Download Chapter 36: Conservation of Biodiversity

Chapter 36: Conservation of
Biodiversity
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Conservation Biology and
Biodiversity
Conservation biology studies all aspects
of biodiversity with the goal of
conserving natural resources.
A primary goal of conservation biology is
the management of biodiversity for
sustainable use by humans.
Many scientific disciplines come together
to achieve this goal.
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Conservation biology supports these
ethical principles:
1. Biodiversity is desirable for all living
things.
2. Extinctions, due to human actions,
are undesirable.
3. Complex interactions in ecosystems
support biodiversity.
4. Biodiversity resulting from
evolutionary change has value in and
of itself.
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Between 10-20% of living species will go
extinct in 20 to 50 years unless
immediate steps are taken to protect
them.
It is important to understand the:
Concept of biodiversity
Value of biodiversity
Causes of present-day extinctions
How to prevent extinctions from
occurring
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Biodiversity
Biodiversity is the variety of life on earth.
There are between 5 to 15 million species
in existence.
Important aspects of biodiversity are:
Genetic diversity
Community diversity
Landscape diversity
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Number of described species
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Genetic diversity refers to the variations
among members of a population.
Community diversity is dependent on the
interactions of species at a particular
location.
Landscape diversity involves a group of
interacting ecosystems within one
landscape.
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Distribution of Diversity
Biodiversity is not evenly distributed
across the biosphere.
Biodiversity hotspots contain large
concentrations of species but may
cover only small portions of the earth.
Rain forest canopies and the deep-sea
benthos are so diverse they are
considered biodiversity frontiers.
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Value of Biodiversity
Biodiversity is a resource of
immense value.
Direct values include:
Medicinal value
Agricultural value
Consumptive use value
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Medicinal Value
Most of the prescription drugs used in
the U.S. were derived from living
things.
For example, many lives have been
saved from cancer with medicine made
from the tropical plant, rosy periwinkle.
It is likely that an additional 328 types of
drugs will be found in tropical rain
forests, with a value to society of $147
billion.
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Agricultural Value
Certain wild plants serve as a source of
genetic variation for related crop
species.
Biodiversity can also provide biological
pest controls that reduce the need for
chemical pesticides.
Wild bees are resistant to mites that have
wiped out the honeybee population that
pollinates many important crops.
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Consumptive Use Value
Much of the freshwater and marine harvest of
organisms used for food depends on natural
ecosystems rather than aquaculture.
Wild fruits and vegetables, fibers, beeswax,
and seaweed are important economically.
Wood, rubber, and latex are tree products of
great economic importance.
Sustained production, rather than ecosystem
destruction, will ensure that these products
are available indefinitely.
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Indirect Value of Biodiversity
Indirect value of biodiversity includes:
Biogeochemical cycles
Waste disposal
Provision of fresh water
Prevention of soil erosion
Regulation of climate
Ecotourism
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Biodiversity and Natural
Ecosystems
Scientific studies have shown that
ecosystem performance improves with
increasing species richness.
Rates of photosynthesis also increases
as diversity increases.
It remains to be determined whether
more diverse ecosystems are better
able to withstand environmental
change.
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Number of plant species and rate
of photosynthesis
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Causes of Extinction
Causes of extinction include:
Habitat loss
Alien species
Pollution
Overexploitation
Most threatened and endangered species
are imperiled for more than one reason.
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Habitat Loss
Habitat loss has occurred in all
ecosystems.
Habitat loss in tropical rain forests and
coral reefs is of great concern because
of the great diversity of species living
in these ecosystems.
Loss of habitat also affects freshwater
and marine biodiversity.
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Habitat loss
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Road construction in Brazil
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Alien Species
Alien species (exotics) are nonnative species
that migrate into new ecosystems or are
introduced there by humans.
Introduction of alien species by humans has
been due to:
Human colonization of new areas
Horticulture and agriculture
Accidental transport
Alien species disrupt food webs.
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Exotics on Islands
Because islands have unique
assemblages of native species that are
closely adapted to one another,
introduction of exotic species is
especially disruptive.
Examples:
Myrtle trees in Hawaii
Brown tree snake in Guam
Black rats in the Galapagos Islands
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Alien species
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Pollution
Pollution is any environmental change
that adversely affects the lives and
health of living things.
Categories include:
Acid deposition
Eutrophication
Ozone depletion
Organic chemicals
Global warming
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Global warming
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Overexploitation
Overexploitation occurs when too many
individuals are taken and population
size is severely reduced.
Overexploitation occurs in:
Decorative plants
Exotic aquarium fish
Colorful parakeets and macaws
Oceanic fishing areas
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Trawling
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Conservation Techniques
To preserve species, it is necessary to
preserve their habitat.
Preserving biodiversity hotspots will help
save greater numbers of species.
The preservation of a keystone species
can preserve biodiversity in a habitat.
Saving metapopulations, including the
source population and sink population,
is important in species preservation.
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Habitat preservation
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Landscape Dynamics
A landscape encompasses different
types of ecosystems.
Landscape protection for one species
often benefits other wildlife sharing the
same space.
When preserving landscapes, the edge
effect must be considered because it
can have a serious impact on
population size.
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Edge effect
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Computer Analyses
Gap analysis uses the computer to find
gaps in preservation, places where
biodiversity is high outside of
preserved areas.
A population viability analysis helps
researchers determine the amount of
habitat a species requires to maintain
itself.
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Habitat Restoration
Restoration ecology is a subdiscipline of
conservation biology that seeks
scientific ways to return ecosystems to
their former state.
A restoration plan has been developed
for the Everglades that will sustain the
Everglades ecosystem while
maintaining flood control.
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Restoration of the Everglades
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Three principles of restoration ecology
have emerged:
1. It is best to begin as soon as possible
before remaining fragments of habitat
are lost.
2. It is best to use biological techniques
that mimic natural processes to bring
about restoration.
3. The goal is sustainable development,
the ability of the ecosystem to
maintain itself while serving human
beings.
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Chapter Summary
Conservation biology is the scientific
study of biodiversity and its
management for sustainability.
Biodiversity must be preserved as
genetic, community, and landscape
diversity.
Biodiversity has direct and indirect
values.
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Researchers have identified the major
causes of extinction, including habitat
loss, alien species introduction,
pollution, and overexploitation.
To preserve species, habitat must be
preserved.
Sometimes habitat must be restored
before sustainable development is
possible.
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