Biological Diversity and Conservation

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Biological Diversity and Conservation

• Vanishing Species

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Biological Diversity

• Biodiversity the variety of life in an area
• Biodiversity is measured by the number of species
  that live in a certain area
• A tropical rainforest has a greater amount of
  biological diversity (biodiversity) than a
  cornfield

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Where is biodiversity found?

• Tropical Rainforest are the most diverse
  ecosystems
• Contain two-thirds of all land species on Earth.
• Tundra and Desert have are the least diverse
  ecosystems.

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Island Effect

• Large islands tend to have a higher biodiversity
  than smaller islands

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Why do larger islands tend to have a greater
biodiversity?

• Greater diversity of ecosystems
• More space
• More niches

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How does diversity on an island affect inland
populations of organisms?

• Managing and designing national parks and
  protected areas
• Islands surrounded by human populations with
  buildings and roads

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Why is biodiversity important?

• Organisms are adapted to live together in
  communities
• Loss of a species may have consequences for other
  living things.
• Other organisms suffer when an organism they feed
  upon is removed from a food web
• Living things create niches for other living
  things

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Keystone Species

• What Is a Keystone Species?A keystone species is
  a species whose very presence contributes to a
  diversity of life and whose extinction would
  consequently lead to the extinction of other
  forms of life.
• Keystone species help to support the ecosystem
  (entire community of life) of which they are a
  part.

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Classic Example of a Keystone Species

• The starfish (Pisaster ochraceus) in the rocky
  intertidal of the Pacific Northwest
• Pisaster ochraceus is an efficient predator of
  the common mussel, Mytilus californicus.
• It reduces abundance of M. californicus, allowing
  other macroinvertebrates to persist.
• Experimental removal of P. ochraceus results in
  near total dominance of intertidal by Mytilus to
  the exclusion of other intertidal
  macroinvertebrates.
• Pisaster present diverse intertidal community
• Pisaster absent non-diverse intertidal
  community dominated by M. californicus

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Pisaster and Mytilus
Pisaster eats Mytilus If starfish is removed
from community, the mussel Mytilus becomes
dominant and excludes all other
macroinvertebrates.
Mytilus californicus
Pisaster ochraceus
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Another Example of Keystone Species

• Sea ottersKelp forest beds off the West coast
  are critical habitat for many species. The
  feeding of Sea urchins on the kelp foothold
  weakens kelp and make it vulnerable to currents
  and storms. At large urchin populations, kelp is
  eliminated. Otters feed on urchins, kelp forests
  are large and healthy. Otters were killed by
  humans in large numbers beginning 1800 until the
  1950 ies

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Sea Otters, Urchins and Kelp
Sea Otters eat Urchins, Urchins eat Kelp
If Sea Otters are removed from the food chain,
Urchins take over the community, eliminating the
kelp beds
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Importance of Biodiversity for Humans

• Humans depend on other organisms for their needs
• Oxygen supply and Carbon Dioxide removal
• Diverse Diet thousands of species help nourish
  the human population
• Clothes, furniture, buildings
• Living things supply the worlds pharmacy
• Penicillin from mold
• Quinine (anti-malarial drug) bark of cinchona
  tree
• Cancer or HIV cure?

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Loss of Biodiversity

• Extinction disappearance of a species when the
  last of its members dies
• Since 1980 almost 40 plant and animal species in
  the U.S. have become extinct
• Caused by natural or human impact
• Threatened Species when the population of a
  species begins declining rapidly
• African elephants, Sea otters, loggerhead
  turtles..
• Endangered Species when numbers of species
  become so low that extinction is possible
• Black rhinoceros, California condor, Manatees

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Threats to Biodiversity

• Habitat Loss
• Habitat Fragmentation
• Biotic Issues
• Abiotic Issues
• Habitat Degradation
• Water Pollution
• Land Pollution
• Introduction of exotic species

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Habitat Loss

• Largest threat to biodiversity
• When habitats are destroyed, the essentials of
  life are lost for species dependent upon these
  habitats and the species disappear.
• Ecosystems most affected by habitat loss
• Tropical Rain Forest
• Coral Reefs

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Habitat Fragmentation

• The separation of wilderness areas from other
  wilderness areas
• Creation of islands
• Smaller islands support fewer species
  less biodiversity
• Natural areas have become islands between
  urbanized areas/cities

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Biotic Issues

• Habitat fragmentation affects organisms that need
  large areas to gather food (range restriction of
  zebras)
• Influence on migratory routes
• Slower re-colonization after natural disaster
  (ie. Forest fire)

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Abiotic Issues

• Habitat fragmentation can change the climate of
  the area.
• Ex. A small plot cut out of a tropical rain
  forest. What was a warm, moist, shady
  environment is now exposed to sunlight and winds
• Edge Effect The different conditions along the
  boundaries of an ecosystem

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Habitat Degradation

• The damage to habitat by pollution
• Types of pollution
• Air
• Land
• Water
• Acid precipitation rain, snow, sleet, and fog
  with low pH values
• Responsible for deterioration of forests and
  lakes
• Caused by sulfur and nitrogen emissions
• Ozone depletion
• Ozone layer serves as a sunscreen for the earth
• Chloroflorocarbons (CFCs) break down ozone
• Found in refrigerators and air conditioners

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Water Pollution

• Degrades aquatic habitats in streams, rivers,
  lakes, and oceans.
• Examples of pollutants
• Fertilizer
• Animal Waste from farms
• Silt
• Detergents, heavy metals, industrial pollutants
• Abandoned drift nets in oceans, and harm or kill
  aquatic life.

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Land Pollution

• Solid waste
• Trash cans, bottles, paper, plastic, metals,
  dirt
• Average American produces 1.8kg of solid waste
  daily.
• Does it ever decompose?

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Introduction of Exotic Species

• When a new species is introduced into an
  ecosystem, either by accident or on purpose
• Causes problems for native species
• Exotic Species organisms that are not native to
  a particular area
• When an exotic species is introduced into an
  area, its population can row at an exponential
  rate due to lack of competitors or predators
• They make take over niches of native species and
  eventually replace the native species.