Download Chapter 11 - apeswstes

Chapter 12
Sustaining Biodiversity:
The Species Approach
Core Case Study:
The Passenger Pigeon - Gone
Forever
 Once
the most
numerous bird on earth.
 In 1858, Passenger
Pigeon hunting became
a big business.
 By 1900 they became
extinct from overharvest and habitat
loss.
Figure 11-1
SPECIES EXTINCTION
 Species



can become extinct:
Locally: A species is no longer found in an area
it once inhabited but is still found elsewhere in
the world.
Ecologically: Occurs when so few members of a
species are left they no longer play its ecological
role.
Globally (biologically): Species is no longer
found on the earth.
Global Extinction
 Some
animals have become prematurely
extinct because of human activities.
Figure 11-2
Endangered and Threatened Species:
Ecological Smoke Alarms
 Endangered
species: so few individual
survivors that it could soon become extinct.
 Threatened species: still abundant in its
natural range but is likely to become
endangered in the near future.
Figure 11-3
Fig. 11-3, p. 224
SPECIES
EXTINCTION
 Some
species
have
characteristics
that make them
vulnerable to
ecological and
biological
extinction.
Figure 11-4
SPECIES EXTINCTION
 Scientists
use measurements and models to
estimate extinction rates.


The International Union for the Conservation of
Nature and Natural Resources (IUCN) publishes
an annual Red List, listing the world’s threatened
species.
The 2004 Red List contains 15,589 species at
risk for extinction.
Figure 11-5
SPECIES EXTINCTION
 Percentage
of various species types
threatened with premature extinction from
human activities.
Figure 11-5
HABITAT LOSS, DEGRADATION,
AND FRAGMENTATION
 Conservation
biologists summarize the most
important causes of premature extinction as
“HIPPO”:





Habitat destruction, degradation, and
fragmentation
Invasive species
Population growth
Pollution
Overharvest
HABITAT LOSS, DEGRADATION,
AND FRAGMENTATION
 Reduction
in
ranges of four
wildlife species,
mostly due to
habitat loss
and
overharvest.
Figure 11-8
Human activities affect species
extinction rates.
- Currently extinction rates are
1,000-10,000 times higher than
prehuman levels
Under current extinction rates
- 20% of world’s present plant and
animals will be extinct by 2030
- 50% will be gone by 2099
Why are greater extinction rates likely?
1) Exponential population growth will
increase biodiversity loss
2) Biological hot spots have extinction rates
as high as 25-50%
3) Possible colonization sites are being
eliminated or degraded reducing the rate of
speciation.
4) A precautionary strategy to prevent
significant decrease in diversity of the earth
is needed.
Importance of wild species
It will take ~5 million years for
speciation to rebuild the animals &
plants we will destroy in 100 years
 Medicinal properties found in many
plants and some animals
 Recreational value/ Eco-tourism
 Some people believe we should only
protect some species, others believe all
species have value
 Remember ALL species have value,
including microorganisms, and roles to
play in ecosystems
US government animal control agents kill
thousands of coyotes, prairie dogs, wolves,
bobcats, and other species every year
- 99% of prairie dogs in US have been
extirpated
- Black-footed ferret is now in trouble
because it preyed on the prairie
dogs
INVASIVE SPECIES
 Many
Kudzu vine was introduced in
the southeastern U.S. to
control erosion. It has taken
over native species habitats.
nonnative
species provide us
with food, medicine,
and other benefits
but a a few can wipe
out native species,
disrupt ecosystems,
and cause large
economic losses.
Figure 11-A
INVASIVE
SPECIES
 Prevention
is the
best way to reduce
threats from
invasive species,
because once they
arrive it is almost
impossible to slow
their spread.
Figure 11-13
The IUCN’s Red List is ___.
a. A list of ecologically damaged ecosystems
b. A list of species facing unusually high risk
of extinction
c. A list of unidentified species
d. An identification of identified species
e. A scorecard of international failures at
conservation
In general, successful introduced species
experience _____.
a. Decreased environmental resistance
b. Increases in limiting factors
c. Increased competition from other
organisms
d. Decreased biotic potential
e. Increased habitat destruction
Which of the following can change global
species diversity.
a.
b.
c.
d.
e.
Immigration and extirpation
Speciation and immigration
Speciation and extinction
Emigration and extinction
Extirpation and extinction
Which of the following can change local
species diversity but not global diversity?
a.
b.
c.
d.
e.
Immigration and extirpation
Speciation and immigration
Speciation and extinction
Emigration and extinction
Extirpation and extinction
Mathematical models indicate that organisms
most vulnerable to habitat loss may be the
a.
b.
c.
d.
e.
Producers
Herbivores
Decomposers
Top competitors
Bacteria
POPULATION GROWTH,
POLLUTION, AND CLIMATE
CHANGE
 Population
growth, affluenza, and pollution
have promoted the premature extinction of
some species.
 Projected climate change threatens a number
of species with premature extinction.
Pollution
 Each




Example of biomagnification
of DDT in an aquatic food
chain.
year pesticides:
Kill about 1/5th of the
U.S. honeybee
colonies.
67 million birds.
6 -14 million fish.
Threaten 1/5th of the
U.S.’s endangered
and threatened
species.
Figure 11-15
OVEREXPLOITATION
 Some
protected species are killed for their
valuable parts or are sold live to collectors.
 Killing predators and pests that bother us or
cause economic losses threatens some
species with premature extinction.
 Legal and illegal trade in wildlife species
used as pets or for decorative purposes
threatens some species with extinction.
Extinction threats from poaching and hunting
Some protected species are killed for
their valuable parts or sold to collectors
live mountain gorilla= $150,000
panda pelt = $100,000
chimpanzee = $50,000
Imperial Amazon macaw = $30,000
rhinoceros horn = $13,000 per pound
Bengal tiger fur= $100,000 & body parts
$5,000-$20,000
What about Bushmeat?
OVEREXPLOITATION
 Rhinoceros
are often
killed for their horns
and sold illegally on
the black market for
decorative and
medicinal purposes.
Figure 11-16
Case Study:
Rising Demand for Bushmeat in
Africa
 Bushmeat
hunting has
caused the local
extinction of
many animals in
West Africa.
 Can spread
disease such as
HIV/AIDS and
ebola virus.
Figure 11-17
Treaties help protect endangered and threatened
species, but enforcement is difficult
1975 Convention on International
Trade in Endangered Species
(CITES) protects 900 species from being traded
& restricts international trade for 29,000
species that may become threatened. Why do
problem still exist?
Lacey Act of 1900 prohibits transporting live or
dead wild animals or their parts across state
borders without a federal permit.
The Endangered Species Act of 1973 identified
and legally protects endangered species in the
US and abroad.
Case Study:
The U.S. Endangered Species Act
 One
of the world’s most far-reaching and
controversial environmental laws is the 1973
U.S. Endangered Species Act (ESA).


ESA forbids federal agencies (besides defense
department) to carry out / fund projects that
would jeopardize an endangered species.
ESA makes it illegal for Americans to engage in
commerce associated with or hunt / kill / collect
endangered or threatened species.
Case Study:
The U.S. Endangered Species Act
 Biodiversity
hotspots in relation to the largest
concentrations of rare and potentially
endangered species in the U.S.
Figure 11-18
Endangered Species
 Because
of
scarcity of
inspectors,
probably no
more than 1/10th
of the illegal
wildlife trade in
the U.S. is
discovered.
Figure 11-19
Endangered Species
 Congress
has amended the ESA to help
landowners protect species on their land.
 Some believe that the ESA should be
weakened or repealed while others believe it
should be strengthened and modified to focus
on protecting ecosystems.
 Many scientists believe that we should focus
on protecting and sustaining biodiversity and
ecosystem function as the best way to
protect species.
PROTECTING WILD SPECIES: THE
SANCTUARY APPROACH
 The
U.S. has set aside 544
federal refuges for wildlife,
but many refuges are
suffering from environmental
degradation.
Pelican Island was the
nation’s first wildlife refuge.
Figure 11-20
Zoos and aquariums can help protect some
endangered animal species, but they are
underfunded
Egg pulling collects wil eggs laid by birds and
hatches them in zoos
Captive breeding takes wild individuals into
captivity for breeding with the commitment to
releasing the offspring back into the wild
Artificial insemination, use of surrgate
mothers, use of incubators, & cross fostering
by a similar species can increase
populations of rare species
Ultimate goal must be to reintroduce
species into the wild.
Reintroductions can fail because..
1) There is not enough suitable habitat
2) Individuals bred in captivity are not able to
survive in the wild.
3) There is renewed overhunting or capturing
of the returned species.
The most important role of zoos and aquariums
is to educate the public.
RECONCILIATION ECOLOGY
 Reconciliation
ecology involves finding ways
to share places we dominate with other
species.



Replacing monoculture grasses with native
species.
Maintaining habitats for insect eating bats can
keep down unwanted insects.
Reduction and elimination of pesticides to protect
non-target organisms (such as vital insect
pollinators).
Using Reconciliation Ecology to
Protect Bluebirds
 Putting
up bluebird
boxes with holes too
small for (nonnative)
competitors in areas
where trees have
been cut down have
helped reestablish
populations.
Figure 11-B
The blue whale is extinction prone for all of
the following reasons except
a.
b.
c.
d.
e.
Low reproduction rate
Feeding at the top trophic level
Specialized feeding habits
Fixed migratory patterns
None of these answers
Underlying causes of extinction and reduction
of wildlife populations include all of the
following except
a.
b.
c.
d.
e.
Affluence
Human population growth
Sustainable development
Governmental policies that undervalue
ecological service
Rising resource
Weedy pioneer species are primarily found in
a.
b.
c.
d.
e.
Pre-Early-successional
Early-successional
Mid-successional
Late-successional
Wilderness
CITES is a(n)
a.
b.
c.
d.
e.
Treaty controlling the international trade in
endangered species
Set of regulations controlling the
introduction of exotic species
Pact that supports critical ecosystems that
support wildlife
International organization dedicated to the
preservation of endangered species
All of these answers
Transporting of live or dead wild animals
across U.S. state borders without a federal
permit is prohibited by
a.
b.
c.
d.
e.
CITES
The Endangered Species Act
The Amber Act
The Lacey Act
The Animal Preservation Act