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Biodiversity
Mr. Kling
• “The worst thing that can happen during the
1980s is not energy depletion, economic
collapse, limited nuclear war, or conquest by
totalitarian government. As terrible as these
catastrophes would be for us, they can be
repaired within a few generations. The one
process ongoing in the 1980s that will take
millions of years to correct is the loss of
genetic and species diversity by the destruction
of natural habitats. This is the folly our
descendants are least likely to forgive us.”
- E. O. Wilson, testifying before Congress in
support of the Endangered Species Act, 1982
What is Biodiversity?
• 1. Species Diversity - The number of
different species within a given area or
habitat.
• 2. Habitat Diversity – The number of
different habitats per unit area that a
particular ecosystem or biome contains.
• 3. Genetic Diversity – The range of genetic
material present in a species or population.
How did we get our Biodiversity?
• Speciation
– Process by which genetic traits in the
population occur in response to environmental
pressure.
• Caused by natural selection
– Often the result of isolation of populations
– Sometimes the result of behavioral differences
– Can take VERY long periods of time
What is at stake?
• 1/4 of bird species are extinct.
• The following are threatened:
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24% of mammal species
12% of bird species
25% of reptile species
30% of fish species
• The rate of species extinction today is
estimated at 100 to 1000 times the normal
rate at which species disappear.
Definitions
• Extinct Species: No longer exists.
• Endangered Species: Has so few
individual survivors that the species could
soon become extinct.
• Threatened Species: Still abundant, but
because of declining numbers is likely to
become endangered in the near future.
• Extirpated: Locally extinct.
• Endemic species: Those only found in one
place.
• Hotspot: Region with a high abundance of
biodiversity.
• Keystone Species: Have a large effect on
their environment.
International Union for the
Conservation of Nature (IUCN)
• Publishes the annual Red List, the world
standard for listing the world’s threatened
species.
• www.iucnredlist.org
Quantitative Measure of Biodiversity
• Simpson’s reciprocal
index
• Measures both number of
species present (species
richness) and the
abundance of each
(species evenness)
• 1 is the lowest biodiversity
and a higher value means
greater biodiversity
N ( N  1)
D
 n(n 1)
Threats to Biodiversity - IB
• Habitat degradation, fragmentation and loss
– It is estimated 80% of species loss is due to habitat
destruction.
• Natural hazard events (ie: volcanoes, drought)
• Global catastrophic events (ie: ice age, meteor impact)
• Pollution
• Overexploitation
– poaching
– overharvesting
– collecting
• Introduction/escape of non-native (exotic) and genetically
modified species
• Modern agriculture (tends toward monoculture)
• Spread of disease
HIPPO
(5 major causes of species decline - AP)
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Habitat Destruction, Degradation, and Fragmentation
Invasive Species
Pollution
Population Growth (Human)
Overexploitation
Risk Factors for becoming an
Endangered Species (AP):
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K-strategist – low reproductive potential
Specialized niche
Have a small range – Example: live on an island
Require a large territory – Ex: Grizzly Bears
Feed at high trophic levels – Ex: Bald Eagle
Unique behaviors
Valuable Parts – Snow leopard, rhinoceros, bengal
tiger
• “The first species to go are the big, the slow, the
tasty, and those with valuable parts such as tusks
or skins.” –E.O. Wilson
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Risk Factors for becoming an
Endangered Species (IB):
Narrow geographical range
Small population size or declining numbers
Low population densities and large territories
Few populations of the species
A large body
Low reproductive potential
Seasonal migrants
Poor dispersers
Specialized feeders or niche requirements
Hunted for food or sport
Causes of Premature Extinction
Habitat
loss
Overfishing
Pollution
Habitat degradation
and fragmentation
Climate change
Commercial
hunting and poaching
Introducing
nonnative species
Predator and pest control
Sale of exotic pets
and decorative plants
Secondary Causes
•Population growth
•Rising resource use
•No environmental
accounting
•Poverty
Basic Causes
Fig. 9-7, p. 190
Reasons to Preserve Biodiversity
• Direct Values
– Food Sources
– Natural products
• Indirect Values
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Ecosystem productivity
Scientific and educational value
Biological control agents
Genes
Environmental monitors
Recreation
Human health
Human rights (indigenous people)
Ethical/intrinsic value
Nature’s Economy
• Biodiversity provides direct economic
benefits.
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Agriculture
Fishing
Forestry
Nature-based tourism
Recreation
Pharmaceuticals
• 1/3 of all prescription drugs are derived
from chemical compounds originally found
in nature.
• 10 of the 25 best-selling drugs are nature’s
invention.
Nature’s Pharmacy
Fig. 9-6, p. 189
Pharmaceutical Potential
• The saliva of the vampire bat is used to
unclog arteries.
• There are MANY other possibilities to
explore!
• Most plant and coral species have yet to be
tested for their medicinal properties.
Aldo Leopold
• “A thing is right when it tends to preserve
the integrity, beauty and stability of the
biotic community.” -A Sand County Almanac
• One of the most remarkable ideas of our
time: that the role of humans is not to
conquer the land, but to be a citizen of it.
• This is known as the “Land Ethic”
Approaches to Protecting
Biodiversity
• Conservation Biology: The sustainable use
and management of natural resources.
Sustainable harvesting and hunting are
permitted.
• Preservation Biology: Attempts to exclude
human activity in areas where humans have
not yet encroached. Non-anthropocentric
viewpoint.
Sustaining Biodiversity:
The Species Approach
• Identify endangered and threatened species.
• Create a plan to restore their populations to
historical levels, or some other goal based
upon current realities.
• Protect one species at a time.
Sustaining Biodiversity:
The Ecosystem Approach
• A strategy for the integrated management of
land, water and living resources that
promotes conservation and sustainable use
in an equitable way.
• If you protect the habitat, they will come.
Island Biogeography
• Protected areas may become “islands”
within a country and will normally lose
some of their biodiversity.
• Typically, we observe that a 90% loss of
habitat causes a 50% loss of the species
living in the habitat.
• We need to create wildlife corridors to
prevent this form happening.
Designing Protected Areas
• SLOSS Debate: Single Large Or Several
Small
• See page 129 Fig. 6.6
In-situ Conservation
(on-site conservation)
• Protecting endangered species in their
natural habitat.
– Ex: wildlife refuges and other protected areas
• Maintains populations in the surrounding
where they developed their unique
properties.
• Helps ensure the ongoing processes of
evolution and adaptation.
Ex-situ Conservation
(off-site conservation)
• Removing an endangered species and
protecting in a new location under the care
of humans. Often used as a last resort.
– Ex: zoos, aquariums, botanical gardens,
arboreta, wildlife farms, seed banks.
• Used as a last resort.
• Serve to educate the public and gain support
for wildlife conservation.
“We need a million Noah’s with a
million arks.” –Thomas Friedman
Biodiversity Laws
• Endangered Species Act (1973)
• Convention on International Trade in
Endangered Species (CITES Treaty) –
ratified by over 150 nations.
• Marine Mammal Protection Act (1972)
Organizations Dedicated to
Preserving Biodiversity
• World Wildlife Fund (WWF) – nongovernmental organization
• United Nations Environment Programme
(UNEP) – governmental organization
World Conservation Strategy
• The World Conservation Strategy was published
in 1980. It emphasized that humanity, which exists
as a part of nature, has no future unless nature and
natural resources are conserved. It asserted that
conservation cannot be achieved without
development to alleviate the poverty and misery of
hundreds of millions of people. Stressing the
interdependence of conservation and development,
the WCS first gave currency to the term
"sustainable development".
• "An apt analogy for this problem is a
man prying rivets out of the wing of an
airplane so that he can sell the rivets--he
sees no reason to worry about the
consequences of his action since he has
already removed numerous rivets from
the wing with no ill effect."
- Walter Reid, Keeping Options Alive: the
scientific basis for conserving biodiversity,
(World Resources Institute), 1989 p.55