thus, humanactivities can result in loss of habitat for plants and animals. Land useissues are complicated, however. Looking after the needs of ecosystemsand both the needs and wants of humans can be very difficult.

Land Use and Habitat Loss 3.43.4

TRY THIS: OBSERVE HABITAT LOSSSkills Focus: observing, inferring, classifying

Explain how each land use in the photos below has resulted in habitat loss. What species of plants andanimals might have been affected? Do you think biodiversity has been reduced? Suggest some ways thathabitat loss could be reduced in these land use situations.


A Case Study in Land Use and HabitatLoss: The Antelope Brush Ecosystem

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3.4 Land Use and Habitat Loss 71NEL

Many human activities cause habitat loss for other species(Figure 1). The case study shows how difficult it is to look afterthe needs of both humans and plants and animals in the sameecosystem. The needs and wants of British Columbians affect howwe use the land in our province. Many of the ways that we use theland result in habitat loss for other species that live in BritishColumbia. Some of the food we eat and the products we use areproduced in other provinces and countries. So our needs and wantsaffect land use in other provinces and countries. The choices wemake here can result in habitat loss in other parts of Canada andin countries around the world.

CHECK YOUR UNDERSTANDING1. It is often difficult to look after the needs of both humans and

ecosystems. Use examples from the article to explain why.

2. What type of land use causes the most habitat loss in the antelopebrush ecosystem?

3. Using information from the article, explain how land use by humanscan result in habitat loss for plants and animals.

4. The Nk’mip First Nation (near Osoyoos) is trying to protect rattlesnakesand their habitat in this ecosystem. Why do you think the Nk’mipconsider rattlesnakes to be important?

5. Do human needs or human wants result in more habitat loss for otherspecies? Explain your answer.

Canadians have a very high standard of living. We are able tomeet many of our wants, as well as our needs. This means that wehave a greater effect on land use and habitat loss than people inpoorer countries with lower standards of living.

Figure 1Building this mall and its parking lotresulted in habitat loss in the localecosystem. The production andtransportation of the products soldin this mall resulted in habitat lossin ecosystems throughout Canadaand in other parts of the world.

LEARNING TIPIt is easier to rememberinformation if youpersonalize it. How do youfeel about your choicesconcerning habitat loss?Compare your opinion witha partner.

Explore an IssueExplore an Issue


Perspectives on Land UseEcosystems are affected by the decisions that people make about landuse. People have different values and needs, so they have differentideas about how to use the land. In this activity, you will work in agroup to explore a land-use issue. Then you will role-play a roundtablediscussion to reach a decision about the issue (Figure 1).

3.53.5

The IssueIdentify a proposal for a change in land use that will affect localecosystems. Here are some examples to start you thinking. Youshould identify a proposal from your own community, or acommunity near you.

• logging in a forested area

• opening up new land for agriculture

Figure 1People share different viewpoints during a roundtable discussion. These differentperspectives combine to help provide a solution to a problem.

LEARNING TIPTo learn more about thesteps to use in exploring anissue, see the “Exploring anIssue” section in the SkillsHandbook.


3.5 Explore an Issue 73NEL

• developing a new landfill site

• opening up a natural area for new housing

• developing a recreational area, such as a ski hill

• setting aside a natural area as a park

• restoring streams in urban areas

• setting aside land for city gardens

• installing a basketball court in a neighbourhood park

• widening a highway

Background to the IssueIdentify PerspectivesWork in groups of four or five. Have each group member choose arole for the role-play. For example, you could be someone who is infavour of the land-use proposal, someone who is opposed, someonewho has a few concerns, or someone who is not sure what to think.Use the following questions to help you identify the differentperspectives:

• Why are people planning to change how the land is used?

• Are there people who think that the change is a good idea? Howdoes the proposal meet their needs and values?

• Are there people who are opposed? How does the proposalaffect their needs and values?

• Are there people who are not opposed but have a few concerns?What are their needs and values?

• Are there people who are undecided?

• Are there people who do not care? Why do they think the issuedoes not matter, or is it not important to them?

Gather InformationResearch what the person you are role-playing is thinking and sayingabout the proposal. You may be able to get this information fromnews articles, the Internet, community groups, or Aboriginal Elders.Take careful notes so that you can accurately represent his or herperspective, whether or not you agree with it.

LEARNING TIPFor help with researching,see the “Researching”section in the SkillsHandbook.


Identify Possible AlternativesWhen all the group members are ready, set up a roundtable. The tabledoes not have to be round, but all the members should sit so that theyface one another. Decide how you will take turns presenting yourperspectives.

Role-play your chosen perspective. Be sure to suggest alternativesto the planned change in land use. These alternatives should notonly meet the needs and values of the person you are role-playing,but also meet the needs and values of people with differentperspectives.

Identify Criteria for Evaluating SolutionsStill in role at your roundtable, discuss to what extent your suggestedalternatives

• meet the needs of community members

• respect the values of community members

• maintain biodiversity in the ecosystem

Make a DecisionTry to reach a decision at your roundtable on what the best course ofaction would be with respect to this land-use proposal.

Communicate Your DecisionAs a group, write a brief report for your school newsletter orcommunity newspaper. Explain your decision and the process youused to arrive at it.

CHECK YOUR UNDERSTANDING1. Why is it important to consider different perspectives on an issue?

2. Why is it important to consider alternative solutions?

3. In what other situations might a roundtable discussion be useful?

ScienceWORKS 75NEL

Evidence for Climate ChangeFor years, scientists have predicted that climate changecaused by global warming would first show up in the FarNorth. The people of Sachs Harbour on Banks Island in theBeaufort Sea know this is true from their own observations.

ScienceWORKSScienceWORKS

Rosemarie Kuptana (Figure 1)is from Sachs Harbour.Rosemarie’s grandfatherpredicted that the icy oceansurrounding their home wouldget warm and the animalswould suffer. Rosemarie nowknows that both the scientistsand her grandfather werecorrect. Climate change causedby global warming is easy to seein her community. Rosemarie isworking to bring it to theattention of the world.

The Inuvialuit people ofSachs Harbour have beenmaking observations aboutweather patterns in their areafor much longer than theCanadian government has beencollecting this information.They are therefore better ableto identify any changes that areoccurring. They have sharedtheir indigenous knowledgewith the scientists. They alsohelped make a video to warnthe rest of the world aboutclimate change.

On the video, the Inuvialuitpeople report early spring thawsand later autumn freeze-ups.They describe winter ice so thinit will not hold hunters—eitherhumans or polar bears. Theydescribe summer ice floes thatare smaller now and farther outat sea, taking the seals that liveon the ice floes beyond thereach of the people who needthe seals for food. They showwhere the permafrost(permanently frozen ground)is melting, causing their housefoundations to shift. They tellof finding sockeye salmon,which normally live 1500 kmfarther south, in the nets theyset for Arctic char. They tell ofseeing robins in the spring, abird so rare this far north thatthere is no word for “robin” intheir language. They tell ofmore frequent storms, whichmake fishing from boats moredangerous. They reportexperiencing thunder andlightning for the first time.

Rosemarie Kuptanatook the video of her people’sobservations to a UnitedNations meeting on climatechange in The Hague,Netherlands, in November2000. Rosemarie is not onlyworking to save her community.Melting Arctic ice will changeweather patterns around theworld, affecting all of us.

Figure 1Rosemarie Kuptana organizes climatechange observations made by thepeople of Sachs Harbour.

Non-native species are organisms that are living outside of their naturalrange. The introduction of non-native species is a lot like pollution.Non-native species can harm or destroy native species because theycompete with them for food and water, or hunt them for food.

There are many examples of non-native species in British Columbia.Table 1 lists several of them.


The Introduction ofNon-Native Species3.63.6

Table 1 Non-Native Species in British Columbia

Species Description

bullfrog large frog that was brought to British Columbia to beraised as restaurant food but was released when therewas no market for frogs legs; eats native species of frogs,ducklings, garter snakes, songbirds, and even mice

domestic cat pet that kills large numbers of songbirds

Atlantic salmon non-native salmon that uses up spawning space andfood supplies of Pacific salmon when it escapes fromfish farms

purple loosestrife garden plant that spreads and quickly takes overmoist marshy areas; crowds out native plants that pro-vide food and shelter for local animals

red-eared slider pet that competes with endangered native species ofturtles when it is released into the wild

smallmouth bass popular fish with fishers, who have introduced it(illegally) into lakes and rivers in many parts of BritishColumbia; competes for food and habitat with nativefish; eats juvenile trout and coho salmon fry

3.6 The Introduction of Non-Native Species 77NEL

It is usually humans who introduce non-native species, eitheraccidentally or on purpose. Non-native plants and animals canarrive on boats, mountain bikes, or hiking boots. They can escapefrom farms, gardens, and pet collections. Some people deliberatelyrelease their pets into the ecosystem because they think their petswill be happier or because they are tired of looking after their pets.Other people knowingly commit a crime by bringing wild animalsfrom other countries here as pets. Fortunately, many people areinvolved in the attempt to control the introduction and spread ofnon-native species.

CHECK YOUR UNDERSTANDING1. Use an example to explain how the introduction of a non-native

species can decrease biodiversity in an ecosystem.

2. Suppose that a class in your school has been studying insects. In ascience kit, the students obtained some insects called stick insects,sometimes called walking sticks (Figure 1). Stick insects normally livein a tropical climate. They reproduce quickly and eat leaves. One day,you notice that the window near the cage is open, and the stickinsects are nowhere to be seen! Should you be alarmed? Explain whyor why not.

LEARNING TIPWhat is your reaction towhat you have read aboutthe introduction of non-native species? Checkyour understanding bycomparing your reactionswith a partner. Offer anopinion about what shouldbe done about thisproblem.

3. Your friend has always loved animals and has three pets: a cat, a cornsnake, and a budgie. Lately, she has decided that it is cruel to keepanimals in cages. She says that she plans to release all her pets intothe wild where they will be free and happy. Write a letter to her,explaining all the reasons why this might not be a good idea.

Figure 1

Many people are concerned about the negative effects that humanshave on ecosystems. They want to do something to help. They wantto be caretakers, or stewards, of ecosystems. Taking personalresponsibility for looking after an ecosystem is called

Preserving EcosystemsMore and more, people recognize the need to keep safe fromdestruction, or preserve, the remaining ecosystems that have not yetbeen damaged by humans. People are working to preserve some ofthe remaining natural areas in British Columbia, such as theantelope brush ecosystem in the Okanagan and the KhutzeymateenValley. Ecosystems that have already been damaged by humans alsoneed our stewardship, however.

Conserving EcosystemsPeople are learning how to conserve, or make wise use of, existingecosystems. For example, the Guichon family is trying to graze cattleon their ranchland in a way that preserves the natural grasslandecosystem (Figure 1). The Guichons move cattle between small areasof grassland, allowing the land time to recover after the cattle havegrazed there. They also plan the movement of cattle between areas toprovide birds, such as ducks and sharptail grouse, with nest sites.

stewardship.


Working to Preserve, Conserve,and Restore Ecosystems3.73.7

Figure 1The Guichon family won an awardfor their careful observations ofthe effects of cattle grazing ongrasslands near Merritt.

3.7 Working to Preserve, Conserve, and Restore Ecosystems 79NEL

Restoring EcosystemsPeople often help to restore or repair the damage to ecosystems thatwas caused by previous human activities. An example of this is theSalmon River Restoration Project.

The Salmon River flows through forest, grasslands, and rockygullies before it empties into Shuswap Lake. In the fall, differentspecies of salmon travel from the ocean to the river to spawn.

Agriculture is the main human use of the area surrounding theriver. Over the years, agricultural activities have changed the river,thus changing living conditions for the salmon. For example, waterwas taken from the river for irrigation. Logging and grazing cattleremoved vegetation from the banks of the river, reducing shade andincreasing water temperature. Water running off the fields carriedfertilizers into the river. The runoff also carried soil into the river,silting up the gravel that salmon need for spawning beds.

Farmers, scientists, Aboriginal peoples, government officials, andvolunteers are involved in the Salmon River Restoration Project(Figure 2). Students from nearby schools have helped plant trees andrepair areas of the river. People with many different interests areworking together to restore this ecosystem, using roundtablediscussions.

Figure 2Cooperative landowners aid student volunteers in the restoration of the Salmon River.

LEARNING TIPPause and think. Canyou explain the differencebetween preserving,conserving, and restoringecosystems in your ownwords? If not, re-read thesection before you move on.

Through preservation, conservation, and restoration projects,humans are having a positive impact on many ecosystems (Figures 3

to 10). These projects usually involve people from within thecommunity and from outside. They all come together and worktoward a common goal.


Figure 3Steelhead are given a helping leap on theBonaparte River.

Figure 6The Kitlope Valley is a completewatershed, from its glacier peaks to theocean floor. In 1994, a timber companygave up its rights to log this area.

Figure 5These bat houses were built by elementarystudents for bats that were left homeless.A fire destroyed their previous home in anold church.

Figure 4Everett Crowley Park in Vancouver is on aformer landfill site.

3.7 Working to Preserve, Conserve, and Restore Ecosystems 81NEL

CHECK YOUR UNDERSTANDING1. List three ways that people can work together to make a positive

impact on ecosystems. Give an example of each, and state whetherbiodiversity is being maintained or increased.

2. Aboriginal groups are working with scientists and community groupson many of the preservation, conservation, and restoration projects inBritish Columbia. In a small group, brainstorm reasons why theinvolvement of Aboriginal groups is important.

3. Suggest at least one way in which people could have a positive impacton an ecosystem in your area.

TRY THIS: PRESERVE, CONSERVE, RESTORESkills Focus: classifying

Look at Figures 3 to 10. Study the photos and read the captions. Decidewhether each photo shows an attempt to preserve, conserve, or restore anecosystem. Do some of the photos fit into more than one category?Discuss your decisions with a partner.

Figure 7Scientists and the Huu-ay-aht community(near Bamfield) are working together tobring back abalone stocks. Abalone areharvested as a food source and for theirshells, which can be used in jewellery.

Figure 8Thousands of wooden fish are shown inschool and community “Stream of Dreams”fence murals. These murals remind localresidents that their storm sewers areconnected to a stream, river, or ocean.

Figure 9To help burrowing owls, these volunteersare inserting large pipes into the groundin the grasslands ecosystem. The owls willbe able to build their nests in the pipes.

Figure 10Strathcona Community Gardens arelocated in East Vancouver. These city-sponsored gardens provide space forpeople to grow flowers and food.

We use resources to meet our basic needs, to make our homes andclothing, and to provide energy for heating and transportation. Wealso use resources to provide a huge number of things that we do notneed. We want these things, however, because they make our livesmore comfortable, interesting, or enjoyable. How people choose tolive has an effect on ecosystems.

On the other hand, there are many ways that people can restore thedamage done to ecosystems. There are also many ways that peoplecan behave to have a smaller negative impact on ecosystems. You canthink of your impact as follows: When you put down your foot, youleave a footprint. In a similar way, when you use resources, you leavea footprint on the ecosystem in which you live (Figure 1). In 1996,Mathis Wackernagel andWilliam Rees, tworesearchers at the Universityof British Columbia,developed a way to measurethis ecological footprint,using summaries ofresources used and wasteproduced. Their goal wasto make us think about ourecological footprint as partof our stewardship ofecosystems.


Learning to Lessen OurEcological Footprint3.83.8

TRY THIS: DETERMINE YOUR FOOTPRINTSkills Focus: collaborating, analyzing

Many Web sites can help you determine how big your ecological footprintis, or how much nature you use in your daily living. Search for the term“ecological footprint” on the Internet. Complete a survey to measure yourecological footprint. Compare your results with a classmate’s results. Whatare the similarities and differences?


Figure 1How large is your ecological footprint?

LEARNING TIPMake inferences—readbetween the lines. Askyourself, “What does theecological footprint ideareally mean? Why is itimportant? How does itaffect me?”

3.8 Learning to Lesson Our Ecological Footprint 83NEL

The David Suzuki Foundation in British Columbia is anorganization that looks at how we can decrease our negative impacton nature (Figure 2). This organization has developed a list of tenideas to help us use less nature in our daily living.

The Nature Challenge

Reduce home energy use Choose a fuel-efficient by 10%. vehicle.

Choose an energy-efficient Walk, bike, carpool, or takehome. transit.

Replace dangerous pesticides. Choose a home close to work or school.

Eat meat-free meals one day Support car-free alternatives.a week.

Buy locally grown and Learn more and share withproduced food. others.

Figure 2Have you ever asked whatyou can do to protectnature? David Suzuki hasresearched the ten mosteffective ways you canconserve nature. Hechallenges you to dothree of them.

Canadians are encouraged to choose three of the ten ideas andcommit to following them for one year. Which three ideas could youcommit to following? If some of the ideas would be impossible foryou, explain why. Is there one idea that your whole class could committo following?

CHECK YOUR UNDERSTANDING1. What does the term “ecological footprint” mean? Why is it important

for people to reduce their ecological footprint?

2. List three ways that you could lessen your ecological footprint, withouthelp from anyone else.


33 Chapter Review

Key Idea: Biodiversity keeps ecosystems strong and stable.

Key Idea: Indigenousknowledge can help usachieve sustainability.

Key Idea: Human activities can decrease biodiversity.

Pollution Habitat loss Introduction of non-nativespecies

Key Idea: Humans can preserve, conserve, and restoreecosystems.

Preserve Conserve Restore

Key Idea: Humans can lessen their ecologicalfootprint.

Vocabularysustainability p. 60biodiversity p. 60

Vocabularystewardship p. 78

Human survival depends on sustainableecosystems.

Chapter 3 Review 85NEL


Review Key Ideas andVocabularyWhen answering the questions, remember touse vocabulary from the chapter.

1. Why is biodiversity important in anecosystem?

2. What is a sustainable environment? Howcan indigenous knowledge help us achievesustainability?

3. In point form, list some of the ways thathuman activities have reduced biodiversityin your local ecosystem.

4. Name and describe three ways that humanscan work to have a positive impact onecosystems.

5. What is an ecological footprint? Why doesits size matter?

Use What You’ve Learned6. How might building your school and

schoolyard have resulted in habitat loss forplants and animals?

7. Imagine that you are a plant or animal inyour local ecosystem. You are sufferingbecause of pollution or loss of habitat.Write a descriptive paragraph from thepoint of view of this plant or animal.

8. Research the reasons why people felt that agrizzly bear sanctuary was needed in theKhutzeymateen Valley. Find out about othersanctuaries or wildlife preserves, and thereasons why they were established.

9. Why does the David Suzuki Foundationsuggest eating meat-free meals one day aweek? What is being conserved and how?


10. Choose one of the following situations.Create a cartoon, with captions, to showthe effects this situation might have onyour local ecosystem.a) A pet red-eared slider escapes.b) A person releases mink from a fur farm.c) A family moves to an apartment where

pets are not allowed. They decide to lettheir pet cat live in the wild.

11. Abalone stocks are so low that it is illegalto harvest them off the coast of BritishColumbia. Use the Internet to researchwhy abalone stocks are so low. What kindof restoration work is going on?

Think Critically 12. Does any other species besides human

pollute? Explain your answer.

13. Research a conservation or preservationsociety in British Columbia. Determinewhat the goals of this society are. Decidewhether you would support this society,and give reasons for your decision.

14. Do you think that the ecological footprintof the average Canadian is larger or smallerthan the ecological footprint of someonewho lives in a less developed country, suchas Haiti? Why?

Reflect on Your Learning15. Describe how something you learned in this

chapter will affect your future behaviour.

16. What topic or issue in this chapter wouldyou like to investigate further? Whatquestions do you still have? How will youfind answers to these questions?

Making Connections

86 Unit A Ecosystems NEL

AA• UNIT •

Looking BackIn this unit, you have learned how ecosystemssupport life. You have learned about thecomplexity of interactions and cycles. Younow know how easily the web of life can bedamaged by human activities. You also knowhow important it is to be a steward, or caretaker,of your ecosystem.

In this activity, you will demonstrate what youhave learned as you exercise stewardship inyour local ecosystem. You will work with otherstudents to solve a problem in your localecosystem.

Demonstrate Your LearningPart 1: Identify a problem.Is there a problem in your local ecosystemthat you could try to solve? Make sure that theproblem you choose is a manageable size foryou. Here are some suggestions:

• loss of native plants

• toxic herbicides being used to controlweeds

• improper disposal of hazardous wastes

• idling engines

• backyard burning

Taking Action in Your Local Ecosystem

Before you take action in your local ecosystem, gather information from many possible sources. Don’t forget to includeindigenous knowledge.

Unit A Making Connections 87NEL

• electronic waste

• erosion from stormwater runoff

• invasive species

• damaged shorelines

• low participation in recycling programs

• overpackaging of consumer products

• damage to ecosystems from recreationalactivities, such as snowmobiling

Define the problem as precisely as you can.

Part 2: Define the task.Decide at which level you are going to work—in your classroom or school, or in yourcommunity. Then decide on an approach tosolve your problem. You can choose one of twobasic approaches: direct action or education. Ifyou choose to take direct action, then you willbe actively involved in planning a project orhelping complete one. If you choose to educatepeople, then you must research your issue andfind a persuasive way to present it.

Part 3: Define criteria for success.How would you define success in ecosystems?How would you define success in your project?

Part 4: Gather information.Problems in ecosystems are complex, so it isimportant to gather background information.Make a list of questions that you will need toget answered. Also make a list of possiblesources of information. Remember to includeindigenous knowledge.

Part 5: Plan. Make a list of specific steps. Decide when youwill work on each step. Your steps may includegetting permission to do certain things. Make alist of all the materials you will need, and whereyou will get them.

Part 6: Test.Test your solution against the criteria youestablished. If you plan to make a direct changein an ecosystem, test the change in a small areafirst.

Part 7: Evaluate.Did your solution go as planned? If not, whydo you think it turned out differently thanyou planned? Did you meet your criteria forsuccess? If not, what could you have donedifferently?

Part 8: Communicate.Communicate your results, as well as anyrecommendations you have for further actions,to an appropriate audience. An appropriateaudience may be your classmates, the generalpublic, an organization, or a government agency.

ASSESSMENTCheck to make sure that your work providesevidence that you are able to

• evaluate human impact in a local ecosystem

• analyze the roles of organisms in a localecosystem

• assess the survival needs of organisms

• assess the interactions between organismsand the non-living parts of their environment

• assess the requirements for maintaining orrestoring biodiversity

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