36-1 Chapter 36: Conservation of Biodiversity. 36-2 Conservation Biology and Biodiversity...
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Transcript of 36-1 Chapter 36: Conservation of Biodiversity. 36-2 Conservation Biology and 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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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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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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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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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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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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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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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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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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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.