Chapter 38 Conservation Biology - Montville Township ... · PDF fileCampbell Biology: Concepts & Connections, Seventh ... Simon, and Dickey Chapter 38 Conservation Biology. Introduction

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Chapter 38 Conservation Biology

Introduction

▪ Over the past century, wild tiger populations have been reduced from about 100,000 to 3,200.

▪ Tigers are threatened by– declining habitat,

– poaching, and

– human populations encroaching into their habitat.

Figure 38.0_1

Chapter 38: Big Ideas

The Loss of Biodiversity

Conservation Biologyand Restoration

Ecology

Figure 38.0_2

THE LOSS OF BIODIVERSITY

▪ Biodiversity has three levels:1. ecosystem diversity,

2. species diversity, and

3. genetic diversity.

38.1 Loss of biodiversity includes the loss of ecosystems, species, and genes

▪ As natural ecosystems are lost, so are essential services, including– productivity of natural environments for human food

supplies and

– the purification of water used by cities.


Figure 38.1A


▪ At present, scientists have described and formally named about 1.8 million species.– It is difficult to estimate species loss.

– Species loss may be 1,000 times higher than at any time in the past 100,000 years.

– Extirpation is the loss of a single population of a species.

– Extinction is the irreversible loss of all populations of a species.

Figure 38.1B

0%Birds Amph

ibiansFreshwaterfishes

Reptiles(N =

1,429)(N = 2,689)

(N = 4,688)

(N = 9,933)

(N = 4,653)

20%

40%

60%

80%

100%

Lowest risk Nearthreatened

Threatened Extinct

Perc

enta

ge o

f spe

cies

ass

esse

d

Mammals

▪ Because of the network of community interactions among populations of different species within an ecosystem,– the loss of one species

– can negatively affect the species richness of an ecosystem.


Figure 38.1C

▪ Genetic diversity of a species is reduced if– local populations are lost and

– the total number of individuals declines.


Figure 38.1D

38.2 CONNECTION: Habitat loss, invasive species, overharvesting, pollution, and climate change are

major threats to biodiversity

▪ Human alteration of habitats poses the greatest threat to biodiversity.

▪ Habitation alteration is caused by– agriculture,

– urban development,

– forestry,

– mining, and

– environmental pollution.

Figure 38.2A

▪ Invasive species rank second behind habitat destruction as a threat to biodiversity.

▪ Invasive species– compete with native species,

– prey on native species, and

– parasitize native species.



Figure 38.2B

▪ Overexploitation is the third major threat to biodiversity. Overharvesting has threatened– rare trees,

– reduced populations of tigers, Galápagos tortoises, whales, and rhinoceroses, and

– depleted wild populations of game fish.



Figure 38.2C

38.2 CONNECTION: Habitat loss, invasive species, overharvesting, pollution, and climate change are major threats to biodiversity

▪ Human activities produce diverse pollutants that may affect ecosystems far from their source.

– The water cycle transfers pollutants from terrestrial to aquatic ecosystems.

– The release of chemicals into the atmosphere promoted the thinning of the ozone layer.

▪ Biological magnification concentrates synthetic toxins that cannot be degraded by microorganisms.

Figure 38.2D

Figure 38.2EConcentration

of PCBs

Herringgull eggs124 ppm

Lake trout4.83 ppm

Smelt1.04 ppm

Phytoplankton0.025 ppm

Zooplankton0.123 ppm

38.3 CONNECTION: Rapid warming is changing the global climate

▪ The scientific debate about global warming is over.

▪ Increased global temperatures caused by rising concentrations of greenhouse gases are changing climate patterns with grave consequences.– Global temperature has risen 0.8°C in the last 100 years.

– 0.6°C of that increase occurred in the last three decades.

– 2 to 4.5°C increases are likely by the end of the 21st century.

– Temperature increases are not distributed evenly.

– Precipitation patterns are changing too.

Figure 38.3A

−4.1 −4 −2 −1 −0.5 −0.2 0.2 0.5 1 2 4 4.1

Figure 38.3B

1938 1981 2005

Figure 38.3B_1

1938

Figure 38.3B_2

1981

Figure 38.3B_3

2005

38.4 CONNECTION: Human activities are responsible for rising concentrations of greenhouse gases

▪ Much of the rapid warming is the result of burning fossil fuels.– Atmospheric CO2 did not exceed 300 ppm for 650,000

years.

– The preindustrial concentration was below 300 ppm.

– Atmospheric CO2 is approximately 385 ppm today.

– High levels of methane and nitrous oxide also trap heat.

Figure 38.4A

400

350

300

2500 50

01000 1500 2000

600

Year

800

1,000

1,200

1,400

1,600

1,800

2,000

CH

4 (pa

rts

per b

illio

n)

Carbon Dioxide (CO2)Nitrous Oxide (N2O)Methane (CH4)

CO

2 (pp

m),

N2O

(par

ts

per b

illio

n)

Figure 38.4B

Photosynthesis Atmosphere

Respiration

Combustion offossil fuels Ocean

38.5 Global climate change affects biomes, ecosystems, communities, and populations

▪ Climate change in western North America has spawned catastrophic wildfires.

Figure 38.5A


▪ The greatest impact of global climate change is affecting organisms that live at– high latitudes and

– high elevations.

Figure 38.5B


▪ Warming oceans threaten coral reef communities.

▪ Earlier arrival of warm temperatures in the spring is disturbing ecological communities.– Birds and frogs have begun their breeding periods earlier.

– Migratory birds may experience mismatches, arriving after peak food availability has already passed.


▪ Climate change has also– increased the range of disease-carrying mosquitoes and

– enabled bark beetles to reproduce faster, promoting the destruction of millions of acres of conifers in western North America.

38.6 EVOLUTION CONNECTION: Climate change is an agent of natural selection

▪ Phenotypic plasticity– has minimized the impact of global climate change on

some species, and

– cases of microevolutionary changes have been observed.

– The rapidity of the environmental changes makes it unlikely that evolutionary processes will save many species from extinction.

▪ In Europe, the great tit bird– has shifted its breeding season earlier, in an example of

directional selection,

– favoring individuals that lay their eggs sooner, and

– better matching the earlier emergence of caterpillars.


Figure 38.6A

▪ In the Yukon Territory of Canada,– where the spring temperatures have increased by

about 2°C,

– red squirrels have begun breeding earlier in the spring.


Figure 38.6B

CONSERVATION BIOLOGY AND RESTORATION ECOLOGY

38.7 Protecting endangered populations is one goal of conservation biology

▪ Conservation biology is a goal-driven science that seeks to– understand and

– counter the rapid loss of biodiversity.

▪ Some conservation biologists direct their efforts at– protecting populations and

– increasing endangered populations.

– Threats posed by human activities are also assessed.


▪ The black-footed ferret in the United States– is one of three ferret species worldwide and the only ferret

found in North America,

– was reduced to just 18 individuals,

– has been bred in captivity, and

– was reintroduced into the wild.

Figure 38.7A


▪ In Hawaii, the silversword plants once abundant on the cinder cone of the volcano Mauna Kea– were bred in greenhouses and

– reintroduced to reestablish wild populations.

Figure 38.7B

38.8 Sustaining ecosystems and landscapes is a conservation priority

▪ Conservation efforts are increasingly aimed at sustaining– ecosystems and

– landscapes, a regional assemblage of interacting ecosystems.

▪ Landscape ecology is the application of ecological principles to the study of the structure and dynamics of a collection of ecosystems.

Figure 38.8A

38.8 Sustaining ecosystems and landscapes is a conservation priority

▪ Edges between ecosystems have distinct sets of features and species.

▪ The increased frequency and abruptness of edges caused by human activities can increase species loss.

▪ Movement corridors connecting isolated habitats may be helpful to fragmented populations.

Figure 38.8B

Figure 38.8C

38.9 Establishing protected areas slows the loss of biodiversity

▪ To establish parks, wilderness areas, and other legally protected reserves, conservation biologists are applying their understanding of– population,

– ecosystem, and

– landscape dynamics.


▪ Choosing locations for protection often focuses on biodiversity hot spots, relatively small areas with– a large number of endangered and threatened species,

and

– an exceptional concentration of endemic species, those that are found nowhere else.

Figure 38.9A

Equator

▪ Migratory species pose a special problem for conservationists.– Monarch butterflies occupy many areas.

– Sea turtles travel great distances.


Figure 38.9B

Figure 38.9_UN

38.10 Zoned reserves are an attempt to reverse ecosystem disruption

▪ Zoned reserves are undisturbed wildlands surrounded by buffer zones of compatible economic development.

▪ Costa Rica has established many zoned reserves.

▪ Ecotourism– is travel to natural areas for tourism and recreation and

– has become an important source of revenue for conservation efforts.

Figure 38.10A

National Parks and Reserves

COSTA RICA

NICARAGUA

PANAMA

Figure 38.10B

38.11 CONNECTION: The Yellowstone to Yukon Conservation Initiative seeks to preserve biodiversity by connecting protected areas

▪ The Yellowstone to Yukon Conservation Initiative – created a string of parks and reserves in a 3,200-km

wildlife corridor,

– extends from Alaska south across Canada to northern Wyoming,

– included the reintroduction of wolf populations, considered a keystone species in this region, and

– sparked angry protests from some ranchers.

Figure 38.11A

YUKONTERRITORY

Whitehorse

MACKENZIE

MOUNTAINS

NORTHWEST TERRITORIES

ALBERTA

ROCKY

MOUNTAI

NS

BRITISHCOLUMBIA

WASHINGTON

OREGON

MONTANA

Calgary

Bozeman

Spokane

Vancouver

COLUMBI

AMOUNTAI

NS

PACIFICOCEAN

Jackson

IDAHO WYOMING

Figure 38.11A_1

YUKONTERRITORY

Whitehorse

MACKENZIE

MOUNTAINS

NORTHWEST TERRITORIES

ALBERTA

ROCKY MOUNTAINS

Figure 38.11A_2

ROCKY MOUNTAINS

BRITISHCOLUMBIA

WASHINGTON

OREGON

MONTANA

Calgary

Bozeman

Spokane

Vancouver

COLUMBIA

MOUNTAINS

PACIFICOCEAN

JacksonIDAHO WYOMING

Figure 38.11B

Figure 38.11C

38.12 CONNECTION: The study of how to restore degraded habitats is a developing science

▪ Restoration ecology uses ecological principles to restore degraded areas to their natural state, a process that may include– detoxifying polluted ecosystems,

– replanting native vegetation, and

– returning waterways to their natural course.

38.12 CONNECTION: The study of how to restore degraded habitats is a developing science

▪ Large-scale restoration projects attempt to restore damaged landscapes.

▪ The Kissimmee River Restoration Project in Florida is– restoring river flow and wetlands and

– improving wildlife habitat.

Figure 38.12A

Widenedcanal

Water controlstructure remaining

Water controlstructure removedRiver channelrestored

Phase 1completed

Water controlstructure tobe removed inPhase 2

Miles

KissimmeeRiver

Floodplain

Canal backfilled

FLORIDA 0 1

0

Ksi sim

Rmee

iver

Figure 38.12B

Former canal

38.13 Sustainable development is an ultimate goal

▪ Sustainable development– seeks to improve the human condition while conserving

biodiversity,

– depends on increasing and applying ecological knowledge, and

– values our linkages to the biosphere.

38.13 Sustainable development is an ultimate goal

▪ We are most likely to– save what we appreciate and

– appreciate what we understand.

▪ Now is the time to– aggressively pursue more knowledge about life and

– work toward long-term sustainability.

Figure 38.13

Figure 38.UN01

Ecosystemdiversity

Speciesdiversity

Geneticdiversity

Figure 38.UN02

Conservationbiology

seeks to conserve may involve

ecosystems and

landscapes

(c)

(a)

attemptto restore

naturereserve

s

may be

restorationprojects

which uses

to

detoxify orreplenish degraded

ecosystems

FLORIDA

ATLANTICOCEAN

(d)

sustainable

development

which support

GULF OFMEXICO

may beprotected in

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Chapter 38 Conservation Biology - Montville Township ... · PDF fileCampbell Biology: Concepts & Connections, Seventh ... Simon, and Dickey Chapter 38 Conservation Biology. Introduction