Ecology, Second Edition - Sinauer Associates

ECOLOGY
Second Edition
MICHAEL L. CAIN • Bowdoin College
WILLIAM D. BOWMAN • University of Colorado
SALLY D. HACKER • Oregon State University
Sinauer Associates, Inc. • Sunderland, Massachusetts
©2012 Sinauer Associates, Inc. This material cannot be copied, reproduced, manufactured
or disseminated in any form without express written permission from the publisher.

Brief Contents
1 The Web of Life 2
UNIT 1 Organisms and Their Environment
2 The Physical Environment 22
3 The Biosphere 49
4 Coping with Environmental Variation: Temperature and Water 81
5 Coping with Environmental Variation: Energy 106
6 Evolution and Ecology 132
UNIT 2 Populations
7 Life History 156
8 Population Distribution and Abundance 177
9 Population Growth and Regulation 199
10 Population Dynamics 221
UNIT 3 Interactions among Organisms
11 Competition 242
12 Predation and Herbivory 262
13 Parasitism 283
14 Mutualism and Commensalism 305
UNIT 4 Communities
15 The Nature of Communities 324
16 Change in Communities 343
17 Biogeography 364
18 Species Diversity in Communities 388
UNIT 5 Ecosystems
19 Production 410
20 Energy Flow and Food Webs 430
21 Nutrient Supply and Cycling 452
UNIT 6 Applied and Large-Scale Ecology
22 Conservation Biology 476
23 Landscape Ecology and Ecosystem Management 501
24 Global Ecology 525
©2012 Sinauer Associates, Inc. This material cannot be copied, reproduced, manufactured
or disseminated in any form without express written permission from the publisher.

Contents
CHAPTER 1 The Web of Life 2
Deformity and Decline in Amphibian Populations:
A Case Study 2
Introduction 3
CONCEPT 1.1 Events in the natural world are
interconnected. 3
Connections in Nature 3
CONCEPT 1.2 Ecology is the scientific study of interactions
between organisms and their environment. 8
Ecology 8
CONCEPT 1.3 Ecologists evaluate competing hypotheses
about natural systems with observations, experiments,
and models. 13
Answering Ecological Questions 13
ECOLOGICAL TOOLKIT 1.1 Designing Ecological
Experiments 16
A CASE STUDY REVISITED Deformity and Decline in Amphibian
Populations 17
CONNECTIONS IN NATURE Mission Impossible? 18
UNIT 1
Organisms and Their Environment
CHAPTER 2 The Physical Environment 22
Climatic Variation and Salmon Abundance:
A Case Study 22
Introduction 23
CONCEPT 2.1 Climate is the most fundamental component
of the physical environment. 23
Climate 23
CONCEPT 2.2 Winds and ocean currents result from
differences in solar radiation across Earthí s surface. 26
Atmospheric and Oceanic Circulation 26
CONCEPT 2.3 Large scale atmospheric and oceanic
circulation patterns establish global patterns of
temperature and precipitation. 31
Global Climatic Patterns 31
CONCEPT 2.4 Regional climates reflect the influence of the
distribution of oceans and continents, mountains, and
vegetation. 34
Regional Climatic Influences 34
CONCEPT 2.5 Seasonal and long term climatic variation are
associated with changes in Earthí s position relative to
the sun. 37
Climatic Variation over Time 37
CONCEPT 2.6 Salinity, acidity, and oxygen concentrations
are major determinants of the chemical
environment. 42
The Chemical Environment 42
A CASE STUDY REVISITED Climatic Variation and Salmon
Abundance 45
CONNECTIONS IN NATURE Climatic Variation and
Ecology 47
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Contents
CHAPTER 3 The Biosphere 49
The American Serengeti—Twelve Centuries of Change
in the Great Plains: A Case Study 49
Introduction 50
CONCEPT 3.1 Terrestrial biomes are characterized by the
growth forms of the dominant vegetation. 50
Terrestrial Biomes 50
CONCEPT 3.2 Biological zones in freshwater ecosystems
are associated with the velocity, depth, temperature,
clarity, and chemistry of the water. 68
Freshwater Biological Zones 68
CONCEPT 3.3 Marine biological zones are determined by
ocean depth, light availability, and the stability of the
bottom substrate. 70
Marine Biological Zones 70
A CASE STUDY REVISITED The American Serengeti—Twelve
Centuries of Change in the Great Plains 76
CONNECTIONS IN NATURE Long-Term Ecological
Research 77
CHAPTER 4 Coping with Environmental
Variation: Temperature and
Water 81
Frozen Frogs: A Case Study 81
Introduction 82
CONCEPT 4.1 Each species has a range of environmental
tolerances that determines its potential geographic
distribution. 82
Response to Environmental Variation 82
CONCEPT 4.2 The temperature of an organism is
determined by exchanges of energy with the external
environment. 85
Variation in Temperature 85
CONCEPT 4.3 The water balance of an organism is
determined by exchanges of water and solutes with the
external environment. 94
Variation in Water Availability 94
A CASE STUDY REVISITED Frozen Frogs 101
CONNECTIONS IN NATURE Desiccation Tolerance, Body Size,
and Rarity 102
CHAPTER 5 Coping with Environmental
Variation: Energy 106
Toolmaking Crows: A Case Study 106
Introduction 107
CONCEPT 5.1 Organisms obtain energy from sunlight,
from inorganic chemical compounds, or through the
consumption of organic compounds. 107
Sources of Energy 107
CONCEPT 5.2 Radiant and chemical energy captured by
autotrophs is converted into stored energy in carbon–
carbon bonds. 109
Autotrophy 109
CONCEPT 5.3 Environmental constraints have resulted in the
evolution of biochemical pathways that improve the
efficiency of photosynthesis. 113
Photosynthetic Pathways 113
CONCEPT 5.4 Heterotrophs have adaptations for acquiring
and assimilating energy efficiently from a variety of
organic sources. 119
Heterotrophy 119
ECOLOGICAL TOOLKIT 5.1 Stable Isotopes 120
A CASE STUDY REVISITED Toolmaking Crows 128
CONNECTIONS IN NATURE Tool Use: Adaptation or Learned
Behavior? 129
CHAPTER 6 Evolution and Ecology 132
Trophy Hunting and Inadvertent Evolution: A Case
Study 132
Introduction 133
CONCEPT 6.1 Evolution can be viewed as genetic
change over time or as a process of descent with
modification. 133
What Is Evolution? 133
CONCEPT 6.2 Natural selection, genetic drift, and gene flow
can cause allele frequencies in a population to change
over time. 136
Mechanisms of Evolution 136
CONCEPT 6.3 Natural selection is the only evolutionary
mechanism that consistently causes adaptive
evolution. 140
Adaptive Evolution 140
CONCEPT 6.4 Long-term patterns of evolution are shaped
by large-scale processes such as speciation, mass
extinction, and adaptive radiation. 144
The Evolutionary History of Life 144
CONCEPT 6.5 Ecological interactions and evolution exert a
profound influence on one another. 148
Joint Effects of Ecology and Evolution 148
A CASE STUDY REVISITED Trophy Hunting and Inadvertent
Evolution 151
CONNECTIONS IN NATURE The Human Impact on
Evolution 151
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Contents
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UNIT 2
Populations
CHAPTER 7 Life History 156
Nemo Grows Up: A Case Study 156
Introduction 157
CONCEPT 7.1 Life history patterns vary within and among
species. 157
Life History Diversity 157
CONCEPT 7.2 Reproductive patterns can be classified along
several continua. 164
Life History Continua 164
CONCEPT 7.3 There are trade-offs between life history
traits. 167
Trade-Offs 167
CONCEPT 7.4 Organisms face different selection pressures
at different life cycle stages. 170
Life Cycle Evolution 170
A CASE STUDY REVISITED Nemo Grows Up 173
CONNECTIONS IN NATURE Territoriality, Competition, and
Life History 174
CHAPTER 8 Population Distribution and
Abundance 177
From Kelp Forest to Urchin Barren: A Case Study 177
Introduction 178
CONCEPT 8.1 Populations are dynamic entities that vary in
size over time and space. 178
Populations 178
CONCEPT 8.2 The distributions and abundances of
organisms are limited by habitat suitability, historical
factors, and dispersal. 182
Distribution and Abundance 182
CONCEPT 8.3 Many species have a patchy distribution of
populations across their geographic range. 186
Geographic Range 186
CONCEPT 8.4 The dispersion of individuals within a
population depends on the location of essential
resources, competition, dispersal, and behavioral
interactions. 188
Dispersion within Populations 188
CONCEPT 8.5 Population abundances and distributions
can be estimated with area-based counts, distance
methods, mark–recapture studies, and niche
modeling. 190
Estimating Abundances and Distributions 190
ECOLOGICAL TOOLKIT 8.1 Estimating Abundance 191
A CASE STUDY REVISITED From Kelp Forest to Urchin
Barren 194
CONNECTIONS IN NATURE From Urchins to Ecosystems 196
CHAPTER 9 Population Growth and
Regulation 199
Human Population Growth: A Case Study 199
Introduction 200
CONCEPT 9.1 Life tables show how survival and
reproductive rates vary with age, size, or life cycle
stage. 201
Life Tables 201
CONCEPT 9.2 Life table data can be used to project
the future age structure, size, and growth rate of a
population. 204
Age Structure 204
CONCEPT 9.3 Populations can grow exponentially when
conditions are favorable, but exponential growth
cannot continue indefinitely. 207
Exponential Growth 207
ECOLOGICAL TOOLKIT 9.1 Estimating Population Growth
Rates in a Threatened Species 208
CONCEPT 9.4 Population size can be determined by
density-dependent and density-independent
factors. 211
Effects of Density 211
CONCEPT 9.5 The logistic equation incorporates limits to
growth and shows how a population may stabilize at a
maximum size, the carrying capacity. 214
Logistic Growth 214
A CASE STUDY REVISITED Human Population Growth 216
CONNECTIONS IN NATURE Your Ecological Footprint 217
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Contents
CHAPTER 10 Population Dynamics 221
A Sea in Trouble: A Case Study 221
Introduction 222
CONCEPT 10.1 Populations exhibit a wide range of growth
patterns, including exponential growth, logistic growth,
fluctuations, and regular cycles. 223
Patterns of Population Growth 223
CONCEPT 10.2 Delayed density dependence can cause
populations to fluctuate in size. 226
Delayed Density Dependence 226
CONCEPT 10.3 The risk of extinction increases greatly in
small populations. 229
Population Extinction 229
CONCEPT 10.4 Many species have a metapopulation
structure in which sets of spatially isolated populations
are linked by dispersal. 234
Metapopulations 234
A CASE STUDY REVISITED A Sea in Trouble 237
CONNECTIONS IN NATURE From Bottom to Top, and Back
Again 237
UNIT 3
Interactions among Organisms
CHAPTER 11 Competition 242
Competition in Plants That Eat Animals: A Case
Study 242
Introduction 243
CONCEPT 11.1 Competition occurs between individuals of
two species that share the use of a resource that limits
their growth, survival, or reproduction. 243
Competition for Resources 243
CONCEPT 11.2 Competition, whether direct or indirect, can
limit the distributions and abundances of competing
species. 246
General Features of Competition 246
CONCEPT 11.3 Competing species are more likely to coexist
when they use resources in different ways. 249
Competitive Exclusion 249
ECOLOGICAL TOOLKIT 11.1 Isocline Analyses 252
CONCEPT 11.4 The outcome of competition can be altered
by environmental conditions, species interactions,
disturbance, and evolution. 254
Altering the Outcome of Competition 254
A CASE STUDY REVISITED Competition in Plants That Eat
Animals 257
CONNECTIONS IN NATURE The Paradox of Diversity 258
CHAPTER 12 Predation and
Herbivory 262
Snowshoe Hare Cycles: A Case Study 262
Introduction 263
CONCEPT 12.1 Most predators have broad diets, whereas
a majority of herbivores have relatively narrow
diets. 264
Predators and Herbivores 264
CONCEPT 12.2 Organisms have evolved a wide range of
adaptations that help them obtain food and avoid
being eaten. 266
Adaptations to Exploitative Interactions 266
CONCEPT 12.3 Predation and herbivory can affect
ecological communities greatly, in some cases causing a
shift from one community type to another. 271
Effects of Exploitation on Communities 271
CONCEPT 12.4 Population cycles can be caused by
exploitative interactions. 275
Exploitation and Population Cycles 275
A CASE STUDY REVISITED Snowshoe Hare Cycles 278
CONNECTIONS IN NATURE From Fear to Hormones to
Population Dynamics 280
CHAPTER 13 Parasitism 283
Enslaver Parasites: A Case Study 283
Introduction 284
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Contents
xix
CONCEPT 13.1 Parasites typically feed on only one or a few
host individuals. 285
Parasite Natural History 285
CONCEPT 13.2 Hosts have adaptations for defending
themselves against parasites, and parasites have
adaptations for overcoming host defenses. 287
Defenses and Counterdefenses 287
CONCEPT 13.3 Host and parasite populations can evolve
together, each in response to selection pressure
imposed by the other. 290
Parasite–Host Coevolution 290
CONCEPT 13.4 Parasites can reduce the sizes of host populations
and alter the outcomes of species interactions,
thereby causing communities to change. 293
Ecological Effects of Parasites 293
CONCEPT 13.5 Simple models of host–pathogen dynamics
suggest ways to control the establishment and spread
of diseases. 297
Dynamics and Spread of Diseases 297
A CASE STUDY REVISITED Enslaver Parasites 301
CONNECTIONS IN NATURE From Chemicals to Evolution and
Ecosystems 302
CHAPTER 14 Mutualism and
Commensalism 305
The First Farmers: A Case Study 305
Introduction 306
CONCEPT 14.1 In positive interactions, neither species is
harmed and the benefits of the interaction are greater
than the costs for at least one species. 306
Positive Interactions 306
CONCEPT 14.2 Each partner in a mutualistic interaction acts
in ways that serve its own ecological and evolutionary
interests. 313
Characteristics of Mutualism 313
CONCEPT 14.3 Positive interactions affect the abundances
and distributions of populations as well as the
composition of ecological communities. 316
Ecological Consequences of Positive
Interactions 316
A CASE STUDY REVISITED The First Farmers 319
CONNECTIONS IN NATURE From Mandibles to Nutrient
Cycling 320
UNIT 4
Communities
CHAPTER 15 The Nature of
Communities 324
“Killer Algae!”: A Case Study 324
Introduction 325
CONCEPT 15.1 Communities are groups of interacting species
that occur together at the same place and time. 325
What Are Communities? 325
CONCEPT 15.2 Species diversity and species composition
are important descriptors of community
structure. 328
Community Structure 328
CONCEPT 15.3 Communities can be characterized by
complex networks of direct and indirect interactions
that vary in strength and direction. 333
Interactions of Multiple Species 333
ECOLOGICAL TOOLKIT 15.1 Measurements of Interaction
Strength 337
A CASE STUDY REVISITED “Killer Algae!” 340
CONNECTIONS IN NATURE Stopping Invasions Requires
Commitment 340
CHAPTER 16 Change in
Communities 343
A Natural Experiment of Mountainous Proportions:
A Case Study 343
Introduction 344
CONCEPT 16.1 Agents of change act on communities across
all temporal and spatial scales. 345
Agents of Change 345
CONCEPT 16.2 Succession is the process of change in
species composition over time as a result of abiotic and
biotic agents of change. 347
Basics of Succession 347
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Contents
CONCEPT 16.3 Experimental work on succession
shows its mechanisms to be diverse and contextdependent.
351
Mechanisms of Succession 351
CONCEPT 16.4 Communities can follow different
successional paths and display alternative states. 357
Alternative Stable States 357
A CASE STUDY REVISITED A Natural Experiment of
Mountainous Proportions 359
CONNECTIONS IN NATURE Primary Succession and
Mutualism 361
CHAPTER 17 Biogeography 364
The Largest Ecological Experiment on Earth: A Case
Study 364
Introduction 365
CONCEPT 17.1 Patterns of species diversity and distribution
vary at global, regional, and local spatial scales. 365
Biogeography and Spatial Scale 365
CONCEPT 17.2 Global patterns of species diversity and
composition are influenced by geographic area
and isolation, evolutionary history, and global
climate. 371
Global Biogeography 371
CONCEPT 17.3 Regional differences in species diversity
are influenced by area and distance, which determine
the balance between immigration and extinction
rates. 378
Regional Biogeography 378
ECOLOGICAL TOOLKIT 17.1 Species–Area Curves 380
A CASE STUDY REVISITED The Largest Ecological Experiment
on Earth 384
CONNECTIONS IN NATURE Tropical Rainforest Diversity
Benefits Humans 385
CHAPTER 18 Species Diversity in
Communities 388
Powered by Prairies? Biodiversity and Biofuels: A Case
Study 388
Introduction 389
CONCEPT 18.1 Species diversity differs among communities
due to variation in regional species pools, abiotic
conditions, and species interactions. 389
Community Membership 389
CONCEPT 18.2 Resource partitioning among the species
in a community reduces competition and increases
species diversity. 393
Resource Partitioning 393
CONCEPT 18.3 Processes such as disturbance, stress,
predation, and positive interactions can mediate
resource availability, thus promoting species
coexistence and species diversity. 396
Processes That Promote Coexistence 396
CONCEPT 18.4 Many experiments show that species
diversity is positively related to community
function. 402
The Consequences of Diversity 402
A CASE STUDY REVISITED Powered by Prairies? Biodiversity
and Biofuels 405
CONNECTIONS IN NATURE Barriers to Biofuels: The Plant Cell
Wall Conundrum 406
UNIT 5
Ecosystems
CHAPTER 19 Production 410
Life in the Deep Blue Sea, How Can It Be?:
A Case Study 410
Introduction 411
CONCEPT 19.1 Energy in ecosystems originates with primary
production by autotrophs. 412
Primary Production 412
ECOLOGICAL TOOLKIT 19.1 Remote Sensing 416
CONCEPT 19.2 Net primary production is constrained by
both physical and biotic environmental factors. 418
Environmental Controls on NPP 418
CONCEPT 19.3 Global patterns of net primary production
reflect climatic constraints and biome types. 423
Global Patterns of NPP 423
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Contents
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CONCEPT 19.4 Secondary production is generated
through the consumption of organic matter by
heterotrophs. 424
Secondary Production 424
A CASE STUDY REVISITED Life in the Deep Blue Sea,
How Can It Be? 425
CONNECTIONS IN NATURE Energy-Driven Succession and
Evolution in Hydrothermal Vent Communities 426
CHAPTER 20 Energy Flow and Food
Webs 430
Toxins in Remote Places: A Case Study 430
Introduction 431
CONCEPT 20.1 Trophic levels describe the feeding
positions of groups of organisms in ecosystems. 431
Feeding Relationships 431
CONCEPT 20.2 The amount of energy transferred from one
trophic level to the next depends on food quality and
consumer abundance and physiology. 433
Energy Flow among Trophic Levels 433
CONCEPT 20.3 Changes in the abundances of organisms at
one trophic level can influence energy flow at multiple
trophic levels. 438
Trophic Cascades 438
CONCEPT 20.4 Food webs are conceptual models
of the trophic interactions of organisms in an
ecosystem. 442
Food Webs 442
A CASE STUDY REVISITED Toxins in Remote Places 448
CONNECTIONS IN NATURE Biological Transport of
Pollutants 449
CHAPTER 21 Nutrient Supply and
Cycling 452
A Fragile Crust: A Case Study 452
Introduction 453
CONCEPT 21.1 Nutrients enter ecosystems through the
chemical breakdown of minerals in rocks or through
fixation of atmospheric gases. 454
Nutrient Requirements and Sources 454
CONCEPT 21.2 Chemical and biological transformations
in ecosystems alter the chemical form and supply of
nutrients. 458
Nutrient Transformations 458
CONCEPT 21.3 Nutrients cycle repeatedly through the
components of ecosystems. 461
Nutrient Cycles and Losses 461
ECOLOGICAL TOOLKIT 21.1 Instrumenting
Catchments 465
CONCEPT 21.4 Freshwater and marine ecosystems receive
nutrient inputs from terrestrial ecosystems. 467
Nutrients in Aquatic Ecosystems 467
A CASE STUDY REVISITED A Fragile Crust 470
CONNECTIONS IN NATURE Nutrients, Disturbance, and
Invasive Species 471
UNIT 6
Applied and Large-Scale Ecology
CHAPTER 22 Conservation Biology 476
Can Birds and Bombs Coexist?: A Case Study 476
Introduction 477
CONCEPT 22.1 Conservation biology is an integrative
discipline that applies the principles of ecology to the
conservation of biodiversity. 477
Conservation Biology 477
CONCEPT 22.2 Biodiversity is declining globally. 480
Declining Biodiversity 480
CONCEPT 22.3 Primary threats to biodiversity include
habitat loss, invasive species, overexploitation,
pollution, disease, and climate change. 484
Threats to Biodiversity 484
CONCEPT 22.4 Conservation biologists use many tools
and work at multiple scales to manage declining
populations. 490
Approaches to Conservation 490
ECOLOGICAL TOOLKIT 22.1 Forensics in Conservation
Biology 492
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CONCEPT 22.5 Prioritizing species helps maximize the
biodiversity that can be protected with limited
resources. 495
Ranking Species for Protection 495
A CASE STUDY REVISITED Can Birds and Bombs Coexist? 497
CONNECTIONS IN NATURE Some Burning Questions 498
CHAPTER 23 Landscape Ecology
and Ecosystem
Management 501
Wolves in the Yellowstone Landscape:
A Case Study 501
Introduction 502
ECOLOGICAL TOOLKIT 23.1 Geographic Information
Systems (GIS) 503
CONCEPT 23.1 Landscape ecology examines spatial
patterns and their relationship to ecological processes
and changes. 504
Landscape Ecology 504
CONCEPT 23.2 Habitat loss and fragmentation decreases
habitat area, isolates populations, and alters conditions
at habitat edges. 508
Habitat Loss and Fragmentation 508
CONCEPT 23.3 Biodiversity can best be sustained by large
reserves connected across the landscape and buffered
from areas of intense human use. 514
Designing Nature Reserves 514
CONCEPT 23.4 Ecosystem management is a collaborative
process with the maintenance of long-term ecological
integrity as its core value. 518
Ecosystem Management 518
A CASE STUDY REVISITED Wolves in the Yellowstone
Landscape 520
CONNECTIONS IN NATURE Future Changes in the Yellowstone
Landscape 521
CHAPTER 24 Global Ecology 525
Dust Storms of Epic Proportions: A Case Study 525
Introduction 526
CONCEPT 24.1 Elements move among geologic,
atmospheric, oceanic, and biological pools at a global
scale. 526
Global Biogeochemical Cycles 526
CONCEPT 24.2 Earth is warming due to anthropogenic
emissions of greenhouse gases. 532
Global Climate Change 532
CONCEPT 24.3 Anthropogenic emissions of sulfur and
nitrogen cause acid deposition, alter soil chemistry, and
affect the health of ecosystems. 539
Acid and Nitrogen Deposition 539
CONCEPT 24.4 Losses of ozone in the stratosphere and
increases in ozone in the troposphere each pose risks
to organisms. 543
Atmospheric Ozone 543
A CASE STUDY REVISITED Dust Storms of Epic
Proportions 546
CONNECTIONS IN NATURE Dust as a Vector of Ecological
Impacts 548
Appendix 551
Answers to Figure Legend and Review
Questions 553
Glossary 575
Illustration Credits 587
Literature Cited 591
Index 613
©2012 Sinauer Associates, Inc. This material cannot be copied, reproduced, manufactured
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