Transcript chapter8_revised

In Class Assignment Biomes
Name:___________________
• ____________ contains widely scattered clumps of trees such as acacia
•
•
•
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which are covered with thorns, has warm temps year round, and alternating
wet and dry seasons
_____________humans have converted much of this biome to farmland
because its fertile soil is good for raising crops and grazing cattle
______________ in this biome very little plant litter reaches the ground,
nutrients that do reach the ground are soon leached from soil by constant
rainfall, and 90% of plant nutrients released by decomposition are taken up
and stored by plants
_______________ contain majority of world’s forests, host many endemic
species, key in hydrologic cycle.
Coral is formed by ______________ . They are in a symbiotic relationship
with __________________ algae.
____________________ coastal forests with extensive root systems that
often extend above the water. Can be found on some tropical coastlines.
ENVIRONMENTAL SCIENCE 13e
CHAPTER 8:
Sustaining Biodiversity:
The Species Approach
“In the end we will conserve only
what we love. We love only what
we understand. We will
understand only what we are
taught.” Baba Dioum
Core Case Study: Polar Bears and Projected Climate Change
In Chapter 7 we discussed climate and biomes.
What affect do you think climate change will have on arctic biomes?
Fig. 8-1, p. 152
Polar bear video
• http://www.youtube.com/watch?v=Ow
ZH_aT0FGI&feature=related
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
Polar Bear Case Study
•Projected 30-35% decline of total
polar bear population by 2050
• Potentially extinct from wild by 2100
Resource: San Diego Zoo Website
• http://www.sandiegozoo.org/polarcam/gall
ery.html
• http://blogs.sandiegozoo.org/category/defa
ult/polar-bears/
San Diego Zoo Global is an international conservation
organization that has been saving species for over 95 years.
Experts in scientifically based breeding, conservation, and
reintroduction programs for endangered species.
What do you think
• How have human activities affected
natural extinction rates?
• How are we likely to affect such rates
in the next 50-100 years?
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- normal extinction of
various species as a result of various changes in local
environmental conditions
• Current rate is 100-1,000 times
background extinction
• Rate likely to rise to 10,000 times
• Is a mass extinction coming?
• Mass extinction- catastrophic, widespread often global
event in which major groups of species are wiped out
over a short time compared with normal (background)
extinctions
Review of terms
• Local extinction-
• Biological extinction-
Review of terms
• Local extinction- species is no longer
found in one area it once inhabited but is
found in other areas but is found
elsewhere on earth
• Biological extinction- species is no
longer found anywhere on earth; biological
extinction is forever! Irreversible
Current Extinction Rate
Estimates Are Conservative
• Rate of species loss and biodiversity
losses will increase in next 50–100 years
• Why?
• Biodiversity hotspot rates higher than global
average
• We are eliminating, degrading, fragmenting and
simplifying many biologically diverse environments that
would serve as the sites for the emergence of new
species
Some animal species that have become prematurely extinct
largely because of human activities, mostly habitat destruction and overhunting.
Fig. 8-2, p. 154
What are endangered and
threatened species?
• Endangered species: wild species with so few
individual survivors that the species could soon become
extinct in all or most of it’s natural range
• Threatened species-wild species that is still
abundant in its natural range but is likely to become
endangered in the near future because of a decline in numbers
•
• Edward O Wilson “The first animal species to go are the big, the
slow, the tasty, and those with valuable parts such as tusks and
skins”
• Some behaviors make species prone to extinction: ex. Passenger
pigeon, Key deer
Characteristics of
species that are
prone to
ecological and
biological
extinction.
Critical
Thinking
Which of these
characteristics
might contribute
to the premature
extinction of the
polar bear
during this
century?
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
Case Study:
Passenger Pigeon: Gone Forever
• John James Audubon, 1813: took 3 days for a
flock to pass over, flock so dense it darkened the
skies
• Yet by 1900, North America’s Passenger Pigeon, once
one of the most abundant birds on earth, was extinct
– Good to eat
– Feathers good for pillows
– Bones good for fertilizer
– Easy to kill, flew in flocks and nested in
colonies
Passenger Pigeon links
• http://mnh.si.edu/onehundredyears/fe
atured_objects/martha2.html
• First link has short video clip
•
http://blogs.smithsonianmag.com/aroundthemall/2011/09/martha-theworlds-last-passenger-pigeon/
Cincinnati Zoo Memorial to Martha and the
Passenger Pigeons
Critical Thinking: What difference does it make that
the passenger pigeon is extinct?
Considerations
• Intrinsic (existence) value: each wild
species has inherent right to exist regardless
of its usefulnes to us
• Stewardship viewpoint: we have an ethical responsibility
to protect species from becoming prematurely extinct as
a result of human activities and to prevent the
degradation of the world’s ecosystems and its overall
biodiversity
• Instrumental value: species usefulness to us because of
the many ecological and economic services they help
provide as part of the earth’s natural capital
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
• We do not know what we lose when
species go extinct
Critically Endangered
• According to the WWF, the 5 most
endangered animals in the wild are the
Javan rhino (70 left), whooping crane (250
left), mountain gorilla (600 left), Siberian
tiger (700 left), and the California condor
(336 left)
• I was fortunate to learn more about the California
condors last year when I went to San Diego and visited
the San Diego Zoo and the San Diego Zoo Safari Park
(Wild Animal Park)
San Diego Zoo Global
International conservation organization that has
been saving species for over 95 years
Experts in scientifically based breeding,
conservation, and reintroduction programs for
endangered species
Case Study: Trying to Save the
California Condor
• Nearly extinct with only 22 condors
remaining in the wild
• Last 22 individuals captured, bred in
captivity
• Released a few at a time
• 2009: 167 condors in the wild
• Greatly threatened by lead poisoning from
animal carcasses and gut piles
Total World Population of California Condors
Condor Population reaches 100 in California
The goal of the California Condor Recovery Plan is to establish two
geographically separate populations,
one in California and the other in Arizona, each with 150 birds and at least 15
breeding pairs. As the Recovery
Program works toward this goal the number of release sites has grown. There
are three active release sites in California,
.
one in Arizona, and one in Baja, Mexico
Condor Puppet
Condor hatching video
• http://www.youtube.com/watch?v=XN
kV02P8Ysc
Condor Training
San Diego Zoo Condor Cam
• http://www.sandiegozooglobal.org/vid
eo/condor_cam
Condor video: Condor nest update
• http://www.youtube.com/watch?v=nO
8Ro94l5C4
Condor References
• http://www.sandiegozoo.org/animalby
tes/t-condor.html
• http://content.usatoday.com/communities/scienc
efair/post/2010/10/california-california-condorpopulation-reaches-100/1?csp=usat.me
Critical Thinking
• What are some differences between the
stories of the condor and the passenger
pigeon that might give the condor a better
chance of avoiding premature extinction
than the passenger pigeon had?
Little Fish, Big Controversy
The Story of Snail Darter, the Endangered Species Act,
TVA, and the Tellico Dam
The Snail Darter Story: Connection to
History, Economics, Politics
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In August of 1973, a University of Tennessee biologist discovered a small fish species, the snail darter, in the Little
Tennessee River while conducting research involving a lawsuit around construction of the Tellico Dam. Creation of
the Tellico Reservoir, to be created by the Tellico Dam, the scientist predicted, would alter the snail darter's habitat
to the point of extirpation.
Opponents of the dam used the snail darter as leverage in attempting to halt construction and invoked the Endangered Species Act to do
so. The Tennessee Valley Authority argued that (1) since the Act was passed after the project began (December 1973) it did not apply
and (2) after Congress passed the Endangered Species Act it continued to appropriate funds to Tellico; therefore, Congress did not intend
for the ESA to apply to Tellico.
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The Supreme Court's ruling in Tennessee Valley Authority vs. Hill (1978) was unprecedented. Speaking for the majority, Chief Justice
Warren Burger announced the court's decision to rule in favor of the snail darter, halting construction on the Tellico Dam. Caution was
taken not to say that Congress broke the law by funding the Dam. According to the ruling, the language and intended goals of the
Endangered Species Act are clear: there are no exceptions for project like Tellico that were well under way when Congress passed the
Act, and that Congress' intent was to slow, stop and reverse the trend toward species extinction—no matter the cost.
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Soon after the ruling, Tennessee legislators in favor of the Tellico Dam began an appeals process which included sponsorship of an
amendment to the Act that would form an investigative committee whenever controversy arose over a listing. Dubbed the "God Squad,"
even this committee deemed the Tellico Dam project “dangerous” to the snail darter and "economically not beneficial." Nonetheless,
legislators appealed again, and the case reached President Jimmy Carter's desk in 1979. Although he wanted to veto the bill that would
override the Supreme Court's decision, political realities and other pressing issues, like the Panama Canal Treaty, forced the President to
sign it on September 25, 1979. As the gates closed on the Tellico Dam and the Tellico Resevoir formed in subsequent years, several
other populations of the snail darter were found elsewhere around the country, and the species was delisted in the late 1980s.
•
The snail darter controversy not only illustrates the conflict between conservation biologists and
economic interest groups, it also shows just how entwined science and politics are in conservation
legislation. Biologists and politicians alike have suggested ways to mitigate the problems arising from this unhappy marriage, which
•
will be discussed in later sections.
http://www.macalester.edu/environmentalstudies/students/projects/citizenscience2007/endangeredspecies/controversy.html
Homework Snail Darter
• What were some of the objections to the Tellico dam
project?
• Why did the dam project get so far along before the
environmentalists called for a halt to it?
• What were the arguments for continuing with the
project?
• What ultimately happened to the snail darter?
• What lessons can we learn from this controversy that will
help us solve environmental, economic, legal problems
in the future?
The Tellico Dam and the Snail Darter
Connections to history, politics, and economics
• http://www.utc.edu/Faculty/JohnTucker/Courses/esc430/esc430mat/darter/tellico
.html
• http://bgpappa.hubpages.com/hub/The-Story-OfThe-Snail-Darter
Why should we care if plant species become extinct?
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
Nature’s pharmacy.
Part’s of these and a number of other plant
and animal species (many of them found in tropical forests) are used to treat a variety
of human ailments and diseases. About 2,100 of the 3,000 plants identified by the
National Cancer Institute as sources of cancer fighting chemicals come from tropical forests.
Fig. 8-7, p. 158
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
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.
Causes of Endangerment and
Premature Extinction (HIPPCO)
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Habitat destruction
Invasive species
Population growth
Pollution
Climate change
Overexploitation
• know for exam
Review for exam
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
Habitat Loss
• Deforestation of tropical areas
greatest eliminator of species
• Endemic species-species that is found in
only one area
• Habitat fragmentation- by roads, logging,
agriculture, and urban development, occurs when a
large, intact area of habitat is reduced in area and
divided into smaller, more scattered, and isolated
patches, or “habitat islands”
Reductions in the ranges of four wildlife species, mostly as the result of habitat loss
and hunting. What will happen to these and million of other species when the world’s
human population doubles and per capita resource consumption rises sharply in the next few
decades?
Black
Indian
Rhino
Tiger
Range 100 years ago
Range today
African
Elephant
Probable range 1600
Range today
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
(species that serve as early warning that a community or
ecosystem is being degraded)
• 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
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
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
Case Study: The Kudzu Vine
“the vine that ate the South”
• Kudzu imported from Japan to control soil
erosion
• Growth is so prolific that it engulfs hillsides,
gardens, trees, abandoned houses, cars, and
anything in its path
• 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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•
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•
•
Downside of global trade
Downside of traveling
Argentina fire ant
Burmese python
Zebra mussel
Zebra Mussels
attached to a water
current meter
in Lake Michigan.
This invader entered
the Great Lakes
through ballast
water dumped from
a European ship.
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
Review for exam: ex zebra mussels
Generalist, rapid reproductive rate, lack of natural enemies+
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
Bioaccumulation and biomagnification. DDT is a fat-soluble chemical that can
Accumulate in the fatty tissues of animals. In a food chain or web the accumulated
DDT is biologically magnified in the bodies of animals at each higher trophic level.
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
• Bioaccumulation= an
increase in the
accumulation of a
chemical in specific
organs or tissues at a
level higher than would
normally be expected
• Biomagnification=
increase in concentration
of DDT, PCBs, and other
slowly degradable, fat
soluble chemicals in
organisms at
successively higher
trophic levels of a good
chain or web
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?
Study Finds Cause of Colony Collapse
Disorder in Bees
• http://www.telegraph.co.uk/gardening/beekeepin
g/8050583/Study-finds-causes-of-ColonyCollapse-Disorder-in-bees.html
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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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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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
• Flagship species
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.