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Chapter 55
Conservation Biology
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Biodiversity Crisis
– Conservation biology integrates the following fields
to conserve biological diversity at all levels
– Ecology
– Evolutionary biology
– Physiology
– Molecular biology
– Genetics
– Behavioral ecology
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• Restoration ecology applies ecological
principles
– In an effort to return degraded ecosystems to
conditions as similar as possible to their
natural state
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Tropical forests
– Greatest concentrations of species
– Are being destroyed at an alarming rate
Figure 55.1
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• Throughout the biosphere, human activities
– Are altering ecosystem processes on which we
and other species depend
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• The current rate of species extinction is high
– And is largely a result of ecosystem
degradation by humans
•  threatening Earth’s biodiversity
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The Three Levels of Biodiversity
• Genetic diversity
• Species diversity
• Ecosystem diversity
Genetic diversity in a vole population
Species diversity in a coastal redwood ecosystem
Figure 55.2
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Community and ecosystem diversity
across the landscape of an entire region
• Endangered species
– in danger of becoming extinct throughout its
range
• Threatened species
– likely to become endangered
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• 12% birds, 24% mammals are threatened
• 20% fish have become extinct during historic
times or are threatened
• 32% amphibians near extinction or endangered
• At current rates 50% of plants and animals will
become extinct
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• Harvard biologist E. O. Wilson has identified
the Hundred Heartbeat Club
– Fewer than 100 individuals
Philippine eagle
)
Chinese river
dolphin
Figure 55.3a–c
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Javan
rhinoceros
Ecosystem Diversity
• The variety of ecosystems in the biosphere is
being affected by human activity
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Benefits of Species and Genetic Diversity
• Many pharmaceuticals originally derived from
plants
Figure 55.4
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Ecosystem services
• Purification of air and water
• Detoxification and decomposition of wastes
• Cycling of nutrients
• Moderation of weather extremes
• ………..
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Four Major Threats to Biodiversity
• Habitat destruction
• Introduced species
• Overexploitation
• Disruption of “interaction networks”
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Habitat Destruction
• Human alteration of habitat is the single
greatest threat to biodiversity throughout the
biosphere
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• Many natural landscapes have been broken up
– Fragmenting habitat into small patches
Figure 55.5
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Introduced Species
• Human introduced
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Pennsylvania Invasive Plants (partial list)
•
Flowers
•
Scientific NameCommon NameNotesAegopodium podagraria GoutweedCommonly planted in the past and escaped; spreads aggressively by
rootsAlliaria petiolata Garlic mustard Invasive in many states; spreading aggressively in woodlands by seedCarduus nutans Musk thistle PA
noxious WeedCirsium arvense Canada thistle PA noxious Weed Cirsium vulgare Bull thistle PA noxious Weed Datura stramonium
JimsonweedSometimes cultivated; spreads by seed, PA Noxious WeedGalega officinalis GoatsruePA and Federal Noxious WeedHeracleum
mantegazzianum Giant hogweed PA and Federal Noxious Weed, sap can cause burning blistersHesperis matronalis Dame's rocket Planted in
gardens; escaped and naturalized along roads; spreads by seedLythrum salicaria, L. virgatumPurple loosestife Garden escape which has
become invasive in many states; PA noxious WeedMyriophyllum spicatum Eurasian water-milfoil Invasive in many states;
aquaticOrnithogallum nutans, umbellatumStar-of-BethlehemCommon garden plant which has widely escapedPastinaca sativa Wild parsnip
Found commonly along roadsides; widespread and abundant; spread by seedPerilla frutescens Beefsteak plant Garden escape; widespread
mostly along roadsides; spread by seedPolygonum (Falopia) cuspidatumJapanese knotweed Invasive in many states; difficult to control;
spreads by roots and seedsRanunculus ficaria Lesser celandine Spreads by roots and shoots; can be very aggressive in wetlandsTrapa natans
Water chestnut Wetland plant; should not be introduced as it will escape, spread, and naturalize Grasses
•
Scientific NameCommon NameNotesBromus tectorum CheatgrassAnnual grass; invasive throughout the west; spreads by seedMicrostegium
vimineum Japanese stilt grassAnnual grass; invasive in many states; spreading through woodlands by seed * Miscanthus sinensis Maiden
grass Commonly planted ornamental grass which can escape and spread by seedPhalaris arundinacea Reed canary grassAggressive wetland
grass; native and introduced strains; widespread and abundant Phragmites australis Common reed Native and introduced strains; wetland
grass which can form huge coloniesSorghum bicolor ssp. drummondiiShattercanePA noxious WeedSorghum halepense Johnson grassPA
noxious Weed; spreads by roots and seedsShrubs
•
Scientific NameCommon NameNotes* Berberis thunbergii Japanese barberry Escaped from cultivation and invasive in many states; spread by
birdsBerberis vulgaris European barberry Escaped from cultivation; spread by birdsElaegnus angustifolia Russian olive Escaped from plantings
and invasive in many states; spread by birdsElaeagnus umbellata Autumn olive Escaped from plantings and invasive in many states; rapidly
spread by birds * Euonymus alatus Winged Euonymus Escaped from plantings; invasive in moist forestsLigustrum obtusifoliumBorder privet
Escaped from cultivation; seeds spread by birdsLigustrum vulgare Common privet Planted very commonly in the past and escaped; invasive in
many statesLonicera maackii Amur honeysuckle Escaped from plantings; seeds spread by birdsLonicera morrowii Morrow's honeysuckle
Escaped from plantings and invasive in many states; seeds spread by birdsLonicera morrowii x tataricaBell's honeysuckle Escaped from
cultivationLonicera standishii Standish honeysuckle Escaped from plantings; seeds spread by birds Lonicera tartarica Tartarian honeysuckle
Escaped from plantings; seeds spread by birds Rhamnus catharticus Common buckthorn Becoming a problem in PARhamnus frangula Glossy
buckthorn Becoming a problem in PARubus phoenicolasius WineberryCommon bramble; not cultivated; spread by seedRosa multiflora
Multiflora rose Invasive in many states; seeds spread by birds; PA noxious Weed* Spiraea japonica Japanese spiraea Frequently planted;
escaped in some areas* Viburnum opulus var. opulusGuelder rose Resembles native Viburnum trilobum which it replaces; both are cultivated
and plantedTrees
•
Scientific NameCommon NameNotes* Acer platanoides Norway maple Commonly planted and escaped; invasive in many states; wind
spreads prolific seedsAcer pseudoplatanus Sycamore maple Escaped from cultivation; wind spreads prolific seedsAilanthus altissima Tree-ofheavenInvasive in many states; wind spreads prolific seedsPaulownia tomentosa Empress tree Prolific seeds fall to start new seedlings* Pyrus
calleryana Callery pear Commonly planted street tree; becoming a problem as an escapeUlmus pumilaSiberian elm Escaped from
cultivationVines
•
Scientific NameCommon NameNotesAkebia quinata Fiveleaf akebia Escaped from cultivation Ampelopsis brevipedunculataPorcelainberryEscaped from cultivation Celastrus orbiculatus Oriental bittersweet Escaped from cultivation and invasive in many states; spreading
rapidly (by birds)Lonicera japonica Japanese honeysuckle Invasive in many statesPolygonum perfoliatum Mile-a-minute vine Range
expanding; PA Noxious WeedPueraria lobata KudzuInvasive in many states; PA Noxious Weed
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• Introduced species disrupt their adopted
community
(a) Brown tree
snake, introduced to Guam
in cargo
Figure 55.6a, b
(b) Introduced kudzu thriving in South Carolina
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Overexploitation
• Human harvesting of wild plants or animals at
rates exceeding the ability of populations of
those species to rebound
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• The fishing industry
– Has caused significant reduction in populations
of certain game fish
Figure 55.7
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Disruption of Interaction Networks
• Extermination of keystone species by humans
Figure 55.8
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The Extinction Vortex
• A small population is prone to positivefeedback loops that draw the population down
an extinction vortex
Small
population
Inbreeding
Genetic
drift
Lower
reproduction
Higher
mortality
Reduction in
individual
fitness and
population
adaptability
Figure 55.9
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Smaller
population
Loss of
genetic
variability
Case Study: Analysis of Grizzly Bear Populations
• Long-term study of grizzly bears in Yellowstone
National Park
Figure 55.11
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• Grizzly bear population has grown substantially
in the past 20 years
150
Females with cubs
Number of individuals
Cubs
100
50
0
1973
Figure 55.12
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1991
1982
Year
2000
Case Study: Decline of the Red-Cockaded
Woodpecker
• Require specific habitat factors for survival
• Forced into decline by habitat destruction
(a)
A red-cockaded woodpecker
in a longleaf pine.
(b) Forest
that can
sustain birds has
low undergrowth.
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(c) Forest
that cannot sustain birds
has high,
dense undergrowth.
Fragmentation and Edges
• Defining features of landscapes
(a) Grasslands
give way to forest ecosystems in
Yellowstone National Park.
(b)
Figure 55.14a, b
Pronounced edges (roads)
surround clear-cuts in this photograph of a heavily logged rain
forest in Malaysia.
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Weighing Conflicting Demands
• Conserving species often requires resolving
conflicts between the habitat needs of
endangered species and human demands
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• As habitat fragmentation increases
– And edges become more extensive,
biodiversity tends to decrease
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Corridors That Connect Habitat Fragments
• A narrow strip of quality habitat connecting
otherwise isolated patches
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• Artificial corridor
Figure 55.16
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Establishing Protected Areas
• Slow the loss of biodiversity
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Finding Biodiversity Hot Spots
• A relatively small area with an exceptional
concentration of endemic species and a large
number of endangered and threatened species
Terrestrial
biodiversity
hot spots
Equator
Figure 55.17
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Nature Reserves
• Biodiversity islands in a sea of habitat
degraded to varying degrees by human activity
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• In some cases the size of reserves is smaller
than the actual area needed to sustain a
population
0
50
100
Kilometers
42
Gallatin R.
Madison R.
43
Montana
Wyoming
Yellowstone
National
Park
Montana
Idaho
Shoshone R.
41
Grand Teton
National Park
Figure 55.18
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Wyoming
Idaho
40
Biotic boundary for
short-term survival;
MVP is 50 individuals.
Biotic boundary for
long-term survival;
MVP is 500 individuals.
Restoration ecology
• Attempts to restore degraded ecosystems to a
more natural state
• The larger the area disturbed the longer the
time that is required for recovery
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Bioremediation
• The use of living organisms to detoxify
ecosystems
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Biological Augmentation
• Uses organisms to add essential materials to a
degraded ecosystem
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restoration worldwide
Equator
Figure 55.22
Truckee River, Nevada.
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Kissimmee River, Florida.
Figure
55.22
Tropical dry forest, Costa Rica.
Succulent Karoo, South Africa.
Rhine River, Europe.
Coastal Japan.
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Sustainable development
• Seeks to improve the human condition while
conserving biodiversity
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Sustainable Biosphere Initiative
• Intelligent and responsible development,
management, and conservation of Earth’s
resources
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Case Study: Sustainable Development in Costa
Rica
• Success in conserving tropical biodiversity has
involved partnerships between the government,
other organizations, and private citizens
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• Human living conditions in Costa Rica have
improved along with ecological conservation
200
80
Life expectancy
70
150
60
100
50
50
40
0
30
1900
Figure 55.23
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1950
Year
2000
Life expectancy (years)
Infant mortality (per 1,000 live births)
Infant mortality
Biophilia and the Future of the Biosphere
• Our modern lives
– Are very different from those of early humans
who hunted and gathered and painted on cave
walls
Figure 55.24a
(a) Detail of animals in a Paleolithic mural, Lascaux, France
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• But our behavior
– Reflects remnants of our ancestral attachment
to nature and the diversity of life, the concept
of biophilia
Figure 55.24b
(b) Biologist Carlos Rivera Gonzales examining a tiny tree frog in
Peru
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• Our innate sense of connection to nature
– May eventually motivate a realignment of our
environmental priorities
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Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings