1. Topic 3: Biodiversity & Conservation
Subtopic 3.3 – Threats to Biodiversity

2. Objective Statements
Discuss the case histories of three different species: one that has become extinct due to human activity, another that is critically endangered, and a third species whose conservation status has been improved by intervention.
Describe the threats to biodiversity from human activity in a given natural area of biological significance or conservation area.
Evaluate the impact of human activity on the biodiversity of tropical biomes.
Discuss the conflict between exploitation, sustainable development, and conservation in tropical biomes.

3. Reading Assignment Read section 3.3, taking notes as needed.
Complete the TO DO and CASE STUDY sections in your notes packet.

4. How Many Species Are There?
Estimate >5-10 million species
1.8 M organisms scientifically
named and described
Most are animals / terrestrial
270,000 plant
45,000 vertebrate animal
950,000 insect

5. Current Extinction Rates
Current Rate of Extinction: 100 species per million per year (background = 1/million/yr)
EO Wilson believes that current rate is 1000 times the background rate, and is caused by humans.
Suggests 30-50% of species could be extinct within 100 years…. That’s 3 per hour.
Extinction rates not equal worldwide:
Far greater in Hotspots………………

6. Extinction in HOTSPOTS
Extinction rates not equal worldwide:
Far greater in Hotspots: highly biodiverse places, mostly in tropics.
Up to 50% of the animals and plants are in one of the 30 hotspots worldwide, but represents only 2% of the land area on earth.
Highly vulnerable
because of:
habitat loss
Endemism

7. Factors that help to maintain biodiversity
Complexity of the ecosystem
More complexity = more resilient to the loss of a species or reduction in population size
Other species may be able to fill the gaps left by an extinct species.
Stage of succession
Diversity increases as succession proceeds
Limiting factors
More limiting factors mean environmental changes are more difficult for a species to withstand.

8. Factors that lead to loss of biodiversity
NON-ANTHROPOGENIC - Natural Hazards
volcanic eruptions, earthquakes, floods, droughts, wildfires, hurricanes….
ANTHROPOGENIC – Human-Caused “HIPPO”…….

9. Factors that lead to loss of biodiversity
ANTHROPOGENIC – Human-Caused “HIPPO”
Habitat Loss, Destruction, Degradation, or Fragmentation
#1 cause of endgangerment. Human need for space, food, etc.
Invasive Species Introduction (class discussion, see following slides)
Pollution
Oil spills, pesticides, air pollution, acid rain, fertilizers…
Can cause direct or indirect harm to species
Population of humans – leads to all other HIPPO problems
Spread of Disease
Many from domesticated animals
can mutate & jump to wild species
Modern Agricultural Practices
Monoculture, pesticides, fertilizers
Overexploitation – pet trade, overharvesting, overfishing, overuse, etc

18. Why are Tropical Rainforests so vulnerable?
Class Discussion

19. What makes a species prone to extinction?
Discuss in small groups. Add your ideas to your notes.
Narrow geographical range
Small population size or declining numbers – low genetic diversity
Low population densities and large territories
Few populations of the species
A large body
Low reproductive potential
Seasonal migrants
Poor dispersers
Specialized feeders or niche requirements
Edible to humans and herding together
Island organisms
Minimum viable population size

20. IUCN Red List International Union for Conservation of Nature
Video: What is the Red List? 

21. 1973 – Endangered Species Act
FWS now can protect threatened/endangered species
1260 species have been listed to date.
Illegal to sell/buy any product made from an endangered or threatened species.
FWS must also select critical habitats and design a detailed recovery plan for each species listed.
They basically find the same information you researched for your brochure.
Considered one of the strongest pieces of US environmental legislation
Species are listed ONLY using biological information… economics cannot influence the list.

22. …the ESA is CONTROVERSIAL!
Advocates: doesn’t do enough for the species!
Critics: goes too far to hurt private landowners!
Can be an impediment to economic progress.
Northern spotted owl & the timber industry in Pacific NW (ch.3)
Few endangered species have recovered enough to be delisted! (only 8 as of 2002)
We ARE expecting several dozen to be delisted in the next years.
Geared more toward saving a few popular species rather
than the many important less-glamorous species!
1995: more than ½ of the funding went to helping just 10 species.
Should manage whole ecosystems and maintain
complete biodiversity rather than help just 1 species.

23. International Conservation Policies & Laws
1975 – Convention on International Trade in Endangered Species of Wild Flora & Fauna “CITES”
Attempts to control international trade in End. Species
160 countries
Bans hunting, capturing, and selling endangered or threatened species
Regulates trade of potentially threatened organisms
Problem: enforcement & penalties aren’t universal or strong
Example: African Elephants
They can ruin the habitat, but should we allow the ivory trade again?

24. CITES ISSUES
African Elephants

25. CITES ISSUES Tigers Sources: TRAFFIC International, 2004