Understanding the Global Biodiversity Crisis: Part 2

							   Understanding the
Global Biodiversity Crisis:
          Part 2



           EnvS 001
        Dr. Lynne Trulio
Information in this talk is compiled from:

     Miller (2007), Living in the
      Environment (15th edition).
     Other sources, with dates of material,
      as noted in the talk.
         Mass
Extinctions/Depletions
25-85% of all species
      disappear

     5 mass species loss
      events in last 500my
     Natural forces, esp.
      climate change
     Current event—
      caused by us!
     What is Extinction?
   Extinction: a species is no longer found
    anywhere on earth; ex: dinosaurs,
    passenger pigeon; a natural and human-
    caused phenomenon

   Extirpation: local extinction; a species is
    no longer found in a portion of its range;
    ex: grizzly bear

   Background rate: extinction rate w/o
    humans; ~1 spp/million/year
    Current Rates of Extinction
   Current losses of species are estimated
    about 14,000 species per year (5000-
    100,000 depending on # of species)

   This rate is 1,000-10,000 times the
    background extinction rate or 0.1%
    to 1% of all species each year.

   We are now in the worst extinction crisis
    in the last 65 million years!
Why is Extinction Forever?
   The answer lies in the process of
    evolution by natural selection.

   Theory of Evolution by Natural
    Selection: Central concept in biology and
    ecology!

   Evolution often takes a LONG time.
        How Natural Selection
              Works
   Populations of species exhibit a range of variation
    within traits; ex: neck length in giraffes
   Conditions in the environment exert “selection
    pressure” on the population; ex. height of forage,
    competition with other species
   Individuals with the traits that best suit them to
    meeting the challenges of the environment
    survive better and produce more offspring.
   These offspring carry the successful traits to the
    next generation.
Examples of human-driven
    natural selection

   Industrial melanism—moths in England
    change with industrial pollution
   Pesticide resistance—crop pests and
    weeds respond to pesticide use
   Antibiotic resistance—bacteria and
    virus evolve resistance to antibiotics
        Each Species is Unique
   The result of:
       Unique range of variation
       Unique environmental conditions
       Series of events that cannot be recreated


   These events cannot be recreated in
    speciation.

   What about Jurassic Park?
     Species need Ecosystems

   Species need their habitats to
    survive and reproduce

   Rare ecosystems = rare species


   Altered 50-80% of
    the earth’s
    land surface
        WE need Ecosystems!
   Natural Capital + Processes =
    $16 trillion to $54 trillion/year
    more information: www.esa.org/science/Issues/


   The earth’s ecosystems sustain our
    economies and our lives.

   They must be used sustainably—meeting the
    needs of current generations without
    compromising the needs of future
    generations
                Solutions
   Preservation: Nature reserves/parks/
    biosphere reserves/biodiversity hotspots
    (need 20% of earth’s land area)
   Adaptive ecosystem management
   Make ecosystems valuable (ecotourism)
   Legal protection (Endangered Species
    Act)
   Ecosystem Restoration worldwide
   Research into the science and social
    science of species preservation
                            Solutions:
    The Endangered Species Act (ESA)
   Federal ESA
       Very powerful law
       US Fish and Wildlife Agency—jurisdiction
       Lists Threatened and Endangered Species
       Designates critical habitat for recovery
       Develops recovery plan
       Has saved hundreds of species from extinction including
        the bald eagle, peregrine falcon, black-footed ferret


   California ESA (CESA)
       Department of Fish and Game
       Helps protect California’s biodiversity
             ESA and the . . .
   Bald Eagle
       Endangered due
        to pesticide use


   Grey Wolf
       Endangered due
        to extermination
          Biodiversity Hotspots
   High diversity areas, threatened by human activity
   Coastal areas, Islands, Tropical and Mediterranean
    habitats
        Why are Biodiversity
             Hotspots
          so important?
   34 hotspots on only 2.3% of earth’s surface
   75% of world’s most threatened vertebrates
   Information: www.biodiversityhotspots.org
    California is a Biodiversity
              Hotspot
   Unique habitats:
       Serpentine rock
       Wetlands
   Endemic Plant and
    Animal Species
       Bay checkerspot
        butterfly
   California is an
    Island!
              A little about the
        Theory of Island Biogeography
   R. MacArthur and E. O.
    Wilson
   What is the number of
    species on…
       Large vs. small islands?
       Far vs. near island?
   And the answer is…
   How can California be an
    island??