Envi Sci

1. Chapter 9

2. 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 over-harvest
and habitat loss.

5.  Passenger pigeon hunted to extinction by
1900
 Commercial hunters used a "stool pigeon”
 Geological record shows five mass
extinctions
 Human activities: hastening more extinctions?

6. 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.

7. 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

8.  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

9. © 2011 Pearson Education, Inc.
Extinction: The disappearance of an entire species from
the face of the Earth.
Extinction Rate: % or # of species that go extinct per
unit time. i.e. 0.00001 species/year
Extirpation: The disappearance of a particular
population from a given area, but not the entire species
globally.
Mass Extinction: The extinction of a large portion of
the world’s species in a very short time period due to
some extreme and rapid change or catastrophic event.
The Earth has seen five mass extinction events in the past
half-billon years.
Define the terms extinction, extirpation and
mass extinction.

10. Extinctions Are Natural But
Sometimes They Increase Sharply
 Background extinction and Mass extinction
• Discussed in Chapter 4
 Extinction rate – the percent of species that go
extinct in a given time period.
• Background extinction
• 1/1,000,000 per year = 0.00001%
• Mass extinction
• 50 – 95% of all living things on the planet

11.  Species can become extinct in three ways:
• Local Extinction:
• A species is no longer found in an area it once
inhabited but is still found elsewhere in the world.
• Typically the result of habitat destruction and affects
more than one species.
• Ecological Extinction:
• Occurs when so few members of a species are left
they no longer play its ecological role.
• Biological Extinction (Global Extinction):
• Species is no longer found on the earth.
• Biological extinction is FOREVER.
Extinctions Are Natural But
Sometimes They Increase Sharply

12.  Estimates of current annual extinction rate:
• 0.01-1.0%
• 100 to 1,000 times greater than the background
extinction rate of 0.0001%
 Experts predict extinction rates will increase over
the next 50-100 years.
 Reason = US!!
Some Human Activities Cause Premature
Extinctions; the Pace Is Speeding Up

13. Animal Species Prematurely Extinct
Due to Human Activities
 Many animals have become prematurely extinct
because of human activities.
• Development, habitat destructions, hunting, etc.

14. “The first animal species to go are the big,
the slow, the tasty, and those with
valuable parts…”
– Edward O. Wilson
(biodiversity expert)
Animal Species Prematurely Extinct
Due to Human Activities

15. Conservative estimates of extinction =
0.01-0.1%
• 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

16.  Threatened (vulnerable) species:
• Still abundant in its natural range but is likely to
become endangered in the near future.
 Endangered species:
• So few individual survivors that it could soon
become extinct.
Endangered Natural Capital:
Species Threatened with Premature Extinction

17.  Extinct Ex.: Dodo, Passenger Pigeon
 Extinct in the wild Ex.: Alagoas Curassow
• Captive individuals survive, but there is no free-living, natural population
 Critically endangered Ex.: Ivory-billed Woodpecker, Javan Rhino
• Faces an extremely high risk of extinction in the immediate future
 Endangered Ex.: Cheetah, Blue Whale, Snow Leopard
 Vulnerable Ex.: Lion, Wolverine
 Conservation Dependent Ex.: Leopard Shark, Bristlecone Fir
• Would be threatened without active conservation programs.
 Near Threatened Ex.: California Red-legged Frog, Silvery Woolly Monkey
• Likely to qualify as threatened soon.
 Least Concern Ex.:Brown Rat, Rock Pigeon, Common Juniper
• No immediate threat to the survival of the species.
Endangered Natural Capital:
Species Threatened with Premature Extinction

18. Endangered Natural Capital:
Species Threatened with Premature Extinction

19. Endangered Natural Capital:
Species Threatened with Premature Extinction

20. Premature extinctions due to
• Habitat destruction
• Overhunting, or overexploitation

23.  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 species
• Characteristics of such species

24. Grizzly bear
Kirkland’s warbler Knowlton
cactus
Florida manatee African
elephant
Utah prairie dogSwallowtail
butterfly
Humpback chubGolden lion
tamarin
Siberian
tiger
Giant panda Black-footed
ferret
Whooping
crane
Northern
spotted owl
Blue whale
Mountain
gorilla
Florida
panther
California condor
Hawksbill sea
turtle
Black rhinoceros
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.

25. Fixed
migratory
patterns
Blue whale,
whooping crane,
sea turtle
Feeds at high
trophic level
Bengal tiger, bald
eagle, grizzly bear
Narrow
distribution
Elephant seal,
desert pupfish
Commercially
valuable
Snow leopard, tiger,
elephant, rhinoceros,
rare plants and birds
Low reproductive
rate (K-strategist)
Blue whale, giant
panda, rhinoceros
Characteristic Examples
Rare African violet,
some orchids
Large territories
California condor,
grizzly bear, Florida
panther
Specialized
niche
Blue whale, giant
panda, Everglades
kite
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?

27.  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

28.  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.”

29.  Instrumental
value –
usefulness to us in
providing
ecological and
economic
services.

30. Ecotourism: wildlife tourism

31. • Use value
Genetic information
 Loss in diversity of crop species is
cause for concern.
http://www.ted.com/talks/cary_fowler_one_se
ed_at_a_time_protecting_the_future_of_food.
html

32. Food crops, recreation, scientific
information, lumber, paper, etc.

34. • Energy flow, nutrient cycling, and population
control—the scientific principles of sustainability
that sustain and support life on earth.

35. Plants and animals have a right to exist!

39. 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

40. 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

41. 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.

42. Habitat destruction, degradation, and
fragmentation
Invasive (nonnative) species
Population and resource use growth
Pollution
Climate change
Overexploitation

43. NATURAL CAPITAL
DEGRADATION
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
Causes of Depletion and Premature Extinction of Wild Species
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.

44. 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)

45. Globally, habitat loss,
greatest in temperate
biomes, pace picking up in
tropics.
Endemic species – Habitat
is restricted to one area
• Hawaii, the extinction capital of
America—63% of species at
risk.
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.

46. Habitat Islands - an area of habitat surrounded
by an area of unsuitable habitat. Can be treated
like an island.
Examples of habitat islands:
1. Man made: forest surrounded by area that has been converted to
grassland
2. 2. Natural: alpine habitat on mountaintops, isolated from other
alpine habitat by lower land
3. 3. Natural, very small scale: dung piles, habitat for dung beetles.
4. 4. Islands generally hold fewer species than an area of the same
size in continuous habitat.
 This is true for genuine oceanic islands and for habitat islands.

47. Habitat fragmentation involves
alteration of habitat resulting in
spatial separation of habitat units
from a previous state of greater
continuity.
Habitat Fragmentation of Great Apes

48. Population growth
Overconsumption
Pollution
Climate change

49. Pesticides
• DDT: Banned in the U.S. in 1972
Bioaccumulation
Biomagnification

50.  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

51. 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

52.  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

53. 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

55. Cerulean warbler Sprague’s pipit Bichnell’s thrush Black-capped vireo Golden-cheeked
warbler
Florida scrub jay
California
gnatcatcher
Kirtland's
warbler
Henslow's sparrow Bachman's warbler
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)

56. Vultures poisoned from
diclofenac in cow
carcasses
More wild dogs eating
the cow carcasses
More rabies spreading
to people

57.  Most species introductions are beneficial.
• Food
• Shelter
• Medicine
• Aesthetic enjoyment
 Nonnative species may have no natural
enemies.
• Predators
• Competitors
• Parasites
• Pathogens

58. 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.

60. Imported from Japan in the 1930s to
control soil erosion.
“ The vine that ate the South”
Could there be benefits of kudzu?

62. 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

64.  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.

67. 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

68. Honeybees responsible for 80% of insect-
pollinated plants
Dying due to?
• Pesticides
• Parasites
• Bee colony collapse syndrome

69.  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 listed as threatened species under US
ESA.

71.  Poaching and smuggling of animals and
plants
• Animal parts
• Pets
• Plants for landscaping and enjoyment
 When commercially valuable species become
endangered, black market prices soar.
 Prevention: research and education

74. Primatologist and anthropologist
45 years understanding and protecting
chimpanzees
• Chimps have tool-making skills

75.  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.

77. 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.

78. 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.

79. 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.)

80. 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 Conservation Plan (HCP) colony

81. Mixed reviews of the ESA
• Weaken it
• Repeal it
• Modify it
• Strengthen it
• Simplify it
• Streamline it

83. 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

84. Suggested changes to ESA
• Increase the budget
• Develop recovery plans more quickly
• Establish a core of the endangered organism’s
survival habitat

85. 1903: Theodore Roosevelt
Wildlife refuges
• Most are wetland sanctuaries
• More needed for endangered plants
• Could abandoned military lands be used for
wildlife habitats?

86. Gene or seed banks
• Preserve genetic material of endangered plants
Botanical gardens and arboreta
• Living plants
Farms to raise organisms for commercial
sale

87. Techniques for preserving endangered
terrestrial species
• Egg pulling
• Captive breeding
• Artificial insemination
• Embryo transfer
• Use of incubators
• Cross-fostering

88. Limited space and funds
Critics say these facilities are prisons for
the organisms

90. Largest North American bird
Nearly extinct
• Birds captured and breed in captivity
By 2007, 135 released into the wild
• Threatened by lead poisoning

91. Species: primary components of
biodiversity
Preservation of species
Preservation of ecosystems