Download Sustaining Biodiversity: The Species Approach

Chapter 9
 Passenger
1900
pigeon hunted to extinction by
 Commercial
 Geological
extinctions
 Human
hunters used a "stool pigeon”
record shows five mass
activities: hastening more
extinctions?
 Concept
9-1A We are degrading and
destroying biodiversity in many parts of
the world, and these threats are increasing.
 Concept
9-1B Species are becoming
extinct 100 to 1,000 times faster than they
were before modern humans arrived on
the earth (the background rate), and by
the end of this century, the extinction rate
is expected to be 10,000 times the
background rate.
 Human
activity has disturbed at least half
of the earth’s land surface
• Fills in wetlands
• Converts grasslands and forests to crop fields
and urban areas
 Degraded
aquatic biodiversity
 Background
 Extinction
extinction
rate
 Mass extinction: causes?
• Poorly understood, but involve global changes in
environmental conditions.
 Levels of species extinction
• Local extinction, or extirpation
• Ecological extinction
• Biological extinction
 Premature
extinctions due to
• Habitat destruction
• Overhunting, or overexploitation
 Conservative
0.01-0.1%
estimates of extinction =
• Growth of human population will increase this
loss to 10 000 times (to 1%)
• Rates are higher where there are more
endangered species
• Tropical forests and coral reefs, wetlands and
estuaries—sites of new species—being
destroyed
 Speciation
crisis
 Endangered species
• International Union for the for the Conservation of
Nature (IUCN), or the World Conservation Union.
 Since 1960, published Red List
 In 2007, listed 16, 306 animals and plants that are in danger
of extinction—60% higher than in 1995.
 Threatened species, vulnerable
• Characteristics of such species
species
Figure 9.4
Endangered natural
capital. Some species that
are endangered or
threatened with premature
extinction largely because of
human activities. Almost
30,000 of the world’s species
and roughly 1,300 of those in
the United States are
officially listed as being in
danger of becoming extinct.
Most biologists believe the
actual number of species at
risk is much larger.
Grizzly
bear
Kirkland’s
warbler
Utah prairie Swallowtail
dog
butterfly
Giant
panda
Black-footed
ferret
Mountain
gorilla
Florida
panther
Knowlton
cactus
Florida
manatee
Humpback Golden lion
tamarin
chub
Whooping
crane
African
elephant
Siberian
tiger
Northern
Blue whale
spotted owl
California Hawksbill sea
Black
condor
rhinoceros
turtle
Figure 9.5
Characteristics of species
that are prone to ecological
and biological extinction.
Question: Which of these
characteristics helped lead
to the premature extinction
of the passenger pigeon
within a single human
lifetime?
Characteristic
Examples
Low reproductive
rate (K-strategist)
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
 Three problems
• Hard to document due to length of time
• Only 1.8 million species identified
• Little known about nature and ecological roles of
species identified
 Document little changes in DNA
• Suggests species survive for 1 to 10 million years
before going extinct.
 Use species–area relationship
• On average, 90% loss of habitat results in a 50% loss
of species living in that habitat.
 Mathematical
models
 Concept
9-2 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.
 “It
will take 5-10 million years for natural
speciation to rebuild the biodiversity we are
likely to destroy during your lifetime.”

Instrumental value – usefulness to us in providing
ecological and economic services.
• Use value
 Ecotourism: wildlife tourism
 Genetic information
 Loss in diversity of crop species is cause for concern.
 Food crops, recreation, scientific information, lumber, paper, etc.
• Nonuse value
 Existence value
 Aesthetic value
 Bequest value

Ecological value
• Energy flow, nutrient cycling, and population control—the
scientific principles of sustainability that sustain and support life
on earth.
 1989
international treaty against poaching
elephants
 Poaching
on the rise
 Track
area of poaching through DNA
analysis of elephants
 Elephants
damaging areas of South Africa:
Should they be culled?
 Intrinsic
value, or existence value
• Species have an inherent right to exist and play
their ecological roles, regardless of their
usefulness to us.
 Edward
O. Wilson: biophilia
phenomenon
 Biophobia
 Vulnerable to extinction
• Slow to reproduce
• Human destruction of habitats
 Important ecological roles
• Feed on crop-damaging nocturnal insects
• Pollen-eaters
• Fruit-eaters
 Unwarranted
fears of bats
 Concept
9-3 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.
 Habitat
destruction, degradation, and
fragmentation
 Invasive (nonnative) species
 Population and resource use growth
 Pollution
 Climate change
 Overexploitation
Figure 9.10
Underlying and direct causes of depletion and premature extinction of wild species (Concept 9-3).
The major direct causes of wildlife depletion and premature extinction are habitat loss, degradation,
and fragmentation. This is followed by the deliberate or accidental introduction of harmful invasive
(nonnative) species into ecosystems.
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
Figure 9.11
Natural capital degradation:
reductions in the ranges of four
wildlife species, mostly as the
result of habitat loss and
hunting. What will happen to
these and millions of other
species when the world’s human
population doubles and per
capita resource consumption
rises sharply in the next few
decades? Question: Would you
support expanding these ranges
even though this would reduce
the land available for people to
grow food and live on? Explain.
(Data from International Union
for the Conservation of Nature
and World Wildlife Fund)
 Globally, habitat
loss,
greatest in temperate
biomes, pace picking up in
tropics.
 Endemic species
• Hawaii, the extinction capital of
America—63% of species at risk.
 Habitat
islands
 Habitat
fragmentation
The Bali Mynah is
distributed and endemic to
the island of Bali, where it is
the island's only surviving
endemic species. This rare
bird was discovered in 1910
and is one of the world's
most critically endangered
birds. In fact, it has been
hovering immediately
above extinction in the wild
for several years.
 Tropical
Biologist Bill Laurance, et al.
 How
large must a forest fragment be in
order to prevent the loss of rare trees?
 http://www.learner.org/vod/vod_window
.html?pid=2277
 70%
of the worlds 10,000 birds are
declining; 12% are threatened with
extinction.
 Habitat
loss and fragmentation of the birds’
breeding habitats
• Forests cleared for farms, lumber plantations, roads,
and development
 Intentional
or accidental introduction of
nonnative species
• Eat the birds
Numbers
Location
Reason(s)
75% of birds species
Sumatra’s lowland forests
Lumber and palm plantations, used for
biofuels
115 bird species
Brazil
Burning/clearing of rainforests for farms
and ranches; 93% loss of Atlantic coastal
rainforest; clearing of savannah-like cerrado
for soybean plantations
30% of bird species,
70% of grassland
species
North America
Habitat loss and fragmentation of breeding
habitat; replaced by roads and other
developments.
28% of species
Worldwide
Introduction of non-native bird-eating
species
52 of 388 parrot species
Worldwide
Pet trade
23 Seabirds
Worldwide
Bycatch from commercial fishing; pollution
40% of waterbirds
Worldwide
Loss of wetlands
 Seabirds
caught and drown in fishing
equipment
 Migrating
birds fly into power lines,
communication towers, and skyscrapers
 Other threats
• Oil spills
• Pesticides
• Herbicides
• Ingestion of toxic lead shotgun pellets
 Greatest
new threat: Climate change
 Environmental
indicators
• Live in every climate and biome
• Respond quickly to environmental changes
• Easy to track
 Economic
and ecological services
Figure 9.13
The 10 most threatened species of U.S. songbirds. Most of these species are vulnerable
because of habitat loss and fragmentation from human activities. An estimated 12% of
the world’s known bird species may face premature extinction due mostly to human
activities during this century. (Data from National Audubon Society)
Cerulean warbler
Sprague’s pipit
Florida scrub jay
California
gnatcatcher
Bichnell’s thrush
Kirtland's
warbler
Black-capped
vireo
Golden-cheeked
warbler
Henslow's sparrow Bachman's warbler
 Vultures
poisoned
from diclofenac in cow
carcasses
 More
wild dogs eating
the cow carcasses
 More
rabies spreading
to people
 Most species introductions
• Food
• Shelter
• Medicine
• Aesthetic enjoyment
 Nonnative
enemies.
•
•
•
•
are beneficial.
species may have no natural
Predators
Competitors
Parasites
Pathogens
Figure 9.14
Some of the more than 7,100 harmful invasive (nonnative) species that have been
deliberately or accidentally introduced into the United States.
 Imported
from Japan in the 1930s to
control soil erosion.
“
The vine that ate the South”
 Could
there be benefits of kudzu?
 Argentina
fire ant: 1930s
• Pesticide spraying in 1950s and 1960s worsened
conditions
 Wiped out competitor ant species and made them
more pesticide resistant.
 Burmese
python


Prevent them from becoming established
Learn the characteristics of the successful invader
species and the types of ecosystems that are
vulnerable to invasion.

Inspection of imports.

Ballast water from cargo ships.


Set up research programs to try to find natural ways to
control them: predators, parasites, bacteria and
viruses.
Ground surveys and satellite observations to detect
and monitor invasions to develop better models for
predicting spread.
 Population
growth
 Overconsumption
 Pollution
 Climate
change
 Pesticides
• DDT: Banned in the U.S. in 1972
 Bioaccumulation
 Biomagnification
DDT in fisheating 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
 Honeybees
responsible for 80% of
insect-pollinated plants
 Dying
due to?
• Pesticides
• Parasites
• Bee colony collapse syndrome
 Environmental impact on polar bears
• Less summer sea ice
• PCBs and DDT
 Can adversely affect their development, behavior, and
reproduction.
 IUCN
• 2006 Study: Population projected to decline by 30-
35%, and may be found only in zoos by end of
century.
• 2007 listed as threatened species
 2008
ESA.
listed as threatened species under US
 Poaching
plants
and smuggling of animals and
• Animal parts
• Pets
• Plants for landscaping and enjoyment
 When
commercially valuable species
become endangered, black market prices
soar.
 Prevention: research
and education
 Primatologist
and anthropologist
 45
years understanding and protecting
chimpanzees
• Chimps have tool-making skills
 Indigenous
people sustained by bush meat
 More
hunters leading to local extinction of
some wild animals
 US
Agency for International Development,
trying to introduce alternatives in some
areas.
• Fish farms
• Breeding large rodents, like cane rats.
 Concept
9-4A We can use existing
environmental laws and treaties and work
to enact new laws designed to prevent
species extinction and protect overall
biodiversity.
 Concept
9-4B We can help to prevent
species extinction by creating and
maintaining wildlife refuges, gene banks,
botanical gardens, zoos, and aquariums.
 Concept
9-4C According to the
precautionary principle, we should take
measures to prevent or reduce harm to the
environment and to human health, even if
some of the cause-and-effect relationships
have not been fully established,
scientifically.
 1975: Convention
on International Trade
in Endangered Species (CITES)
• Signed by 172 countries
 Convention
on Biological Diversity (BCD)
• Focuses on ecosystems
• Ratified by 190 countries (not the U.S.)
 Endangered
Species Act (ESA): 1973 and
later amended in 1982, 1983, and 1985
 Identify
and protect endangered species
in the U.S. and abroad
 Hot
Spots
 Habitat
colony
Conservation Plan (HCP)
 Mixed
reviews of the ESA
• Weaken it
• Repeal it
• Modify it
• Strengthen it
• Simplify it
• Streamline it
 Species
listed only when serious danger
of extinction
 Takes
decades for most species to
become endangered or extinct
 More
than half of the species listed are
stable or improving
 Budget
has been small
 Suggested
changes to ESA
• Increase the budget
• Develop recovery plans more quickly
• Establish a core of the endangered organism’s
survival habitat
 1903: Theodore
 Wildlife
Roosevelt
refuges
• Most are wetland sanctuaries
• More needed for endangered plants
• Could abandoned military lands be used for
wildlife habitats?
 Gene
or seed banks
• Preserve genetic material of endangered plants
 Botanical
gardens and arboreta
• Living plants
 Farms
sale
to raise organisms for commercial
 Techniques
for preserving endangered
terrestrial species
• Egg pulling
• Captive breeding
• Artificial insemination
• Embryo transfer
• Use of incubators
• Cross-fostering
 Limited
 Critics
space and funds
say these facilities are prisons for
the organisms
 Largest
 Nearly
North American bird
extinct
• Birds captured and breed in captivity
 By
2007, 135 released into the wild
• Threatened by lead poisoning
 Species: primary
components of
biodiversity
 Preservation
of species
 Preservation
of ecosystems