Essentials of Ecology

xi

8-5 How Have Human Activities Affected Freshwater
Ecosystems? 179
CASE STUDY Inland Wetland Losses in the
United States 179
REVISITING Coral Reefs and Sustainability 180

SUSTAINING BIODIVERSITY

9 Sustaining Biodiversity:

The Species Approach 183

CORE CASE STUDY The Passenger Pigeon:

Gone Forever 183

KEY QUESTIONS AND CONCEPTS 184

9-1 What Role Do Humans Play in the Premature
Extinction of Species? 184
SCIENCE FOCUS Estimating Extinction Rates
Is Not Easy 188

9-2 Why Should We Care about Preventing
Premature Species Extinction? 189
SCIENCE FOCUS Using DNA to Reduce Illegal
Killing of Elephants for Their Ivory 191
SCIENCE FOCUS Why Should We Care
about Bats? 192

9-3 How Do Humans Accelerate Species
Extinction? 193
SCIENCE FOCUS Studying the Effects of Forest
Fragmentation on Old-Growth Trees 195
CASE STUDY A Disturbing Message from
the Birds 195
SCIENCE FOCUS Vultures, Wild Dogs, and Rabies:
Some Unexpected Scientific Connections 197
CASE STUDY The Kudzu Vine 198
CASE STUDY Where Have All the Honeybees
Gone? 202
CASE STUDY Polar Bears and Global Warming 203
INDIVIDUALS MATTER Jane Goodall 205

9-4 How Can We Protect Wild Species from
Extinction Resulting from our Activities? 206
CASE STUDY The U.S. Endangered Species Act 207
SCIENCE FOCUS Accomplishments of the
Endangered Species Act 209
CASE STUDY Trying to Save the California
Condor 210
REVISITING Passenger Pigeons and Sustainability 211

10 Sustaining Terrestrial Biodiversity:

The Ecosystem Approach 214

CORE CASE STUDY Reintroducing Gray Wolves

to Yellowstone 214

KEY QUESTIONS AND CONCEPTS 215

10-1 What Are the Major Threats to Forest
Ecosystems? 215

SCIENCE FOCUS Putting a Price Tag on Nature’s

Ecological Services 218

CASE STUDY Many Cleared Forests in the United

States Have Grown Back 223

10-2 How Should We Manage and Sustain

Forests? 227

SCIENCE FOCUS Certifying Sustainably

Grown Timber 228

CASE STUDY Deforestation and the

Fuelwood Crisis 229

INDIVIDUALS MATTER Wangari Maathai and Kenya’s

Green Belt Movement 230

10-3 How Should We Manage and Sustain

Grasslands? 231

CASE STUDY Grazing and Urban Development

in the American West—Cows or Condos? 233

Photo 9 Energy efficient straw bale house in Crested Butte,

Colorado (USA) during construction

Alison Gannett

Photo 10 Completed energy efficient straw bale house in Crested

Butte, Colorado (USA)

Alison Gannett