1. 4.2 Evaluating Biodiversity and Vulnerability
Extinction and threats to biodiversity

2. Remember Extinct is FOREVER!!

3. Causes of Extinction Two major causes Natural Causes (Non-Human)
Human Causes

4. Natural Causes (Non-Human)
Volcanic Eruptions
Drought
Meteors
Glaciers and ice age
Competition and Predation

5. Human Causes (HIPPO) H-Habitat destruction and fragmentation
I- Introduced species
P-Pollution
P-Practices of agriculture
O-Over hunting
Dodo Bird – Extinct

6. Habitat Destruction/ Fragmentation
Degradation: reducing the quality of available habitat
Ex. Logging, agriculture, sewage
Fragmentation: splitting a single large, contiguous system into many disconnected areas
Ex. Putting a road through a wilderness area, or building a dam across a river
Loss: Disappearing of an entire habitat
Ex. Paving natural area for building sites, converting prairies to farmland or residential subdivisions

7. Invasive Species (Alien, exotic, non-native)
Organisms that are living in an environment outside of its normal range or natural environment
Many are transported by accident
Biocontrol: Species transported intentionally to control other “problem” species populations
Characteristics:
Fast growth/reproduction
Live in wide range of environments
Usually harmful to environment
Outcompete native organisms for local food sources
Leads to extinction of native organisms

8. Examples of Invasive Species
Asian Carp
Kudzu
Rabbits
Starlings
Cane Toads

9. Kudzu “the vine that ate the South” and “The Green Menace”.
Grow up to 1 foot in a day!
Introduced from Japan as quick ground cover to prevent soil erosion

10. Asian Carp

11. Asian Carp
Originally imported to clear algae from catfish ponds in the southern USA,
Flooding allowed some carp to escape into the Mississippi River and its tributaries where they quickly became MANY carp
Pose a strong threat to the Great Lakes
Asian Carp Research

12. Rabbits
“The introduction of a few rabbits could do little harm and might provide a touch of home, in addition to a spot of hunting.”
-Thomas Austin in 1859
(Released 24 rabbits)
1950 ~ 600 million rabbits
1951 ~ 100 million
Government Drugged Watering Hole

14. Starlings
Today starlings are blamed for agricultural losses of up to $800 million annually in the United States, as well as being implicated in a number of deadly plane crashes.
~ 60 were released in New York’s Central Park in 1890.

15. Cane Toad

16. Cane Toad Good Example of biocontrol!
In 1937 cane toads were released in Australia's sugar cane plantations to control insect populations
By 1938 ~60,000 cane toads left sugar cane fields for more natural habitat (ate all majority of insect populations and outcompeted native amphibians for food)
Can grow up to 15 inches and eat anything!

17. Pollution
Toxins added to the environment lead to a loss or degradation of habitat.

18. Practices of Agriculture
Farming causes habitat loss and reduces biodiversity because of…
Monoculture: Farming of only one crop on a large scale
Pesticides: Often lethal to many non-pest species
Herbicides: Lethal to species other than the weeds

19. Over Hunting
Collecting, and harvesting wild populations: unregulated, it can diminish local populations or even drive some to extinction
Tasmanian tiger
dodo
North American sea mink
Prairie buffalo
Blue whale

20. Tragedy of the commons (THE SEA)
OVERFISHING IS HUGE PROBLEM TODAY!
CURRENT RATE OF CATCH IS UNSUSTAINABLE

21. Rates of Extinction
Fossil Records reveal average “lifetimes” of species.
Extinction occurs naturally and is referred to as the background rate of extinction
Humans have lead to a 1000x extinction rate
Estimated 137 species lost each day
50,000 species a year

22. Mass Extinctions
The Earth has experienced 5 mass extinctions

23. Extinction Events
Extinction # 1 ~445 MYA Ordovician Stage – Dramatic loss of sea level due to forming Antarctica -57% Extinct
Extinction # 2 ~ 370 MYA Devonian Stage – Changes in sea level and global cooling stage -50% Extinct
Extinction #3 ~250 MYA Permian Stage- Breaking up of Pangea changed ocean currents- 83% Extinction
Extinction #4 ~200 MYA Triassic Stage – Climate warming from volcanic eruptions -48% Extinct
Extinction #5 ~65 MYA Cretaceous – Asteroid impacting the earth – 50% Extinct

24. Average Lifespan of mammals
Mammals: ~ 1 million years
With approximately 5,000 mammals the background rate is 1 every 200 years
In past 400 years 89 extinctions have been recorded.
45x background rate.
Over 50 extinctions have occurred in the past century
100x background rate

25. Characteristics of Vulnerable Species
Organisms that are…
Limited habitat
Extremely specialized niche
Low reproductive potential
Require a large territory
Migratory
Valuable economically (hunted)
Vulnerable to pollution
Incompatible with civilization
may be more likely to go extinct

26. Rainforest Vulnerability
Contain 50% of Earth’s known species
Most species have specialized niches
Humans disrupt environment for logging
Changing one part of ecosystem alters the entire web of relationships
Breakdown of rainforest likely lead to extinction of 10% worlds species in 25 years
Regeneration rate is slow due to poor soil quality (rapid year round nutrient cycling depletes soil)

27. 4.2.5 Red List Criteria

28. Red List Criteria
IUCN (International Union for Conservation of Nature)
Red list used to determine extinction risk
Specific Aims:
Provide system that can be applied consistently
Improve evaluation of different factors which affect the risk of extinction

29. Factors used to determine list
Population size:
How many of this species exist?
Reduction in population size:
How fast is population decreasing?
Numbers of mature individuals:
These are past their reproductive years and may lead to further decline
Geographic range and fragmentation:
Wide range makes the species less likely to be threatened
Fragmented habitat reduces interbreeding populations
Quality of habitat:
Degraded habitat supports fewer individuals

30. Categories
Extinct (Ex) – No reasonable doubt that the last individual has died. Determined after exhaustive surveys of animals known range and expected habitats
Endangered (E)- Survival is unlikely if causal factors continue operating. Drastically reduced populations and habitat

31. Categories
Vulnerable (V) – Near endangered if causal factors continue. Numbers are abundant but are under threat from serious factors (overexploitation, habitat destruction)
Rare (R) – Small world populations that are at risk. Unexpected threat could easily cause a critical decline (small geographic disturbance)
Unknown (K) – Suspected to fit in one of the above categories but there is a lack of information