324 Lesson 1

LESS

ON 1

Most of the resources we take from the natural world are limited. Recall that resources such as minerals and fossil fuels are nonre-newable on human time scales. Other resources, such as soil, fresh water, wild animals, and timber, are considered renewable. But even renew-able resources can run out if they are not harvested sustainably—that is, only as rapidly as they can be replaced. In addition, if resources are not harvested sustainably, their entire ecosystem can change. And if the ecosystem changes, some resources may run out. For example, suppose that people in a coastal town relied on a species of fish that only lived in a nearby estuary. But a large fishing company came in and harvested most of those fish. Even if the company were to pay the community, the com-munity would still have lost its most important resource.

Resource managers must balance people’s needs for a resource and an ecosystem’s need for that resource. This is the importance—and the challenge—of resource management.

renewable resource Management People need to manage the harvesting of renewable resources

in order to ensure their availability.

Several types of renewable resources are vital to our civilization. These include soil, fresh water, wild animals, and timber, as shown in Figure 1. In addition to fulfilling important human needs, all natural resources, both renewable and nonrenewable, also serve functions in their ecosystems. So to preserve the health of those ecosystems, renew-able resources need to be harvested sustainably. When industries that harvest renewable resourcess do so sustainably, they help preserve both the resources and their businesses.

Resource management is the managing of resource harvesting so that resources are not depleted. Resource managers are guided in their decision making by scientific research, but their decisions are also influenced by politics, economics, and social issues.

Resource Management

• Explain the importance of managing specific renewable resources.

• Describe three resource management approaches.

Reading Strategy Before you read, create an outline using the blue and green headings in this lesson. As you read, fill in key phrases or sentences about each heading.

Vocabulary resource management, maximum sustainable yield (MSY), ecosystem-based management, adaptive management

Guiding Question: How can we manage renewable resources for sustainable use?

FOCUS Give students two minutes to discuss with a partner whether the following statement is true or false. “Renewable resources cannot run out, no matter how much humans use them.” Have students share their responses and support their reasoning.

GUIDING QUESTION

11.1 LESSON PLAN PREVIEWreal World Students relate the use of renewable resources to their own lives.Differentiated Instruction Less proficient readers use a step-by-step approach to learn about ways of managing resources.

11.1 RESOURCESLesson 11.1 Worksheets • Lesson 11.1 Assessment • Chapter 11 Overview Presentation

Forestry and Resource Management 325

A key question in managing resources is whether to focus on a specific resource or to consider the entire ecosystem of which the resource is a part. Considering the entire ecosystem makes resource management more complicated, but many scientists say that it is the best way to protect a resource in the long term.

Soil Soil is always being made by natural processes such as the weather-ing and erosion of rocks and the decomposition of organisms. However, the fertile top layer of soil that plants grow in, called topsoil, is made very slowly—one inch can take hundreds of years to form. Topsoil nourishes the plants we grow for food and fiber, so its quality is essential to our health. Forests and other plant communities also rely on healthy topsoil. So people need to maintain the quantity and quality of existing topsoil. Safeguards against land pollution help protect the fertility of topsoil, and some farming practices can conserve topsoil. You will learn more about soil in the next chapter.

Fresh Water Like soil, fresh water is continually supplied by natural processes. And, as with soil, people need to maintain the quality of water. Because people cannot live without drinking water, ensuring a depend-able supply of fresh water is, literally, a matter of life or death. Fresh water is also necessary for agriculture. In fact, we use most of Earth’s fresh water not for drinking but for watering crops. Clean waterways and wetlands are also crucial for wildlife and properly functioning ecosystems. People who manage water resources try to maintain clean, adequate supplies for all of these (sometimes conflicting) reasons.

ReadingCheckpoint

What are two ways that soil and water are similar as renewable resources?

Figure 1 Renewable Resources Our civilization depends on many renewable resources, including soil, fresh water, wild animals, and timber.

Timber

Soil

Wild Animals

Fresh Water

ANSWERS

reading Checkpoint Soil and water are continuously supplied by natural processes, but people need to maintain the quality of soil and water.

How can we use earth’s resources sustainably?Interpretation Have students read over the definition of resource man-agement in the text. Then, have them reword the definition to include the word sustainable or the word sus-tainably. (Sample answer: Resource management is the managing of resource harvesting so that the use of the resource is sustainable.)

BIG QUESTION

326 Lesson 1

Wild Animals People have always hunted animals for food. (Animals that can be hunted legally are called game.) In the United States, state and federal wildlife managers regulate the hunting of game, such as deer and quail, to maintain populations of these animals at desired levels. But, as populations of many animals fall because of habitat loss and other rea-sons, management of nongame species is becoming increasingly impor-tant. Nongame animals provide people with many benefits—wildlife watching, scientific research, and ecosystem services, to name just a few.

▶ Fishing People also harvest aquatic animals, including fishes and shell-fish. Unfortunately, despite management of fisheries, populations of many aquatic animals have dropped drastically. Fleets of enormous, technologi-cally advanced fishing boats, or trawlers, swarm the oceans. Most use sonar, mechanized nets, and satellite images to find fish. In some ways, the fishing industry has become a victim of its own success, along with the ecosystems in which it operates. For example, in the 1990s, cod popu-lations in some areas dropped to less than 5 percent of their highest levels. Cod fishing is now outlawed in many areas, such as parts of Georges Bank off the New England coast. Unfortunately, even though cod fishing has slowed, North Atlantic cod populations are only at 40 percent of their level of 40 years ago. Because the cod is the top predator in its ecosystem, scientists fear a permanent change to this ecosystem. And in fact, in many areas, fishes that were formerly prey of cod have now become top predators.

▶ Poaching Laws are only as effective as their enforcement. Poaching of wild animals, such as the macaws in Figure 2, continues. In both developing and developed nations, people kill animals for food and sport in illegal and unsustainable ways. Laws such as the Convention on International Trade in Endangered Species (CITES) have reduced the poaching of endangered animals. Monitoring of trade is difficult in remote areas and some developing nations, however, and CITES is hard to enforce in those places. Poaching of non-endangered animals also con-tinues, affecting their populations and ecosystems.

Figure 2 Poaching This zoo employee is holding scarlet macaws that were rescued from poachers. The poachers had intended to sell the macaws as pets.

Average Annual Change in Forest Area, 1990–2005 (millions of hectares)

Forest for biodiversity conservation

Uncut forest

Total forest

Forest for timber production

Timber plantations

Forest for soil/water protection

Forest for recreation

–6–8 –4 –2 0 2 4 6Data from U.N. Food and Agriculture Organization (FAO), 2005. Global forest resources assessment.

Forestry and Resource Management 327

Timber Wood from trees, or timber, is the raw material for an amazing variety of products you need every day. These products include the wood used to support your house, school, and other buildings; the furniture in those buildings; the paper and cardboard that make up your books and magazines; packaging materials such as boxes, bags, wrappers, and cellophane; rayon fabric; pencils; hamster chew toys; signposts; sponges; doghouses; picture frames; and thousands of others.

The harvesting of timber is essential to our standard of living. In fact, our reliance on products like those above is exactly why we need to care-fully manage our forests. Some management has been a success—forests in developed nations are slowly regrowing. Forests in developing nations, however, including rain forests, are disappearing at an alarming rate. So overall, the world is still losing forestlands, as you can see in Figure 3. You will read more about forest resources and efforts to manage them sustainably in the next two lessons.

ReadingCheckpoint

Make a concept map relating some common objects around you to the type of wood product from which they are made.

Management Approaches Maximum sustainable yield, ecosystem-based management,

and adaptive management are three approaches to resource management.

The management of different areas at different times under different politi-cal leadership puts different sorts of pressure on resource managers. To try to satisfy these often-conflicting influences and still protect the ecosystem, resource managers use a variety of management approaches. Three of the most common resource management approaches are maximum sustain-able yield, ecosystem-based management, and adaptive management.

Figure 3 Deforestation Forest uses are shifting toward conservation and away from timber production.

ANSWERS

Reading Checkpoint Concept maps will vary depending on students’ sur-roundings, but might be organized around terms such as paper products, timber, or plywood.

What Doyou think?

What Doyou think?

Logistic Growth and MSYPo

pu

lati

on s

ize

Time

Slowgrowth

Slowgrowth

Carrying capacity

Fastestgrowth

328 Lesson 1

Maximum Sustainable Yield A common approach to resource management is management for maximum sustainable yield (MSY). The aim of MSY is to harvest the maximum amount of a resource without reducing the amount of future harvests. See the logistic growth curve in Figure 4. It shows that a population of a resource, such as trees, grows most quickly when it is at an intermediate size (the steep part of the curve). A large population, on the other hand, grows slowly. Once a population reaches the carrying capacity of its environment (the dotted line) growth stops. The goal of harvesting for MSY is to keep a population at an intermediate size, where it will grow fastest.

The maximum sustainable yield approach may at first sound ideal, but in practice it can change the ecosystem that provides the resource. Left alone, a population will stay around the carrying capacity of its environment. But a population managed for MSY is kept far below its carrying capacity. A population that stays below its carrying capacity is not consuming, being consumed by, or competing with other organ-isms as much as it would if it were not being harvested. So the man-agement of one population for MSY could result in changes for other populations.

In addition, finding the maximum sustainable yield of a population is a matter of trial and error. Some of the errors may result in overhar-vesting, which can have both economic and ecological effects.

Ecosystem-Based Management Because of the drawbacks of the maximum sustainable yield approach, increasing numbers of managers today have adopted ecosystem-based management. The goal of ecosystem-based management is to harvest resources in ways that minimize impact on the ecosystems and ecological processes that provide the resources. The plan approved in 1995 by British Columbia’s government for Clayoquot Sound’s forests was basically a plan for ecosystem-based management. The plan aimed to allow some timber harvesting while preserving the functioning of the ecosystem. Steps in the plan included carefully managing ecologically important areas such as river valleys, considering patterns in plant cover, and protect-ing some forested areas. Although ecosystem-based management has gained a great deal of support in recent years, it is challenging for managers to determine how best to put it into action. Ecosystems are complex, and our understanding of how they work is incomplete. As a result, ecosystem-based management can mean different things to dif-ferent people, and that can result in inconsistent management.

Adaptive Management Any given management approach will succeed in some places and fail in others. Adaptive management involves scientifically testing different management approaches in an area, one after the other, and then customizing an approach based on the results. Adaptive management is intended as a true union of sci-ence and management because hypotheses about how best to manage resources are tested under controlled conditions.

Figure 4 Logistic growth and Maximum Sustainable Yield The goal of managing for MSY is to maximize harvests without reducing future harvests. With a population that grows according to a logistic growth curve (above), resource managers aim to keep the population well below the carrying capacity, at the point at which the population grows fastest (the steep part of the curve).

You have just become the supervisor of a national forest. Ten percent of it is old-growth forest. Your managers are split among preferring maximum sustainable yield, ecosystem-based manage-ment, and adaptive management. What questions would you have for scientists? What management approach(es) will you follow?

ANSWERS

What Do You Think? Answers will vary. Student questions for the scien-tists must reflect an understanding of differences among the three manage-ment practices and the advantages and disadvantages of each.

Monitor

Evaluate

Design

Implement

Source: U.S. Department of the Interior

ASSESS PROBLEM

Adjust

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13. Explore the BIGQUESTION How may managing a

resource for maximum sustainable yield sometimes conflict with what is best for its ecosystem?

1. Review Define resource management. Why is it important?

2. Compare and Contrast Describe the goals of maximum sustainable yield management, ecosystem-based management, and adaptive management. List a drawback of each.

Adaptive management requires managers and scientists to closely monitor current practices and to continually adjust them. You can see a cycle diagram showing how adaptive management works in Figure 5. Because of the large quantity of data that must be processed and the need for adjustments, adaptive management can be time-consuming and complicated. It also poses a challenge for many managers, who, before they can change an approach, must overcome resistance from supporters of existing, failed approaches.

FiguRe 5 Adaptive Management Adaptive management requires constant monitoring of a resource and adjustments to its management, as the cycle diagram shows. The time and effort can be richly rewarded, however, as in the case of the successful ecological restoration projects at Siuslaw National Forest in Oregon (photo).

ANSWERS

Lesson 1 Assessment For answers to the Lesson 1 Assessment, see page A–16 at the back of the book.