Transcript Chapter 8 - Angelfire

ENVIRONMENTAL SCIENCE 13e
CHAPTER 8:
Sustaining Biodiversity:
The Species Approach
Core Case Study: Polar Bears
and Projected Climate Change
• 20,000 – 25,000 polar bears in Arctic
• Hunt seals on winter sea ice
• Global warming is quickly reducing the
amount of sea ice and how long it lasts in
winter
• Polar bears have less time to hunt and
store fat for summer fasting
• Projected 30-35% decline by 2050
• Potentially extinct from wild by 2100
Fig. 8-1, p. 152
8-1 What Role Do Humans Play in
the Premature Extinction of Species?
• Concept 8-1 Species are becoming
extinct 100 to 1,000 times faster than
they were before modern humans
arrived on earth, and by the end of
this century, the extinction rate is
expected be 10,000 times higher than
the background rate.
Human Activities and Extinction
• Background extinction rate
• Current rate is 100-1000 times
background extinction
• Rate likely to rise to 10,000 times
• Is a mass extinction coming?
Current Extinction Rate
Estimates Are Conservative
• Species and biodiversity decrease in
next 50–100 years
• Biodiversity hotspot rates higher than
global average
• Degrading, simplifying, and
destroying diverse environments
Fig. 8-2, p. 154
Passenger pigeon Great auk
Dodo
Golden Toad
Aepyornis
(Madagascar)
Fig. 8-2, p. 154
Science Focus: Estimating
Extinction Rates (1)
•
Three difficulties
1. Not easy to document – takes a long
time
2. Only 2 million species of 8-100 million
identified
3. Little is known about the 2 million
species
Science Focus: Estimating
Extinction Rates (2)
• Study records of post-human extinctions
with previous extinctions from the fossil
record
• DNA copying mistakes
• How habitat reduction increases extinction
• Mathematical models
• Inadequate data and models
• Normal: 1 million to 10 million years
• Humans have greatly accelerated this
Ecological Smoke Alarms
• Endangered species
• Threatened species
• The first to go: large, slow, tasty, or
have valuable parts
• Some behaviors make species prone
to extinction
Fig. 8-3, p. 156
Grizzly bear
Kirkland’s
warbler
Utah prairie dog Swallowtail
butterfly
Knowlton cactus Florida manatee African elephant
Humpback chub Golden lion
tamarin
Siberian tiger
Fig. 8-3, p. 156
Fig. 8-3, p. 156
Giant panda
Black-footed
ferret
Mountain gorilla Florida panther
Whooping crane Northern spotted
owl
California condor Hawksbill sea
turtle
Blue whale
Black rhinoceros
Fig. 8-3, p. 156
Fig. 8-4, p. 157
Characteristic
Examples
Low reproductive
rate
Blue whale, giant
panda, rhinoceros
Specialized
niche
Blue whale, giant
panda, Everglades
kite
Narrow
distribution
Elephant seal,
desert pupfish
Feeds at high
trophic level
Bengal tiger, bald
eagle, grizzly bear
Fixed migratory
patterns
Blue whale,
whooping crane,
sea turtle
Rare
African violet, some
orchids
Commercially
valuable
Large territories
Snow leopard,
tiger, elephant,
rhinoceros, rare
plants and birds
California condor,
grizzly bear, Florida
panther
Fig. 8-4, p. 157
Characteristic
Examples
Low reproductive
rate
Blue whale, giant
panda, rhinoceros
Specialized
niche
Narrow
distribution
Blue whale, giant
panda, Everglades
kite
Elephant seal,
desert pupfish
Feeds at high
trophic level
Bengal tiger, bald
eagle, grizzly bear
Fixed
migratory
patterns
Rare
Commercially
valuable
Large territories
Blue whale,
whooping crane,
sea turtle
African violet,
some orchids
Snow leopard, tiger,
elephant, rhinoceros,
rare plants and birds
California condor,
grizzly bear, Florida
panther
Stepped Art
Fig. 8-4, p. 157
Fig. 8-5, p. 157
Fish
34% (51% of freshwater species)
Amphibians
32%
Mammals
25%
20%
Reptiles
Plants
Birds
14%
12%
Fig. 8-5, p. 157
Case Study: Extinction of the
Passenger Pigeon
• Audubon, 1813: 3 days for a flock to
pass over
• Extinct by 1900
– Good to eat
– Feathers good for pillows
– Bones good for fertilizer
– Easy to kill
8-2 Why Should We Care about
Preventing Species Extinction?
• Concept 8-2 We should prevent the
premature extinction of wild species
because of the economic and
ecological services they provide and
because they have a right to exist
regardless of their usefulness to us.
Value of Species
• Instrumental value of biodiversity
– Food crops
– Genetic information
– Medicine
– Bioprospectors
– Ecotourism
• Do not know what we lose when
species go extinct
Fig. 8-6, p. 158
Fig. 8-7, p. 158
Rauvolfia
Rosy periwinkle
Pacific
yew
Neem tree
Foxglove
Cinchona
Rauvolfia sepentina,
Southeast Asia
Anxiety, high
blood pressure
Taxus brevifolia,
Pacific Northwest
Ovarian cancer
Digitalis purpurea,
Europe
Digitalis for heart failure
Cathranthus roseus,
Madagascar
Hodgkin's disease,
lymphocytic leukemia
Cinchona ledogeriana,
South America
Quinine for malaria treatment
Azadirachta indica,
India
Treatment of many
diseases, insecticide,
spermicide
Fig. 8-7, p. 158
Ethical Obligations
• Intrinsic (existence) value
• Stewardship viewpoint
8-3 How Do Humans Accelerate
Species Extinction?
• Concept 8-3 The greatest threats to
any species are (in order) loss or
degradation of its habitat, harmful
invasive species, human population
growth, pollution, climate change, and
overexploitation.
Fig. 8-8, p. 160
Natural Capital Degradation
Causes of Depletion and Premature Extinction of Wild Species
Underlying Causes
• Population growth
• Rising resource use
• Undervaluing natural capital
• Poverty
Direct Causes
• Habitat loss
• Pollution
• Commercial hunting and poaching
• Habitat degradation and fragmentation
• Climate change
• Sale of exotic pets and decorative plants
• Introduction of nonnative species
• Overfishing
• Predator and pest control
Fig. 8-8, p. 160
Causes of Endangerment and
Premature Extinction (HIPPCO)
•
•
•
•
•
•
Habitat destruction
Invasive species
Population growth
Pollution
Climate change
Overexploitation
Habitat Loss
• Deforestation of tropical areas
greatest eliminator of species
• Endemic species
• Habitat fragmentation
Fig. 8-9, p. 161
Fig. 8-9, p. 161
Indian
Tiger
Range 100 years ago
Range today
African
Elephant
Probable range 1600
Range today
Black
Rhino
Range in 1700
Range today
Asian or Indian
Elephant
Former range
Range today
Stepped Art
Fig. 8-9, p. 161
Case Study: Declining Bird
Species (1)
• Decline of ~70% of ~10,000 known
species
• 12% threatened with extinction
• Birds around humans benefited, but
forest species declined
• Long-distance migrants – greatest
decline
Case Study: Declining Bird
Species (2)
• Reasons
– Habitat loss
– Habitat fragmentation
– Climate change
• Birds are environmental indicators
• Perform economic and ecological
services
Species Introductions
• Most beneficial – food crops,
livestock, pest control
• 500,000 alien invader species
globally
• 50,000 nonnative species in the U.S.
• Some definitely not beneficial
Fig. 8-10, p. 163
Deliberately Introduced Species
Purple loosestrife European starling African honeybee Nutria
(“Killer bee”)
Marine toad
(Giant toad)
Water hyacinth
Japanese beetle
Hydrilla
Salt cedar
(Tamarisk)
European wild boar
(Feral pig)
Fig. 8-10, p. 163
Fig. 8-10, p. 163
Accidentally Introduced Species
Sea lamprey
Argentina fire
(attached to lake ant
trout)
Brown tree
snake
Eurasian ruffe
Common pigeon
(Rock dove)
Formosan
termite
Asian longhorned beetle
Asian tiger
mosquito
Gypsy moth larvae
Zebra mussel
Fig. 8-10, p. 163
Deliberately introduced species
Purple
European
loosestrife starling
Marine toad
(Giant toad)
African honeybee Nutria
(“Killer bee”)
Water
hyacinth
Japanese
beetle
Hydrilla
Salt cedar
(Tamarisk)
European wild
boar (Feral pig)
Accidentally introduced species
Sea lamprey
(attached to
lake trout)
Formosan
termite
Argentina
fire ant
Zebra
mussel
Brown tree
snake
Eurasian
ruffe
Common pigeon
(Rock dove)
Asian long- Asian tiger Gypsy moth
horned beetle mosquito
larvae
Stepped Art
Fig. 8-10, p. 163
Case Study: The Kudzu Vine
• Kudzu introduced to control erosion
• Prolific growth
• Uses
– Asians use powdered starch in
beverages
– Edible
– Source of tree-free paper
– Japanese kudzu farm in Alabama
Fig. 8-11, p. 164
Disruptions from Accidentally
Introduced Species
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•
•
•
•
Downside of global trade
Downside of traveling
Argentina fire ant
Burmese python
Zebra mussel
Fig. 8-12, p. 165
Prevention of Nonnative
Species (1)
• Identify characteristics of successful
invaders
• Detect and monitor invasions
• Inspect imported goods
• Identify harmful invasive species and
ban transfer
Prevention of Nonnative
Species (2)
• Ships discharge ballast waters at sea
• Introduce natural control organisms of
invaders
Fig. 8-13, p. 165
Fig. 8-14, p. 166
Human Choices Drive Extinction
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•
•
•
Human population growth
Excessive, wasteful consumption
Use of pesticides
Climate change
DDT and Bioaccumulation
• 1950s–1960s fish-eating bird
populations drop
• DDT biologically magnified in food
webs
• Bird’s eggshells thin and fragile
• Leads to unsuccessful reproduction
Fig. 8-15, p. 166
DDT in fish-eating
birds (ospreys)
25 ppm
DDT in large
fish (needle fish)
2 ppm
DDT in small
fish (minnows)
0.5 ppm
DDT in
zooplankton
0.04 ppm
DDT in water
0.000003 ppm,
or 3 ppt
Fig. 8-15, p. 166
DDT in fish-eating
birds (ospreys)
25 ppm
DDT in large fish
(needle fish)
2 ppm
DDT in small
fish (minnows)
0.5 ppm
DDT in
zooplankton
0.04 ppm
DDT in water
0.000003 ppm,
or 3 ppt
Stepped Art
Fig. 8-15, p. 166
Case Study: Where Have All the
Honeybees Gone?
• Honeybees responsible for 80% of
pollination of insect-pollinated plants
• Population down 30% since the 1980s
– Pesticides
– Parasitic mites
– Invasive African honeybees
• 2008: 36% of honeybee colonies lost
– Colony collapse disorder
– New nicotine-based pesticides to blame?
Illegal Killing and Trading of
Wildlife
• Poaching endangers many larger
animals, rare plants
• Over two-thirds die in transit
• Illegal trade: $1.1 million per hour
• Wild species depleted by pet trade
• Exotic plants often illegally gathered
Fig. 8-16, p. 168
Fig. 8-A, p. 168
The Value of Wild Rare Species
• Declining populations increase black
market values
• Rare species valuable in the wild –
eco-tourism
• Some ex-poachers turn to ecotourism
Rising Demand for Bush Meat
• Demand increasing with population
growth
• Increased road access
• Loggers, miners, ranchers add to
pressure
• Local and biological extinctions
• Spread of HIV and Ebola virus
Fig. 8-17, p. 169
8-4 How Can We Protect Wild
Species from Premature Extinction?
• Concept 8-4 We can reduce species
extinction and help to protect overall
biodiversity by establishing and
enforcing national environmental laws
and international treaties, creating a
variety of protected wildlife
sanctuaries, and taking precautionary
measures to prevent such harm.
International Treaties
• Convention on International Trade of
Endangered Species (CITES)
• Convention on Biological Diversity
(CBD)
U.S. Endangered Species Act
(1)
• National Marine Fisheries Services –
ocean species
• U.S. Fish and Wildlife Service – other
species
• Listings based on biological factors
• Forbids federal agency projects that
jeopardize listed species or habitats
U.S. Endangered Species Act
(2)
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•
•
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Fines violations on private land
Illegal to sell or buy listed species
1,318 species listed
USFWS and NMFS supposed to
prepare recovery plan – 86% species
in 2009
U.S. Endangered Species Act
(3)
• Successful recovery plans include
American alligator, grey wolf, and
bald eagle
• Lax enforcement of imports and
exports
• Amended to give private landowners
economic incentive to save species
Science Focus: Accomplishments
of the Endangered Species Act
• Biologists defend limited success
– Species listed only when gravely
threatened
– Takes long time for species to recover
– >50% endangered species improving
• Need more funding
• Develop recovery plans more quickly
• Core habitat established when listed
Protection of Marine Species
• ESA and international treaties protect
endangered marine reptiles and
mammals
• Challenges to protecting marine
species
– Limited knowledge of species
– Difficulty in monitoring and enforcing
treaties – open oceans
Sea Turtles Threatened
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•
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•
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Six species critically endangered
Loss or degradation of habitat
Illegal harvest of eggs
Threats from fishing methods
Protection measures have helped
Fig. 8-18, p. 171
Case Study: Protecting Whales
(1)
• Easy to kill
• International Whaling Commission
– Sets quotas
– Often ignored
– No enforcement powers
• 1986: Whaling ban, although violated,
greatly decreased whale kills
Case Study: Protecting Whales
(2)
• Key countries that violate whaling ban
– Japan
– Norway
– Iceland
Fig. 8-19, p. 172
Establish Wildlife Refuges
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National Wildlife Refuge System
Wetland refuges: ~75%
40 million American visitors
20% of listed species in refuge
system
• Many refuges in disrepair, and many
allow mining, oil drilling, and off-road
vehicles
Storing Genetic Information
• Gene or seed banks
• Botanical gardens and arboreta
• Farms – commercial sale of
endangered species removes
pressure
Zoos and Aquariums for
Protection
• Collect species with long-term goal of
returning them into habitat
• Egg pulling
• Captive breeding
• 100–500 captive individuals to avoid
extinction
• 10,000 individuals to maintain
capacity for biological evolution
Case Study: Trying to Save the
California Condor
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Last 22 individuals captured
Released a few at a time
2009: 167 condors in the wild
Threatened by lead poisoning from
animal carcasses and gut piles
The Precautionary Principle
• When substantial preliminary evidence
indicates an activity could harm humans or
the environment, we should take
precautionary measures to prevent or
reduce the harm
• Do even if cause-and-effect relationships
are not yet clearly established
• “Better safe than sorry”
Three Big Ideas from This
Chapter - #1
We are greatly increasing the
premature extinction of wild species
by destroying and degrading their
habitats, introducing harmful invasive
species, and increasing human
population growth, pollution,
contributing to projected climate
change, and over-exploitation.
Three Big Ideas from This
Chapter - #2
We should prevent the premature
extinction of wild species because of
the economic and ecological services
they provide and because they have
a right to exist regardless of their
usefulness to us.
Three Big Ideas from This
Chapter - #3
We can work to prevent the premature
extinction of species and to protect
overall biodiversity by using laws and
treaties, protecting wildlife
sanctuaries, and making greater use
of the precautionary principle.
Animation: Species Diversity By
Latitude
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ANIMATION
Animation: Area and Distance
Effects
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Animation: Humans Affect
Biodiversity
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Animation: Resources Depletion
and Degradation
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Animation: Biodiversity Hot
Spots
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Animation: Habitat Loss and
Fragmentation
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Video: New Species Found
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Video: Hsing Hsing Dies
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Video: Penguin Rescue
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Video: Bachelor Pad at the Zoo
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Video: Sea Turtle Release
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Video: Human Zoo
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