• “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
• 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?
– Process by which genetic traits in the
population occur in response to environmental
• 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:
– 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.
• 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
• Hotspot: Region with a high abundance of
• Keystone Species: Have a large effect on
International Union for the
Conservation of Nature (IUCN)
• Publishes the annual Red List, the world
standard for listing the world’s threatened
Quantitative Measure of Biodiversity
• Simpson’s reciprocal
• Measures both number of
species present (species
N ( N 1)
richness) and the
abundance of each
• 1 is the lowest biodiversity
and a higher value means
Threats to Biodiversity - IB
• Habitat degradation, fragmentation and loss
– It is estimated 80% of species loss is due to habitat
• Natural hazard events (ie: volcanoes, drought)
• Global catastrophic events (ie: ice age, meteor impact)
• Introduction/escape of non-native (exotic) and genetically
• Modern agriculture (tends toward monoculture)
• Spread of disease
(5 major causes of species decline - AP)
• Habitat Destruction, Degradation, and Fragmentation
• Invasive Species
• Population Growth (Human)
Risk Factors for becoming an
Endangered Species (AP):
• 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
• “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
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 degradation Climate change Commercial
and fragmentation hunting and poaching
Introducing Sale of exotic pets
Predator and pest control
nonnative species and decorative plants
•Rising resource use
Fig. 9-7, p. 190
Reasons to Preserve Biodiversity
• Direct Values
– Food Sources
– Natural products
• Indirect Values
– Ecosystem productivity
– Scientific and educational value
– Biological control agents
– Environmental monitors
– Human health
– Human rights (indigenous people)
– Ethical/intrinsic value
• Biodiversity provides direct economic
– Nature-based tourism
• 1/3 of all prescription drugs are derived
from chemical compounds originally found
• 10 of the 25 best-selling drugs are nature’s
Fig. 9-6, p. 189
• The saliva of the vampire bat is used to
• There are MANY other possibilities to
• Most plant and coral species have yet to be
tested for their medicinal properties.
• “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
• Conservation Biology: The sustainable use
and management of natural resources.
Sustainable harvesting and hunting are
• Preservation Biology: Attempts to exclude
human activity in areas where humans have
not yet encroached. Non-anthropocentric
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.
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.
• 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
• See page 129 Fig. 6.6
• Protecting endangered species in their
– Ex: wildlife refuges and other protected areas
• Maintains populations in the surrounding
where they developed their unique
• Helps ensure the ongoing processes of
evolution and adaptation.
• 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
• 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
• World Wildlife Fund (WWF) – non-
• 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
• "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