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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 biodiversityCauses of present-day extinctionsHow 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 ValueMost 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 SpeciesAlien 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 GuamBlack rats in the Galapagos Islands

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Alien species

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PollutionPollution is any environmental change

that adversely affects the lives and health of living things.

Categories include:Acid depositionEutrophication

Ozone depletionOrganic chemicals

Global warming

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Global warming

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OverexploitationOverexploitation 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.