Download Biodiversity is the variety or richness of life at all structural levels

What is Biodiversity?
Biodiversity is the variety or richness of life
at all structural levels (molecular/genetic,
species, ecosystem). It is an essential
renewable resource. It is exploited and
depleted as a result of the “Tragedy of the
Commons” phenomenon. The current rate of
biodiversity loss is comparable to previous
extinction events.
Why is biodiversity important?
Biodiversity provides us with:

Natural Resources (food, water, wood,
energy, and medicines)

Natural (Ecosystem) Services including:
air and water purification, soil fertility,
waste disposal, pest control)

Aesthetic pleasure
“
“The decline of Earth’s biodiversity is an
unintended consequence of multiple
factors that have been enhanced by
human activity. They can be summarized
by the acronym HIPPO, with the order of
the letters corresponding to their rank in
destructiveness.”
E.O. Wilson “The Creation”
”
“
H
Habitat loss, including that caused by
human-induced climate change.
I
Invasive species (harmful aliens,
including predators, diseases, and
competitors that displace native species
P
Pollution
P
Population, Human overpopulation to be
exact, a root cause of the other four factors
O
Overharvesting, Overuse (hunting,
fishing, gathering)
E. O. Wilson “The Creation”
Habitat loss/destruction
http://en.wikipedia.org/wiki/File:Lacanja_burn.JPG
Habitat loss is the greatest
reason for biodiversity loss.
Habitat loss is due to:
• Conversion of natural
areas to farms, houses,
etc
• Fragmentation of
ecosystems by human
activities, housing,
transportation,
agriculture etc.
• Simplification of genetic
diversity and complex
ecosystems by
planting/selecting
monocultures.
Invasive / Exotic Species
Invasive, exotic species introduced from
elsewhere outcompete native species
because they:
Have no natural predators
Colonize disturbed habitats quickly
Have a high biotic potential (r-species)
http://en.wikipedia.org/wiki/File:Kudzu_on_trees_in_Atlanta,_Georgia.jpg
http://en.wikipedia.org/wiki/File:Bufo_marinus_from_Australia.JPG
Cane Toads – The Conquest movie
Pollution
Pollution (Oil spills, human agricultural waste,
fertilization, pesticides, acid deposition,
greenhouse gases etc) caused by human
activities has a negative effect on biodiversity
http://en.wikipedia.org/wiki/File:AlfedPalmersmokestacks.jpg
Population, Human overpopulation that is.
7.4 Billion and counting. The expansion of human
population and affluence, especially in the
developing world harms natural ecosystems.
http://en.wikipedia.org/wiki/File:World_population.svg
Overharvesting, Overuse, Overexploitation
Overhunting, overfishing, destructive
harvesting practices (cyanide, dynamite),
illegal trade, exotic pet industry
http://en.wikipedia.org/wiki/File:Fishing_down_the_food_web.jpg
Your examples…
• Make a quick list of factors that have
impacted your specific species…
• Which of these are easiest to
change/influence?
Raven, Berg, and Hassenzahl put it this way
Human
Population
Increase
Land use change
(Habitat loss)
Increasing
Economic
Activity
Increasing
Economic
Activity
Increased use
of technology
Increased use
of technology
Social, political
and cultural
factors
Social, political
and cultural
factors
Indirect
(Underlying
causes)
Direct
causes
Declining
Biological
Diversity
Characteristics shared by many
endangered species include:
•
•
•
•
Low reproductive rate (biotic potential)
Feed at high trophic levels (apex predator)
Large body size
Specialist
Specialized feeding habits
Specialized nesting and/or breeding areas
Fixed migratory patterns
Found in one place or region
• Rare
• Commercially valuable
• Negative human interactions including attacks on
people or livestock