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Chapter 18
Conservation of Biodiversity
Module
59
The Sixth Mass Extinction
Learning Objectives
After this module, you should be able to:

Explain the global decline in the genetic diversity of wild species.

Discuss the global decline in the genetic diversity of domesticated
species.

Identify the patterns of global decline in species diversity.

Explain the values of ecosystems and the global declines in
ecosystem function.
Decline in the Diversity of Wild Species

A decline in population results in a decline in
genetic diversity:
High genetic diversity ensures a wider range of
genotypes, which improves the probability of
surviving future change in the environment.
‒ Low genetic
diversity makes
species prone to
inbreeding which
causes the offspring
to have a poor
chance of survival.
‒
Decline in the Diversity of
Domesticated Species

Major concerns exist about declining genetic variation
in the domesticated species on which humans depend.
‒
‒

Ag science has concentrated efforts on breeds (animals)
and varieties (plants) that are most productive and most of
the genetic variation is being lost.
Decreased variety leaves us vulnerable if the biotic or
abiotic environment changes.
A global response has been storing seed varieties in
specially designed warehouses to preserve genetic
diversity.
Species diversity has declined
around the world
 Background
extinction and Mass
extinction
‒ Discussed
in Chapter 5
rate – the percent of species
that go extinct in a given time period.
 Extinction
‒ Background
•
1/1,000,000 per year = 0.0001%
‒ Mass
•
extinction
extinction
50 – 95% of all living things on the planet
Species diversity has declined
around the world
 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
= HUMANS
Animal Species Prematurely Extinct
Due to Human Activities
 Many animals have become prematurely extinct
because of human activities.
• Development, habitat destructions, hunting, etc.
Animal Species Prematurely Extinct
Due to Human Activities
“The first animal species to go are the big,
the slow, the tasty, and those with
valuable parts…”
– Edward O. Wilson (biodiversity expert)
Species Threatened with
Premature Extinction
 Threatened
(vulnerable) species:
‒ Still
abundant in its natural range but is
likely to become endangered in the near
future.
 Endangered
‒ So
species:
few individual survivors that it could
soon become extinct.
Species Threatened with
Premature Extinction
 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
• Species are widespread and abundant
Declining Species Diversity
 Problems
with estimating extinction rate:
Don’t have reliable data on very many of the
1.8 million species identified
‒ New species are being discovered all the time
‒ Time consuming and expensive
‒ Difficult to determine when the LAST one dies
‒
Currently classified risk of extinction:
Species Threatened with
Premature Extinction
Species Threatened with
Premature Extinction
Characteristics of Species That
Are Prone to Extinction
 Some species have
characteristics that make
them more vulnerable
extinction.
 These characteristics
make survival especially
hard when environmental
conditions change or
when humans interfere.
Characteristics of Species That
Are Prone to Extinction
 Endemic Species
• Only live in one specific place (geographic location or
habitat type) – not endemic to an area if they are also
found somewhere else
• Species can be endemic to large or small areas
– Very vulnerable to extinction if only endemic to a small
area, like islands
Ecosystem Values

Intrinsic value: Value independent of any benefit
to humans. May be based on philosophical
convictions or a sense of moral obligation.
Existence value – happy knowing they are around
‒ Aesthetic value – pleasing to the eye
‒ Bequest value – available for future generations
‒
Ecosystem Values

Instrumental value: Worth as an instrument or a
tool that can be used to accomplish a goal.

There are 5 categories of ecosystem services:
‒
‒
‒
‒
‒
Provisions: A good that humans can use directly – Ex. lumber,
food crops, medicinal plants, natural rubber, and furs
Regulating Services: Natural ecosystems help to regulate
environmental conditions. – Ex. Cycles, climate
Support Services: services that would be costly for humans to
generate – Ex. Pollination of plants, pest control, etc.
Resilience: species diversity allows ecosystems to continue
providing the other services – less susceptible to disturbances
Cultural Services: The beauty of nature has aesthetic benefit
for which people are willing to pay – ecotourism
The Decline of Ecosystem Services
 Since
species determine the services, a
decline in species means an obvious decline
in services.
‒
 If
Most global ecosystem services/functions are on
the decline.
we want to improve ecosystem functions, we
need to improve the fate of the species and
ecosystems that provide these services.
Module
60
Causes of Declining
Biodiversity
Learning Objectives
After this module, you should be able to:

Discuss how habitat loss can lead to declines in species diversity.

Explain how the movement of exotic species affects biodiversity.

Describe how overharvesting causes declines in populations and
species.

Understand how pollution reduces populations and biodiversity.

Identify how climate change affects species diversity.
Causes of Declining Biodiversity:
Remember H.I.P.P.C.O.
 H.I.P.P.C.O. – the most important causes of
premature extinction:
‒
Habitat destruction, degradation, and fragmentation
‒
Invasive (nonnative) species
‒
Population and resource use growth
‒
Pollution
‒
Climate change
‒
Overexploitation
H.I.P.P.C.O. – HABITAT LOSS,
DEGRADATION, AND FRAGMENTATION

Habitat loss is the GREATEST threat to
biodiversity on this planet.
Deforestation
‒ Degradation of coral reefs
‒ Draining wetlands
‒ Plowing grasslands
 Habitat fragmentation – when a large continuous
habitat is divided into smaller, scattered patches.
‒
‒

By roads, agriculture, urban developed, etc.
A species may decline in abundance or become
extinct even without complete habitat destruction.
H.I.P.P.C.O. – HABITAT LOSS,
DEGRADATION, AND FRAGMENTATION
H.I.P.P.C.O. – HABITAT LOSS,
DEGRADATION, AND FRAGMENTATION

Reduction in
ranges of four
wildlife species,
mostly due to
habitat loss and
overharvest.
H.I.P.P.C.O. – INVASIVE SPECIES

During the past several centuries, humans have
frequently moved animals, plants, and pathogens
around the world – either deliberately or accidentally.
‒
‒

Many nonnative species are beneficial:
‒

Native species: Species that live in their historical
range, typically where they have lived for thousands or
millions of years.
Non-native or Exotic species: A species living outside
its historical range. Also known as alien species.
Food, Medicine, Aesthetic enjoyment
However, a few can wipe out native species, disrupt
ecosystems, and cause large economic losses
H.I.P.P.C.O. – INVASIVE SPECIES
Invasive species: A species that spreads rapidly
across large areas.
 Around the world, invasive exotic species pose a
serious threat to biodiversity by acting as predators,
pathogens, or superior competitors to native species.
 Nonnative species can become a problem since they
may have no natural:

‒
‒
‒
Predators
Competitors
Pathogens/Diseases
Kudzu vine was introduced to the southeastern U.S. in the 1930’s to
control erosion. Since then, it has taken over native species habitats.
H.I.P.P.C.O. – INVASIVE SPECIES

Many invasive species have been introduced intentionally…
H.I.P.P.C.O. – INVASIVE SPECIES
…other invasive species have been introduced unintentionally.
Characteristics of Invasive Species and
Ecosystems Vulnerable to 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.
H.I.P.P.C.O. – POPULATION GROWTH
 Humans have increased the species extinction rate
by approximately 1,000 times.
 Experts predict that these rates will continue, or
accelerate, in the future.
H.I.P.P.C.O. – POLLUTION

Human activities can pollute the water, soil, or air on both
on a local and global scale:
‒
‒
‒
Water – sewage, fertilizers, toxic chemicals and oil
Soil – pesticides, waste, herbicides and toxic chemicals
(which may be washed from the land into water)
Air – smoke and gases such as SO4, CO2, CH4 or other
gases that can lead to climate change
H.I.P.P.C.O. – CLIMATE CHANGE

As climate change affects patterns of temperature
and precipitation in different regions of the world, a
species could:
‒
‒
‒

Adapt quickly enough to respond to changing conditions.
Migrate to a place where the climate is well suited to the
species niche.
Go extinct.
An estimated 25% of all land plants
and animal could become extinct
by the year 2100.
‒
Many (but not all) extinctions will take
place in the upper latitudes where the
warming is the greatest.
H.I.P.P.C.O. – OVEREXPLOITATION

Overexploitation (“using” them too much) threatens
some species with premature extinction.
‒
‒
‒
Hunting, fishing, and other forms of harvesting are the
most direct human “uses” of wild plants and animals.
Killing predators and pests that bother us or cause
economic losses.
Legal and illegal trade in wildlife species used as pets
or for decorative purposes.
Most species can be harvested to some degree, but
a species is overharvested when individuals are
removed at a rate faster than the population can
replace them.
 In the extreme, overharvesting of a species can
cause extinction.

H.I.P.P.C.O. – OVEREXPLOITATION
 Some
species are killed for their
valuable parts or are sold live to
collectors – Poaching



Rhinoceros are killed for their horns and sold
illegally on the black market.
Elephants are killed for their ivory tusks
Tigers and other “cats” killed for their pelts
National and International
Laws/Treaties Help Protect Species
The legal and illegal trade in plants and animals
represents a serious threat to their ability of some
species to persist in nature.
 National and international laws help protect species.


Lacey Act: A U.S. law that prohibits interstate
shipping of illegally harvested plants and animals
‒
‒
Originally signed in 1900 to focus on game animals
In 2008, the Act was amended to include plant products
such as timber and paper. This was the world's first ban
on trade in illegally sourced wood products.
National and International
Laws/Treaties Help Protect Species
 The
1973 Convention on International Trade
of Endangered Species (CITES)
‒
Protects wildlife against over-exploitation, and
prevents international trade from threatening
species with extinction.
•
•
•
‒
Signed by 172 countries
Enforcement is difficult
Probably only 10% of illegal trade in the U.S. is caught
Red List: Lists hundreds of species that cannot be
commercially traded as live specimens or wildlife
products.
Module
61
The Conservation of
Biodiversity
Learning Objectives
After this module, you should be able to:

Identify legislation that focuses on protecting single species.

Discuss conservation efforts that focus on protecting entire
ecosystems.
National and International
Laws/Treaties Help Protect Species

Marine Mammal Protection Act: A 1972 U.S. act to
protect declining populations of marine mammals.
‒
Prohibits killing of all marine mammals in the U.S. and
prohibits the trade of marine mammal body parts.
•
‒
Includes seals, whales, dolphins, porpoises, manatees,
otters, walruses, and polar bears
Was the first act to call specifically for an ecosystem
approach to conservation.
•
Maintain the health and stability of the marine
ecosystem
National and International
Laws/Treaties Help Protect Species
 The
overall goal of the 1973 U.S. Endangered
Species Act (ESA) is to identify and protect
endangered species in the U.S. and abroad.
‒
The ESA is meant to compliment the international
CITES agreement
 The
U.S. Fish and Wildlife Service determines
which species are listed as endangered
‒
The endangered species list contains
600+ animals and 800+ plants
National and International
Laws/Treaties Help Protect Species
 One
of the world’s most far-reaching and
controversial environmental laws:
ESA makes it illegal for Americans to engage in
commerce associated with, or hunt / kill / collect,
endangered or threatened species.
‒ ESA forbids federal agencies (besides defense
department) to carry out or even fund projects
that would jeopardize an endangered species.
‒ ESA calls for the development of recovery plans
to increase populations
‒ The act also authorizes the government to
purchase habitat that is critical to the species.
‒
National and International
Laws/Treaties Help Protect Species
 Accomplishments:
‒
‒
More than half of the species listed are stable or improving
99% of all listed species are still living
 Challenges:
‒
‒
‒
Very small budget
Species are listed when faced with serious threat of extinction
It can take decades to bring a species’ populations up
 Suggested
‒
‒
‒
changes to ESA:
Increase the budget
Develop recovery plans more quickly
Establish a core of the endangered organism’s survival habitat
Some conservation efforts focus on
protecting entire ecosystems

Rather than attempting to preserve just a species,
preserve the entire ecosystem in which they (and
other species) live.
One of the major motivating
factors in setting aside
national parks and marine
reserves.
‒ Since the 1960s, there has
been a large increase in the
amount of land that is under
various types of protection
throughout the world.
‒
Some conservation efforts focus on
protecting entire ecosystems
 Biosphere
reserve: Protected area consisting
of zones that vary in the amount of permissible
human impact.
– Biosphere
reserves ideally
consist of core
areas that have
minimal human
impact and outer
zones that have
increasing levels
of human impacts.