Understanding the Global Biodiversity Crisis: Part 2

1
Understanding the Global Biodiversity Crisis
Part 2

• EnvS 001
• Dr. Lynne Trulio

2

• 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.

3
Mass Extinctions/Depletions25-85 of all species
disappear

• 5 mass species loss events in last 500my
• Natural forces, esp. climate change
• Current eventcaused by us!

4
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

5
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!

6
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.

7
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.

8
Examples of human-driven natural selection

• Industrial melanismmoths in England change with
  industrial pollution
• Pesticide resistancecrop pests and weeds respond
  to pesticide use
• Antibiotic resistancebacteria and virus evolve
  resistance to antibiotics

9
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?

10
Species need Ecosystems

• Species need their habitats to survive and
  reproduce
• Rare ecosystems rare species
• Altered 50-80 of
• the earths
• land surface

11
WE need Ecosystems!

• Natural Capital Processes
• 16 trillion to 54 trillion/year
• more information www.esa.org/science/Issues/
• The earths ecosystems sustain our economies and
  our lives.
• They must be used sustainablymeeting the needs
  of current generations without compromising the
  needs of future generations

12
Solutions

• Preservation Nature reserves/parks/
• biosphere reserves/biodiversity hotspots (need
  20 of earths 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

13
Solutions The Endangered Species Act (ESA)

• Federal ESA
• Very powerful law
• US Fish and Wildlife Agencyjurisdiction
• 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 Californias biodiversity

14
ESA and the . . .

• Bald Eagle
• Endangered due to pesticide use
• Grey Wolf
• Endangered due to extermination

15
Biodiversity Hotspots

• High diversity areas, threatened by human
  activity
• Coastal areas, Islands, Tropical and
  Mediterranean habitats

16
Why are Biodiversity Hotspots so important?

• 34 hotspots on only 2.3 of earths surface
• 75 of worlds most threatened vertebrates
• Information www.biodiversityhotspots.org

17
California is a Biodiversity Hotspot

• Unique habitats
• Serpentine rock
• Wetlands
• Endemic Plant and Animal Species
• Bay checkerspot
• butterfly
• California is an Island!

18
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??